Effects of high‐temperature air fluidization (HTAF) on eating quality, digestibility, and antioxidant activity of black rice (Oryza sativa L.)

Abstract

Phytochemical‐rich black rice provides health benefits but is not consumed widely because of its poor eating quality. In this study, high‐temperature air fluidization (HTAF) was used to improve the eating quality of black rice. The changes in its digestibility and antioxidant activity were also investigated. Fissures appeared on HTAF‐treated black rice, and partial starch gelatinization took place. The thermal and pasting properties of black rice starch significantly improved due to the amylose–lipid complex that formed during starch gelatinization; this contributed to the improvement of the eating quality of black rice. In addition, the cooked HTAF‐treated black rice showed a lower hardness (748.30 g) and a higher sensory comprehensive score (77.37) than cooked untreated black rice (1320.66 g and 57.09, respectively). Most importantly, HTAF treatment significantly decreased rapidly digestible starch (RDS) and slowly digestible starch (SDS) and increased resistant starch (RS) in black rice. The glycemic index (GI) of black rice was reduced from 88.60 to 85.49, but the antioxidant activity did not significantly decrease.