直链/支链比对青稞淀粉凝胶与消化性的影响

Effect of Amylose/Amylopectin Ratios on the Gel Properties and Digestibility of Highland Barley Starch

为深入探讨不同直链/支链比例对淀粉凝胶特性和消化行为的影响,本研究选取糯青稞和普通青稞品种,通过提取淀粉并复配制备直链/支链比例8%、14%、20%、25%的青稞淀粉,比较其在结晶结构、糊化特性、凝胶特性以及消化性方面的差异。结果表明,直链/支链比例未改变青稞淀粉的晶型,但直链/支链比例的增加降低了结晶度,使淀粉内部结构更紧密、双螺旋结构更稳定。同时,随着直链/支链比例的增加,淀粉糊化时的峰值黏度(3296~4226 mPa·s)逐渐降低、回生值(481.67~1604.33 mPa·s)逐渐增加。流变学结果表明,淀粉存在弱凝胶行为(G′>G″),淀粉凝胶的弹性行为增强会增加硬度和咀嚼度。消化特性方面,直链/支链比例的增加会增加抗性淀粉含量,降低快速消化淀粉含量、淀粉消化率和预估血糖生成指数。本研究结果对开发具有特定工业用途的功能性“定制”青稞淀粉具有一定的理论价值。

In order to explore the effects of different amylose/amylopectin ratios on starch gel characteristics and digestive behavior,glutinous barley and common barley varieties were selected in the study.Highland barley starches with amylose/amylopectin ratios of 8%,14%,20%,and 25%were prepared by extracting the starch and compounding,and to compare their differences in the crystalline structure,pasting characteristics,gel characteristics and digestibility.The results showed that the amylose/amylopectin ratios did not change the crystalline shape of highland barley starch.However,the increased amylose/amylopectin ratios decreased the crystallinity,which resulted in a tight internal structure of the starch and a more stabilized double-helix structure.Meanwhile,the peak viscosity(3296-4226 mPa∙s)gradually decreased with the increase of the ratio of amylose/amylopectin,and the the retentate value(481.67-1604.33 mPa∙s)gradually increased were found during starch pasting.Rheological results showed that there was a weak gelation behavior of starch(G′>G″),and that the enhanced elastic behavior of starch gel increased the hardness and chewiness.As to the digestive properties,the increase of amylose/amylopectin ratios could increase the resistant starch content,and decrease the rapidly digestible starch content,the digestibility of starch and the predicted glycemic index.The results of this study have theoretical value for the development of functional"customized"highland barley starches with specific industrial applications.