Impact Of Physicochemical Properties On The Digestibility Of Brazilian Whole And Polished Rice Genotypes

Background and objectives Some factors related to rice processing, composition, and grain microstructure may interfere with starch digestibility. The objective of this work was to evaluate the impact of physicochemical properties and rice processing on the starch digestibility of genotypes produced in Brazil. Five traditional white rice genotypes, one black rice, and one red rice genotype were studied. The traditional white rice genotypes were evaluated as brown rice as well as in the polished rice form, while both black and red rice were evaluated in the unpolished form.Findings The digestibility ranged from 41.40% to 99.81%, being positively correlated with starch content and peak viscosity and negatively correlated with pasting temperature. The unpolished rice group exhibited lower digestibility value than the polished rice group as a result of the presence of bran. Low amylose cultivars had higher starch hydrolysis percentage.Conclusions The type of processing influenced the starch digestibility profile, in which the presence of bran and pigments in whole rice reduce starch hydrolysis percentage. The extent of gelatinization of the starch, identified through the peak viscosity and the pasting temperature of RVA, also had a direct influence on digestibility.Significance and novelty For the first time, different types and processing of Brazilian rice genotypes have been studied about the starch viscosity and digestibility profiles and related to other quality traits, what can drive consumption of a greater diversity of rice according to different market demands and energy needs.