EFFECT OF VARIOUS PRESERVATION TECHNIQUES ON THE QUALITY OF PINEAPPLE
A dissertation submitted to the University of Calicut in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE IN FOOD SCIENCE AND TECHNOLOGY Submitted by
MUHAMMED BADUSHA M. P. Reg. No: CUANMFT013
Under the guidance of
Dr. JOY P.P. Associate Professor& Head Kerala Agricultural University Pineapple Research Station Vazhakulam, Muvattupuzha, Ernakulam District, Kerala, PIN-686 670 Web: http://prsvkm.kau.in
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY SCHOOL OF HEALTH SCIENCES UNIVERSITY OF CALICUT 2015
DECLARATION
I hereby declare that this dissertation entitled EFFECT OF VARIOUS PRESERVATION TECHNIQUES ON THE QUALITY OF PINEAPPLE is a bonafide record of project work done by me during the course of M.Sc. Food Science and Technology in the Department of Food Science and Technology at the University of Calicut and that the work has not been submitted previously for any other degree.
Teacher in charge
Muhammed Badusha M. P. CUAMNFT013
Department of Food Science & Technology School of Health Sciences University of Calicut
SCHOOL OF HEALTH SCIENCES UNIVERSITY OF CALICUT Phone: 2401144 to 50 2401665 to 70 0494 2400277 CALICUT UNIVERSITY P.O. PIN. 673 635 KERALA, INDIA
Dept. of Food Science & Technology University of Calicut
Date: ……………..
CERTIFICATE
This is to certify that the dissertation work entitled EFFECT OF VARIOUS PRESERVATION TECHNIQUES ON THE QUALITY OF PINEAPPLE is the bonafide work done by Mr. MUHAMMED BADUSHA M. P. in partial fulfillment of the requirements for the Degree of Master of Science in Food Science and Technology, University of Calicut.
Teacher in charge Dept. of Food Science & Technology
External Examiners: 1. 2.
Director School of Health Sciences University of Calicut
Tel. & Fax: 0485-2260832, Mobile: 9446010905 E-mail:
[email protected] , Web: http://prsvkm.kau.in
KERALA AGRICULTURAL UNIVERSITY
PINEAPPLE RESEARCH STATION Vazhakulam, Muvattupuzha, Ernakulam, Kerala- 686 670 No. PRS/S34/15
Dated: 25.07.2015
CERTIFICATE
This is to certify that the dissertation entitled EFFECT OF VARIOUS PRESERVATION TECHNIQUES ON THE QUALITY OF PINEAPPLE is an authentic record of the studies and research work carried out by Mr. MUHAMMED BADUSHA M. P. (Reg. No: CUAMNFT013), School of Health Sciences, University of Calicut under our supervision and guidance for the partial fulfilment of the requirements for the award of degree of Master of Science in Food Science and Technology of University of Calicut and that, to the best of our knowledge and belief, no part of this work has been presented earlier for any degree or diploma in this or any other Universities.
Anjana R. Head Biotechnology Division
Anisha M. Haridas Head Food Technology Division
Dr. P. P. Joy Guide Associate professor & Head
ACKNOWLEDGEMENT All gratitude and praise to the Almighty God, for the blessings he has showered on me. I am ever indebted to him for providing an opportunity to carry out my project work successfully at Pineapple Research Station, Vazhakulam. I bow my head in front of my adorable Parents whose love, blessings and support always encouraged me. I am thankful to my siblings for their never ending encouragement and moral support I hereby express my sincere gratitude to Dr. P. P. Joy, Associate professor (Agronomy) & Head, Pineapple Research Station, Kerala Agricultural University, Vazhakulam for giving me the chance to pursue the project work in Pineapple Research Station, Vazhakulam. I shall ever be grateful to Dr. C. D. Sebastian, Director, School of Health Sciences, Calicut University for providing required facilities to discharge my project work to the satisfaction of all concerned. I express my sincere thanks to Ms. Anjana R. (Head, Biotechnology Division) for permitting to do this project, giving full support and esteemed concern throughout the project work. I owe deep sense of gratitude to Ms. Anisha M. Haridas (Head, Food Technology Division), Ms. Naveena Varghese (Plant Pathology Division), Mrs. Aswathi, and Ms. Stephy (Bio-Technology division) and Mr. Iby O.M. (Section Officer) for giving advice and technical support. I am deeply indebted to all other supervisors and staff of Pineapple Research Station for assisting me and sharing their valuable knowledge in spite of their busy schedule. I express my sincere thanks to Dr. Riji Hari, Dilna K. C. and other staffs of School of health sciences, University of Calicut for the support and encouragement throughout the study. MUHAMMED BADUSHA M. P.
Dedicated to My Beloved Parents
CONTENTS
Chapter No.
Title
Page No.
I
INTRODUCTION
13
II
REVIEW OF LITERATURE
17
III
MATERIALS AND METHODS
34
IV
RESULTS AND DISCUSSIONS
50
V
SUMMARY AND CONCLUSION
77
VI
REFERENCES
79
LIST OF TABLES
Sl. No.
Title
Page No.
1
Area (ha), production (tons) and productivity (tons/ha) of pineapple in India
19
2
Pineapple area (ha) and production (tons) in Kerala
20
3
Recipe for the preparation of pineapple jam
36
4
Recipe for the preparation of pineapple squash
37
5
Recipe for the preparation of pineapple syrup
37
6
Recipe for the preparation of osmo-dehydrated pineapple
38
7
Nine point hedonic scale for sensory evaluation
44
8
Score card for organoleptic evaluation
45
9
pH of different pineapple preserved products during 20 days of storage
52
10
TSS of different pineapple preserved products during 20 days of storage(°Brix)
54
11
Total titrable acidity of different pineapple preserved products during 20 days of storage (%) Ascorbic acid of different pineapple preserved products during 20 days of storage (%) Reducing sugar of different pineapple preserved products during 20 days of storage (%)
12 13
56 58 60
14
Non reducing sugar of different pineapple preserved products during 20 days of storage (%)
62
15
Total sugar of different pineapple preserved products during 20 days of storage (%)
64
16
Moisture of different pineapple preserved products during 20 days of storage (%)
65
17
Taste of different pineapple preserved products during 20 days of storage (Nine point hedonic scale)
67
18
Colour of different pineapple preserved products during 20 days of storage
69
19
Flavour of different pineapple preserved products during 20 days of storage
71
20
Overall acceptability of different pineapple preserved products during 20 days of storage
73
21
Total plate count of different pineapple preserved products during 20 days of storage Mean values showing the effect of various preservation techniques on the quality of pine apple
22
75 75
LIST OF FIGURES
Fig. No.
Title
Page No.
1
Vazhakulam Pineapple from the field of Pineapple Research Station, Vazhakulam
14
2
Ingredients for jam
47
3
Ingredients for squash
47
4
Ingredients for syrup
47
5
Laminar air flow chamber
47
6
Plating of sample in laminar flow chamber
47
7
Analysis of sample
47
8
Hot air oven
48
9
Autoclave
48
10
Bacteriological Incubator
48
11
Colony counter
48
12
pH meter
48
13
Hand refractometer
48
14
Electronic weighing balances
49
15
Desiccator
49
16
Micropipettes
49
17
Burettes
49
18
Refrigerator
49
19
Water bath - thermostatic
49
20
Water still unit
49
21
pH of different pineapple preserved products during 20 days of storage
52
22
TSS of different pineapple preserved products during 20 days of storage (˚Brix)
54
23
Total titrable acidity of different pineapple preserved products during 20 days of storage (%)
56
24
Ascorbic acid of different pineapple preserved products during 20 days of storage (%)
58
25
Reducing sugar of different pineapple preserved products during 20 day of storage (%)
60
26
Non reducing sugar of different pineapple preserved products during 20 days of storage (%)
62
27
Total sugar of different pineapple preserved products during 20 days of storage (%)
64
28
Moisture of different pineapple preserved products during 20 days of storage (%)
66
29
Taste of different pineapple preserved products during 20 days of storage
67
30
Colour of different pineapple preserved products during 20 days of storage
69
31
Flavour of different pineapple preserved products during 20 days of storage
71
32
Overall acceptability of different pineapple preserved products during 20 days of storage
73
33
Osmo-dehydrated pineapple
76
34
76
35
(a) Dried pineapple and (b) frozen pineapple Pineapple squash, jam and syrup
36
Microbial growth on preserved pineapple product on 5th day
76
37
Results of Moisture analysis
76
76
ABSTRACT
The present work was designed to study the “Effect of various preservation techniques on the quality of pineapple”. For the study, pineapple jam, pineapple squash, pineapple syrup, frozen pineapple, dried pineapple and osmo-dehydrated pineapple were prepared as various preservation techniques. The storage periods for samples were set as 20 days. Samples were tested for pH, TSS, total titrable acidity, ascorbic acid, reducing sugar, non-reducing sugar, total sugar, moisture content following standard protocols of phyto-chemical analysis. Sensory evaluation and microbial plate count were also conducted. During the period of storage, preserved products showed a decrease in pH, TSS, Ascorbic acid, reducing sugar, nonreducing sugar, total sugar and moisture content. But Total titrable acidity was increased. On the basis of the results on phyto-chemical analysis of this research, pineapple syrup showed good quality. Frozen pineapple showed best colour, flavour and overall acceptability than other preserved pineapple products. But squash showed excellent taste. Freezing showed poor phyto-chemical characteristics. Sensory parameters of syrup were acceptable. From the present study, it can be concluded that among these preservation techniques syrup was more acceptable preservation techniques.
INTRODUCTION
Introduction 14
1. INTRODUCTION The pineapple (Ananas comosus) is also known as the “king of fruits”. It belongs to the family of Bromeliaceae. It is believes to be originated in South America. Columbus recorded the existence of pineapple in West Indies Island in 1493 (kuriakose, 2011). Pineapple is cultivated extensively in Hawaii, Philippines, Caribbean, Malaysia, Australia, Mexico, South Africa and Brazil (Silveira et al., 2009).India ranks sixth with a share of about 8% of the world production of pineapples. ‘Kew’ and ‘Mauritius’ are the two varieties of pineapple grown in India. It is grown in Karnataka, Meghalaya, West Bengal, Kerala, Assam, Manipur, Tripura, Arunachal Pradesh,
Fig. 1. Vazhakulam Pineapple from the field of
Mizoram, and Nagaland. The finest quality ‘Mauritius Pineapple’
comes
from Kerala. The
Pineapple Research Station, Vazhakulam
produce of Kerala is very much in demand as a fresh fruit throughout India and also in foreign countries
for
having
the
best
quality,
sweetness
and
good
flavour.
The
major pineapple producing district in Kerala is Ernakulam. In Ernakulam, pineapple cultivation is more concentrated in certain areas of Vazhakulam (Joy, 2013). Geographically indexed ‘Vazhakulam Pineapple’ is exceptionally good in juiciness, vibrant tropical flavour and immense health benefits. Pineapple generally, is a source of calcium, potassium, fibre, and vitamin C. It is low in fat and cholesterol. Vitamin C is the body’s primary water soluble antioxidant. Pineapple is also good source of vitamin B1, vitamin B6 and copper.It is a digestive aid and a natural anti-inflammatory fruit. A group of sulphur containing proteolytic enzymes (bromelain) in pineapple help in digestion. Fresh pineapples are rich in bromelain which is used for tenderizing meat. It reduces swelling in inflammatory conditions such as acute sinusitis, sore throat, arthritis, gout and speedy recovery from injuries and surgery (Joy, 2010). Pineapple fruits are primarily used in three segments namely; fresh fruits, canning and juice concentrate. Many processing techniques can be employed to preserve pineapple like drying, osmotic dehydration, freezing and preserves like jam, syrup, squash etc.
Effect of Various Preservation Techniques on the Quality of Pineapple
Introduction 15 Drying and dehydration are the most important operations that are widely practiced because of considerable saving in packaging, storage etc. (Chavan, 2012).Drying is the most widely used method of fruit preservation. It yields highly concentrated material nutritionally. It is done at 3860°C. Dried products are easy to store and have long shelf life (3-6 months at 80° F) reduced weight and bulk for transport and distribution costs, and provide raw materials for further processing. Minimized growth of micro-organisms is another benefit of drying (Hui, 2006). Osmotic dehydration is widely used for the partial removal of water from plant tissues by immersion in a hypertonic solution. The diffusion of water is accompanied by the simultaneous counter diffusion of solutes from the osmotic solution into the tissue. This will reduce the moisture content and also prevent the growth of micro-organisms. It is possible to enhance natural flavour and colour retention in fruit products by osmotic dehydration (Kumar and Devi, 2011). Another important type of preservation is freezing. It is the best method for long-term storage of pineapple. Freezing preserves the original colour, flavour and nutritive value. It reduces the rate of degradation reactions and inhibits microbiological activity. At -18°C, fruits are preserved even for one year or more. In this low temperature crystallization of water will occur. It is the main component of plant tissue. Water in pineapple constitutes 85% of their total composition. Crystallization of water during freezing reduces water activity in these tissues (Hui, 2006). Study on refrigerator freezing of fruits will be a novel approach as it is beneficial to household purposes. Jam is a common preserve made by cooking crushed or chopped fruits with sugar until the mixture will round up on a spoon. The pectin in fruit or commercial pectin added precipitates out and form insoluble fibers that traps the fruit juice or other liquid. This enables a gel to form with a shelf life of 6-12 months (Bastin, 2004). Squash is another processed food produced from sweetened juice of fruits containing some pulp. They contain at least 25% (by volume) of fruit juice and are consumed after dilution. Since preservatives are added in adequate quantities, the shelf life of squashes is fairly longer (www.ediindia.org). Pineapple syrup imparts desirable natural flavour and colour of the fruit. Its use as pancake or waffle syrups, as ice cream toppings, or as similar dessert items is amazing. It contains more than
Effect of Various Preservation Techniques on the Quality of Pineapple
Introduction 16 65% by weight of sugar which makes them very resistant to microbial spoilage (Brekke, 1968). It is more stable at acidity of 1.1% (Morris, 2012). The present study envisaged, effective preservation techniques of pineapple fruit. It throws light in making the fruits available year round even in the form of preserves. Pineapples have exceptional juiciness and a vibrant tropical flavour that balances the tastes of sweet and tart. It is economically stable. Other than this, pineapple has lot of health benefits, high medicinal and nutritive value. Pineapple has a big scope in value addition and further processing. Also, our efforts are there to make the pineapple fruit, a typical, healthy, homely fruit using the simplest methods of preservation even disregarding the use of sulphate preservatives.
1.1 objectives 1. To prepare preserved pineapple products 2. To analyze phytochemical and microbial quality of preserved products 3. To compare the quality of different preserved products 4. To identify the best preservation technique for a period of 20 days
Effect of Various Preservation Techniques on the Quality of Pineapple
REVIEW OF LITERARTURE
Review of literature 18
2. REVIEW OF LITERATURE Bartholomew and maleieux (1994) point out that pineapple (Ananas sp.) belongs to the family bromeliaceae which encompasses about 50 genera and 2000 species mostly epiphytic. It is a tropical fruit native to Central and South America specifically southern Brazil and Paraguay where wild relatives occur (Fernandez et al., 2008).
2. 1 Origin and Distribution Oylekke et al., (2013) reported that pineapple is a tropical, perennial, drought tolerant plant that grows up to 5-8ft (1.5-2.5 meter) in height and spreads around three to four feet. It is essentially a short stout stem with a rosette of waxy long, needle-tipped leaves. The fruit is described as compound (multiple) fruit that develops from many small fruits fused together around the central core. Its pulp is juicy and fleshy with the stem serving as a supporting fibrous core. It is an excellent source of antioxidant vitamin C which is required for the collagen synthesis in the body According to Duval et al. (2003) pineapple belongs to the bromeliad family, which contains 50 genera and about 2,500 known species, all but one of them from Central and South America. The exact origin of the cultivated species – Ananas comosus var. comosus – is hard to pinpoint, but Ananas comosus var. ananassoides (with very small, seedy fruit and spiny leaves) is considered a wild ancestor of the domestic pineapple. Its origins are in Brazil/Paraguay straddling the equator between latitudes 15°N and 30°S.
Yaakoob (2012) point out that Ananas comosus is the botanical name for pineapple. Native to South America, it was named from the similarity of the fruit to a pine cone. The term pineapple in Middle English did not appear in print until nearly three centuries later in 1664. Christopher Columbus is credited with discovering the pineapple on the island of Guadeloupe in 1493, although the fruit had long been grown in South America. He called it piña de Indus meaning pine of the Indians. South American Guarani Indians cultivated pineapples for food. They called it “nana”, meaning excellent fruit. Another explorer, Magellan, is credited with finding pineapples in Brazil in 1519, and by 1555, the luscious fruit was being exported with gusto to England. It soon spread to India, Asia, and the West Indies. Although the pineapple thrived in Florida, it was still a rarity for most Americans.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 19 2. 1. 1 Pineapple in India In India, pineapple is grown mainly in the north-eastern states and west Bengal, Kerala, Karnataka etc. In all states, except Kerala, the main variety grown is Kew which is suited for processing. In Kerala the main variety grown is Mauritius suited for fresh fruit consumption. However in recent years other states also started grown Mauritius variety. Table 1. Area (ha), production (tons) and productivity (tons/ha) of pineapple in India State
area
production
productivity
West Bengal
9.9
303.7
30.6
Assam
14
220.7
15.8
Karnataka
3
186.1
62
Bihar
4.9
129.4
26.5
Meghalaya
9.7
86
8.9
Tripura
6.8
153.3
22.6
Manipur
12.2
104.4
8.6
2. 1. 2 Pineapples in Kerala Production and marketing of Mauritius variety of pineapple in Kerala is centered on Vazhakulam a small town 10 km east of Muvattupuzha, and it later spread throughout the state, but it is the commercial centre of pineapple production in Kerala. Pineapple is being cultivated at Vazhakulam area from early 1940’s onwards. At that time, the variety grown was mainly Kew and the produce was mainly marketed to processing industries. Up to the end of 1970’s, Kew variety was widely grown in the districts of Ernakulam, Kannur, Kottayam, Thrissur, Pathanamthitta etc.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 20
Table 2. Pineapple Area (ha) and production (tons) in Kerala District
Area (ha)
Production (tons)
Thiruvananthapuram
160
400
Kollam
324
8100
Pathanamthitta
635
15875
Alappuzha
70
1750
Kottayam
240
53500
Idukki
1615
40375
Ernakulam
5250
131250
Thrissur
320
8000
Palakkad
356
8900
Malappuram
428
10700
Kozhikode
620
15500
Wayanad
45
1125
Kannur
390
9750
Kasaragod
226
5650
Growers are leasing land for pineapple cultivation in all parts of the state, mainly in rubber replanting areas. During 1990’s the area under Mauritius variety increased considerably and the farmers started intensive cultivation in all kinds of land. In Kerala pineapple is grown mainly as an intercrop in rubber and coconut, and also as pure crop in garden land and in converted paddy fields. Harvesting is done within one year and two to three ratoon crops are taken which require only shorter period. All this contributes to the availability of fruits round the year (Kuriakose, 2011)
2. 2 The Pineapple Plant Yaakoob (2012) observed that pineapples do not grow on trees, as many erroneously think. They are the fruit of a bromeliad, rising from the center on a single spike surrounded by sword-like leaves. The pineapple plant is the only bromeliad to produce edible fruit. Pineapple is grown all
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 21 year long in the warmer climates. The pineapple plant is an herbaceous perennial that grows to be two to five feet high, and three to four feet across. Pineapples are usually grown by propagation. That is, they are grown by replanting a part of themselves. The four common parts are; the slips which is located on the stem below the fruits, the suckers that start at the leaves, the crowns the leafy growth on top of the pineapple, and the rations that are located on the roots. The pineapple is technically not a single fruit, but a sorosis. The fruits of a hundred or more separate flowers grow on the plant spike. As they grow, they swell with juice and pulp, expanding to become the "fruit." In the natural form, every variety of pineapple has rough, diamond pattern skin. Their tasted vary slightly; through they all basically have the same juicy, tart taste. Lewcock (1939) pointed that for several thousand years, superior types of pineapples had been selected, domesticated and distributed by native Indians throughout the tropics and subtropics of South/Central America (notably the Guarani in whose language ‘ananas’ meant ‘excellent fruit’).Westerners first saw pineapples in 1493 on the island of Guadeloupe during Columbus’ second voyage to “The New World”, and on other islands in the West Indies later. It was recorded that King Ferdinand of Spain was eating pineapples as early as 1530, and the Spanish navigators distributed pineapple plants throughout the tropics so early and widely that it was considered indigenous. Pineapples were in India by 1548, and cloth was being made from pineapple leaf fibres (piña cloth) in the Philippines in the 1500’s. Collins (1949) reported that nearly 70% of the pineapple is consumed as fresh fruit in producing countries. And also he explained about the pineapple origin. Its origin has been traced to Brazil and Paraguay in the Amazonic basin where the fruit was domesticated. It has been defined as the most probable Area of origin the zone comprised from upper Panama and Brazil, Paraguay and Argentina, Including the northern Amazonian forest and the semi-arid regions of Brazil, Venezuela and Guyanas. According to crane (2006), pineapple has apparently been cultivated by indigenous people of the tropical Americas and the Caribbean Region for thousands of years. New World explorers then distributed pineapple during the 1500s to 1700s to new areas including Europe, Africa, and Asia. The commercial export trade began during early 19th century from the West Indies. This led to further commercial development of in the Caribbean during the mid-19th century. However, with the improvement in refrigerated sea transportation by the end of the 19th century,
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 22 production shifted to Hawaii, Asia, and Africa. In the U.S., Puerto Rico and Hawaii have moderately large and important industries. Pineapples are not grown commercially in Florida but are common dooryard yard plants in warm locations throughout the state. The first recorded introduction of pineapple into Florida was in 1860. As noted in FAO (2004) worldwide production started by 1500 when pineapple was propagated in Europe and the Tropical regions of the world. The most spread variety is Cayena lisa (Smooth Cayenne) which was first introduced in Europe from French Guyana. It was until late XIX century when canned pineapple was produced commercially in Hawaii. Thailand, Philippines, Brazil and China are the main pineapple producers in the world supplying nearly 50 % of the total output. Collins (1960) reported that other important producers of pineapple include India, Nigeria, Kenya, Indonesia, México and Costa Rica and these countries provide most of the remaining fruit available (50%) Pineapples are not found in true wild state. Coveca (2002) identified that it does not appear to have been derived from other Edible fruit species of the Ananas genera such as A. bracteatus, A. fritzmuelleri, A. erectifolia and A. ananasioides, which produce very small and almost seedless fruit. Pineapple is the second harvest of importance after bananas, contributing to over 20 % of the World production of tropical fruits (Coveca, 2002). 2. 2. 1 Nutritional Value According to Samson (1986) Pineapple mainly contains water, carbohydrates, sugars, vitamins A, C and beta carotene. It contains low amounts of protein, fat, ash and fiber and antioxidants namely flavonoids in addition to citric and malic acids and moderate amounts of ascorbic acid (Tochi et. al., 2008). MacDonald and Low (1996) stated that Pineapple also helps several enzymes present in the body to produce energy as it contains magnesium and vitamin B1 which are essential for the normal functioning of some enzymes. Pineapple has the enzyme complex protease (bromelain). Bromelain contains peroxidase, acid phosphatase, several protease inhibitors and organically bound calcium and have antiinflammatory properties as it blocks the formation of kinins which are responsible for inflammations (deliza et. al). Bromelain is used for relieving the pains, sprains, swelling, bruises, and arthritis and assist in diluting mucous and thus is beneficial for treating sinusitis, bronchitis, sore throat and tuberculosis. Pineapple peel is rich in cellulose, hemicelluloses and other
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 23 carbohydrates. Ensilaging of pineapple peels produces methane as a biogas (Rani and Nand, 2004). Pineapples offer additional advantages for a whole utilization, in particular as a dietary fiber source. Among the qualities of the fiber is the texture, its length (60 cm), high water and dye holding capacity, high whiteness, brightness, resistance to salt and tension strength. The dietary fibre helps alleviate constipation as an indigestible portion of plant food that pushes through the digestive system, absorbs water and ease defecation and changes the nature of the gastrointestinal tract by changing how other nutrients and chemicals are absorbed.(Eastwood and Kritchevsky, 2005; National Academy of Sciences, 2010) Sabahelkhier et al., (2010) point out that Pineapple is a wonderful tropical fruit having exceptional Juiciness, vibrant tropical flavor and immense health benefits. Pineapple contains considerable amount of calcium, Potassium, vitamin C, carbohydrates, crude fibre, water and Different minerals that is good for the digestive system and Helps in maintaining ideal weight and balanced nutrition. Pineapple is a common fruit and it has Minimal fat and sodium. It contains 10-25 mg of vitamin (Rasid et al., 1987). According to Dull (1971) Pineapple composition has been investigated mainly in the edible portion. Pineapple contains 81.2 to 86.2% moisture, and 13-19% total solids, of which sucrose, glucose and fructose are the main components. Carbohydrates represent up to 85% of total solids whereas fibre makes up for 2-3%. Of the organic acids, citric acid is the most abundant in it. The pulp has very low ash content, nitrogenous compounds and lipids (0.1%). From 25-30% of nitrogenous compounds are true proteins. Out of this proportion, Ca. 80% has proteolytic activity due to a protease known as bromelain. Fresh pineapple contains minerals as Calcium, Chlorine, Potassium, Phosphorus and Sodium. Pineapple juice contains ascorbic acid and is a good source of Vitamin C. Ascorbic acid or vitamin C fights bacterial and viral infections which is an effective antioxidant and helps the body absorb iron. Half a cup of pineapple juice provides 50 percent of an adult's daily recommended amount of vitamin C (www.livewell.jillianmichaels.com). Debnath et al. (2012) stated that, several essential minerals exist in pineapples, including manganese, a trace mineral instrumental to the formation of bone, as well as the creation and activation of certain enzymes. Pineapples also include copper, another trace mineral. It assists in the absorption of iron and regulates blood pressure and heart rate.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 24 Pineapple is also a good source of vitamin B1, vitamin B6, copper and dietary fibre. Pineapple is a digestive aid and a natural anti-inflammatory fruit. Fresh pineapples are rich in bromelain used for tenderizing meat. Pineapple contains a proteolytic enzyme bromelain, which digests food by breaking down protein. Only modest quantities of bromelain are in the edible parts of the fruit, all commercially available bromelain is derived from the stem. Bromelain supplements are particularly popular among athletes for treating all sorts of physical aches and injuries. Drinking pineapple juice can help hydrate the body and restore the immune system. It helps to build healthy bones. Pineapples are rich in manganese, a trace mineral that is needed for body to build bone and connective tissues. One cup of pineapple provides 73% of the daily recommended amount of manganese. The benefits of pineapple can affect the growth of bones in young people and the strengthening of bones in older people. Pineapple juice's high manganese content means it is a good choice for boosting fertility through sperm quality (Debnath et al., 2012) 2. 2. 2 Health benefits According to Hemalatha and Anbuselvi (2013) pineapple can be used as supplementary nutritional fruit for good personal health. Pineapple fruits are an excellent source of vitamins and minerals. One healthy ripe pineapple fruit can supply about 16.2% of daily requirement for vitamin C. Debnath et al., (2012) found that Vitamin C is the body's primary water soluble antioxidant, against free radicals that attack and damage normal cells. A powerful antioxidant, vitamin C supports the formation of collagen in bones, blood vessels, cartilage and muscle, as well as the absorption of iron. Vitamin C also retards the development of urinary tract infections during pregnancy and reduces the risk of certain cancers, including colon, esophagus and stomach. The root and fruit are either eaten or applied topically as an anti-inflammatory and as a proteolytic agent. It is traditionally used as an anthelmintic agent in Tripura, India. A root decoction is used to treat diarrhea. It is advised to take advantage of pineapple's myriad healing powers, by drinking 3 ½ ounces of fresh pineapple juice three times daily before meals or by eating a slice of fresh pineapple at each meal. Malic acid makes up 13 percent of pineapple juice's acidic content. Malic acid is also beneficial for health. It boosts immunity; promotes smooth, firm skin; helps maintain oral health; and reduces the risk of toxic metal poisoning (www.livewell.jillianmichaels.com).
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 25 According to joy (2010) Bromelain in pineapple has demonstrated significant anti-inflammatory effects, reducing swelling in inflammatory conditions such as acute sinusitis, sore throat, arthritis and gout and speeding recovery from injuries and surgery. Pineapple enzymes have been used with success to treat rheumatoid arthritis and to speed tissue repair as a result of injuries, diabetic ulcers and general surgery. Pineapple reduces blood clotting and helps remove plaque from arterial walls. Pineapple enzymes may improve circulation in those with narrowed arteries, such as angina sufferers. Pineapples are used to help cure brochitis and throat infections. Pineapple is an excellent cerebral toner; it combats loss of memory, sadness and melancholy. For any kind of morning sickness, motion sickness or nausea, drinking pineapple juice is advised. It works effectively in getting rid of nausea and vomiting sensation. Pineapple is known to be very effective in curing constipation and bowel movement. This is because it is rich in fibre, which makes bowel movements regular and easy. Pineapple is effective in getting rid of intestinal worms and also keeps the intestines and kidneys clean. It helps prevent gum disease and also prevents the formation of plaque, thus keeping the teeth healthy. The flesh of very young (toxic) fruits is deliberately ingested to achieve and as a drastic treatment for venereal diseases. In Africa the dried, powdered root is a remedy for edema. The crushed rind is applied on fractures and the rind decoction with rosemary is applied on hemorrhoids. Indians in Panama use the leaf juice as a purgative, emmenagogue and vermifuge. Pineapple creates low blood pressure, cure inflammation disease, used for weight loss, control the death rate and prevent diabetes & radical damage. It cures the damaged teeth and makes them strong and healthy. Also help to cure sinusitis and throat problem. Cure different diseases like asthma, obesity, swollen in the body, problems of digestion and heart problem. Pineapples are rich of manganese which creates strong bones and muscular body. Atherosclerosis and immune disease can be also cured due to high antioxidant. It does not let damage the cells of body, it is so hot so it is used to ignore cold weather, also used for perfect powerful unbreakable body, prevent cancer, heart attack, nausea and gives the long natural hairs. Use to solve acne, wrinkles, age problem and create strong nails, soft lips and thick hair (www.worldknowing.com). Faisal et al., (2014) stated that Ananas comosus leaves have antihyperglycemic and analgesic properties. That can be used as a cheaper and alternative source of medicine for reducing high blood sugar level of diabetic patients. Phytochemical screening showed presence of alkaloids, flavonoids, saponins and tannins in the pineapple leave extract, which components can be responsible for the observed blood glucose lowering and analgesic effects.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 26 According to Mundogar (2004) one of the best known properties of pineapple is as a diuretic. This helps to eliminate toxins through the urine, helping patients with ailments of kidneys, bladder and prostate. Due to the fiber content of the pulp, pineapple prevents constipation and regularizes the intestinal flora. Furthermore, there is evidence of appetite reducer, heart protection and aid for fever, sore throat and mouth aches and inflammation. Lightly boiled ground pineapple can be used to clean infected wounds because it eliminates dead tissues, not affecting live tissue, acts as disinfectant. Gastronomia (2004) Pineapple is a rich source of vitamin C as well as other vitamins and fibre. Pineapple's bromelain stimulates digestion and the proper performance of the small intestine and kidneys; it helps in detoxification, normalizes colonic flora, helps in hemorrhoid alleviation, and prevents and corrects constipation. It has been used to heal colds, mouth, throat and bronchial infections. Cooked peel cleans blood and alleviates swellings. Juice helps to cure cystitis, and fevers. 2. 2. 3 Uses as Food Samson (1986) reported that the consumption of pineapple is largely as canned pineapple slices, chunk and dice, juice, fruit salads, sugar syrup, alcohol, citric acid, chips and puree. It is also exported to other countries as fresh produce. Sixty percent of fresh pineapple is edible and average yield in processing ranges from 45% to 55%. According to Hemalatha and Anbuselvi (2013) pineapple fruits exhibit high moisture, high sugars, soluble solid content ascorbic acid and low crude fibre. Thus pineapple can be used as supplementary nutritional fruit for good personal health. Debnath et al., (2012) point out that the pineapple fruits are normally consumed fresh or as fresh pineapple juice. Field ripe fruits are best for eating fresh, and it is only necessary to remove the crown, rind, eyes and core. Pineapple may be consumed fresh, canned, juiced, and are found in a wide array of food stuffs - dessert, fruit salad, jam, yogurt, ice cream, candy, and as a complement to meat dishes. Joy (2010) reported that In Panama, very small pineapples are cut from the plant with a few inches of stem to serve as a handle. The flesh of larger fruits is cut up in various ways and eaten fresh, as dessert, in salads, compotes and otherwise, or cooked in pies, cakes, puddings, or as a
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 27 garnish on ham, or made into sauces or preserves. Malayans utilize the pineapple in curries and various meat dishes. In the Philippines, the fermented pulp is made into a popular sweetmeat. The pineapple does not lend itself well to freezing, as it tends to develop off flavours. Canned pineapple is consumed throughout the world. In Africa, young, tender shoots are eaten in salads. The terminal bud or "cabbage" and the inflorescences are eaten raw or cooked. Young shoots, called "hijos de pina" are sold on vegetable markets in Guatemala. 2. 3 Pineapple preservation According to Sharma (2010) preservation is extending shelf life of fresh or processed food by various methods and prevention or reduction of spoilage. Fruit does not spoil unless its outer covering is removed and till it is there on the plant. But as soon as the outer covering is removed the damage begins and the fruit spoils soon. As noted in FAO (2011) Fruit processing and preservation is a set of physical, chemical and biological processes that are performed to prolong the shelf life of fruits and at the same time retain the features that determine their quality, like colour, texture, flavor and especially nutritional value. Fruit preservation is achieved by destroying enzymes and microorganisms using heat (blanching, pasteurization), or preventing their action by: removal of water, or increasing acidity or using low temperatures. Many processes designed to preserve food will involve a number of fruit preservation methods. Preserving pineapple fruit by turning it into jam, for example, involves boiling (to reduce the fruit’s moisture content and to kill bacteria, yeasts etc.), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent recontamination).Maintaining or creating nutritional value, texture and flavor is an important aspect of fruit preservation. 2. 3. 1 Drying Drying is one of the oldest preservation methods. The moisture level of agricultural products is decreased to 10-15% so that the microorganisms present cannot thrive and the enzymes become inactive. Further dehydration is usually not desired, because the products then often become brittle. To ensure that the products do not spoil after being dried, they have to be stored in a moisture-free environment (James and Kuipers, 2003). Dried fruit is delicacy, because of the nutritive value (66-90% carbohydrates) and shelf life. Fruit can be dried whole, in halves, or as slices, or alternatively can be chopped after drying. The
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 28 residual moisture content varies 8% - 18% according to the fruit type. Dried fruit widely used in confectionary, baking, and sweets industries. Fruit drying involves removing water in different forms and different amounts (Hui, 2008). Mujumdar (2008) observed that, Physical changes that may occur during drying include: shrinkage, puffing, crystallization, glass transitions. In some cases, desirable or undesirable chemical or bio-chemical reactions may occur leading to changes in color, texture, odor or other proper-ties of the solid product. Drying is highly energy consuming unit operation and competes with distillation as the most energy-intensive unit operation due to the high latent heat of vaporization of water and the inherent inefficiency of using hot air as the (most common) drying medium.Most dried foods have less flavour than the original. ascorbic acid are soluble until the moisture content of the food falls to very low levels and react with solutes at higher rates as drying proceeds (Smith, 1998). When compared to raw fruit Ascorbic acid loss in fruit by drying is 56% (Rolls, 1982 and Calloway 1962). 2. 3. 2 Freezing Along with osmotic dehydration, freezing is another important method. Fruit freezing can be resulted to change in color, flavor and texture of fruits as well as to maintain enzyme activity. Freezing of fruits can be resulted in decrease quality, due to poor texture and enzymatic browning action (Tregunno and Goff, 1996). The frozen products can be stored at temperature of -29°C in Europe to maintain the quality of frozen products. At a temperature of -18°C or lower can stop the products from microbiological damages, if the temperature fluctuation is not wide (Buckle et al., 1987). Freezing as a preservation method probably was observed by prehistoric people during cold weather; and, until frozen storage cabinets were developed in the late 1800s, naturally occurring snow and ice were used to freeze foods outside. With the development of mechanical refrigeration and of quick-freezing techniques, the frozen food industry has expanded rapidly. Even in homes, freezing of foods has now become common because home deep-freezers are readily available. In frozen condition microbial growth is prevented completely and the action of food enzymes greatly retarded. The rate of freezing of food depends upon a number of factors such as the method employed, the temperature, circulation of air or refrigerant, size and shape of package, kind of food, etc. At (-18°C) fruits can usually retain good quality for 12 months and vegetables for 8-12 months. Freezing is cheaper than canning and frozen products are of better
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 29 quality than canned products, but for storage of frozen products uninterrupted supply of electricity if essential, which is a problem at least in homes (Reddy and Sagar, 2012) According to zaritzky (2006) The use of the freezing process to increase the length of fruit viability has gained widespread attention since the reduction of available water due to ice crystal formation and subzero temperatures provides an environment which favours reduced chemical reactions leading to increased storage stability. Lim et al., (2004) observed that, freezing is not a perfect method of preservation since even at low temperatures food quality deterioration may still occur. The formation of ice can result in textural changes and disruption of cell compartments causing the release of chemically reactive components. Due to the high water content of many fruit types, fruits are one of the most difficult of all food products to freeze without causing changes in appearance, texture, flavour, and colour of the freeze-thawed product. In particular one major effect of fruit freezing is a loss of tissue firmness (Coggins and Chamul, 2004), Bartholomew et al. (1996) studied the sugar content and composition of pineapple after being frozen and stored in a cold room at -18°C for a 12 month period. They reported that freezing the pineapple fruit slices led to minimal changes in soluble solids and sugar content (fructose, glucose and sucrose) after 1 year of frozen storage. 2. 3. 3 Osmo-dehydration Alkali et al., (2006) and Torres et al., (2006) stated that Osmo-dehydration (OD) is one of most important complementary treatment and fruits preservation technique in the processing of dehydrated fruits, since it presents some benefits such as reducing the damage of heat to the flavour, colour, inhibiting the browning of enzymes and decrease the energy costs. Osmo-dehydration results in increased shelf-life, little bit loss of aroma in fruit stuffs, lessening the load of freezing and to freeze the food without causing unnecessary changes in texture (Petrotos and Lazarides, 2001). It has been reported that osmo-dehydration reduced up to 50% weight of fresh vegetables and fruits (Rastogi and Raghavarao, 1997).According Erle and Schubert (2001) Osmotic dehydration involves the immersion of fruits in osmotic solution such as salts, alcohols, starch solutions and concentrated sugars, which some extent to dehydrate the food.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 30 Different types of solutes such as fructose, corn syrup, glucose, sodium chloride and sucrose are used as osmotic agent for OD (Azuara and Beristain, 2002). Sousa et al., (2003) stated that Low molar mass saccharides (sucrose, glucose and fructose) make easy the sugar uptake due to high diffusion of molecules. It has proved to be a good quality method to get modestly processed fruits, due to the much sensory resemblance between the natural and dehydrated products. The diffusion of water is effected to natural substances such as acids, vitamins, minerals, colourants and saccharides (Lombard et al., 2008). But this flow is quantitatively negligible. Osmotic dehydration which improves the sensorial and nutritional properties, preserve and improve the organoleptic properties of foods. It is efficient in room temperature. In food processing industry, osmotic dehydration has become more popular (Tortoe et al., 2007). Osmotic dehydration is used with other drying methods such as freezing and deep fat frying to make available better quality final product (Torreggiani and Bertolo, 2001a; Behsnilian and Speiss, 2006). The immersion of fruit in osmotic medium was helpful for improving the final product quality since acidity of fruit reduced and prevents the oxidative browning (Ponting, 1973). Ramarjuna and Jayaraman (1980) studied the microbial quality of intermediate moisture banana stored at 0° C and 37° C and showed that at 0° C the total plate count was 250 to 300 colonies/g but at room temperature and 37°C, it was negligible and product was microbiologically safe for direct consumption. 2. 3. 4 Jam According to Morris (2004) jam is a preparation consisting of whole fruit boiled with sugar, having a Consistency firm enough to meet the demands of confectioners. All jam shall contain not less than 68.5% total soluble solids. Sugar is necessary to give strength of the pectin-sugaracid gel. It is assumed that about 3-5% total weight of jam is represented by sugar derived from the fruit. Fruit pulp, pectin, sugar and acid are contained in jam as it is an intermediate moisture food (Santanu et al., 2007). Street (1991) state the boiling fruit with sugar until the total soluble solvents reaches 69.5% to produce jam. But bakery purposes a stiffer jam of about 72% solids is often used. The solids content can be monitored by using Refractometer. Jam is made from crushed or ground fruit. The end product is less firm than jelly, but still holds its shape.
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 31 Jam is a product made by boiling fruit pulp with sufficient quantity of sugar to a reasonably thick consistency, firm enough to hold the fruit tissues in position. Apple, sapota, papaya, plums, mango, grapes, jack, pineapple, banana, guava and pears are used for preparation of jam. It can be prepared from one kind of fruit or from two or more kinds. In its preparation about 45% of fruit pulp should be used for every 55% of sugar. The FPO specification of jam is 68.5% TSS, 45% of fruit pulp and 0.5-0.6% of acid (citric acid) per 100 g of the prepared product (www.agridr.in). Essential Ingredients Horrison et al, (2013) point out that the essential ingredients of jam. Fruit furnishes the flavor and part of the needed pectin and acid. Some irregular and imperfect fruit can be used. Do not use spoiled, moldy or stale fruit. Pectin is the actual gelling substance. The amount of pectin found naturally in fruits depends upon the kind of fruit and degree of ripeness. Under ripe fruits have more pectin; as fruit ripens, the pectin changes to a non-gelling form. Cooking brings out the pectin, but cooking too long destroys it. High pectin fruits are apples, crabapples, quinces, red currants, gooseberries, Eastern Concord grapes, plums and cranberries. (Harrison et al., 2013) Paul (2010) explains the importance of ingredients of jam. In his study all types of jam contain four essential ingredients such as Fruit, pectin, acid and sweeteners. Fruit Provides unique flavor and characteristic color as well as some pectin and acid Pectin is found naturally in fruits and is the ingredient, when combined with sugar or other sweeteners (Not artificial sweeteners), that causes the fruit to gel. Pectin is concentrated in the skins and cores of fruits. This is why recipes often call for using skins and cores for juicing or pulping. Commercial pectin comes in liquid and powdered form. Acid is necessary for gel formation and flavor. Fruits naturally contain acid, but the amount of acid varies with the fruit and degree of ripeness. Sugar is essential to help form the gel and contributes to flavor and taste. The type of sugar used in recipes is granulated white sugar. Use the specific amount of sugar called for in the recipe. The amount of sugar must be in proper proportion with pectin and acid to make a good gel(Paul, 2010).
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 32 According to Bourne (2007) moisture of jam reduced to 31%, TSS reduced to 66%, total titrable acidity reduced to 0.3 – 1.1% and boiling convert sucrose into glucose and fructose. Boiling is also darken the colour. 2. 3. 5 Syrup Sharma (2010) suggests that syrup is a beverage similar to squash which is consumed after dilution in water and contains minimum 25% fruit juice or pulp and minimum 65% TSS. And the acidity is kept at about 1.3% According to Brekke (1968) pineapple juice can be used in preparation of syrups to impart desirable natural flavours and colours. Syrups usually contain more than 65 percent by weight of sugar, which makes them very resistant to microbial spoilage. To enhance the instability, it is common practice to add anti-fungal agents such as sodium benzoate, potassium sorbate or combinations of anti-fungal preservatives. This is done to prevent spoilage after the container has been opened. Usually a container of table syrup is kept many days or weeks after it is opened, giving rise to the need for a chemical preservative. Syrup is a type of fruit beverage contains 25% fruit juice or pulp, 65% TSS, 1.3 - 1.5% acidity. It is diluted before serving. Fruits like aonla, jamun, pomegranate, grape, lemon, orange and sometimes ginger can be used for the preparation of syrup. It is also prepared from extracts of rose, sandal almond etc. Heavy sugar syrup of 70-75 per cent strength is used as the base of all synthetic syrups and they are flavoured and coloured with artificial essence/flavours and colours. They never contain fruit pulp/juice. A large proportion of these syrups can, however, be replaced by real fruit juices, squashes and syrups which are more nutritious. Large quantities of synthetic syrups (orange, lemon, pineapple, strawberry) are manufactured and sold in various countries. These can be prepared by using 1.5 kg of sugar, 500 ml of H2O and 15 g of citric acid. Different colours and flavours are added as required. Among colours, orange red, lemon yellow, green, raspberry red etc. are mostly used, while artificial essence/flavours of rose, orange, pineapple, strawberry, lemon etc. are added as flavouring substances. All juices are sweetened by adding sugar, except those of grape and apple. Sugar also acts as preservative for the flavour and colour and prolongs the keeping quality. Sugar based products can be divided into 3 groups on the basis of sugar content: Low sugar (30 per cent sugar or below), Medium sugar (sugar above 30 and below 50%) and High sugar (50% sugar and above).
Effect of Various Preservation Techniques on the Quality of Pineapple
Review of literature 33 Sugar can be added directly to the juice or as syrup made by dissolving it in hot water, clarifying by addition of a small quantity of citric acid or a few drops of lime juice and filtering (www.agridr.in). According to Bourne (2007) total solid of fresh fruit increased during syrup preparation, also sugar is converted and colour was changed. 2. 3. 6 Squash Squash is prepared by blending the juice with sugar, citric acid and water and preserved chemically with 350 ppm SO2. As per F.P.O. specification the squash must contain 25 percent juice and at least 40°Brix (T.S.S.).First of all sugar syrup is prepared by dissolving sugar in water by heat application. During heating, citric acid dissolved in little quantity of water is mixed with syrup. The syrup is then allowed to cool and after straining, the sugar syrup is mixed with juice. The squash is served after diluting three times with water (www.tmnehs.gov.in). Pineapple squash contains (per 250g) energy 3 kcal, total fat 0g, carbohydrate 0.3g, protein 0g (www.eatthismuch.com) Squashes are sweetened juice of fruits containing minimum prescribed quantity of pulp. As per Indian Standards, squash should contain at least 25 per cent (by volume) of fruit juice. The squashes are consumed after dilution by drinking water in 1:3 ratios. These beverages contain added flavours and permitted class II preservatives. Since preservatives are added in adequate quantities, the shelf life of squashes is fairly longer at room temperature (www.nabard.org)
Effect of Various Preservation Techniques on the Quality of Pineapple
MATERIALS AND METHODS
Materials and methods 35
3. MATERIALS AND METHODS
Studies were carried out on the effect of various preservation techniques on the quality of pineapple. Pineapple jam, squash, syrup, dried, frozen and osmo-dehydrated samples were prepared. Experiments were carried out at pineapple research station, Vazhakulam. Procurement of materials: Pineapple fruits required for the study were obtained from the field of Pineapple Research Station, Vazhakulam Materials for phytochemical analysis: 0.1N Sodium hydroxide Solution (NaOH) (QUALIGENS 36105), Sodium hydroxide pellets purified (MERCK MA6M560052), Phenolphthalein indicator solution (NICE P40871), buffer capsules – pH4±0.05 (MERCK AI1AF61421), buffer capsules – pH 7±0.05 (MERCK AC2AF62110), Oxalic acid dihydrate purified (MERCK QA3Q630011), Dichlorophenol indophenol (DCPIP) Dye (SRL 0440155), Fehling’s solution No.1 (MOLYCHEM 14360), Fehling’s solution No.2 (MOLYCHEM 14380), Lead acetate (NICE L10129), Methylene blue (aqueous) stain solution (MERCK AC5AF55113), Citric acid monohydrate (CDH 027780), Nutrient agar (SRL NM011) and Agar agar for microbiology (MERCK JJ0JF60073) and distilled water. All the above chemicals were purchased from local chemical dealers. Treatments: 30 factorial combinations of 6 preserved products and 5 storage periods. A sample Jam
Squash
Syrup
Frozen
Dried
Osmotic dehydrated
A1
A2
A3
A4
A5
A6
B periods of storage 0 day
5 day
10 day
15 day
20 day
B1
B2
B3
B4
B5
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 36
Treatment combinations: A1B1
A1B2
A1B3
A1B4
A1B5
A2B1
A2B2
A2B3
A2B4
A2B5
A3B1
A3B2
A3B3
A3B4
A3B5
A4B1
A4B2
A4B3
A4B4
A4B5
A5B1
A5B2
A5B3
A5B4
A5B5
A6B1
A6B2
A6B3
A6B4
A6B5
Replication: 3 METHODS Protocol for jam preparation Ingredients for jam preparation: Pineapple fruit, Sugar, citric acid, pectin powder, water (Fig.2) Recipe for jam preparation: Pineapple jam was prepared from fresh pineapple. The pineapple pulp was cooked with water on a low fire. Stir continuously using a wooden ladle. While it boils, sugar was added into it. Boiled it well by stirred continuously. Pectin powder was added and stirred continuously. When the jam was done, citric acid was added. Removed from fire and poured into bottle. When the jam cooled, mouth of the bottle was closed.
Table 3. Recipe for the Preparation of pineapple jam Ingredients (for 350g)
Quantity
Pineapple juice
250g
Sugar
250g
Citric acid
2.5ml
Pectin powder
2.5ml
Water
625ml
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 37 Protocol for squash preparation Ingredients for squash preparation: Pineapple fruit juice, Sugar, citric acid, water (Fig.3) Recipe for sugar preparation: Allow the sugar and water to boil in a deep vessel. Sticky syrup was prepared, which is not one thread. Added dissolved citric acid, take off from fire. Cooled and juice was added. Stirred till well blended. Poured into sterilized bottles and sealed.
Table 4. Recipe for the Preparation of Pineapple squash
Ingredients (for 500 ml)
Quantity
Pineapple juice
250 ml
Sugar
500 g
Citric acid
5ml
Water
5ml
Protocol for syrup preparation Ingredients for syrup preparation: Pineapple fruit juice, Sugar, water (Fig 4) Recipe for syrup preparation: Brought the water to boil in a deep vessel and sugar was added to make the sugar syrup. Pineapple juice added to the boiling sugar syrup. Boiled Till the solution becomes a thread form and takes off from fire. After cooling poured the syrup into sterilized bottle
Table 5. Recipe for the Preparation of Pineapple syrup
Ingredients (for one litre)
Quantity
Pineapple juice
600ml
water
200ml
sugar
800g
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 38 Protocol for frozen product preparation Ingredients for frozen product preparation: pineapple Recipe for frozen product preparation: Fresh ripened pineapple were taken, core and skins were removed. Wash it thoroughly by fresh water, cut into slices of thickness one centimetre. Place it in a freezer (Fig.18) at 0°C for overnight. Protocol for dried product preparation Ingredients for dried product preparation: pineapple Recipe for dried product preparation: Fresh ripened pineapple were taken, core and skins were removed. Wash it thoroughly by fresh water, cut into slices of thickness one centimetre. Dry it for 16hours at 65°C in a hot air oven (Fig.8). Protocol for osmo-dehydrated product preparation Ingredients for osmo-dehydrated product preparation: pineapple, sugar, water Recipe for osmo-dehydrated product preparation: Made syrup by using given sugar and water. Fresh ripened pineapple were taken, core and skins were removed. Wash it thoroughly by using fresh water, sliced the pineapple of one centimetre thickness and two centimetre diagonal. Pineapple slice added into freshly prepared syrup and allow it for five hours. Took product from syrup and placed it in a hot air oven for 90 minutes at 40°C.
Table 6. osmo-dehydrated pineapple Ingredients
Quantity
Pineapple
1500g
Sugar
2000g
Water
1000ml
The final products such as jam, syrup and squash were packed in pre-sterilised bottles and dried and frozen products were packed polythene bags. These products were kept at room temperature.
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 39 Frozen products were packed in polythene bags and kept in freezer. The samples were taken for chemical and sensory analysis on 0th, 5th, 10th, 15th and 20th days. The chemical analyses like pH, total soluble solids (TSS), total acidity, reducing, non-reducing and total sugar, ascorbic acid, moisture, microbial quality and sensory parameters like taste, colour, flavour and overall acceptability were carried out at each interval (Fig.7). Analysis of variance was conducted following Microsoft Excel (2010). Determination of chemical constituents 3.1pH Materials pH meter (Fig. 12), water still unit (Fig. 20). Reagents Buffer solutions (pH 4±0.05 and pH 7±0.05) were prepared as indicated in the capsule bottle, Sample and Distilled water Method The pH meter was calibrated with buffer solutions (pH 4±0.05 and 7±0.05) and the electrode was wiped with tissue paper and then dipped into the samples. When the first reading was completed, the electrode was rinsed with distilled water and again cleaned up with tissue paper (Ruck, 1963). 3.2 Total Soluble Solids (TSS) Materials Hand Refractometer (Fig. 13), Distilled water, Sample, Water still unit. Method TSS was determined using hand Refractometer. Before use, the instrument was cleaned and adjusted to zero using distilled water. 3 ml of distilled water was added to 1ml of sample and mixed thoroughly. This solution was used as sample. An appropriate quantity of sample was placed on the prism-plate of the Refractometer with the help of a glass rod and folding back the
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 40 cover. For each sample, the instrument was calibrated by using distilled water. The reading was multiplied with 3 and recorded as total soluble solids (Brix) (www.fssai.gov.in). 3.3 Total Titrable Acidity Materials Burette (Fig. 17), Micropipettes (Fig. 16), conical flask, (beaker 1000 ml), Measuring cylinder, water bath- thermostatic (Fig. 19), Electronic weighing balance (Fig. 14), Water still unit Reagents 0.1N Sodium hydroxide (NaOH), Phenolphthalein indicator, Distilled water Method 25 ml sample was taken in a conical flask and 100 ml distilled water was added to it. The solution was heated for 10 minutes and made up to 250 ml with distilled water. Pipetted 10 ml of this solution and titrated against 0.1N NaOH solution. A few drops of phenolphthalein were added as indicator (Ruck, 1963). The volume of alkali used was noted and acidity was calculated using the following formula;
Acidity (%) = 0.128 x Titre Value
3.4 Ascorbic acid Materials Conical flask, Micropipettes (5 ml and 10 ml), Burette, Measuring cylinder and Electronic weighing balance Reagents 4% Oxalic acid: 4 g oxalic acid was weighed and dissolved in 100 ml distilled water.
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 41 DCPIP (Dichlorophenolindophenol) Dye: Dissolved 0.250 g of sodium salt of 2,6dicholorophenol indophenols in about 500 ml of water containing 0.210 g of NaHCO3 and diluted to 1 litre of water. Stored the solution in refrigerator and standardized it with freshly prepared standard solution of ascorbic acid every time just before use (Sadasivam et al., 1996). Standard ascorbic acid (C6H8O6): 0.01 % ascorbic acid was dissolved in oxalic acid Method 5 g of sample was made up to 100 ml using 4% oxalic acid. 5 ml from this was pipetted and 10 ml
of
4%
oxalic
acid
was
added.
The
solution
was
titrated
against
standard
Dichlorophenolindophenol (DCPIP) dyes solution. The volume of DCPIP dye used was noted and ascorbic acid was calculated using the following formula (Ruck, 1963);
Ascorbic acid or vitamin C (mg/100g) = 60.6 x Titre Volume
3.5 Sugars 3.5.1 Reducing sugar Materials Conical flask (250 ml), Water bath-thermostatic, Pipette, Burette, Electronic weighing balance Reagents Fehling’s solution (30 ml): 5 ml Fehling’s No.1 + 5 ml Fehling’s No.2 + 20 ml distilled water 45% Lead acetate: 45 g lead acetate was weighed and dissolved in 100 ml distilled water 22% Oxalic acid: 22 g oxalic acid was weighed and dissolved in 100 ml distilled water methylene blue indicator solution, 0.1N Sodium hydroxide (NaOH) solution Method 25 g of sample was taken in a conical flask and heated for 10 minutes. 2 ml of 45% lead acetate was added to it. After 2 minutes 2 ml of 22% oxalic acid was added to remove excess of lead acetate. Yellow tint was appeared. NaOH was added to neutralize the solution and the bubble
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 42 retains in the sample. The solution was made up to 250 ml and it was taken in the burette, titrated against hot Fehling’s solution (30 ml). Methylene blue was added as indicator. Burette reading was noted when a red precipitate formed and reducing sugar was calculated using the formula(Ruck, 1963); Reducing Sugar % = 50/Titre value
3.5.2 Total sugar Materials Conical flask (250 ml), Water bath-thermostatic, Burette, pipette, Electronic weighing balance, Water still unit Reagents Fehling’s solution, 45% Lead acetate, 22% Oxalic acid, 0.1 N NaOH, Citric acid, Methylene blue and Distilled water Method 25 g of sample was taken in a conical flask and heated for 10 minutes. 2 ml of 45% lead acetate was added to it. After 2 minutes, 2 ml of 22% oxalic acid was added to remove excess of lead acetate. Yellow tint was appeared. 0.1 N NaOH was added to neutralize the solution until the bubble retains in the sample. The solution was made up to 250 ml using distilled water. From this 50 ml was pipetted into another conical flask and 5 g citric acid was added to it. The solution was heated and made up to 250 ml. This solution was taken in the burette and titrated against hot Fehling’s solution (30 ml). Methylene blue was added as indicator. Burette reading was noted when a red precipitate formed. Total sugar content was calculated as follows (www.fssai.gov.in);
Total sugar % = (250/Titre value)
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 43 3.5.3 Non reducing sugar Non reducing sugar content was estimated as the difference between the total sugar content and reducing sugar content on subtraction (total sugar-reducing sugar) by using the following formula (www.fssai.gov.in);
Non reducing sugar % = (Total sugar-Reducing sugar) x 0.95 3.6 Moisture Moisture is the major component of food. The moisture content of any food is determined not only to analyse the chemical composition of food material but also to assess the shelf life of the product. Materials Hot air oven, Petri plates, Desiccator (Fig. 15), Electronic weighing balance Method The moisture content of the sample was determined by following oven drying method. 5g of samples were kept in pre-dried Petri plate. The mass of the sample was recorded as Wm. The plate was placed in the hot air oven maintained at 105oC for three hours. After drying, the plate was kept in the desiccators and cooled. Then the plate with dried sample was weighed. The mass of the dried sample was recorded as Wd. All measurements were replicated thrice. After measuring the weight, plates were again kept in hot air oven for one hour to ensure no moisture remaining in the dried sample. And the average moisture content was calculated using the formula below (www.fssai.gov.in); Moisture content (M.C. %) = Wm / (Wm+Wd) x100 Where, M.C. = Moisture content per cent wet basis Wm= Mass of water evaporated (g) Wd
= Mass of dry matter (g)
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 44 3.7 Sensory Evaluation Materials Beaker, Distilled water, Water still unit Method A panel of judges was selected from Pineapple Research Station, Vazhakulam who were supposed to be organoleptically familiar with processed food assessment. Sensory analysis (taste, colour, flavour) was carried out and overall acceptability was calculated by taking the mean of three values of samples. Evaluation was carried out using a 9 point hedonic scale (Table 2).
Table 7. Nine Point Hedonic Scale for Sensory Evaluation
Scale
Legend
9
Like extremely
8
Like very much
7
Like moderately
6
Like slightly
5
Neither like nor dislike
4
Dislike slightly
3
Dislike moderately
2
Dislike very much
1
Dislike extremely
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 45
Table 8.Score card for organoleptic evaluation Treatments Characteristics jam
Squash
syrup
Frozen
Dried
Osmodehydrated
Colour Flavour Taste Overall acceptability
3.8 Microbial plate count Materials Distilled water, Incubator (Fig. 10) Petri plates, Test tubes, Laminar airflow chamber (Fig. 5), Pipette, Autoclave (Fig. 9), Water still unit, Colony counter (Fig. 11) Reagents Nutrient agar media, Agar Pour Plate Method Nutrient agar medium was prepared and it was sterilized in autoclave. 1 ml of Sample was pipetted into a tube containing 9 ml of sterile distilled water (diluents). 1 ml from the first dilution was transferred to second dilution tube containing 9ml diluents. 1 ml from second dilution was pipetted to third tube. Second (10-2) and third tubes (10-3) were selected as desired dilutions. All the Petriplates were labelled with sample number, dilution and date. 1 ml of fruit
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 46 syrup homogenate was pipetted from 10-2dilution which has been selected for plating into a Petriplate in triplicates. Similarly, 1 ml fruit syrup homogenate from 10-3 dilution was pipetted into another Petriplates in triplicates. 25 ml of the molten nutrient agar was poured into each Petri plate. Media and dilutions were mixed by swirling gently clock wise, anti-clock wise, to and fro thrice. The plates were allowed to set (Fig. 6). The prepared plates were incubated, inverted at 37oC for 48 hours. All the colonies from the plates were counted followed by the incubation and results were recorded per dilution counted. Actual number of colony was calculated as per the formula below (www.fssai.gov.in);
N=C/ (N1+0.1N2) D
Where, C = Sum of colonies counted on all the plates retained N1 = Number of plates retained in the first dilution N2 = Number of plates retained in the second dilution D = Dilution factor corresponding to first dilution
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 47
Fig.2. Ingredients for Jam
Fig.4. Ingredients for syrup
Fig.3. Ingredients for Squash
Fig.5. Laminar Air Flow Chamber
Fig.6. Plating of sample in Laminar flow chamber
Fig.7. Analysis of sample
Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 48
Fig. 8 Hot air oven
Fig.9 Autoclave
Fig.8. Hot Air Oven
Fig. 11 Colony Counter
Fig.10. Bacteriological Incubator
Fig. 12 pH meter
Fig.13. Hand Refractometer Effect of Various Preservation Techniques on the Quality of Pineapple
Materials and methods 49
Fig.14. Electronic weighing balances
Fig.15. Desiccator
Fig.17. Burettes
Fig.16. Micropipettes
Fig.18. Refrigerator
Fig.19. Water Bath - Thermostatic
Fig.20. Water Still Unit
Effect of Various Preservation Techniques on the Quality of Pineapple
RESULTS AND DISCUSSIONS
Results and Discussions 51
4 RESULTS AND DISCUSSIONS
Studies were carried out on the effect of various preservation techniques on the quality of pineapple. Pineapple jam, squash, syrup, dried, frozen and osmo-dehydrated samples were prepared. Experiments on phytochemical, microbial and sensory analysis were carried out at pineapple research station, Vazhakulam. The results obtained from the studies and their discussions are as follows; 4.1 Phytochemical Analysis 4.1.1 pH The pH of preserved pineapple products was examined to investigate the quality of different pineapple products during a period of storage. pH is different for different products of pineapple and varies on storage. pH of different preserved pineapple product was highly significant. Mean pH obtained was 4.13. Mean pH of pineapple jam, squash and syrup, dried, frozen and osmo-dehydrated pineapple products was varies on storage. pH was lowest (3.30) for jam at 20th day and highest (5.18) for osmo-dehydrated pineapple at 0th day. Mean pH observed for jam, squash, syrup, frozen, dried and osmo-dehydrated products during 20 days of storage was3.49, 3.41, 4.08, 4.15, 4.57 and 5.09 respectively. In the present study pH of jam and squash were more similar and more acceptable. pH of other preserved pineapple product such as pineapple syrup, frozen, dried and osmo-dehydrate pineapples were higher than jam and squash pH. But the pH of all preserved products was decreased during the storage periods. Among these jam had better pH when compared to raw pineapple pH (3.77) (Table. 9 and Fig. 21). Evaluation of pH in food is important as it influences palatability. pH of pineapple product was decreased within 20 days. On the previous study of Talasila, (2011) the pH of the preserved juice decreased from 3.4 to 2.93 up to 90 days. Most of the bacteria will not grow at low pH and hence good keeping quality of the juice is maintained (Ranganna, 1986). A minute change (decrease) in the pH of pulp samples were noted by Ogiehoret al. (2004). In the present study the pH declined after 20 days of storage.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 52 Musingo et al. (2001) and Soong et al. (2006) observed that mangoes during their storage period the pH got decreased. Malik et al. (1994) observed that, pH value of the mango pulp sample decreased with the passage of time. Here also passage of time has got lowest pH.Bajwa et al. (2003) and Hussain et al. (2008) found that pH plays dual function in the fruit juices or beverages by acting as a preservative and as well as flavour enhancer. Findings showed that there was increase in the acidity of the sample corresponding to decrease in pH of the pulp. Here also after 20 days pH got decreased while acidity increased.
Table. 9. pH of different pineapple preserved products during 20 days of storage
TREATMENT Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
Product means Time means Interaction means CV% GM
0th day 3.70 3.53 4.17 4.18 4.63 5.18 4.23
5th day 3.61 3.42 4.10 4.16 4.60 5.14 4.17
10th day 3.50 3.40 4.07 4.16 4.57 5.11 4.14
15th day 3.34 3.37 4.02 4.14 4.53 5.01 4.07
SEm 0.001 0.001 0.002
CD (0.05) 0.004 0.004 0.008
20th day 3.30 3.35 4.05 4.13 4.52 5.01 4.06
Mean 3.49 3.41 4.08 4.15 4.57 5.09 4.13
0.117 4.132
6.00 0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
5.00
pH
4.00
3.00
2.00
1.00
0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
Preserved Pineapple Products
Fig. 21. pH of different pineapple preserved products during 20 day of storage
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 53 4.1.2 TSS TSS of the samples was decreased with the increase in storage period. At the starting of storage time TSS was high. TSS of different preserved pineapple product was significant. Mean TSS was obtained as 50.33°brix. TSS was highest (67.17°brix) for syrup at 0th day and lowest (1.1°brix) for frozen pineapple at 10th day. Mean TSS observed during 20 days for pineapple jam, squash and syrup, frozen, dried and osmo-dehydrated pineapple was 60.97, 55.87, 65.01, 17.74, 50.98 and 51.38°Brix respectively. In the present study TSS of pineapple syrup had higher value. Because of this high TSS Syrup had good acceptability. TSS of other preserved pineapple product such as pineapple jam, squash, frozen, dried and osmo-dehydrate pineapples was lower. The TSS of all preserved products was decreased on the passage of storage periods except dried and osmo-dehydrated pineapple. In the case of dried pineapple, TSS was increased from oth day to 15th day. in 20th day TSS reduced, but value was higher than on 0th day. in the case of osmo-dehydrated pineapple TSS on 20th days was less than 0th day. but in between TSS was varied alternatively. On 5th TSS was decreased but on 10th day the value was increased. From there TSS was decreased upto 20th day. TSS of frozen pineapple was showed an increase on 15th day to 20th when compared to 5th day and 10th day. And was not increased than TSS on 0th day. all day TSS of syrup was higher than other preserved products. So among these, syrup had better TSS (Table. 10 and Fig. 22). According to joy (2014) TSS of raw pineapple and passion fruit was 16°Brix and 18°Brix respectively, in the present study mean TSS of preserved pineapple was 50.83°Brix. TSS of frozen pineapple in present study was approximate to TSS of raw pineapple in the study of joy (2014). That means freezing had very low effect on TSS of pineapple. Talasila et al. (2012) reported that, there was a significant decrease in TSS of all the samples. In another study, TSS did not alter during the period of storage (Ramesh et al., (2004) and Renuka et al. (2009) but here it decreased with storage period. According to Beatrice et al., (2013)Temperature had no significant effect on total soluble solid (TSS) ofthe osmo-dehydrated pineapple and pineapple jam. Jam made from pineapple fruits had 70 –72°Brix. In the present study TSS was 66-57°Brix. These values arecomparable to those reported by Garcia et al., (2002) for kiwi jam and orange marmalade (32.1 – 68.4°Brix). The TSS value in present study were also comparable with the valuesreported by Oyeyinka et al
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 54 (2011) for cashew where TSS value obtained is 68°Brix. Sugar influences The shelf-life of jam products decisively through the soluble solid content (Herbstreith, 2011).
Table. 10. TSS of different pineapple preserved products during 20 days of storage(°Brix) TREATMENT Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
0th day 67.17 60.89 71.48 18.52 50.02 51.72 53.30
5th day 64.48 56.73 68.34 17.40 50.35 50.83 51.35
10th day 59.67 56.17 65.67 17.17 50.65 51.82 50.19
SEm
CD (0.05)
Product means
0.370
1.345
Time means
0.337
1.326
Interaction means
0.827
2.441
CV (%)
2.848
GM
50.330
15th day 57.56 52.58 60.27 17.83 53.59 51.75 48.93
20th day 55.98 53.00 59.33 17.78 50.33 50.82 47.87
Mean 60.97 55.87 65.01 17.74 50.98 51.38 50.33
4.1.3 Total titrable acidity Total titrable acidity of preserved pineapple products for 20 days was quantified volumetrically. Acidity of preserved pineapple products was highly significant. When storage period increased, acidity of sample also increased. At 0th day, the acidity was lower. Mean acidity was obtained as 0.07%. After 20 days, except dried pineapple, all other products show an increase in acidity. Mean acidity observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples at during 20 days was 0.10, 0.09, 0.07, 0.15, 001 and 0.01% respectively. In the present study acidity of dried and osmo-dehydrated pineapples were more acceptable. Acidity of other preserved pineapple product such as pineapple jam, squash, syrup, frozen
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 55 pineapple were higher than dried and osmo-dehydrated pineapples. Acidity of all preserved products was increased on the passage of storage periods. Acidity of frozen pineapple was maintained on 5th day to 15th day as 0.15%. acidity of dried pineapple was maintained as 0.01% through out the storage period. Osmo-dehydrated pineapple maintained the acidity from oth day to 15th day as 0.01%. On 20th day acidity of osmo-dehydrated pineapple was increased slightly. Considering the acidity dried and osmo-dehydrated pineapple were better (Table.11 and Fig. 23). The result obtained showed the effect of various preservation techniques on acidity of the pineapple. In the study of joy (2014) acidity of raw pineapple and raw passion fruit was 0.16% and 0.52% respectively, in the present study only frozen pineapple had same acidity as in study of joy. That means freezing had very low effect on the acidity of pineapple. Acidity was increased with the passage of storage period (Iqbal et al., 2001; Amin et al., 2008; Hussain et al., 2008). A relative increase in the acidity of the preserved pulp during the storage period was also observed by Ogiehor et al. (2004) and Akhtar et al. (2009). According to Fulya et al. (1999) and Gowda and Huddar (2001) during the storage period, changes can occur in the physico-chemical characteristics of mango pulp. Their results showed that there was an increase in acidity of samples during the period of storage. A slight increase in acidity at ambient temperature was noted in processed mango chunks and pasteurized pulp (Tovar et al., 2000) as the storage period proceeded. Musingo et al., (2001) and Soong et al., (2006) observed that mangoes go on increasing its acidity as the storage period increases. An increase in acidity in chemically preserved mango pulp samples was also observed by Aguilar et al,. (2000).
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 56
Table. 11. Total Titrable acidity of different pineapple preserved products during 20 days of storage (%)
TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
0.03 0.01 0.01 0.14 0.01 0.01 0.04
0.06 0.08 0.05 0.15 0.01 0.01 0.06
0.10 0.10 0.08 0.15 0.01 0.01 0.08
0.14 0.10 0.09 0.15 0.01 0.01 0.08
0.17 0.15 0.12 0.17 0.01 0.03 0.11
0.10 0.09 0.07 0.15 0.01 0.01 0.07
Product means Time means Interaction means CV (%) 2.629 GM 0.073
SEm 0.005 0.004 0.001
CD (0.05) 0.001 0.001 0.003
0th DAY
0.20
5th DAY
10th DAY
15th DAY
20th DAY
Total titrable accidity (%)
0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 23. Total titrable acidity of different pineapple preserved products during 20 days of storage (%)
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 57 4.1.4 Ascorbic acid Ascorbic acid of preserved pineapple samples for a period of 20 days was quantified volumetrically. Ascorbic acid in preserved pineapple product was decreased on passage of storage period. Ascorbic acid of preserved pineapple products was highly significant. Mean ascorbic acid obtained as 23.88%. Highest ascorbic acid (42.42%) was observed for squash at 0th day. Mean ascorbic acid observed for pineapple jam, squash, and syrup and frozen, dried and osmo-dehydrated pineapples were 21.18, 28.45, 23.27, 24.39, 23.60 and 23.39 respectively. In the present study ascorbic acid content of pineapple squash was more acceptable because squash had high amount of ascorbic acid. Vitamin C content of other preserved pineapple products such as pineapple jam, syrup, frozen, dried and osmo-dehydrate pineapples was lower than pineapple squash. Vitamin C content of all preserved products was decreased during storage periods. But vitamin C content of frozen pineapple was maintained on 0th, 5th, 10th, 15th days. On 10th and 15th day vitamin C content of jam (18.18%) and squash (24.24%) was maintained. On 0th and 5th day vitamin C content of syrup and dried pineapple was maintained. On 5th and 10th day vitamin C content of osmo-dehydrated pineapple was maintained. Considering these pineapple squash was better (Table.12 and Fig. 24). In the study of Joy (2014), he found that ascorbic acid content of pineapple and passion fruit was 37.26% and 37.1% respectively. In the present study only squash had near value. Squash had low effect on ascorbic acid content. Ascorbic acid is light and heat sensitive, the concentration of ascorbic acid follows first order kinetics and thus storage time affects ascorbic acid content (Singh and Heldman, 1984). Hill lemon juice was preserved for a period of 6 months it also showed some decrease in ascorbic acid content (Barwal and Shrera, 2009). Degradation rate of ascorbic acid is affected by several factors such as temperature, water activity, pH, storage time and metal ions (PardioSedas et al., 1994; Uddin et al., 2002; Nunes et al., 1998). Temperature has a major effect on the rate of loss of ascorbic acid. Losses of ascorbic acid were increased with the increase in temperature (Johnson and Hessel, 1982). This was observed by Vidhya and Narain, (2010) in the storage of preserved wood apple. Fennema (1977) found that the ascorbic acid content decreased during storage due to oxidation of ascorbic acid to dehydro ascorbic acid. Hence vitamin C estimation was carried out during the storage period. This is due
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 58 to oxidation or exposure to atmosphere oxygen while preparing the jam. In the study of Sindumathi and Amutha (2014) ascorbic acid of coconut was decreased. The present study also showed the decrease.
Table. 12. Ascorbic acid of different pineapple preserved products during 20 days of storage (%)
TRIAL Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
Product means Time means Interaction means CV (%) GM
0th day 30.30 42.42 30.30 24.24 30.30 30.30 31.31
5th day 24.24 36.36 30.30 24.24 30.30 24.24 28.28 SEm 0.136 0.124 0.304
10th day 18.18 24.24 24.24 24.24 24.24 24.24 23.23
15th day 18.18 24.24 18.18 24.24 18.18 18.18 20.20
20th day 15.00 15.00 13.33 25.00 15.00 15.00 16.39
Mean 21.18 28.45 23.27 24.39 23.60 22.39 23.88
CD(0.05) 0.494 0.487 0.897
2.206 23.881
45.00
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
40.00
Ascorbic acid (%)
35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 24. Ascorbic acid of different pineapple preserved products during 20 days of storage (%)
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 59
4.1.5 Reducing sugar The reducing sugar was analyzed to investigate the quality of different pineapple products during storage period. Reducing sugar is different in different products of pineapple and varies on storage. Reducing sugar of preserved pineapple products was highly significant. Mean reducing sugar obtained was 16.53%. Highest value (27.28%) of reducing sugar was observed for syrup at 0th day and lowest value (11.90%) for frozen and dried pineapples at 20th day of storage. Mean reducing sugar for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 12.38, 16.75, 23.68, 12.36, 12.44 and 21.54% respectively. Reducing sugar of preserved pineapple products such as pineapple jam, squash, frozen, dried and osmo-dehydrate pineapples was lower than pineapple syrup and reducing sugar of all preserved products was decreased during storage periods. But on 5th, 10th, and 15th reducing sugar of jam was maintained and slightly decreased and maintained on 15thand 20th day. Reducing sugar of squash was maintained on 10th, 15th and 20th day. Reducing sugar of syrup was maintained on 15th and 20th day. Reducing sugar of frozen pineapple was maintained on 10th and 15th day. Reducing sugar of dried pineapple was maintained on 5th and 10th day. Considering these results pineapple syrup is the best preservation technique (Table.13 and Fig. 25). According to joy (2014) reducing sugar of raw pieapple was 5.72%. the result of analysis showed that, the values obtained for reducing sugar on preserved pineapple products were not similar to joy. That means all preservation had high effect on reducing sugar. Amin et al. (2008) observed an increase in reducing sugar throughout the period. The same was reported by Husain et al, (2003). Heikal and EI-Sidawi (1972) observed that browning in mango pulp was due to the reducing sugars and amino acids. In the study of sindumathi and amutha (2014), reducing sugar of preserved coconut product was increased gradually during storage. The increase in reducing sugar content of the sample stored at refrigeration temperature was slightly lesser than the sample stored at room temperature. During storage reducing sugar content changed from 15.00 to 15.75, 15.79, 15.45 and 15.52g/100g respectively. Similar observation was found by Aruna et al (1998) where, there was an increase in reducing sugar content of preserved sapota product from 38.60 to 43.73 per cent at the end of the storage period. But the present study showed a decrease of reducing sugar on storage.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 60
Table. 13. Reducing sugar of different pineapple preserved products during 20 days of storage (%)
TREATMENT Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
Product means Time means Interaction means CV (%) GM
0th day 12.50 17.65 27.28 12.61 13.03 24.60 17.95
5th day 12.50 16.66 26.36 12.50 12.50 23.80 17.39 SEm 0.094 0.085 0.210
10th day 12.50 16.66 23.08 12.40 12.50 21.73 16.48
15th day 12.19 16.66 20.83 12.40 12.29 19.74 15.69
Mean
20th day 12.19 16.12 20.83 11.90 11.90 17.85 15.13
12.38 16.75 23.68 12.36 12.44 21.54 16.53
CD (0.05) 0.342 0.337 0.620
2.205 16.528
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
30.00
Reducing sugar (%)
25.00
20.00
15.00
10.00
5.00
0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 25, Reducing sugar of different pineapple preserved products during 20 day of storage (%)
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 61 4.1.6 Non Reducing sugar The Non-reducing sugar of preserved pineapple products was examined to investigate the quality of different pineapple products during storage period. Non-Reducing sugar is different for different products and varies on storage. Non-reducing sugar of preserved pineapple products was highly significant. Mean Non-reducing sugar obtained was 16.52%. Highest value (63.16%) of non-reducing sugar was observed for syrup at 0th day and lowest value (30.16%) for osmo-dehydrated pineapple at 5th day of storage. Mean non reducing sugar observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 44.47, 57.48, 55.72, 43.31, 32.46 and 32.65 respectively. Non-Reducing sugar of preserved pineapple products such as pineapple jam, squash, frozen, dried and osmo-dehydrate pineapples was lower than pineapple syrup and non-reducing sugar of all preserved products were decreased on the passage of storage periods. But in the case of osmodehydrated pineapple on 5th day value decreased and then increased from 10th day to 20th day. Considering non-reducing sugar content, syrup was better preservation method (Table.14 and Fig. 26). In the study of joy (2014) the non reducing sugar of pineapple was 25.03%. but after the preseration in this study no preserved product had similar value .that means preservation had significant effect o quality of pineapple. According to Shahnawazet al. (2013) non-reducing sugar content of orange juice was decreased from 1.4156% to 1.200% in a period of 45 days. There was a decrease in non-reducing sugars. Sucrose (non-reducing sugar) contents decreased constantly throughout the storage period (Hussain et al., 2003). Here also the non-reducing sugar content was decreased.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 62
Table. 14. Non reducing sugar of different pineapple preserved products during 20 days of storage (%) TREATMENT
0th day 49.55 60.69 63.16 43.68 33.58 32.28 47.16
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
5th day 45.12 61.63 62.90 43.34 32.92 30.16 46.01
10th day 43.34 58.38 52.29 43.44 32.65 32.12 43.70
SEm 0.182 0.166 0.408
Product means Time means Interaction means CV (%) GM
15th day 42.38 54.18 52.17 43.44 32.03 34.01 43.04
20th day 41.96 52.53 48.06 42.66 31.10 34.66 41.83
Mean 44.47 57.48 55.72 43.31 32.46 32.65 44.34
CD (0.05) 0.664 0.654 1.204
1.595 44.34
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
70.00
Non reducing sugar (%)
60.00 50.00 40.00 30.00 20.00 10.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 26. Non reducing sugar of different pineapple preserved products during 20 days of storage (%)
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 63 4.1.7 Total sugar The effect of various preservation techniques on total sugar was investigated at 0th, 5th, 10th, 15th and 20thdays after storage. The analysis of variance suggested that total sugars of samples were highsignificantly affected by various techniques and also with the storage period. When storage period passed total sugar was decreased. Mean total sugar was obtained as 63.17%. Highest value (93.72%) of total sugar was observed for syrup at 0th day of storage and lowest value (54.34%) was observed for osmo-dehydrated pineapple at 20th day. Mean total sugar observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 59.18, 77.23, 82.30, 57.78, 46.61 and 55.92 respectively. Total sugar of all preserved products were decreased during storage period. Syrup maintained total sugar content on 0th day and 5th day. Frozen pineapple maintained the value on 0th, 5th, and 10th day of storage period. Osmo-dehydrated pineapple maintained total sugar content on 5th, 10th, and 15th day. When considering total sugar content syrup was better preservation method (Table.15 and Fig. 27). According to sindumathi and aamutha (2014), the breakdown of total sugar into simple sugar would have decreased the quantum of total sugar. The initial total sugar preserved coconut product were 52.20 g/100g which was decreased to 51.60, 51.65, 51.28, 51.32g/100g.The present study also showed decrease of total sugar on passage of period of storage. Joy (2014) found that total sugar of raw pineapple was 30.5%. in the present study total sugar of all pineapple preservation have greater than raw pineapple. That means preservations had significant effect on the total sugar of pineapple.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 64 Table. 15. Total sugar of different pineapple preserved products during 20 days of storage (%)
TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
64.66 81.54 93.72 58.13 48.38 58.59 67.50
59.91 81.54 92.50 58.13 47.16 55.55 65.80
58.13 78.12 78.12 58.13 46.87 55.55 62.49
56.81 73.52 75.75 57.69 46.01 55.55 60.89
56.39 71.42 71.42 56.81 44.64 54.34 59.17
59.18 77.23 82.30 57.78 46.61 55.92 63.17
SEm 0.175 0.159 0.319
CD (0.05) 0.636 0.627 1.155
Product means Time means Interaction means CV (%) GM
1.073 63.184
100.00
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
90.00 80.00
Total sugar (%)
70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 27. Total sugar of different pineapple preserved products during 20 days of storage (%)
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 65 4. 1. 8 Moisture Moisture of preserved pineapple products for a period of 20 days were quantified volumetrically. Moisture of preserved pineapple product was significant. Mean moisture of preserved pineapple product was 42.5%. Moisture was lowest (10%) for jam at 0th day and highest (90%) for frozen pineapple at 0thday. Mean moisture observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 22.67, 40.67, 33.33, 83.33, 33.33 and 32.00% respectively. On the passage of time period every sample showed variation in the value of moisture. On 15th day and 20th day moisture content of jam was maintained. On 0th day and 5th day moisture contents of squash and syrup were maintained. On 5th day and 10th day the value maintained for frozen pineapple and slightly increased on 15th day and it was maintained up to 20th day. Moisture content of dried pineapple was maintained on 15th day and 20th day. When considering the moisture content, jam was better preservation method (Table.16 and Fig. 28). Product with high moisture will have low shelf life (Ayub et al., 2004). According to Lavelli and Vantaggi (2009) the moisture content of the fresh fruitwas 82.1 g/100 g sample. In addition, the moisture content of the ingredients obtained was similar in the golden berry fruit products.
Table 16. Moisture of different pineapple preserved products during 20 days of storage (%)
TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
10.00 40.00 30.00 90.00 46.67 56.67 45.56
23.33 40.00 30.00 80.00 26.67 20.00 36.67
20.00 46.67 43.33 80.00 33.33 26.67 41.67
30.00 40.00 30.00 83.33 30.00 30.00 40.56
30.00 36.67 33.33 83.33 30.00 26.67 40.00
22.67 40.67 33.33 83.33 33.33 32.00 40.89
Product means Time means Interaction means CV (%) GM
SEm 1.092 0.997 2.442
CD (0.05) 3.971 3.914 7.204
10.345 40.888
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 66
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
100.00 90.00 80.00
Moisture (%)
70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 28. Moisture of different pineapple preserved products during 20 days of storage (%)
4.2 Sensory analysis 4.2.1 Taste The taste of preserved pineapple products was examined to investigate the acceptability of different pineapple products during storage period. Taste is different in different product of pineapple and varies on storage. Taste of preserved pineapple product was significant.
Mean taste obtained as 6.37. Taste was highest (8.00) for syrup at 0th day and was lowest (5.00) for frozen and dried products at 20th day. Mean taste observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 6.40, 6.80, 6.67, 6.67, 5.60 and 6.13 respectively. In the present study taste of all products decreased during the 20 days of storage. Taste of jam and dried pineapple was maintained on 5th day and 10th day. Taste of squash was maintained on 10th day and 15th day. Also, taste of frozen pineapple was maintained on 5th day, 10th day and 15th day. Considering the taste squash was better preservation method (Table.17 and Fig. 29).
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 67
The mean sensory scores of the preserved pineapple product presented significant difference in taste during 0 to 20 days.This was previously studied by Talasila et al. (2011) in cashew apple juice. According to him, taste of cashew apple juice was increased from 3.5 to 9 within 60 days. In the present study the taste got decreased with the passage of storage period. According to joy (2014) taste of raw pineapple was 6. In the present study, after preservation taste was increased. Table17. Taste of different pineapple preserved products during 20 days of storage (Nine point hedonic scale) TREATMENT
0th day
5th day
10th day
15th day
20th day
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
7.00 7.67 8.00 7.00 6.33 7.33 7.22
6.67 7.33 7.33 6.67 5.67 6.67 6.72
6.67 6.67 7.00 6.67 5.67 6.00 6.45
6.00 6.67 6.00 6.67 5.33 5.67 6.06
5.67 5.67 5.00 6.33 5.00 5.00 5.45
SEm 0.134 0.123 0.301
Product means Time means Interaction means CV (%) GM
Mean 6.40 6.80 6.67 6.67 5.60 6.13 6.38
CD (0.05) 0.490 0.483 0.890
8.195 6.377 0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
9.00 8.00
Taste
7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 29. Taste of different pineapple preserved products during 20 days of storage
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 68 4.2.2 Colour The preserved pineapple products were presented to panel of judges for assessment of colour at different period of storage. Colour was different in different products of pineapple and varies on storage. colour of preserved pineapple product was significant. Mean colour obtained was 6.28. Colour of jam was lowest for dried pineapple at 15th and 20th days of storage and was highest (7.67) for frozen pineapple at 0th and 5th days. Mean colour observed pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 6.13, 6.53, 6.47, 7.20, 5.33 and 6.07 respectively. In the present study colour of all products were decreased during the 20 days of storage. colour of jam and squash were maintained on 5th day and 10th day. colours of syrup and dried pineapple were maintained on 15th day and 20th day. Also, colour of frozen pineapple was maintained on 0th day and 5th day. On 10th day and 15th day colour reduced and maintained. Considering the colour freezing was better preservation method (Table.18 and Fig. 30). Hiremath and Rokhade, (2012) observed that there is periodical decrease in the colour of the pulp samples. According to Lavelli and Vantaggi (2009) the drying system had a significant influence on the colour of the Final product. Compared to the original golden berry fruit (either fresh or slurry), the drying process decreased the lightness and the yellow index. Raw pineapple had a colour of 7 (joy, 2014). In the present study the value ulmost same as the value obtained joy.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 69 Table 18. Colour of different pineapple preserved products during 20 days of storage(Nine point
hedonic scale) TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
6.67 7.00 7.67 7.67 5.67 7.00 6.95
6.33 6.67 7.00 7.67 5.33 6.33 6.56
6.33 6.67 6.33 7.00 5.67 6.00 6.33
6.00 6.00 5.67 7.00 5.00 5.67 5.89
5.33 6.33 5.67 6.67 5.00 5.33 5.72
6.13 6.53 6.47 7.20 5.33 6.07 6.29
Product means Time means Interaction means CV % GM
SEm 0.139 0.127 0.312
CD (0.05) 0.507 0.506 0.921
8.603 6.288
9.00
0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
8.00 7.00
Colour
6.00 5.00 4.00 3.00 2.00 1.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig 30. Colour of different pineapple preserved products during 20 days of storage
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 70 4.2.3 Flavour The flavour of preserved pineapple products was examined to investigate the quality of different pineapple product during storage period. Flavour was different in different product of pineapple and varies on storage. flavour of preserved pineapple product was significant. Mean flavour was obtained as 6.24. Lowest value of flavour (5.00) was observed for both
dried and osmo-dehydrated pineapple at 20th day of storage and highest value (8.00) was observed for syrup at 0th day. Mean flavour observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 5.67, 6.87, 6.67, 7.07, 5.46 and 5.73 respectively. In the present study flavour of all products decreased during the 20 days of
storage except jam, frozen and osmo-dehydrated pineapple. It showed both increase and decrease. Up to 5th flavour of jam was decreased but on 10th flavour was increased and then decreased. On 5th day flavour of frozen pineapple was increased and it maintained up to 10th day, then the value decreased. Also, flavour of osmo-dehydrated pineapple was decreased up to 5th day. But the value slightly increased on 10th day then decreased. Dried pineapple maintained the flavour from 5th day to 15th day. Considering flavour, freezing was better preservation method (Table.19 and Fig. 31). Flavour of preserved pineapple product samples were decreased by storage. Previous studies by Verma and Durrani (2014) stated the flavour of honey aonla squash decreased from 7.66 to 6.33 in a storage periods of 6 months. Joy found that flavour of raw pineapple was 6. Here jam and dried pineapple had reduced flavour.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 71
Table 19. Flavour of different pineapple preserved products during 20 days of storage(Nine point
hedonic scale) TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam Squash Syrup Frozen Dried Osmo-dehydrated Mean
6.00 7.67 8.00 7.00 6.33 6.33 6.89
5.33 7.33 7.00 7.33 5.33 5.67 6.33
6.00 7.00 6.67 7.33 5.33 6.00 6.39
5.67 6.33 6.00 7.00 5.33 5.67 6.00
5.33 6.00 5.67 6.67 5.00 5.00 5.61
5.67 6.87 6.67 7.07 5.46 5.73 6.24
SEm 0.145 0.132 0.324
Product means Time means Interaction means CV % GM
CD (0.05) 0.528 0.520 0.958
9.014 6.244
9.00 0th DAY
5th DAY
10th DAY
15th DAY
20th DAY
8.00
Flavour
7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved product
Fig. 31. Flavour of of different pineapple preserved products during 20 days of storage
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 72 4.2.4 Overall acceptability The overall acceptability of preserved pineapple products was examined to investigate the quality of different pineapple products during 20 days of storage period. Overall acceptability was different for different product of pineapple and varies on storage.Overall acceptability of preserved pineapple product was significant. Mean overall acceptability was obtained as 6.22. Overall acceptability was lowest (5.00) for dried and osmo-dehydrated products at 15th and 20th days and highest (7.67) for syrup at0th day. Mean overall acceptability observed for pineapple jam, squash, syrup and frozen, dried and osmo-dehydrated pineapples were 5.96, 6.64, 6.24, 6.89, 5.60 and 6.00 respectively.
In the present study overall acceptability of all products decreased during the 20 days of storage. Jam maintained the overall acceptability on 10th and 15th day, squash and frozen pineapple were maintained overall acceptability on 15th and 20th day. Dried pineapple was maintained overall acceptability from 5th day to 10th day and 15th day to 20th day. Osmo-dehydrated pineapple was maintained overall acceptability on 5th and 10th day. Considering overall acceptability freezing was better preservation method (Table.20 and Fig. 32). High overall acceptability scores were observed in refrigerated coconut during storage (Chauhan et al, 2012). observed that the preserved coconut product pulp and pine apple product showed a good overall acceptability after 6 months of storage at room and refrigerated conditions.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 73
Table 20. Overall acceptability of different pineapple preserved products during 20 days of storage(Nine
point hedonic scale) TREATMENT
0th day
5th day
10th day
15th day
20th day
Mean
Jam
6.67
5.78
6.00
6.00
5.33
5.96
Squash
7.33
6.89
7.00
6.00
6.00
6.64
Syrup
7.67
6.89
6.33
5.33
5.00
6.24
Frozen
7.00
7.11
7.00
6.67
6.67
6.89
Dried
6.67
5.67
5.67
5.00
5.00
5.60
Osmo-dehydrated
6.67
6.33
6.33
5.67
5.00
6.00
Mean
7.00
6.45
6.39
5.78
5.50
6.22
SEm
CD (0.05)
Product means
0.145
0.530
Time means
0.133
0.522
Interaction means
0.326
0.961
CV (%)
9.075
GM
6.222
9.00
0th DAY
8.00 5th DAY
7.00
Overall acceptability
6.00
10th DAY
5.00 15th DAY 4.00 20th DAY
3.00 2.00 1.00 0.00 JAM
SQUASH
SYRUP
FROZEN
DRIED
OSMO-DEHYDRATED
pineapple preserved products
Fig. 32. Overall Acceptability of different pineapple preserved products during 20 days of storage
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 74 4.3 Total plate count Total plate count of preserved pineapple products was investigated at 0, 5, 10, 15 and 20 days of storage. Total plate count of jam was lowest at 0th day (1636.36 cfu) and highest at 10th day (tntc), total plate count of squash was lowest at 0th and 20th day (666.66 cfu) and highest at 5th and 10th day (12151.26 cfu), total plate count of syrup was lowest at 20th day (424.23 cfu) and highest at 10th day (tntc), total plate count of frozen pineapple was lowest at 0th day (7030.29 cfu) and highest at 10th ,15th and 20th days (tntc), total plate count of dried pineapple was lowest at 20th day (1363.63 cfu) and tntc at all other days, and total plate count of osmo-dehydrated pineapple was lowest at 0th day (303.02 cfu) and highest at 10th day (tntc). Considering total plate count freezing was better preservation method (Table.21). Ramarjuna and Jayaraman (1980) studied the microbial quality of intermediate moisture banana stored at 0° C and 37°C and showed that at 0°C the total plate count was 250-300 colonies/g but at room temperature and 37°C, it was negligible and product was microbiologically safe for direct consumption. Khandekar et al, (2005) carried out research on standard plate count of fig toffee after six months of preservation. The toffees, which were treated with sodium benzoate, reported lower microbial count (11 x 103 /g) compared to untreated toffee (23 x 103 /g). According to Hussain, et al. (2003) mango pulp preserved without any chemical preservative showed increased TPC from 2.8*105 to 4.6*109 in a period of 90 days. Golden et al. (1993) and Penteado et al. (2004) observed that the pulp stored at 25oC for a period of three months produced no significant signs of microbial load in chemically preserved pulp even after end of storage period.
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 75
Table 21. Total plate count of different pineapple preserved products during 20 days of storage (cfu)
TREATMENT
0th day
5th day
10th day
15th day
20th day
Jam
1636.36
1727.27
TNTC
9848.48
1969.69
Squash
666.66
12151.51
12515.14
7606.05
666.66
Syrup
696.97
5030.30
TNTC
3606.06
424.24
Frozen
7030.30
7484.84
TNTC
TNTC
TNTC
Dried
TNTC
TNTC
TNTC
12851.18
1363.63
Osmo-dehydrated
303.02
4263.63
TNTC
11403.33
1030.30
TNTC: Too Numerous To Count
Table 22. Mean values showing the effect of various preservation techniques on the quality of pine apple Parameters A1 pH 3.49 TSS (°Brix) 60.84 TTA (%) 0.10 AA (%) 21.18 RS (%) 12.38 NRS (%) 44.47 TS (%) 59.18 Moisture (%) 22.67 Taste (9 hedonic scale) 6.40 Colour (9 hedonic scale) 6.13 Flavour (9 hedonic scale) 5.67 OA (9 hedonic scale) 5.96
A2 3.41 56.52 0.09 28.45 16.75 57.48 77.23 40.67 6.80 6.53 6.87 6.64
A3 4.08 65.76 0.07 23.27 23.68 55.72 82.30 33.33 6.67 6.47 6.67 6.24
A4 4.15 18.32 0.15 24.39 12.36 43.31 57.78 83.33 6.67 7.20 7.07 6.89
A5 4.57 51.00 0.01 23.60 12.44 32.46 46.61 33.33 5.60 5.33 5.46 5.60
A6 5.09 52.50 0.07 22.39 21.54 32.65 55.92 32.00 6.13 6.07 5.73 6.00
TSS: Total soluble solids; TTA: Total titrable acidity; AA: Ascorbic acid; RS: Reducing sugar; NRS: Non reducing sugar; TS: Total sugar; OA: Overall acceptability
Effect of Various Preservation Techniques on the Quality of Pineapple
Results and Discussions 76
Fig.32. Osmo-dehydrated Pineapple
b
a
Fig.33. (a) Dried pineappleand (b) frozen Pineapple
Fig.34. Pineapple Squash, Jam and Syrup Squash
jam
syrup
osmo-dehydrated
Fig.35. microbial growth on different preserved pineapple product on 5th day Frozen
dried
syrup
osmo-dehydrated
jam
squash
Fig.36. Results of Moisture analysis
Effect of Various Preservation Techniques on the Quality of Pineapple
SUMMARY AND CONCLUSION
Summary and Conclusion 78
5. SUMMARY AND CONCLUSION
Fruits are highly perishable in nature, so it is important to be preserved. Jam, squash, syrup, freezing, drying and osmo-dehydration are some of the methods for fruit preservation. Preserved sample were studied for 20 days. At an interval of 0, 5, 10, 15 and 20 days the phyto-chemical, sensory and microbial analysis were carried out. The phyto-chemical parameter such as pH, TSS, total titrable acidity, ascorbic acid, reducing sugar, non-reducing sugar, total sugar and moisture were quantified. In microbial analysis total plate count using pour plate method was done. Taste, colour, flavour and overall acceptability were organoleptically tested and evaluated using 9 hedonic scale. There were an increase in acidity and decrease in pH, TSS, ascorbic acid, reducing sugar, nonreducing sugar, total sugar and moisture during the storage period. At the middle of the experiment all preserved products showed too numerous to count (TNTC) the microbial growth. But at the last microbial growth were reduced. All preserved pineapple products were subjected for sensory evaluation, frozen pineapple showed best flavour, good colour and better overall acceptability than other preserved product except taste. And squash showed good taste. Among these preserved products dried product showed poor taste, colour, flavour and overall acceptability. So considering sensory analysis, freezing was the better preservation technique and next to frozen, syrup was better. On the basis of present results of phyto-chemical analysis and microbial status, among the six preserved pineapple product, syrup was found to be excellent. However frozen product showed poor quality. Sensory parameters of syrup were also relatively acceptable. Considering the phyto-chemical, sensory and microbial characteristics syrup was the best product.
Effect of Various Preservation Techniques on the Quality of Pineapple
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