Enzymatic hydrolysis optimization of whey proteins for reducing phenylalanine using membrane filtration

Studies on the production of protein supplements for phenylketonuria (PKU) patients indicate that whey protein is one of the most important protein sources for production of these compounds، owning to its specific combination of amino acids. Whey is considered as one of the most polluting by-product in environment، otherwise، it is an excellent source of functional proteins that can be used in medicine and special diet products. In this study، three different concentrations of whey protein concentrate (WPC) were used as a substrate for three enzymes Flavourzyme®، Neutrase®and Protamex®. Effect of substrate concentration and hydrolysis time were studied on the separation efficiency of phenylalanine using response surface methodology (RSM) design. Phenylalanine was removed from hydrolyzed samples using ultra filtration (UF) and its concentration was measured using HPLC technique. Results of this study showed that samples hydrolyzed by Flavourzyme® contain the lowest level of phenylalanine. Also، process optimization was done in order to predict the best conditions of hydrolyzing. The best condition in order to remove the maximum phenylalanine from whey proteins was found for the minimum hydrolyzing time and the lowest substrate concentration for all three enzymes.