湿热处理对不同淀粉理化特性的影响

Effects of Heat-moisture Treatment on the Physicochemical Properties of Different Starches

以普通玉米淀粉、高直链玉米淀粉、马铃薯淀粉和绿豆淀粉为试验材料,研究湿热处理对不同淀粉颗粒形貌、颗粒大小、糊化特性以及抗消化特性的影响。结果表明,在淀粉乳水分含量为30%,在120℃处理湿热处理10h,不同来源的淀粉,其颗粒形貌变化不同,其中普通玉米淀粉和高直链玉米淀粉的部分颗粒间发生粘结,少许淀粉颗粒中出现了较小的颗粒,淀粉表面有较大的凹坑;马铃薯淀粉和绿豆淀粉部分颗粒形态发生变化,颗粒的脐点处出现凹坑、部分淀粉颗粒有破碎;但湿热处理前后淀粉的偏光十字没有明显变化。与原淀粉相比,不同来源淀粉经过湿热处理后淀粉糊的溶解度、膨胀度和透明度均降低,降低幅度因淀粉种类的不同而有差异。湿热处理能够提高抗性淀粉含量。湿热处理后淀粉的糊化特性发生变化,糊化温度升高,峰值黏度、低谷黏度和破损值降低。普通玉米淀粉和绿豆淀粉的最终黏度和回生值下降,马铃薯淀粉的最终黏度和回生值增大。

The effect of heat-moisture treatment on the particle morphology, particle size, gelatinization characteristics and in vitro digestibility of different starches is analyzed, using normal maize starch, high amylose maize starch, potato starch and mung bean starch as the experimental materials. The results showed that after HMT （moisture content 30%, temperature 120 ~C, time 10 h）, the particle morphology of different starches （normal maize, high amylose maize, potato and mung bean） had different changes. Granule shape changes happening in some part of potato starch, mung bean starch, potholes and breaking were observed in some starch granules. But after HMT, polarized cross did not significantly change. Compared with the native starch, the solubility, swelling and transparency of different starches reduced after HMT. HMT could increase the RS content of starches, and this was related to the increase of amylose content. After HMT, the pasting temperature of different starches increased, while peak viscosity, trough viscosity and breakdown decreased. The final viscosity of maize starch and mung bean starch increased, while the potato starch decreased.