Studies On Effects Of Different Antiseptics On Storing Characteristics Of Bag-packed Liquid Diet

There are two parts in this study:1. Effects of different initial pH on storing characteristics of bag-packed liquid diet;2. Effects of combination and dose of different antiseptics on storing characteristics of bag-packed liquid diet during different storage period.The first part, graded levels of initial pH value (4,5,6) were adjusted with lactic acid in order to study the effects of different initial pH on storing characteristics were assessed using the sensory indexes, pH value change, microorganism quantity, mycotoxin content and starch gelatinization degree. Results showed that reducing pH of bag-packed liquid diet to4was conducive to improve its stability, restrain bacteria growth in30d, reduce mycotoxin content, reduce the ageing of the starch.The second part, set the initial pH of bag-packed liquid diet at the level of4with lactic acid based on the result that derived from the first experiment for the purpose of studying the effects of nisin, potassium sorbet and tea polyphenols on storing characteristics of bag-packed liquid diet. Nine treatments were designed according to orthogonal design of three factors and three levels, each treatment has three replications and was assessed with sensory indexes, pH value change, microorganism quantity, mycotoxin content and starch gelatinization degree at0d,15d,30d,45d and60d, respectively. Results showed that the addition of nisin, potassium sorbet and tea polyphenols to the bag-packed liquid diet at different levels extended its storage time, inhibited microbial growth, and had no significant influence on mycotoxin content and starch gelatinization degrees; the results of synthesis balance method and variance analysis showed that the effect of this three antiseptics on the storing characteristic ranks as follow: nisin> potassium sorbate> tea polyphenols, the optimal combination and level of these antiseptics is nisin200mg/kg+potassium sorbet200mg/kg+tea polyphenols100mg/kg, in this condition, bag-packed liquid diet’s storage period can be prolonged to about45days.