The effect of type of enzyme and activated carbon concenteration on phenylalanine removal from milk

Phenylketonuria is a hereditary disease caused by a lack or deficiency of the enzyme phenylalanine hydroxylase, its most severe clinical manifestation being irreversible mental retardation. Presently, the only therapy available is the dietary restriction of phenylalanine. The objective of this study was to produce laboratory-scale low-phenylalanine milk to be used as a dietary supplement by phenylketonurics. Low-phenylalanine milk can be used to make a variety of palatable, low-phenylalanine foods and beverages. Three milk hydrolysates were prepared enzymatically (1g of enzyme/100 g of substrate), using a protease from Aspergillus oryzae and papain, separately and in combination (0.5 g of either enzyme/100 g of substrate), followed by adding different amounts of activated carbon (0.3, 0.9, and 1.5 g) to them to remove phenylalanine. The combination of Aspergillus oryzae protease and papain, along with the use of 0.9 g activated carbon in the post-hydrolysis process, resulted in the lowest final phenylalanine content. The best condition for removing phenylalanine from milk was use of a combination of Aspergillus oryzae enzyme(0.5g of enzyme/100g of substrate) and papain (0.5 g of enzyme/100 g of substrate) with 0.9 g activated carbon in the post-hydrolysis process, resulting in removal of 99% of the phenylalanine.