雪菜中芥子苷酶解特性的研究

Study on the Properties of Enzymatic Hydrolysis of Potassium Myrosinate in Brassica juncea Coss

借助于硫脲紫外分光光度法，对雪菜中的芥子苷的酶解性质进行了研究。经检测，实验用雪菜中芥子苷含量为０．０７％。单因素实验显示，芥子酶的最适ｐＨ６．０～７．０，最适温度７０℃，Ｖｃ对芥子酶有明显的激活作用，而０．５％ＮａＣｌ对芥子酶有显著的抑制作用。正交试验表明，ｐＨ是影响芥子酶活的高度显著性因素，ＮａＣｌ浓度为显著性因素。ＲＳＡ优化试验得出，在室温２０℃下２０％雪菜汁中芥子苷酶解的最佳条件为：ｐＨ６．５６，ＮａＣｌ浓度３．４７％，冷冻干燥芥子酶粗酶粉添加量５．３７ｍｇ（５ｍｌ２０％雪菜汁中），反应１ｈ，最大酶活可达７．６７ｕ。研究结果可供腌制雪菜加工参考使用。

Based on the specific UV absorbance of thioureas , the properties of enzymatic hydrolysis of potassium myronate in Brassica juncea Coss were studied. The determined result of potassium myronate content was 0.07%. It showed that the optimal pH of tested myrosinase was 6.0～7.0, the optimal temperature was 70℃. The hydrolytic ability of the myrosinase was strongly stimulated by ascorbic acid. The enzyme could be easily inhibited by NaCl from the content of 0.5%. The results of orthogonal-regression experiment indicated that pH played the most important role in enzymatic hydrolysis, the content of NaCl was important factor. The optimum enzymatic hydrolysis conditions were optimized by RSA at room temperature(20℃), which were:pH 6.56, NaCl% 3.47, using quantity of crude enzyme powder was 5.37mg(5ml , 20%Brassica juncea Coss juice).