Abstract:[Objective]This study aims to investigate the effects of α-amylase addition on the characteristics of infant rice flour.[Method]Infant rice flour samples with different α-amylase addition were prepared. The basic composition, relative molecular mass of starch, gelatinization properties, hydration properties, texture properties, in vitro digestion characteristics, and microstructure of infant rice flour were determined. Furthermore, the correlations between the physicochemical characteristics and quality characteristics of infant rice flour were analyzed.[Result]The weight-averaged molecular weight and the number-averaged molecular weight of starch in infant rice flour decreased with the increase in α-amylase addition. The gelatinization curve of infant rice flour with α-amylase addition was relatively gentle, and the gelatinization properties of infant rice flour without α-amylase addition were higher than those of infant rice flour supplemented with this enzyme (P<0.05). The water absorption index and swelling power decreased with the increase in α-amylase addition. Infant rice flour with α-amylase addition of 1.8 U/L had the highest sensory scores. The texture properties decreased with the increase in α-amylase addition. The infant rice flour with α-amylase addition showed small and numerous starch granules and denser pores on the surface. The mass fraction of ready digestible starch increased and that of resistant starch decreased in the infant rice flour with α-amylase addition. The sensory scores of infant rice flour were negatively correlated with the valley viscosity (P<0.01). The mass fraction of resistant starch, hardness, consistency, cohesion, and adhesion were positively correlated with the relative molecular mass of starch, water absorption index, and gelatinization properties (P<0.01), and they were negatively correlated with water solubility index (P<0.01).[Conclusion]The characteristics of infant rice flour are significantly improved by α-amylase addition, and the comprehensive quality of infant rice flour with the addition of 1.8 U/L is the best.
