Deacidification, Clarification and Antimicrobial growth of Grapefruit Juice by Chitosan

• Main Authors: Jen-I Wu, 吳貞誼
• Other Authors: Jin-Hwei Rwan, Ph.D
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/10338630477000018947

碩士 === 東海大學 === 食品科學系 === 83 === The study was focused on investigating optimum conditions for utilizing chitosan in deacidification, clarification and antisepsis of grapefruit juice, also discussing effects of these treatments on the change in components and the sensory evaluation of the treated products. As a result, chitosan that had 90% deacylation showed a superior deacidified degree. A batch-type deacidification carried out by adding the chitosan into grapefruit juice at a concentration of 0.015 g/mL and stirring under room temperature for 30~60 min, gave the deacidified process was removed about titratable acidity 52.6%. On the other hand, a continuos-type deacidification operated by pumping the original grapefruit juice with a flow rate of 5 mL/min through a glass-column reactor(2×18 cm) containing 5 g(dw) chitosan gave the total effluent having the ratio of Brix/acid about 13.5 after operation of 80 min. The chitosan had excellent properties of regeneration and reuse. As the clarification was carried out at a concentration about 90 ppm under stirring at room temperature, the urbidity of the clarified juice was 0.49 NTU. About the microbial growth in juice, the clarification treated with a chitosan solution largely decreased the growth of total aerobic counts from 1720 to 390 CFU/mL. The antimicrobial effect was good in the case of adding chitosan solution into the clarified juice at a concentration of 100 ppm, the total aerobic acid count decreased to about 100 CFU/mL. In comparation to the original juice, the chitosan treated juice decrease 94% of total aerobic counts. It also showed inhibition of yeast and mold growth during 30 day''s storage at 6℃.