Free amino acids in shrimp - Changes elapsed during the decomposition

Abstract

Paper chromatography has been applied to the research of free amino acids in shrimps. The presence of lysine, histidine, asparagine, arginine, aspartic acid, serine, glycine, threonine, glutamic acid, alanine, proline, valine, phenylalanine, leucine and isoleucine has been observed in shrimps analysed immediately post-mortem. These same amino acids, except aspartic acid, threonine and phenylalanine, were found in the edible portion of shrimps (head, shell and appendages were taken off, but the digestive tube was maintained). The content of lysine, histidine, glutamic acid, alanine, valine, phenylalanine, leucine and isoleucine increases very much during the deterioration whereas proline decreases considerably. In addition, during the spoilage, we identified tyrosine, α-aminobutyric acid, methionine and norleucine. In the present paper, the amino acids not mentioned by other authors are the following: asparagine, aspartic acid, glutamic acid, alanine, proline, α-aminobutyric acid, valine, isoleucine anel norleucine.