Effects of micronization pretreatments on the physicochemical properties of navy and black beans (Phaseolus vulgaris L.)

Tempering pretreatments were evaluated for the micronization of navy and black beans. Navy and black beans were tempered to 28 g/100 g and 26 g/100 g moisture, respectively, using water, a mixture of salts of bicarbonate, carbonate and phosphate, a mixture of citric acid and ascorbic acid, or ethylenediaminetetraacetic acid (EDTA) and monitored for texture after cooking, and changes in starch, protein and colour. The mixture of sodium bicarbonate, sodium carbonate and dibasic sodium phosphate was more effective than the mixture of citric and ascorbic acid or disodium EDTA or water alone in reducing the hardness of micronized black beans, while the water and salt mixture were equally effective in reducing the hardness of navy beans and the firmness of both navy and black beans. Lower soluble protein levels and higher levels of gelatinized starch were significantly correlated with a decrease in the hardness of micronized beans. Colour was affected for all micronized black beans, but the colour of micronized navy beans was only affected by the acid treatment. The ability of the bean to imbibe and distribute water in its seed renders seed constituents more sensitive to the effect of heat and solutes, thereby influencing the tempering strategy.