A comparative study on the chemical composition of wild and cultivated germplasm of phaseolus lunatus l.

ABSTRACT

Wild Lima beans (Phaseolus lunatus L.) were compared with cultivated seed sample (LBS.1) in proximate composition, seed protein fractions, amino acid profiles of total seed proteins, mineral composition, in vitro protein digestibility (IVPD) and certain anti-nutritional factors. The wild beans contained more protein (22.84% vs. 20.05%), ash (3.42 vs. 2.91%), crude fiber (5.48% vs. 4.54%), crude lipid (2.63% vs. 2.55%), less carbohydrates (NFE) (65.63% vs. 69.95%) and the energy level of the seed (1576.60 vs. 1599.14 kJ100g-1 DM) than the cultivated seeds. Globulins formed the major bulk of seed proteins in both the seed samples. The essential amino acid profile of total seed proteins compared favorably with FAO/WHO (1991) requirement pattern, except that there were deficiencies of sulphur containing amino acids in the varieties. Wild seeds were found to be a rich source of potassium, calcium, magnesium and phosphorus. The wild seed samples presented a less free phenolics (0.66 %), tannins (0.90%), higher content of L-DOPA (0.91 %), and less trypsin inhibitor activity (17.80 TIU mg-1 protein) than the cultivated seeds. Lower levels of phytohaemagglutinating activity for human erythrocytes of “O” blood group than for “A” and “B” blood groups were found. From the chemical point of view, domestication seems to be positive; however, the better protein nutritive quality of the wild beans should be further confirmed by biological assays.