不同热处理方式对玉米醇溶蛋白特性的影响

Effect of Different Heat Treatments on the Properties of Zein

研究了不同热处理方式(水浴、微波、射频)和处理终点温度(70、80、90℃)对玉米醇溶蛋白功能性质与结构的影响。结果表明:多种热处理均会提高玉米醇溶蛋白溶解度、乳化能力和巯基含量,且这3项指标随着处理终点温度的升高而升高,射频处理至90℃使玉米醇溶蛋白溶解度、乳化能力和巯基含量分别提高了74.65%、171.7%和53.94%。应用差示扫描量热法测定玉米醇溶蛋白变性温度,发现微波处理后蛋白质变性温度略有升高。此外,紫外光谱分析提示,玉米醇溶蛋白经微波和射频加热处理后,蛋白质分子结构舒展、基团暴露,这使得蛋白质的溶解性和乳化能力有所改善。傅里叶变换红外光谱分析发现热处理改变了玉米醇溶蛋白的二级结构,其中微波和射频处理效果更明显。

The effects of different heat treatments（hot water bath, microwave heating and radio frequency heating） and final temperatures（70, 80 and 90 ℃） on physicochemical properties and structure of zein were investigated. The results showed that three heat treatments could enhance the water solubility, emulsifying capacity and free thiol content of zein, and the effect increased with the increase in final temperature. The solubility, emulsifying capacity and of free sulfhydryl content of radio frequency treated samples at final temperature of 90 ℃ were increased by 74.65%, 171.7% and 53.94%, respectively. By differential scanning calorimetry, it was found that protein denaturation temperature increased slightly after microwave treatment. Furthermore, ultraviolet spectroscopy showed that the unfolding of the protein molecule associated with group exposure was induced by microwave and radio frequency, which improved the solubility and emulsifying ability of the protein. Meanwhile, Fourier transform infrared spectroscopy showed that heat treatment altered the secondary structure of zein, and the effects of microwave and radio frequency treatment were more pronounced.