微波干燥对高水分稻谷酶活力及稳定性的影响

本文以热风干燥法为对照,研究了微波干燥对高水分稻谷中脂肪酶、脂肪氧化酶和过氧化物酶活性的影响,并选出最佳的加工方式,以起到抑制酶活性、延缓储藏过程中稻谷陈化的作用,达到高水分稻谷快速安全入仓的标准。结果表明:微波处理对稻谷脂肪酶、脂肪氧化酶和过氧化物酶的反应最适温度和热稳定性、最适pH和pH稳定性均有影响。热风和微波处理后三种酶的酶学性质均发生变化,其中采用实际功率为(980.34±16.42)W的微波条件处理2 min将稻谷加热至60℃,经过缓苏处理(70℃于烘箱4 h取出)后,三种酶的性质变化影响最为明显。在此条件下稻谷脂肪酶、脂肪氧化酶、过氧化物酶的灭活率分别为50.33%、63.83%、26.20%,可以在高水分稻谷入仓前快速有效地抑制酶活,起到延缓储藏过程中稻谷陈化的作用,进而为我国安全储粮提供可行方案。

Effect of Microwave Drying on Enzyme Activity and Stability of High Moisture Rice

In this paper,the effects of microwave drying on the activities of lipase,lipoxygenase and peroxidase in high-moisture rice were studied by hot air drying method.The best processing method was selected to inhibit enzyme activity,delay the storage process,and reach the standard of fast and safe warehousing of high moisture rice.The results showed that microwave treatment had a significant effect on the optimal temperature and thermal stability,pH and pH stability of rice lipase,lipoxygenase and peroxidase. Also,the enzymatic properties of the three enzymes changed significantly after hot air and microwave treatment. The microwave was treated with(980.34±16.42) W and the rice was heated to 60℃ for 2 min. After the slow-treatment(70℃ in the oven for 4 h),the properties of the three enzymes were most significantly affected. Under these conditions,the inactivation rates of rice lipase,lipoxygenase and peroxidase were 50.33%,63.83% and 26.20%,respectively,which could inhibit enzyme activity quickly and effectively before storage in high moisture rice,and delay the rice aging in the process,and thus provide a feasible scheme for safe grain storage in China.