Nutritional and antinutritional evaluation of raw and processed seeds of a wild legume, Canavalia cathartica of coastal sand dunes of India

Seeds of a wild legume, Canavalia cathartica collected from coastal sand dunes of the southwest coast of India were processed (roasted and cooked) and analyzed for proximate composition, mineral constituents, protein fractions, amino acid profiles, fatty acids and some antinutritional factors. Raw, roasted and cooked seeds contained 35.5%, 30.5% and 29.2% crude protein; 52.8%, 65.3% and 65.4% crude carbohydrates; 1.3%, 1.4% and 1.4% crude lipids; 1.7%, 1.6% and 1% crude fibre and 3.1%, 3% and 3.1% ash, respectively. Among the minerals, potassium was the highest (895, 821 and 190 mg/100 g), followed by phosphorus (137, 112 and 99 mg/100 g) and calcium (84, 70 and 44 mg/100 g). Among the true protein fractions of raw seeds, globulins (18.3 g/100 g) and albumins (7.3 g/100 g) were the major seed proteins. Essential amino acids, threonine, valine, methionine + cystine, isoleucine, leucine, phenylalanine + tyrosine and lysine, were above the FAO/WHO pattern in raw seeds. In roasted and cooked seeds, essential amino acid score ranged between 54 (threonine) and 224 (methionine). Essential amino acids, leucine, phenylalanine and lysine, in raw seeds were more than those of whole egg protein, soybean and rice. Total phenolics slightly declined in cooked seeds. Seeds did not possess tannins and trypsin inhibitors. Proteins of raw seeds possessed strong hemagglutination activity, which was lowered in processed seeds. The current study demonstrated that seeds of C. cathartica were high in protein, essential amino acids and low in saturated fatty acids and anti-nutritional factors.