In vitro digestibility and resistant starch content of some industrialized commercial beans (Phaseolus vulgaris L.) P. Osorio-Dı ´ az a , L.A. Bello-Pe´rez a, *, E. Agama-Acevedo a , A. Vargas-Torres a , J. Tovar b , O. Paredes-Lo´pez c a Centro de Desarrollo de Productos Bio ´ ticos del IPN. Km 8.5 carr. Yautepec-Jojutla, colonia San Isidro, apartado postal 24, 62731 Yautepec, Morelos, Mexico b Instituto de Biologı´a Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Apartado Postal 47069, Caracas 1041-A, Venezuela c Centro de Investigacio ´n y Estudios Avanzados del IPN, Unidad Irapuato, Apartado Postal 629, 36500, Irapuato, Guanajuato, Mexico Received 13 February 2001; received in revised form 3 January 2002; accepted 3 January 2002 Abstract 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 (=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 a-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. # 2002 Published by Elsevier Science Ltd. Keywords: Resistant starch; Beans; Starch hydrolysis; Legumes; Chemical composition 1. Introduction Dry legumes are a rich and inexpensive source of protein and calories for a large part of the world’s population, mainly in developing countries. The dry bean (Phaseolus vulgaris) has an important place among the legumes of major production and consumption in Africa, India, Latin America and Mexico (Bourges, 1987; Reyes-Moreno & Paredes-Lo´pez, 1993; Sathe, Rangnekar, Deshpande, & Salunkhe, 1982). Carbohydrates constitute the main fraction of grain legumes, accounting for up to 55–65% of the dm. Of these, starch and nonstarch polysaccharides (dietary fibre) are the major constituents, with smaller but significant amounts of oligosaccharides (Bravo, Siddhuraju, & Saura-Calixto, 1998). Besides, being a major plant metabolite, starch is also the dominating dietary carbo- hydrate in the human diet (Bjorck, Granfeldt, Liljerberg, Tovar, & Asp, 1994; Skrabanja, Liljeberg, Hedley, Kreft, & Bjorck, 1999). Until recently, starch had been considered to be an available carbohydrate that was completely digested and absorbed in the small intestine. However, it is now known that there exists a starch fraction that is resistant to enzyme digestion, passing through the small intestine and reaching the large bowel where it may be fermented by the colonic microflora. This fraction is called resistant starch (RS) and is defined as the sum of starch and the products of starch degradation not absorbed in the small intestine of healthy individuals (Asp, 1992). The main classification of RS has been proposed by Englyst, Kingman, and Cum- mings, (1992); it is based on nature of the starch and its environment in the food. RS1 corresponds to physically inaccessible starches, entrapped in a cellular matrix, as in legume seeds (Tovar, Bjorck, & Asp 1992a). RS2 are native granules of starch, whose crystallinity makes them less susceptible to hydrolysis, e.g. raw potato or banana starches (Englyst & Cummings, 1987; Faisant, Gallant, Bouchet, & Champ, 1995). RS3 are retrograded starch 0308-8146/02/$ - see front matter # 2002 Published by Elsevier Science Ltd. PII: S0308-8146(02)00117-6 Food Chemistry 78 (2002) 333–337 www.elsevier.com/locate/foodchem * Corresponding author. Fax: +52-73941896. E-mail address: labellop@ipn.mx (L.A. Bello-Pe´rez).