Effects of cooking and market classes on nutritional and antioxidant properties of dry bean flours and soluble dietary fiber-rich fractions

Dry beans are a rich source of proteins, starch, dietary fiber, and phenolic compounds, thus exhibiting potential health benefits. Fractionating dry beans, especially soluble dietary fiber (SDF), could be considered a valuable functional food ingredient. This study investigated the effects of pinto and black dry bean market classes and atmospheric pressure cooking on the physicochemical attributes of dry bean flours and the extraction and characterization of SDF-rich fractions. Cooking significantly (p < 0.05) increased the dietary fiber content, altering the macronutrient profile. Raw flours exhibited higher levels of extractable phenols and antioxidant capacity, while cooked flours had more hydrolyzable phenols and associated antioxidant activities. Pinto beans were found to have higher levels of slowly digestible starch (23.76%) and resistant starch (5.24%) compared to black beans (20.63% and 3.22%, respectively). The SDF-rich fraction from cooked flours showed a reduced residual protein content and included pectic polysaccharides, hemicelluloses, and raffinose family oligosaccharides (RFOs), with cooking affecting their molecular weight distribution. These fractions demonstrated shear-thinning behavior and temperature-dependent viscosity. The study highlights the significant influence of market class and cooking process on the nutritional and antioxidant properties of dry beans, suggesting their potential contributions to dietary health.