Effect of Food and Probiotic Supplement Interactions on GABA Formation in Microbiota: <i>In</i><i> </i><i>Vitro</i> Gastrointestinal System Approach

Gamma-aminobutyric acid (GABA) is a naturally occurring bioactive compound found in plants, microorganisms, animals, and humans. Specifically, it functions as a neurotransmitter in the central nervous system. Therefore, GABA-enriched functional foods are widely preferred by consumers. This study aimed to investigate the effects of adding various probiotic strains to selected foods on GABA formation during in vitro digestion. In the study, various probiotic supplements were added to banana, kiwi, avocado, pineapple, strawberry, tomato, onion, walnut, hazelnut, peanut, and pumpkin seed samples, and the formation of γ-aminobutyric acid (GABA), one of the neurotransmitters, was examined in in vitro digestion. In vitro pre-digestion GABA values were determined as 14.04 mg/100 g in banana, 13.42 mg/100 g in kiwi, 14.10 mg/100 g in avocado, 15.25 mg/100 g in pineapple, 15.74 mg/100 g in strawberry, 19.34 mg/100 g in tomato, 17.74 mg/100 g in onion, 14.98 mg/100 g in walnut, 18.28 mg/100 g in hazelnut, 17.10 mg/100 g in peanut, and 16.54 mg/100 g in pumpkin seed. In vitro digestions performed by adding probiotic supplements to these foods showed that the highest increase in the fruit and vegetable group was 243%, 248% in tomatoes and strawberries, respectively, and 238% in pumpkin seeds in the nut group, with the addition of the probiotic supplement 10. The study's findings showed that probiotic supplements containing combination of different bacterial strains were effective in increasing GABA production. These results are important for optimizing the interaction of probiotics with nutrients and GABA production.