γ-Aminobutyric acid (GABA) was produced by the sequential fermentation of the fruit extract of Pyrus ussuriensis Maximowicz (PFE) with two strains of lactic acid bacteria. The soluble solid content of the PFE was 5.25 o Brix and it also displayed a high potassium content of 127.6 mg/100 g. The first lactic acid fermentation of PFE was performed with Leuconostoc citreum S5 at 25℃ for 2 days. Subsequently, the second lactic acid fermentation was carried out with the first fermented PFE fortified with 3% monosodium ʟ-glutamate (MSG) by Lacobacillus plantarum EJ2014 at 30℃ for 5 days. During the first fermentation, the pH of the PFE medium decreased from 4.42 to 4.19 and the acidity increased from 0.28% to 1.03%. After the second fermentation, pH was 4.64 and acidity was 1.23%. The viable cell counts of Lc. citreum S5 and L. plantarum EJ2014 were 7.94 log CFU/mL and 9.18 log CFU/mL, respectively. The amount of the reducing sugar in PFE increased during the first fermentation period and was nearly consumed during the 2 nd fermentation. Notably, MSG was successfully converted into 1.78% of GABA during the second fermentation. In conclusion, high yield for production of GABA was achieved by a novel mixed fermentation of lactic acid bacteria, which highlights PFE as a functional food material.

Lactic acid fermentation of non-alcoholic Makgeolli a traditional Korean rice wine was optimized for increased production of γ-aminobutyric acid (GABA). The Makgeolli was concentrated by vacuum evaporation at 85℃ for 30 min to yield non-alcoholic Makgeolli and sterilize the indigenous microorganisms. As a result, yeast and lactic acid bacteria were not observed in the non-alcoholic Makgeolli. The non-alcoholic Makgeolli had an unpleasant odor in the absence of glucose in lactic acid fermentation. Therefore, the non-alcoholic Makgeolli was mixed with 3% mono sodium-L-glutamate (MSG) and 1% glucose followed by fermentation with Lactobacillus plantarum EJ2014 at 30℃ for 7 days in stationary culture. During this period, the pH increased from 5.1 to 5.5 and acidity decreased from 0.41% to 0.2%. The viable cell count increased to 3.0×10 8 CFU/mL by the end of the 7 day period. The production was determined using TLC; results showed that Most of the MSG was bio-converted on within 5 days. of lactic acid fermentation. HPLC analysis confirmed GABA production 1.59%. In conclusion, non-alcoholic Makgeolli with 1% glucose and 3% MSG could produce functional rice ingredients including GABA and probiotics as well as wholesome rice products through lactic acid fermentation.