韧化处理对3种晶型淀粉消化特性的影响

比较玉米淀粉(A型)、马铃薯淀粉(B型)和锥栗淀粉(C型)韧化处理前后的颗粒形貌、结晶特性和热特性变化,探究韧化处理对3种晶型淀粉消化特性的作用机理。SEM图片显示,韧化处理后玉米淀粉表面出现凹坑,马铃薯淀粉表面出现少许裂痕,锥栗淀粉表面变得光滑,褶皱消失;XRD和FTIR分析表明,3种淀粉经韧化后晶型未有改变,但结晶度均显著提高,分子短程有序性增加,晶体结构更趋稳定;DSC分析表明,韧化处理后3种晶型淀粉的糊化温度显著升高,热焓值无显著变化;韧化处理对不同晶型淀粉消化特性的影响存在差异,3种淀粉经韧化后RS含量均显著增加,水解指数HI和血糖指数GI显著降低;玉米淀粉韧化后RDS含量显著增加,SDS含量显著减少,水解平衡浓度由84.81%降至76.79%;马铃薯淀粉中SDS和RDS含量均显著减少,水解平衡浓度由30.59%降至21.84%;韧化处理对锥栗淀粉的RS、SDS、RDS含量及水解平衡浓度变化影响较小。

Effect of Annealing Treatment on the Digestibility of Starches of Three Types of Crystal Structures

The changes of particle morphology, crystallization and thermal properties of maize starch (type A), potato starch (type B) and castanea henryi starch (type C) before and after annealing treatment were compared, for exploring the mechanism of annealing treatment on the digestibility of starches in three different crystalline?patterns. SEM photos displayed that pits appeared on the surface of maize annealed starch, a few cracks appeared on the surface of potato starch, and the surface of castanea henryi starch became smoother and wrinkles disappeared. XRD and FTIR analysis showed that the crystal types of the three starches did not change after annealing treatment, but the crystallinity significantly increased, the molecular short-range orderliness improved, and the crystal structure became more stable. DSC analysis showed that the gelatinization temperature of three starches increased after annealing treatment, but without significant changes in their thermal enthalpy. The effects of annealing treatment on the digestibility were different among starches of different crystal type. After annealing treatment, the contents of RS in the three starches were significantly increased, and their hydrolysis index HI and glycemic index GI were significantly decreased. In maize annealed starch, RDS content increased significantly, SDS content decreased significantly, and the equilibrium concentration of hydrolysis decreased from 84.81% to 76.79%. The content of SDS and RDS in potato annealed starch both decreased significantly, and the equilibrium concentration of hydrolysis decreased from 30.59% to 21.84%. The annealing treatment had little effect on RS, SDS, RDS content and hydrolysis equilibrium concentration of Castanea henryi starch.