几种储粮霉菌脱氢酶活性测定方法的建立

Determination of Dehydrogenase Activity in Four Moulds from Stored Cereal Grains

基于氯化三苯基四氮唑(TTC)脱氢酶还原反应原理,建立适用于粮食中几种代表性霉菌如黄曲霉、灰绿曲霉、白曲霉和青霉脱氢酶活性的测定方法。结果表明:霉菌细胞脱氢酶在Tris-HCl缓冲液中反应较稳定,反应体系中TTC最适质量浓度为0.2g/100mL,80%丙酮提取三苯基甲臢(TF)的效果较佳。4种霉菌最适反应温度均为30℃,黄曲霉和白曲霉最适pH值均为11.0,灰绿曲霉和青霉最适pH值分别为10和10.5。黄曲霉和青霉反应1.5h后基本达到反应终点,而灰绿曲霉和白曲霉需2.5h。该方法测定结果显示,小麦霉变过程中霉菌脱氢酶活性升高与霉菌数量增长具有较高的相关性。

Based on the principle of TTC-dehydrogenase reductive reaction, a procedure for the determination of dehydrogenase activity was established in four typical moulds such as Aspergillusflavus sp., A. candidus sp., A. glaucus sp. and Penicillium sp. that are widely distributed in stored cereal grains. The results revealed that the dehydrogenase had stable reaction in Tris-HC1 buffer with optimal TTC concentration of 0.2 g/100 mL and acetone volume of 80%. The optimal determination temperature for four moulds was 30 ℃ and the optimal pH forAspergiUusflavus sp. and A. candidus sp. was 11.0, while the optimal pH for A. glaucus sp. and Penicillium sp. was 10 and 10.5, respectively. The reaction duration for Aspergillusflavus sp. and Penicillium sp. was 1.5 h, whereas the reaction duration forA. candidus sp. andA. glaucus sp. was 2.5 h. A high correlation was observed between dehydrogenase activity and mould number during wheat mildew process.