Studies on the nutritional composition and antinutritional factors of three different germplasm seed materials of an under-utilized tropical legume, Mucuna pruriens var. utilis.

Abstract

Two different germplasms of a white variety and one germplasm of a black variety of Mucuna pruriens var. utilis were evaluated for their physicochemical properties as well as their nutritional and antinutritional characteristics. All germplasms had higher grain weight, density, hydration, and swelling capacity than other common legumes. The dehulled samples contained 303.2-335.5 g(-1) protein and 46.1-53.5 g x kg(-1) lipid, and these values were higher than the respective whole seeds. The levels of macro- and microelements in both whole and dehulled seeds were comparable to those in common pulses. All germplasms had a high dietary fiber content (18-19.5%), made up of mainly insoluble dietary fiber (DF). Seed lipids were high in unsaturated fatty acids (64.7-66.9%), specifically linoleic acid (48-49%). Whole and dehulled seeds of the white variety from Salem were particularly rich in sulfur-containing amino acids with significantly higher levels of in vitro protein digestibility than the other two germplasms. All germplasms had high levels of total phenols and phytate, trypsin, and chymotrypsin inhibitor activities, but were low in tannins, saponins, and alpha-amylase inhibitor activity. Only weak hemagglutinating activity against cow erythrocytes and no hemagglutinating activity against human erythrocytes (O) was observed in all the samples. Dehulled seeds were higher in total starch, including resistant starch and oligosaccharides (with verbascose as the major fraction) than the respective whole seeds. Both whole and dehulled samples of the white variety of Salem germplasm showed significantly lower concentrations of L-dopa, nonmethylated, and methylated tetrahydroisoquinolines than the respective whole and dehulled samples of other germplasms. In general, dehulling didn't affect the overall nutritional status in any of the presently investigated samples.