新收获稻谷储藏期间蛋白含量及PPO活性的变化

分析了40℃、RH80%条件处理4d后置于15℃和23℃的籼稻和糯稻发芽率、多酚氧合酶(PPO)活性及蛋白质含量的变化。结果表明,40℃、85%RH温湿处理4d,显著提高2个稻谷品种发芽率,降低稻谷PPO活性。PPO活性在60～90d期间出现高峰,籼稻PPO活性对高温高湿敏感度高于糯稻。水溶性、盐溶性、醇溶性蛋白在30d出现一峰值,60d之后还有积累高峰;谷蛋白60d前急剧积累,之后积累缓慢。储藏期间稻谷巯基含量呈现下降趋势。短时间老化处理降低籼稻谷蛋白/醇蛋白比率峰值和巯基含量,却提高糯稻谷蛋白/醇蛋白比率峰值和巯基含量,即籼稻和糯稻陈化过程存在差别。

Change in contents of proteins and activity of polyphenol oxidase in newly-harvested rough rice during storage

The effects of a four-day treatment of two rough rice varieties with 40 ℃ and 85% RH on the germination rate,polyphenol oxidase(PPO) activity,and contents of protein and sulfhydryl group were determined during 180 days storage under 15 ℃ and 23 ℃.The high temperature and humidity treatment significantly increased germination rate of two rice varieties,but induced the peak of PPO activity in indica rice at 60 d,and delayed the peak of PPO activity in glutinous rice at 90 d.The contents of water-soluble,salt-soluble and alcohol-soluble proteins peaked at 30 d,and then had accumulation peaks during 90 d to 180 d.The glutenin content in rice increased drastically before 60 d,but accumulated continueously from 90 d to 180 d.The content of sulfhydryl(SH) group in rice tended to decrease during storage.The high temperature and humidity treatment reduced the content of SH and the peak value of glutenin/gliadin ratio in indica rice,but increased the content of SH group and the peak value of glutenin/gliadin ratio in glutinous rice.It is concluded that the aging process was different between indica rice and glutinous rice.