Recent advances in enzymatic modifications of food proteins for improving their functional properties

The tailoring of food proteins by enzymes is a powerful tool to improve their functional properties. Mainly proteinases from various origins have been used for such purposes. Controlled proteolysis leads generally to more soluble products with improved emulsifying properties but relatively poor foaming properties. This latter was the case in our studies on proteolysis of wheat gluten. We also have demonstrated that polypeptides characterized by a high functionality could be produced by proteolysis of wheat gluten. Depending on the conditions of the proteolytic attack, the cleavage sites as well as the type of generated peptides could be modified. In the case of milk proteins, peptic action on the proteins in ethanolic medium or on moderately esterified proteins results in unique fragmentation. Besides fragmentation achieved by proteases, the cross‐linking of proteins to yield higher molecular size forms with transglutaminases was shown to improve the functional properties of proteins. These enzymes catalyse the binding of amines to proteins, cross‐link the polypeptide chains and deamidate the glutaminyl residues. In the case of soybean isolates, gelification was obtained with lower protein concentrations. In the case of wheat gliadins, enzymatic deamination increased drastically the solubility in a wide range of pH. Additionally, enzymatically deaminated gliadins were shown to be very efficient in stabilizing emulsions, due to the formation of soluble polymers.