Grain quality deterioration of hybrid rice is associated with alterations in physicochemical and structural properties of starch under saline conditions

Abstract

AbstractSaline water could affect the structural and physicochemical properties of starch and rice (Oryza sativa L.) quality. In the present study, two high‐quality hybrid rice varieties, that is, Y Liangyou 957 (YLY957) and Jing Liangyou 534 (JLY534), were grown in a mixture of underground and sea water having 0, 5, and 11 dS m−1 electrical conductivity (EC). The mixtures of water were applied at active tillering stage. Results showed that the application of saline water decreased the total starch and amylose content and increased the protein content, thus reduced the taste value. In addition, the B2 chain content in amylopectin increased by 3.83%–5.30% under the application of saline water, leading to delayed pasting and higher gelatinization temperature. Application of saline water also altered the relative crystallinity, which affected the surface smoothness of starch granules (increased the percentage of small and medium starch granules [d < 10 μm]). Overall, the results indicated that salt stress during the whole growth period changed the physicochemical properties and structure of starch and reduced the eating and cooking qualities.