Study On Processing Cloudy Strawberry Juice By Enzymatic Method

Strawberry is not only delicious but also nutritional. There are the most strawberry yield in China, but the strawberry is not utilized fully. That making the strawberries into natural, healthy cloudy strawberry juice has a huge market-potential, which is also benefit to social economy.This thesis was to develop a novel process with enzymatic liquefaction for cloudy strawberry juice and investigate their color stability and cloud stability. As well, the processing technologies of strawberry juice concentrates and strawberry yoghourt were also studied. The main results were as follows.First, the enzymatic hydrolysis parameters were researched, and the optimal parameters were obtained according to the juice yield, the contents of the anthocyanin and the vitamin C. The results showed that the optimal conditions were 0.005% RAPIDASE C80 MAX at 50℃for 1h.Second, color stability, cloud stability and storage stability were studied. Different anti-browning reagents were added into the strawberry and by comparing the results we could find that adding 0.003% L-cysteine could improve the color stability evidently. By adding 0.05%XG and 0.1% CMC into the strawberry juice, we could improve the cloudy stability of the juice.Third, the strawberry juice concentrates were researched. Both of them behaved as non-Newtonian fluids (shear thinning). The 52oBrix strawberry juice concentrates appeared a pseudoplasticity; the over 60oBrix strawberry juice concentrates exhibited a thixotropic property.Finally, the processing technology of strawberry yoghourt was researched. The results showed that adding 11% strawberry juice and 0.5% HMP into the yoghourt could get the nutritional and sweet production.