36E-77 |
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Z. WANG1, S. Xu, and S. Wang. (1) School of Food Science and Technology, Southern Yangtze Univ., 170 Huihe Road,P.B 98, Wuxi, Jiangsu, China, Wuxi, 214036, China Banana is a famous tropical fruit, which is widely favored for its abundant nutrition, cheerful flavour and aroma. Therefore, developing processed banana products would be a method for reducing the loss of fresh fruit during storage and distribution. Clear banana juice, with highly acceptable aroma, can be used in various foods and drinks. Our objective was to develop an enzymatic technology for processing clear banana juice and to investigate its stability. A combination of 0.08% pectinex SMASH (v/w), 0.02% acidic ¦Á-amylase (w/w) and 0.1% cellulase (w/w) was added into banana puree to liquefy the cell tissue at 45oC for 2 hours to obtain a high yield of banana juice. Enzymatic and non-enzymatic browning of banana juice was investigated by determining the residual activity of polyphynol oxidase, the change in free amino acid amount and reducing sugar and the increase in the content of 5-hydroxymethyl furfural. The causes of the second sedimentation during juice storage were explored by measuring the zeta-potentical and particle size of the suspended particles, and the composition of the sediment in the banana juice. The yield of juice can be produced to 76.43% and the juice was highly clarified (T670>95%). Component analysis indicated that clear banana juice retained most of the nutritional components in fresh banana. Oxidation of polyphenols induced browning of banana juice during enzymatic liquefaction, while caramelization and Maillard reaction induced browning during sterilization and following storage. The second sediments were mainly composed of dextrins. There were small amounts of haze-active phenols and proteins in banana juice, however, dextrin retrogradation was the most important factor for the sedimentation of banana juice. The results demonstrate that the enzymatic liquefaction is a suitable technology to prepare a clear juice from fresh banana. The mechanism of browning and second sedimentation of the juice indicates the direction of further work.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |