A comparative study on the physicochemical properties, texture characteristics, mineral element profile, and volatile compounds of selected soft and non-soft Japonica rice varieties

Abstract

This study aimed to compare and understand the differences of the composition, thermal properties, pasting properties, texture characteristics, mineral element profile, and volatile compounds between selected soft and non-soft Japonica rice varieties. Amylose content differed significantly between soft and non-soft rice varieties, while protein and crude lipid contents did not show significant difference. Meanwhile, significant differences were noted in the K, Cu, Zn, Se, and Cd content between soft and non-soft rice varieties. Additionally, most thermal and pasting properties of rice flour and texture properties of cooked rice exhibited significant differences between soft and non-soft rice varieties. Furthermore, thirteen and eighteen volatile markers distinguishing soft and non-soft rice were identified in raw and cooked rice, respectively, with headspace solid phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Several volatile markers in raw rice (1-pentanol, 1-hexanol, 3,5-octadien-2-one, methyl benzoate, 2-butyl-2-octenal, and cis-calamenene) were involved in secondary metabolism pathways. Most volatile markers in cooked rice were lipid oxidation products or could interact with amylose, which more abundant in soft rice. The results can be helpful for optimizing breeding strategies to develop improved rice varieties.