Yogurt production with GABA-producing cultures: physicochemical properties and GABA content

In this study, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains isolated from traditional yogurts in Türkiye were screened for their gamma-aminobutyric acid (GABA) production potential. High GABA-producing strains were selected and used to develop GABA-enriched yogurt through monosodium glutamate (MSG) supplementation. It was determined that GABA content increased in yogurts produced with MSG addition compared to the control. While GABA levels in the control group ranged between 0.07-0.10 mg mL^-1 during storage, they were found to be between 0.95 and 1.19 mg mL^-1 in MSG-supplemented yogurts. Titratable acidity and pH values differed from the control throughout the storage period. Water-holding capacity and syneresis results were not statistically different compared to the control. Improvements in textural properties were observed at the end of the storage period. According to these results, the selected starter culture combination and MSG addition are an effective strategy for producing GABA-enriched yogurt. These findings support the development of functional dairy products with enhanced bioactive potential.