~ 1782 ~ International Journal of Chemical Studies 2018; 6(6): 1782-1786 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2018; 6(6): 1782-1786 © 2018 IJCS Received: 09-09-2018 Accepted: 13-10-2018 Akula Rahim Department of Horticulture and Postharvest Technology, Institute of Agriculture, Visva- Bharati, Sriniketan, West Bengal, India Prahlad Deb Department of Horticulture and Postharvest Technology, Institute of Agriculture, Visva- Bharati, Sriniketan, West Bengal, India Nirmala P Reshmi Department of Horticulture and Postharvest Technology, Institute of Agriculture, Visva- Bharati, Sriniketan, West Bengal, India Correspondence Akula Rahim Department of Horticulture and Postharvest Technology, Institute of Agriculture, Visva- Bharati, Sriniketan, West Bengal, India Effect of different sugar syrup concentrations on osmotic dehydration of pineapple fruits during storage Akula Rahim, Prahlad Deb and Nirmala P Reshmi Abstract The present investigation was carried out in Department of Horticulture and Postharvest Technology, Institute of Agriculture, Visva-Bharati, Sriniketan, West Bengal during 2017-18. Pineapple cv. Kew cut into 0.5 mm slices and were subjected to osmotic dehydration with different sugar concentration (35°B, 40°B, 45°B, 50°B, 55°B, 60°B) during the experiment. Various chemical qualities of the osmotic dehydrated fruit products were analyzed at Initial, 2, 4, 6 and 8 months during the cold storage. The results revealed that highest TSS at Initial (22.48 o B), 2 (21.74 o B), 4 (16.81 o B), 6 (17.76 o B) and 8 (19.84 o B) months were observed in 60 o B, 60 o B, 50 o B, 60 o B and 40 o B sugar syrup respectively. Highest Titratable acidity at Initial (2.3%), 2 (2.33%), 4 (2.31%), and 6 (1.91%) months was observed in T4 (40°B) sugar solution, whereas highest acidity at 8 (1.83) month was observed in T5 (55°B) sugar solution. Whereas highest reducing sugar found at initial (18.48), 2 (18.90), 4 (17.22), 6 (17.94) and 8 (18.27) months were observed at T4 (50°B). Total sugars at Initial (27.29), 2 (27.57) months were found highest at T3 (45°B) and in 4 (23.49), 6 (21.42), 8 (19.65) months were maximum at T4 (50°B). Thus it can be concluded that treating the pineapple slices with sugar syrup having concentration at (50⁰B) T4 is ideal for osmotic dehydration of pineapple. Keywords: sugar concentrations, osmotic dehydration, storage, chemical properties Introduction Pineapple (Ananas comosus L. Merr.) is one of the commercial fruit crops of tropical world belonging to the family Bromeliaceae, comprising chromosome number (2n=50). It has about 50 genera and 2000 species mostly epiphytic (Bartholomew and Maleieux, 1994) [3] . It has originated from American continent, Brazil and Paraguay (NHB, 2014). It is introduced to India in 1548. It is an important economic fruit of tropical areas with the top world producers being Costa Rica, Brazil, Philippines, Thailand, Indonesia, India, Nigeria, China, Mexico, and Colombia. In India pineapple is commercially grown in the states of Assam, Meghalaya, Tripura, Manipur, West Bengal, Kerala, Karnataka, Goa, Gujarat, and Maharashtra. In year 2014-2015 the total area of pineapple under cultivation in India was about 116.0 thousand ha with a production of 1984.0 thousand MT. Area and production in West Bengal (2016-2017) is 11.20 thousand ha and 336.11 thousand MT (Anonymous. 2017). Pineapple is a good source of beneficial nutrients as 100 gram of fresh edible pineapple contains 81-91g of moisture, 0.3-0.6 g of crude fibre, 37 mg calcium, 11.9 mg phosphorus, Iron 1.05 mg, carotene 0.003-0.055 mg and finally ascorbic acid of 27-162 mg. Pineapple fruits are characteristics of pleasant flavour, distinct aroma, exquisite taste and absence of seeds and it contains water, carbohydrates, sugar, vitamin A and β-carotene. It contains low amount of protein, fat, ash, fiber and anti-oxidants namely flavonoids in addition to citric acid and malic acid and moderate amount of ascorbic acid (Hebbar et al., 2008) [8] . Pineapple helps several enzymes present in the body to produce energy as it contains magnesium and vitamin B, which are essential for the normal functioning of some enzymes (Samson, 1986). Over 70% of the annual production is consumed in the fresh form. Pineapple fruits are an excellent source of bromelein, an enzyme used as meat tenderizing agent and as a neutraceutical (Lotz- Winter, 1990). Pineapple plant grows within tropical and sub-tropical climate. The optimal climatic conditions for growing pineapple are an average temperature of between 21 – 27°C and relative humidity of 70-80%. Injury occurs from transpiration and respiration at temperatures above 27°C. The crop is grown with annual rainfall of 1200-1500 mm. The soil pH is 5-6.5.