AMINO-ACID PROFILES OF KINEMA, A SOYBEAN-FERMENTED FOOD

Kinema is an important protein source of traditional Nepalese diets. T otal (protein-bound plus free) amino acid profiles of kinema and free amino acid profiles of unfermented and fermented soybeans were determi ned by reversed-phase highperformance liquid chromatography. Acidic, b asic and aromatic amino acids constituted 30.8, 15.1 and 13.0%, respec tively, of the total amino acid residues in kinema. The protein compon ent (35.6%, dry weight basis) was rich in all essential amino acids (E AA); EAA(7) and EAA(10) values (41.7% and 52.6%, respectively, of tota l protein) were comparable to those of egg and milk proteins. The free amino acid content of unfermented soybeans was only 0.2% of the total dry mass. Processing with Bacillus subtilis led to a 60-fold increase in free amino acid content of soybeans. There was a relative increase in free acidic, hydrophobic and apolar amino acids, but depletion of free basic, hydrophilic and sulphur-containing amino acids. However, t he sum of free charged amino acids did not change. Although Enterococc us faecium had no influence, the presence of yeasts significantly redu ced the levels of alanine, isoleucine, serine, aspartic acid, asparagi ne, arginine, tyrosine, methionine and hydroxyproline, suggesting thei r preferential uptake by the yeasts. On the other hand, amino acid ass imilation by yeasts was indicated by the smaller increase in glycine, leucine, glutamine, lysine, histidine, phenylalanine and proline. The fermentation temperature of 45 degrees C had a significantly adverse e ffect on free amino acid release. (C) 1997 Elsevier Science Ltd. All r ights reserved.