Phenylalanine

Phenylalanine is an essential amino acid with an aromatic side chain, obtained in the diet from proteins such as ovalbumins, lactalbumins, and zein. Like other amino acids, only the L-enantiomer is utilized significantly by humans. It serves as a substrate for manufacturing the dipeptide sweetener aspartame, which is approximately 160 to 200 times as sweet as sucrose. In nutrition and food safety, phenylalanine is notable because individuals with phenylketonuria cannot metabolize it normally, so products containing aspartame must carry warning labels. Food scientists monitor phenylalanine in protein hydrolysates and sweetener production, balancing its nutritional essentiality against the labeling needs of sensitive consumers.