GAMMA-AMINOBUTYRIC ACID (GABA) PRODUCTION BY DIFFERENT BIOTECHNOLOGICAL METHODS
Project no. 1389 · Status: Kapanmış · 2017
Summary
GABA (?-aminobutyric acid) is a four-carbon non-protein amino acid and potential bioactive compound that acts as the major inhibitory neurotransmitter in the central nervous system. GABA has significant effects on human health due to its physiological and biological functions. Although many microorganisms could produce GABA including bacteria, fungi and yeasts, GABA-producing lactic acid bacteria (LAB) have been focus of researches in recent years. Production of GABA by lactic acid fermentation is safe, natural and eco-friendly since LAB possess special physiological activities and are generally regarded as safe and extensively used in food industry. Thus, in the present study were aimed to determine GABA-producing ability of LAB isolated from natural microflora of cabbage-based fermented products such as pickled cabbage (PC), sauerkraut (SK) and kimchi (KM) and to prove production of GABA at controlled fermentation conditions. By evaluating of GABA-producing ability and GAD enzyme activities, 6 of LAB strains from SK and 5 of LAB strains from KM were acquired among 72 of total LAB isolates. Afterwards, isolates were confirmed as belonging to bacterial species of Lactococcus ve Leuconostoc with identification of their strains. In following stage, production process of SK and KM were performed by inoculating of GABA-producing strains as starter cultures at controlled fermentation conditions. Hence, Lc. lactis ssp. lactis 1 SK1-C29-inoculated SK (15184.0±687.0 mg GABA/kg) sample showed the highest production of among the SK samples, whereas Leu. mesenteroides ssp. mesenteroides 1 KM1-C102-inoculated KM (1442.0±204.7 mg GABA/kg) sample showed the highest production of GABA among the KM samples. By the evaluating of total phenolic content, the highest content of SK sample was detected in spontaneous SK fermentation (676.56±37.0 mg GAE/100 g fresh weight). KM sample inoculated with Leu. mesenteroides ssp. mesenteroides 1 KM3-C117 (836.11±4.09 mg GAE/100 g fresh weight) showed highest content of phenolic content among the KM samples. SK produced by Lc. lactis ssp. lactis 1 SK1-C36 (9.34±0.72 mg/ml) inoculation and KM obtained by Leu. mesenteroides ssp. mesenteroides 1 KM2-C98 (13.38±1.77 mg/ml) presented the highest antioxidant activity among each sample group. Leu. mesenteroides ssp. mesenteroides 1 SK3-C61 and Leu. mesenteroides ssp. mesenteroides 1 KM3-C117 used as starters in SK and KM production led to shorter fermentation period with higher acidity related to rapid adaptation performance during fermentation. It was also demonstrated that strains could grow in SK and KM samples produced with %3.0 and %2.5 NaCI concentrations. In light of this information, it was confirmed that a high quality SK and KM could be produced by pure culture of Lc. lactis ssp. lactis 1 SK1-C29 and Leu. mesenteroides ssp. mesenteroides 1 KM1-C102 with increased GABA content. Anahtar sözcükler: Pickled cabbage, sauerkraut, kimchi, lactic acid bacteria, ?-aminobutyric acid, glutamate decarboxylase.