淮山中多酚氧化酶特性及无硫护色脱水工艺

酶促褐变是导致淮山脱水加工过程中色泽变化的主要原因。通过研究淮山中多酚氧化酶的最适pH 值、最适温度等主要特性，设计选取适当的非硫成分NaC1、VC、柠檬酸进行护色，通过正交实验得到一种安全有效的无硫复合护色液，即含质量分数0.7%NaC1、0.3%Vc、0.6%柠檬酸的水溶液。在脱水加工过程中，用该护色液对淮山片浸泡护色4h后，在65℃下干燥4.5h，得到与传统硫熏漂白同样好色泽的终产品。

Characteristics of Polyphenol Oxidase in Chinese Yam and Non-sulfur Prevention of Discoloration in Chinese Yam Processing

Enzymes browning is the key reason of color variation in Chinese yam processing. Some main characteristics of polyphenol oxidase in Chinese yam such as the optimum pH value and temperature were sudied, and some appropriate non-sulfur agents such as NaCl,Ve and citric acid were selected to prevent the discoloration of the Chinese yam.By an orthogonal experiment of L9(3),a kind of mixed saking solution,i.e.NaCI0.7%,Ve 0.3% and citric acid 0.6%, which was safe and effective for color protection, was obtained.After the fresh Chinese yam was soaked in the designed mixed solution for 4 hours, then dried at 65℃ for 4.5 hours, the color of the dried Chinese yam was same as that of the dried Chinese yam by sulfur dioxide.