Approaches for enzymes behavior on phenylalanine removal from different dairy protein sources

Individuals with specific metabolic disorders, such as phenylketonuria, require a diet low in phenylalanine for the duration of their lives. In this work, phenylalanine (Phe) was extracted by absorption from whey protein, casein, and skim milk powder enzymatic hydrolysates using activated carbon, barium sulfate, or a combination of activated carbon and barium sulfate in order to prepare dietary foods for patients with phenylketonuria. Initially, the amount of phenylalanine for different dairy proteins was determined by HPLC. Three hydrolysate enzymes were prepared, using a protease+papain, pepsin or papain and the percentages of phenylalanine removal after enzyme hydrolysates followed by absorption treatments were detected by HPLC. The results indicated different phenylalanine amounts 20.49, 5.50 and 41.36 mg/mL for the skim milk, whey protein and casein, respectively. The best treatment showed to the use of barium sulphate, which produced 100% of Phe removal from whey proteins using each tested enzyme. Also, the use barium sulphate was removal 99.56, 99.30 and 98.96% of Phe from casein and 99.56, 99.6 and 99.6% from skim milk when applied protease+papain, pepsin or papain, respectively for hydrolsates. Moreover, the usage activated carbon was the best for absorption Phe hydrolysates from different proteins. Also, when using combined activated carbon and barium sulphate, the removal percent was improved, but for whey protein with pepsin was dropped the percentage to 46.72%. In general, the using papain enzyme for different dairy proteins more effective or the same effect for hydrolase phe than using combined protease+papain.