Determination of free amino acid profiles and gamma aminobutyric acid (GABA) content of white, kasar and tulum cheeses

In this study, a total of thirty cheese samples belonging to three cheese varieties (White, Kashar and Tulum) which have an important place in community nutrition and consumed the most in our country were analyzed in terms of GABA content and free amino acid profile. At the same time, some microbiological, physicochemical properties and soluble nitrogen fractions of cheese samples were examined. It was determined that great variability in most of parameters evaluated showed not only between the three types cheese but also among samples belonging to same cheese variety. The highest counts of total bacteria, lactic acid bacteria growth on MRS and M-17 agar and Enterococcus bacteria were determined in Tulum cheese samples. The counts of coliform group bacteria varied on between <2-6.52 log cfu /g for White cheese samples and <2-4.86 log cfu/g for Tulum cheeses. The counts of coliform bacteria of Kashar cheeses was below <2 log cfu/g. In all the cheese varieties analyzed, yeasts were detected at a high level, however mold counts were below the detectable level (<2 log cfu /g). It was determined that dry matter, fat and protein values were higher in Kashar cheese samples and salt in dry matter values were higher for White cheese samples. The mean highest acidity and lowest pH values were determined in Tulum cheese samples. It was determined that the soluble nitrogen fractions (soluble nitrogen in pH 4.6, soluble nitrogen in TCA and PTA) and the ripening index values of these fractions were significantly higher in Tulum cheese, followed by Kashar and White cheese respectively. The highest total free amino acid contents were found in Tulum cheese samples while the lowest values were found in White cheese samples. Gln, His, Ala, Ile, Lys were also determined as major amino acids in the three cheese varieties. It was detected that there was no statistically different between the cheese varieties in terms of GABA concentration and the highest GABA concentration (83.05 mg /100g) was found in one of White cheese samples