红阳猕猴桃酵素发酵工艺优化及其体外抗氧化活性

本实验以红阳猕猴桃为原料,羟基自由基清除率(50%)和感官评价(50%)为综合指标,采用双正交试验优化红阳猕猴桃酵素发酵工艺。首先在酵母(Saccharomyces cerevisiae)、乳酸菌(Lactobacillus bulgaricus和Streptococcus thermophilus)、果胶酶和纤维素酶单因素实验基础上通过正交试验优化添加量,并确定酵母、乳酸菌、果胶酶和纤维素酶添加量分别为2.0%、2.0%、0.5%和2.0%。然后在此基础上进行初始糖添加量、料液比、发酵温度、发酵时间单因素实验并通过正交试验确定红阳猕猴桃酵素最优发酵工艺条件分别为:初始糖添加量20%,料液比1:1.3,36℃持续发酵35 d。最后,在最优发酵条件下制备红阳猕猴桃发酵产品并测定羟基自由基清除率、感官最佳和综合指标分别为94.33%,76.33和85.33。试验表明通过正交试验可以优化红阳猕猴桃酵素发酵工艺以及提高产品品质。抗氧化测定发现优化的红阳猕猴桃发酵产品抗氧化活性明显高于自然发酵(p<0.05),其羟基自由基清除率、DPPH·和ABTS·+自由基清除率分别增加了8.69%、11.89%和36.57%。本研究为推动本地特色红阳猕猴桃深加工产品提供新方法。

Optimization of Fermentation Process for Hongyang Kiwifruit Jiaosu and Antioxidant Activity in Vitro

The fermentation process of Hongyang kiwi jiaosu produced in Chongqing was optimized by biorthogonal experiment with hydroxyl radical scavenging rate(50%)and sensory evaluation(50%)as comprehensive indexes.Firstly,the addition of yeast(Saccharomyces cerevisiae),lactobacillus(Lactobacillus bulgaricus&Streptococcus thermophilus),pectinase and cellulase were chosen as the independent variables and optimized through the first orthogonal experiments on the basis of single-factor experiments.The addition amounts of yeast,Lactobacillus,pectinase and cellulase were determined to be 2.0%,2.0%,0.5%and 2.0%,respectively.Then on this basis,the initial amount of sugar,fermentation temperature,fermentation time and solid-liquid ratio were investigated through the second orthogonal test as another part of the independent variables.The optimal technological parameters were as follows:20%of initial amount of sugar,1:1.3 of solid-liquid ratio,and fermentation at 36℃for 35 d,under these conditions the hydroxyl free radical clearance rate,sensory evaluation and comprehensive indexes were 94.33%,76.33 and 85.33,separately.The results showed that the fermentation process of Hongyang kiwifruit jiaosu could be optimized by the orthogonal experiment.In addition,it was found that the antioxidant activity of the fermentation product was significantly higher than that of the natural fermentation group(p<0.05),and the hydroxyl free radical clearance rate,DPPH·,ABTS·+were increased by 8.69%,11.89%and 36.57%,separately.This study provides a new way to promote the deep processing of Hongyang kiwifruit with local characteristics.