摘要：

为探究不同水稻品系稻米淀粉组成成分含量差异及其米饭消化速率的变化。采用体外酶消化法分析了126个籼稻品系稻米直链淀粉(AC)、总淀粉(TS)、快消化淀粉(RDS)、慢消化淀粉(SDS)和抗性淀粉(RS)含量,并从中选取AC、SDS和RS含量明显差异的18个品系,分析了米饭消化速率与预测血糖生成指数(eGI)。结果表明:不同品系稻米淀粉含量差异很大,AC为4.29%~25.58%,平均为10.43%,TS含量为71.69%~82.45%,平均为77.73%,RDS含量为43.31%~57.47%,平均为50.07%,SDS含量为18.96%~32.56%,平均为25.26%,RS含量为0.59%~4.87%,平均为2.39%。不同水稻品系eGI值与淀粉组分含量存在一定相关性,高AC品系的eGI值明显低于低AC的品系,但发现低AC品系滇谷2030和低SDS含量品系滇盘3429的eGI值也低。SDS含量高品系的eGI值低于SDS含量低品系,但也存在SDS含量低品系的eGI值也低的情况。高含量RS品系的eGI值显著低于低RS含量品系。所有品系米饭在餐后30 min内消化速率快,糖释放量最多,到60 min后持续下降,AC、SDS和RS含量高品系稻米的eGI值普遍低于相应淀粉含量低的品系。不同水稻品系米饭消化速率差异很大,除了受到其AC、SDS、RS含量因素影响外,还可能受到其他因素影响。研究结果可为培育低GI品种提供数据参考。

关键词: 水稻, 淀粉组分, 体外酶消化, 预测血糖生成指数, 消化糖释放量

Abstract:

In order to explore the difference in starch composition content and the change of rice digestion rate in rice lines. In this study, the contents of amylose (AC), total starch (TS), rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS)in 126 indica rice strains were analyzed by enzyme digestion method in vitro. And then detected the digestion rate of the cooked rice and estimated the glycemic index (eGI) of 18 rice lines with significant differences in AC,SDS and RS. The results indicated that the starch contents of these lines differ greatly, AC was 4.29%—25.58% with an average of 10.43%, TS was 71.69%—82.45% with an average of 77.73%, RDS was 43.31%—57.47% with an average of 50.07%, SDS was 18.96%—32.56% with an average of 25.26%, and RS was 0.59%—4.87%with an average of 2.39%. There was a certain correlation between eGI values and starch content in different rice lines. The eGI values of high AC were significantly lower than low AC, but it was also found that the eGI values of Diangu 2030 with low AC and Dianpan 3429 with low SDS were also low. The eGI values of high SDS were lower than low SDS, but there were also cases where the eGI values of low SDS were also low. The eGI value of high RS was significantly lower than low RS. The rice digestion rate was fast and the sugar release was the highest of all the rice stains within 30 min after the meal, which continued to decrease after 60 min. The eGI values of the lines with high AC, SDS or RS content were generally lower than those with low starch content. The grain digestion rates were different among the tested rice lines, and it suggested that the digestion rates of rice grain could be affected by other factors except the AC, SDS and RS. These results can offer valuable references for the development of low-GI rice varieties.

Key words: Rice, Starch component, Enzyme digestion in vitro, Estimated glycemic index, Digestible sugar content