Free amino acid profile of Spanish artisanal cheeses: Importance of gamma-aminobutyric acid (GABA) and ornithine content

The content of 18 free amino acids in 34 Spanish artisanal cheeses was measured. The amino acids were determined by high performance liquid chromatography (HPLC) with pre-column derivatization, reversed-phase separation, and UV detection. The total content of free amino acids in the cheese samples ranged from 0.19 g/kg to 67.95 g/kg. The amount of lactic acid bacteria (LAB), the main microflora in cheese, is also reported. Considerable amounts of free amino acids, such as gamma-aminobutyric acid (GABA; average 330 ± 50 mg/kg) and ornithine (Orn; 450 ± 60 mg/kg), were found in some samples, thus indicating specific microbial activities. GABA concentrations were not influenced by the kind of ripening or milk origin (p < 0.05); however, the concentration of Orn in cheese made from cowʹs milk was higher (p < 0.05) than that found in cheese made from goatʹs milk, regardless of whether these products were ripened or semi-ripened. These amino acids are considered potentially bioactive because of their various physiological activities which are beneficial for health.