Long Changzhi, Du Yanli, Zeng Mingyang, Deng Xueyun, Zhang Zhengwei, Liu Dong, Zeng Yongjun
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China.
Lushan Botanical Garden, Chinese Academy of Sciences, Lushan 332900, China.
Foods. 2024 May 13;13(10):1516. doi: 10.3390/foods13101516.
The chalkiness, starch fine structure, and physiochemical properties of rice starch were analyzed and their correlations were investigated under different nighttime temperatures during the early grain-filling stage. Compared to MT, medium temperature (MT) and low (LNT) and high (HNT) nighttime temperatures resulted in an increased chalky grain rate (CGR) and chalkiness degree (CD). LNT mainly affected the chalkiness by increasing peak1 (short branch chains of amylopectin), the branching degree, and the proportion of small starch granules but decreasing peak2 (long branch chains of amylopectin) and peak3 (amylose branches). This altered the pasting properties, such as by increasing the peak viscosity and final viscosity. However, HNT mainly affected the chalkiness by increasing peak2 and the crystallinity degree but decreasing peak1 and peak3. Regarding the thermal properties, HNT also elevated peak and conclusion temperatures. The CGR and CD were significantly and positively correlated with the proportions of small and medium starch granules, peak1, branching degree, gelatinization enthalpy, setback viscosity, and pasting time but markedly and negatively correlated with the proportion of large starch granules, amylose content, peak3, peak viscosity, and breakdown viscosity. These findings suggest that LNT and HNT disrupted the starch structure, resulting in increased chalkiness. However, their mechanisms of action differ.
在灌浆初期不同夜间温度条件下，对水稻淀粉的垩白度、淀粉精细结构及理化性质进行了分析，并研究了它们之间的相关性。与中等温度（MT）相比，低温（LNT）和高温（HNT）夜间温度导致垩白粒率（CGR）和垩白度（CD）增加。LNT主要通过增加峰值1（支链淀粉的短支链）、支化度和小淀粉颗粒比例，但降低峰值2（支链淀粉的长支链）和峰值3（直链淀粉分支）来影响垩白度。这改变了糊化特性，例如增加了峰值粘度和最终粘度。然而，HNT主要通过增加峰值2和结晶度，但降低峰值1和峰值3来影响垩白度。关于热性质，HNT还提高了峰值温度和终了温度。CGR和CD与中小淀粉颗粒比例、峰值1、支化度、糊化焓、回生粘度和糊化时间呈显著正相关，但与大淀粉颗粒比例、直链淀粉含量、峰值3、峰值粘度和崩解粘度呈显著负相关。这些发现表明，LNT和HNT破坏了淀粉结构，导致垩白度增加。然而，它们的作用机制不同。
