Determination of total, soluble and insoluble dietary fibre in two new varieties of Phaseolus vulgaris L. using chemical and enzymatic gravimetric methods

Two new varieties of uncooked legumes were analysed by proximal analysis and biochemical methods. The ‘Montalban’ variety of black kidney beans showed values of protein, fat, carbohydrate and ash very similar to those of the ‘Tacarigua’ variety. The application of chemical-gravimetric methods to measure acid detergent fibre (ADF) and neutral detergent fibre (NDF) yielded higher values of NDF (32.1%) for ‘Montalban’ than for ‘Tacarigua’ (15.4%), while ADF values were higher for ‘Tacarigua’ (14.5%) than for ‘Montalban’ (6.9%). The application of the Hellendoorn enzymatic-gravimetric method showed similar values of unavailable carbohydrate for both varieties; however, these values (21.6%) were higher than those previously reported for food grain legumes in the literature using the same method. The determination of soluble dietary fibre (SDF) yielded insignificant values for the ‘Tacarigua’ variety; the insoluble dietary fibre (IDF) was higher for the ‘Montalban’ variety (16.8%) and the total dietary fibre was higher for the ‘Montalban’ variety (19.9%) using the Prosky method. These differences could possibly be due to the higher content of SDF and to the starch quality of the ‘Montalban’ variety.