College of Agronomy, Hunan Agricultural University, Changsha, Hunan 410128, China; State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, China.
State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, China.
Food Chem. 2020 Apr 25;310:125817. doi: 10.1016/j.foodchem.2019.125817. Epub 2019 Nov 7.
This study investigated the effects of natural high temperature in the field during grain filling stage on the morphological structure and physicochemical properties of rice starch. High natural field temperature during rice grain filling stage resulted in poor processing and appearance quality, higher gelatinization properties including gelatinization temperature, gelatinization enthalpy, swelling power, and water solubility due to the reduction of amylose content. High temperature decreased the setback and trough viscosities, and increased breakdown, implying that the pasting properties were slightly better. High temperature did not change the starch crystalline type, while it significantly affected relative crystallinity, as well as pitting and unevenness on the surface of the starch granules with lower granule size. The above results imply that high temperature can degrade cooking and eating quality, and increase pasting properties of starch slightly.
本研究探讨了稻谷灌浆期田间自然高温对稻米淀粉形态结构和理化性质的影响。稻谷灌浆期田间自然高温导致稻米加工和外观品质变差，直链淀粉含量降低，导致稻米淀粉的糊化特性如糊化温度、糊化焓、膨胀力和溶解度升高。高温降低了回生值和低谷值黏度，增加了崩解值，表明糊化特性略有改善。高温不改变淀粉的结晶类型，但显著影响相对结晶度，以及较小粒径淀粉颗粒表面的凹坑和凹凸不平。上述结果表明，高温会降低稻米的蒸煮食用品质，同时略微增加淀粉的糊化特性。
