Water migration, texture and oral processing properties of semi-waxy rice during retrogradation.

Abstract

Semi-waxy rice, a low-amylose content (8%-13%) rice variety, can resist retrogradation. It is becoming more and more popular and widely cultivated in East China where consumers prefer cooked rice with soft and tender texture. In this study, water migration, texture and oral processing properties of cooked rice during retrogradation were investigated in order to characterize semi-waxy rice. The results confirmed that the water mobility and migration of semi-waxy rice during retrogradation is weaker than that of waxy rice and stronger than that of nonwaxy rice. Simultaneously, the hardness of semi-waxy rice was higher than that of waxy rice and lower than that of nonwaxy rice. The oral processing properties confirmed that freshly waxy rice was too adhesive and needed more work to breakdown slow breakdown structure (Type Ⅱ structure) compared to freshly semi-waxy rice. Meanwhile, nonwaxy rice was too hard, and more work was needed to break both fast breakdown structure (Type I structure) and slow breakdown structure (Type Ⅱ structure). The oral processing properties confirmed that retrograded semi-waxy rice generated more reducing sugar than retrograded waxy rice and nonwaxy rice. Thus, semi-waxy rice can retard retrogradation, and the texture of cooked semi-waxy rice is neither too adhesive as waxy rice nor too hard as nonwaxy rice. PRACTICAL APPLICATION: Semi-waxy rice cultivars have been widely cultivated in East China and well accepted by the consumers. This study aims to characterize semi-waxy rice and provide theoretical basis for semi-waxy rice study.