Impact of dehulling on the physico-chemical properties and in vitro protein digestion of common beans (Phaseolus vulgaris L.)

The objective of this study was to understand the effect of dehulling on the microstructural, physico-chemical characteristics, and in vitro protein digestion of common bean flours with particular regard to differences between adults and infants. The microstructure of flour samples from undehulled (WB) and manually dehulled (SB) beans, observed through scanning electron microscopy, showed that WB starch granules appeared to be surrounded by an integral matrix, while the SB starch granule structure was still visible although covered by protein clusters. The starch granules were oval and spherical, with heterogeneous sizes ranging from 19 to 30 μm in diameter. Particle size analysis determined with a laser diffraction particle size analyzer showed similar bimodal particle size distributions of small (1-25 μm) and large (>100 μm) granules, though the particle size of WB was obviously higher than SB. Color and other physico-chemical analyses showed that dehulling had significant ( P < 0.05) influence on all investigated characteristics. The in vitro gastric and duodenal digestion experiments carried out under physiological conditions showed that the SB samples are more likely to be digested by infants. From our results, it is possible to conclude that the dehulling process improves bean flour protein digestion which could be utilized in various food applications. The dehulling process improves bean flour nutritional functionality making beans more likely to be digested by infants.