Studies On Browning Control Technologies Of ZhaoZhou Snow Pear Juice

Browning is one of the major technical problems in the pear juice processing. Zhaozhou snow pear as the main raw material, study the factors and control technologies of the zhaozhou snow pear browning during processing. The followings are the results.Let the Two adjacent benzene polyphenol be the the object, study the Enzymatic Properties of zhaozhou snow pear’s Polyphenol oxidase, the results show that the most appropriate ph of zhaozhou snow pear’s ppo is 6.8, the Optimum temperature is 30℃, the activity of ppo can be deactivated effectivly in 4 min at 90℃. To control the ph and temperature can prevent browning effectivly at the process. Enzymes in response to the dynamics, Let the Two adjacent benzene polyphenol be the the object,The maximum PPO activity Vmax=437 U/min,Km=0.0156 mM。In the research of the change of various index at the process of zhaozhou snow pear’s storage, it is showed that the Concentration of sugar is increased at the process of zhaozhou snow pear’s storage,at the highest piont at the tenth week; the Concentration of sour is not changed greatly:the most Optimum temperature and ph are not changed greatly; the activity of ppo is inceased by the atorage time. So it should be processed as soon as possible in ten weeks of the snow pear’s picking, try our best to reduce the browing in the process and the Economic losses in the storage which is caused by decay disease.At the research of the traditional chemical inhibitor recipe, it is showed that ascorbic acid, isoascorbic acid, L-cysteine’s effects are the best, they can apporach 100 %. The high iont of oxalate is good too, but at the low piont is not very good; the restrain effect of citric acid is pianissimo. In the Experimental of use Response surface analysis to Optimization the formula, the most importan factors to restrain effect by pb are ascorbic acid, L-cysteine,then the result of software’s good accordance: The concentration of L-cysteine,ascorbic acid and isoascorbic acid is 0.001 %,0.003 %�'�0.0021 %, the restrain rate is 100 % at this time.At the research of retrain of natural inhibition, it is showed that Duzhong leaf、Ginkgo leaf、grape leaf ’s natural inhibition can restrain the ppo of vegetable and fruit, the restrain rate is increased as the concentration’s increase. These three natural inhibitionto can increase the restrain of vc to brown, the Ginkgo leaf is the greatest. The result of Response surface analysis is:Vc:0.006, Ginkgo leaf extraction: 1.5 mL Duzhong leaf extraction:0.5 mL,Ginkgo leaf extraction:1.5 mL,inhibit rate is 95 %.