The Formation of Phenethyl Alcohol From 14c-Labelled Phenylalanine

The two pathways leading to the formation of higher alcohols have been studied by using 14C-labelled phenylalanine together with an amino acid mixture as substrate, and determining the proportion of phenethyl alcohol derived from the radioactive phenylalanine. Different levels of phenylalanine and total nitrogen have been used to examine the factors regulating the relative importance of the degradative Ehrlich pathway and the synthetic pathway. The results indicate that both pathways must be regarded as potentially important in the formation of higher alcohols in brewing. As these two pathways may be influenced by external factors in different ways, higher alcohol formation is evidently a process determined by a very great number of variables.