Particle size distribution of rice flour affecting the starch enzymatic hydrolysis and hydration properties

Abstract

Rice flour is becoming very attractive as raw material, but there is lack of information about the influence of particle size on its functional properties and starch digestibility. This study evaluates the degree of dependence of the rice flour functional properties, mainly derived from starch behaviour, with the particle size distribution. Hydration properties of flours and gels and starch enzymatic hydrolysis of individual fractions were assessed. Particle size heterogeneity on rice flour significantly affected functional properties and starch features, at room temperature and also after gelatinization; and the extent of that effect was grain type dependent. Particle size heterogeneity on rice flour induces different pattern in starch enzymatic hydrolysis, with the long grain having slower hydrolysis as indicated the rate constant (k) .. No correlation between starch digestibility and hydration properties or the protein content was observed. It seems that in intact granules interactions with other grain components must be taken into account. Overall, particle size fractionation of rice flour might be advisable for selecting specific physicochemical properties.Keywords: rice flour; particle size; starch damage; physical properties; starch hydrolysis Highlights• Particle size heterogeneity of rice flour affects hydration properties• Rice flour hydration properties increase with the reduction of particle size• Starch enzymatic hydrolysis varies with the particle size distribution• There was not a clear relationship between particle size and starch hydrolysis rate 3

Changes in physicochemical properties and in vitro starch digestion of native and extruded maize flours subjected to branching enzyme and maltogenic α-amylase treatment

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Physicochemical characteristics of sauce model systems: Influence of particle size and extruded flour source

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