该研究探讨了微波处理小麦粉对鲜湿面片褐变及其特性的影响。利用微波技术处理小麦粉，测定鲜湿面片的色泽、小麦粉多酚氧化酶（Polyphenol Oxidase，PPO）活性，并通过分析面片水分分布、游离多酚含量、流变学特性以及小麦粉中蛋白质二级结构、巯基和二硫键变化，从而研究微波处理对鲜湿面片褐变及其特性的影响。研究结果表明：随着微波时间和功率的增加，鲜湿面片的白度呈现上升的趋势，在低微波功率下色泽无显著性差异，在较高功率700 W，处理时间为100 s时白度会因糊化现象而下降；PPO活性下降了42.78%，游离多酚24 h内变化量与未处理组比较下降了54.78%；面片弛豫时间T22和T23呈现先上升后降低的趋势，在中等强度处理时达到最大值；游离巯基整体呈现下降趋势，二硫键含量增加，在700 W处理100 s时分别为1.29、4.38 μmol/g；蛋白质二级结构中α-螺旋含量显著性下降，无规则卷曲含量显著性增加；在鲜湿面片的流变学特性中，G′和G″均呈现先增大后减小的趋势，tanδ呈现先减小后增大的趋势。综上所述，在微波功率为700 W，处理时间为80 s效果最佳，该研究可为面制品行业提供一定理论基础。

The effects of microwave treatment of wheat flour on the browning and properties of fresh wet noodle were investigated in the present study. Wheat flour was microwaved, before the color of fresh wet dough sheet and polyphenol oxidase (PPO) activity were determined. Also, the effects of microwave treatment on the browning and its characteristics of fresh-wet noodle were studied through analyzing the changes in moisture distribution, free polyphenol content and rheological characteristics of dough sheet, as well as changes in the secondary structure of protein, sulfhydryl group and disulfide bond of wheat flour. The results showed that the whiteness of the fresh wet dough sheet increased with the increasea of microwaving time and microwave power. There was no significant difference in color at a low microwave power, but the whiteness of dough sheet decreased due to gelatinization of wheat flour at a high power of 700 W for 100 s. The PPO activity decreased by 42.78%, and the content of free phenolics decreased by 54.78% within 24 hours compared with the untreated group. The relaxation times T22 and T23 of the dough sheet increased first then decreased, and reached the maximum when a medium-intensity treatment was applied. The free thiol group showed a downward trend, whilst the content of disulfide bond increased, which were 1.29 and 4.38 μmol/g, respectively, for a 100-s treatment at 700 W. As for protein’s secondary structure, the content of α-helices decreased significantly, whilst the content of random coils increased significantly. In terms of the rheological properties of fresh wet dough sheet, both the G' and G" increased first then decreased, and Tanδ also decreased first then increased. In summary, the treatment with a microwave power of 700 W and treatment time of 80 s leads to the best outcome. This study provides a theoretical basis for the noodle industry.

河南省科技厅重大专项（141100110900）；国家自然科学基金-青年基金项目（32101985）