Relationships between starch molecular components and eating and cooking qualities of rice using single-segment substitution lines with different Wx loci

Waxy (Wx) gene in rice endosperm synthesizes amylose and amylopectin extra-long chain (ELC). Five rice lines with different Wx locus single-segment substitutions under the same genetic background were investigated for relationships of their starch molecular components and eating and cooking qualities (ECQs) including pasting, thermal, textural and sensory properties. Rice lines with different Wx loci exhibited different ECQs, and their starches had different apparent amylose contents (AACs), true amylose contents (TACs), ELC contents (ELCCs), and amylopectin chain length distributions. The AAC was correlated positively to hardness and cohesiveness of cooked rice, and negatively to adhesiveness and palatability of cooked rice and breakdown viscosity of rice flour. The TAC was correlated positively to gelatinization temperature range and negatively to gelatinization temperature and enthalpy. ELCC showed a positive relationship with pasting peak time of rice flour and chewiness of cooked rice, and could potentially be used as an important reference for rice ECQ evaluation. This study could help the applications of Wx loci in rice quality breeding.

Automated summary

This study investigates the relationships between starch molecular components and eating and cooking qualities (ECQs) in different rice lines with different Wx loci. It finds that the apparent amylose content (AAC) is positively correlated with the hardness and cohesiveness of cooked rice, while negatively correlated with the adhesiveness and palatability of cooked rice and the breakdown viscosity of rice flour. The true amylose content (TAC) is positively correlated with the gelatinization temperature range, and negatively correlated with the gelatinization temperature and enthalpy. The extra-long chain (ELC) content is positively correlated with the pasting peak time of rice flour and the chewiness of cooked rice, and could be used as an important reference for rice ECQ evaluation.