湿热处理对糯米粉血糖生成指数值及相关指标的影响

利用湿热处理工艺降低糯米粉血糖生成指数（glycemic index，GI）值，并对相关指标进行比较研究。通过水分含量、温度、处理时间对糯米粉直链淀粉含量和消化特性的影响，确定单因素范围，然后采用Box-Behnken设计，以直链淀粉含量（和GI值显著负相关）为指标，优化了糯米粉湿热处理工艺。最后将最优工艺所得的糯米粉（HMT）和普通糯米粉（WR）、仅进行酶解后的糯米粉（ER）进行体外消化特性和GI值的对比研究，以分析湿热处理对糯米粉GI值的影响。研究表明，经优化的最佳湿热处理时间为2.3 h、湿热处理温度为116 ℃、水分含量为20%，在优化条件下糯米粉直链淀粉含量为3.62%±0.01%，实测值均值与理论值（3.62%）一致，表明该模型可用于优化糯米粉湿热处理工艺。最优条件下制备的糯米粉快消化淀粉（rapidly digestible starch, RDS）含量下降，慢消化淀粉（slowly digestible starch, SDS）和抗消化淀粉（resistant starch, RS）含量上升；水解指数（hydrolysis index）明显降低，同时GI值降低30.1%。该法制备的糯米粉具有较低的GI值，可为低GI糯米粉开发的进一步研发提供实验思路。

Effects of Heat-moisture Treatment on Glycemic Index and Relevant Indexes of Glutinous Rice Flour

In this study, the heat-moisture treatment was used to decrease the glycemic index (GI) value of glutinous rice flour, and then relevant indexes were compared with those of other treatments. Based on the influence of moisture content, temperature and treatment time on amylose content and digestion characteristics of glutinous rice flour, the single factor ranges were determined, and then the Box-Behnken design was used to optimize the heat-moisture treatment process with amylose content (which is significantly negative correlation with GI value) as a crucial index. Finally, the in vitro digestion characteristics and GI value of glutinous rice flour obtained by optimal heat-moisture treatment process (HMT), by ordinary process (WR), and only by enzymatic hydrolysis process (ER) respectively were compared to investigate the influence on GI value and other relevant indexes. The optimum heat-moisture conditions were: The treatment time was 2.3 h, the temperature was 116 ℃, and the moisture content was 20%. Under the optimum heat-moisture treatment conditions, the amylose content was 3.62%±0.01%, and it was confirmed that the average measured value was consistent with the theoretical value (3.62%), indicating that the model could be used to optimize the heat-moisture treatment process of glutinous rice flour. Compared with WR, the content of rapidly digestible starch and hydrolysis index were decreased significantly, and the contents of slow digestible starch and resistant starch were increased obviously, and GI value decreased by 30.1% in HMT. Taken altogether, the glutinous rice flour prepared by this heat-moisture treatment method had a relatively low GI value, which could provide experimental reference for the further development of low GI glutinous rice flour.