萌发苦荞淀粉的理化特性及消化性研究

摘要

Using the germination of buckwheat as the research object,Buckwheat starch composition Was investigated during the germination,especially the changes of starch granule morphology and digestive characteristics.The experimental results showed that:buckwheat starch components after the germination change,of which the total starch content was decreased by 28.35％.With the increase of amylose,the proportion of amylose and amylopectin was also increased,on the third day reached 0.63;the composition of germinated buckwheat starch was also changed,of which the content of slowly digestion starch was significantly increased(P ＜0.05);Meanwhile,moderate germination only affects the crystal structure of amorphous regions of starch granules,crystallinity was increased gradually as germination days increases to form part of the small molecular aggregates.Digestive experiment in vitro indicates compared with the situation before germination,buckwheat starch digestion performance was improved significantly.From correlation analysis results of the germination of buckwheat starch granule structure and digestibility in vitro,in vitro digestibility of the glycemic index,i.e.glycemic index was positively related with the average particle size of germinated buckwheat starch,while negatively correlated with the degree of crystallinity.Therefore,it was showed smaller partical size of germinated buckwheat starch size and increased crystallinity can reduce the blood sugar index.The glycemic index (GI) of germinated buckwheat starch was less than 55,belonging to low GI food,and was currently the ideal food nutrition and food field at home and abroad.%本试验以萌发苦荞为研究对象,对苦荞萌发过程中淀粉的组成,尤其是淀粉颗粒形态的变化规律以及消化特性进行了研究.试验结果表明:经萌发处理后苦荞淀粉组成发生了变化,其中总淀粉质量分数下降了28.35％,随着直链淀粉的增加,直链淀粉与支链淀粉的比例也随之增大,在第3d时达到0.63;萌发苦荞淀粉的组成也发生变化,其中慢消化淀粉含量明显提高(P＜0.05);同时,适度萌发仅对淀粉颗粒的无定形区晶体结构产生影响,结晶度随着萌发时间增加逐渐增大,形成部分小分子聚合体.体外消化试验表明:较萌发前,苦荞淀粉消化性能明显改善.从萌发苦荞淀粉颗粒结构与体外消化性相关性分析结果可以看出体外消化率即血糖指数与萌发苦荞淀粉平均粒径呈显著正相关,与其结晶度呈显著负相关.从而揭示了萌发后苦荞淀粉粒径变小,结晶度变大,有利于血糖指数的降低.萌发苦荞淀粉血糖指数(GI)均小于55,属于低GI食品,是目前国内外营养与食品界推荐糖尿病人群理想食物.