Open Access

ARTICLE

Amylose Content, Morphology, Crystal Structure, and Thermal Properties of Starch Grains in Main and Ratoon Rice Crops

Na Kuang, Huabin Zheng, Qiyuan Tang^*, Yuanwei Chen, Xiaomin Wang, Youyi Luo

College of Agronomy, Hunan Agricultural University, Changsha, 410128, China

* Corresponding Author: Qiyuan Tang. Email:

(This article belongs to the Special Issue: High-Yield Rice Physiology & Genetics)

Phyton-International Journal of Experimental Botany 2021, 90(4), 1119-1230. https://doi.org/10.32604/phyton.2021.014637

Received 14 October 2020; Accepted 29 January 2021; Issue published 27 April 2021

Abstract

Rice ratooning, or the production of a second rice crop from stubble after the harvest of the main crop, is considered to be a green and resource-efficient rice production system. The present study was conducted to examine variance in amylose content (AC), grain morphology, crystal structure, and thermal properties of starch between main- and ratoon-season rice of seven varieties. Ratoon-season rice grains had higher ACs and significantly lower transition gelatinization temperatures (To, Tp, and Tc) than did main-season rice grains. The relative crystallinity and lamellar peak intensity of ratoon-season rice starch were 7.89% and 20.38% lower, respectively, than those of main-season rice starch. In addition, smaller granules with smoother surfaces and lower thermal parameters were observed in the starch of ratoon-season rice. The relative crystallinity and lamellar peak intensity of starch correlated negatively with the AC and positively with transition gelatinization temperatures. These results suggest that the superior cooking quality of ratoon-season rice is attributable to the moderate increase of grain AC, which reduces the relative crystallinity, weakens the crystal structure, and lead to a decrease in the gelatinization temperature.

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Keywords

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