Research On Optimization Of Processing Conditions And Control Of Browning And Sterilization Of Celery Juice

Celery is a nutritional and healthy vegetable and has the function of reducing blood lipids, reducing blood pressure, celery juice thus becomes a new favorites of health drinks. The experiment with parsley as experimental materials, to study how to improve the juice yield of celery, enzymatic characteristics of polyphenol oxidase from celery and effects of inhibitors on enzyme, effect of sterilization technology on the quality of celery juice and the total number of colonies of celery juice. At last, carry out the experiment of celery juice blending.But the high cellulose content in celery affected the juice yield. In order to improve celery juice yield, this experiment study A cellulase adding quantity 、 B enzyme hydrolysis time、C enzyme solution temperature on celery juice yield separately and response surface analysis were optimized by Box-Behnken design, analyzing the interaction of single factor on celery the juice yield, establish the regression equation prediction model. The results showed that the optimum conditions for the application of cellulase in celery juice were as follows: cellulase addition quantity 0.06%, enzymatic hydrolysis time 1.56 h, enzymatic hydrolysis temperature 40.14℃, the yield of celery juice was 78.38%. The proving experiment showed that the yield of celery juice was(78.72±0.25)%, and the fitting of the predictive value was better, which could provide technical basis for the production of celery juice.By heating inactivation treatment and test of adding enzyme inhibitor, found thatcelery juice could lead to enzymatic browning. Polyphenol oxidase(PPO) is the key enzyme of enzymatic browning. The aim of this experiment was to research the effect of the enzyme characteristics and inhibitors on the activity of polyphenol oxidase in celery. The results showed that, the most suitable temperature was 36 ℃,and the optimum pH for celery PPO activity was 5.0,the high temperature treatment could effectively inhibit PPO activity. The kinetics of the enzyme-catalyzed reaction of PPO was conform to Michaelis-Menten equation, whereas Km and Vmax values were respectively 0.11 mol/L and 97.09U/g. Inhibitors tests found that, ascorbic acid、Lcysteine 、 citric acid and calcium chloride could inhibit PPO. The most effective inhibitor was L-cysteine, 10mmol/L completely inhibited the activity of PPO in celery.Through the heat treatment and ozone treatment, the test of the celery juice was carried out, and the change of the quality index and the total number of colonies were evaluated. The results showed that heat treatment could increase the content of soluble solid content of celery juice, inhibit browning significantly, made the color of celery juice green, and increase the suspension stability of celery juice. The effect of celery juice on the inhibition of browning and the suspension stability of celery juice was increased. 80℃processing 20 min and ozone at 60 s can make celery juice to meet the requirements of commercial sterilization.Test by adding food additive white granulated sugar, ascorbic acid and citric acid of celery juice, found that: add 4% white granulated sugar, 1%citric acid, 0.2% ascorbic acid, celery juice of the overall score was the highest.