Production of gamma-aminobutyric acid ontaining yogurt by using Lactobacillus sakei and brown rice malt extract

Gamma-aminobutyric acid or GABA is a non-protein functional amino acid. It functions as an inhibitory neurotransmitter that is involved in the regulation of cardiovascular functions, such as blood pressure and heart rate and also plays role in the sensations of pain, anxiety, stimulation of insulin secretion from the pancreas and preventing diabetes. Fermentation and germinating of cereal seeds are of biosynthetic methods for GABA production. This study aimed to investigate the production of GABA enriched yogurt by using of Lactobacillus sakei and brown rice malt extract. In this regard, brown rice malt extract was added to low-fat milk in 0, 50,75 and 100 ml quantities and set yogurts were produced after addition of skimmed milk powder and inoculation of commercial yogurt starters and Lactobacillus sakei. Then the concentrations of GABA, phenolic compounds, amino acids, the antioxidant capacity, and sensorial characteristics were evaluated.According to the results, yogurts that were produced by brown rice malt extract contained GABA. The highest GABA content (5.62 mg/100 g d. w) was observed in yogurt with 100 ml brown rice malt extract. Using brown rice malt extract and Lactobacillus sakei caused significant increasing (p≤0/05) of phenolic compounds and their antioxidant capacities in yogurt samples compared to control. In amino acid profile analysis, glutamic acid showed the highest concentration and lysine was the highest among essential amino acids. In sensory evaluation tests, the sample with 50 ml brown rice malt extract, had the highest overall acceptability. Regarding the results, production of GABA enriched functional yogurt containing phenolics and antioxidant compounds by using brown rice malt extract and fermenting with Lactobacillus sakei and general yogurt starter cultures is feasible.