The Preservation And Sterilization For China Jujube By Chlorine Dioxide Gas

Zizphus Jujube Mill. has high nutrition quality, but one of the most serious problems is that the China Jujube easily to dehydrate, quick red-turning, alcohol-based, mildew and decay in 3-5d during storage. In this study, Chinese jujube surface disease was sterilizaed by chlorine dioxide gas, thereby economic value and fresh-keeping dates were improved, which were of great theoretical and practical significance.In the first place, individual sterilization experiment was carried out. In this process, rot fungi (Alternaria alternata, Penicillium) were inoculated into fresh Jujube, then were sterilizated using Chlorine dioxide gas, and sterilization efficiency was determined by the reducing amount of bacteria. The single factor and quadratic orthogonal rotation design with three factors was used to study the effects of chlorine dioxide gas concentration (X1),bactericidal time (X2) and bactericidal temperature (X3) solutions on bactericidal efficiency, and the function model of sterilizing rate of Chinese jujube versus three factors (the three solutions) was established. The analysis on this model showed that the effect order of the three factors was as follows:chlorine dioxide gas concentration> bactericidal time> bactericidal temperature. The result showed that the optimum parameters of sterilization were 3mg/m3,20min,2℃。Second, fresh-keeping experiment in large scale was conducted to the Zizyphus Mill. The antimicrobial test,before fresh-keeping experiment,showed that the bactericidal effect was optimal through using ClO2 gas for 1h and that sterilized Zizyphus Mill presented well effect for nutrition and appearance. The treatment using ClO2 gas could reduce rotten rate and browning rate, slow the reduction of Vc quantity in the fruit, exhibit slow tendency of total sugar quantity, and inhibit-accumulation of ethanol(decrease the rate of alcoholization) and increase of MDA quantity. Furthermore, combined effect of ClO2 gas and low temperature was effective measurement of keeping the Zizyphus Mill fresh, which could prolong the fresh-keeping period from 3-5d to 60-90d in room temperature.