The Complexion Of Tea-polyphenol With Papain And Its Application In Meatpacking

Papain has become more and more popular in the food field because of its hydrolytic characteristics. Tea-polyphenol was used to complex papain in order to improve poor thermal stability which limited its application.Taking tea-polyphenol as material, the best condition for the complexion of tea-polyphenol and papain was optimized in the way of Box-Behnken for this study. Based on quadratic model(Y=2.939608-0.614889x₁─1.901077x₂─0.760597x₂²+ 0.671426x₄²), the analysis of variance and the test for the significance of coefficient in the model were conducted. The results showed that temperature and pH value were significant, but reaction time was not significant to the evaluation index. This model could explain 81.58% response value. The best conditions for complexion of tea-polyphenol and papain were: temperature was 4℃, pH was 6.0 and quality ratio of tea-polyphenol and papain was 2:1.On the basis of the above-mentioned research, the properties of papain before and after complexion were investigated, including thermal stability,anti-oxidation,appetency of enzyme to substrate. The active center of enzyme was investigated and the Tea-polyphenol monomers were analysed through HPLC. The results indicated that the thermal stability of papain was advanced after complexion, and the rate of heat loss failed from 0.7288/min to 0.2893/min. The inhibitive ratio of the compound to pyrogallol increased from 10.1% to 16.4%, and anti-oxidation was strengthened obviously. Appetency of enzyme to substrate was not changed greatly and Km value increased from 12.38mg/ml to 16.76mg/ml. Mercapto group content of papain was measured and found the decreaseing tendency of mercapto group content and enzyme activity were consistent, which shows the active center was mercapto. There were two kinds of monomers in the tea-polyphenol which could complex papain through HPLC analysis and the EGCG content was the highest.Due to the perspective of applications of complex of tea-polyphenol and papain, the influence of complexion of them on pork quality was investigated. The sensitive idex, POV value, sum of bacteria and tenderness of pork product were investigated. The results were the compound added to the pork product could increase the shelf life from 3days to 5days and restrained the acid value and POV value, which decreased from 15.787mg/g to 14.525mg/g and from0.105mg/g to 0.0906mg/g respectively after 7 days'storage. The sum of bacteria decreased from 8.903 to 8.602 after 7days'storage,which was also fewer than the comparative one; The tenderness of pork product was improved to a certain extent and the cut force decreased from 0.43N to 0.228N.