Free amino acids and biogenic amines in red and white muscle of tuna stored in controlled atmospheres

Summary. This paper analyses the presence of and changes in free amino acids and biogenic amines in red and white muscle of bigeye tuna during storage in controlled atmospheres with 2 gas mixes containing different concentrations of CO₂ and O₂. Levels of amines were generally higher in white than in red muscle, with the exception of putrescine and spermidine. Levels of biogenic amines increased (p<0.05) throughout storage, commencing later in red than in white muscle. A correlation between the amino acid histidine and the biogenic amine histamine was observed, but only in white muscle. Only in the case of tryptophan did white and red muscle differ (p<0.05) in terms of essential free amino acid content. They also differed in anserine content. Concentrations of the non-essential FAAs glutamic acid, glycine and alanine were higher in red than in white muscle. The effectiveness of the atmospheres was reflected in the evolution of both biogenic amines and FAAs. Gas mix 1, containing a higher concentration of CO₂, was the more effective.