Investigation of functional properties of partially hydrolyzed proteins

Hydrolyzates were prepared from soy protein and milk protein by treatment with Alcalase(R) 0.6 L and Neutrase(R) 0.5 L (NOVO INDUSTRI A/S, Bagsvaerd, Denmark). The pH-stat is a good method to control the change of degree of hydrolysis (DH) during enzymatic reactions and gives as well a good possibility to produce partially hydrolyzed products. In case of both investigated substrates we found a good correlation between the DH-values measured by pH-stat and TNBS-method. Determining the functional properties, we found that the emulsifying activity of hydrolyzates with low DH (below 10%) is significantly improved. At the same time the enzymatic treatment decreases the water-binding considerably but increases the velocity of water binding.