基于响应面法优化鲜切莴笋复合涂膜保鲜剂

以鲜切莴笋为研究对象,根据12种化学物质对多酚氧化酶(PPO)和过氧化物酶(POD)活性的抑制作用,选择3种酶活抑制效果显著的化学物质(茶多酚、抗坏血酸和L-半胱氨酸)和4种涂膜剂(羧甲基纤维素钠、黄原胶、海藻酸钠和葡甘露聚糖),考察不同保鲜剂浓度对鲜切莴笋4 ℃贮藏4 d后外观和色泽的影响. 以此单因素实验为基础,进行响应面分析,结果显示复合涂膜最佳组合为0.38%抗坏血酸+0.85%L-半胱氨酸+0.67%羧甲基纤维素钠,在此条件下,鲜切莴笋在4 ℃贮藏6 d后红绿色差Δa^*值为0.170,与回归方程预测值0.166相近,且货架寿命可延长至12 d以上,表明优化后的复合涂膜保鲜剂具有良好的实际保鲜效果.

Optimization of Composite Coating Preservative for Fresh-cut Asparagus Lettuce Based on Response Surface Methodology

Fresh-cut asparagus lettuce is taken as the research object. According to the inhibitory effects of 12 kinds of chemical substances on PPO and POD activities,3 kinds of chemical substances(tea polyphenols,ascorbic acid and L-cysteine)with significant inhibitory effects on PPO and POD activities and 4 kinds of coating agents(carboxymethylcellulose sodium,xanthan gum,sodium alginate and glucomannan)are selected. Meanwhile,the effects of different concentrations on the appearance and chromatic aberration of fresh-cut asparagus lettuce are investigated after 4 days of storage at 4 ℃. The results of response surface analysis show that the optimal condition is 0.38% ascorbic acid+0.85% L-cysteine+0.67% carboxymethylcellulose sodium. Under this condition,the red-green chromatic aberration after storage for 6 days is 0.170,which is close to 0.166 predicted by regression equation. Moreover,the shelf life can be extended to more than 12 days at 4 ℃,indicating that the optimized composite coating preservative has great practical fresh-keeping effect.