Influence of enzymatic treatment on the nutritional and functional properties of pea flour

The effect of enzymatic treatment on the nutritional value and functional properties of pea flour was investigated. Pea flour was hydrolyzed with acid protease from Aspergillus saitoi, to give two different hydrolyzed pea flours. This enzymatic treatment led to a significant (p < 0.05) decrease in crude and true protein and to an increase of free amino acids and non-protein nitrogen. The nutritional value decreased, but an increase in the avilability of protein was expected as result of lower trypsin inhibitor activity and phytic acid content in hydrolyzed pea flours. The amino acid profile of unhydrolyzed pea flour was slightly modified after enzymatic hydrolysis, increasing (significantly) the isoleucine, leucine, lysine, cystine, phenylalanine, threonine, alanine, arginine and aspartic acid contents as a result of the added enzyme. In addition, enzymatic treatment released hydrophobic amino acids, which significantly improved the protein solubility at acid pH, the oil absorption capacity and the emulsification capacity of pea flours. Protein solubility, foaming capacity, foam stability, water absorption capacity, gelation capacity and green colour decreased. It was thus confirmed that treatment with acid protease improves some functional properties of pea flour, but the effect on nutritional properties was unclear.