In vitro digestibility and resistant starch content of some industrialized commercial beans (Phaseolus vulgaris L.)

Commercial bean products were studied in terms of chemical composition and starch digestibility. In general, commercial cooked flours did not show differences in protein and ash contents. Canned beans also did not show statistical differences (alpha = 0.05) in protein, but they were different in ash, perhaps due to botanical variety. Lipid content varied in the different flours, due to the formulation used in their preparation, whereas the canned bean samples had similar lipid values. Canned samples had the highest available starch (AS) values. These results suggest that the drying of samples decreases AS. Canned beans had the lowest total resistant starch (RS) values, and the flours obtained from canned seeds had the highest. These results agree with AS content in the samples. Retrograded resistant starch (RS type 3) showed the same pattern as RS (type 2 +type 3), but with lower absolute values. The in vitro alpha-amylolysis rate for canned beans and commercial flours was lower than for samples dried in the laboratory. Thus, the additional drying step increased the hydrolysis rate of the samples. Therefore, depending on the specific dietetic use of beans, appropriate processing methods and formulations are needed. (C) 2002 Published by Elsevier Science Ltd.