Characterisation of pseudocereal and cereal proteins by protein and amino acid analyses

Maize, wheat, amaranth, rice and soybean were screened for protein content. Alcohol-soluble (A1 and A2) and glutelin (G1 and G2) fractions were isolated and compared in terms of their amino acid and protein compositions. The average proportions of nitrogen content between total alcohol-soluble proteins (TASP) and total glutelins (TGlu) in the pseudocereals amaranth and soybean were about 1.8:26.9 and 14.9:12.3 respectively. In the cereals maize and wheat these proportions were 47.8:33.2 and 44.7:31.2 respectively. The sum of essential amino acids was 47.6 and 60.3g per 100g protein in amaranth and soybean respectively. The highest contents of methionine, lysine and arginine were found in the pseudocereals. The relatively high content of essential amino acids shows that pseudocereals could be used as a nutrient substitute for cereals. (C) 2002 Society of Chemical Industry.