Study on koji with high content of gamma-aminobutyric

The varieties of rice and mold for making the koji with high content of gamma-aminobutyric (GABA) and high saccharifying enzyme activities were selected. Aspergillus oryzae 3. 800 and rice from Shangzhi were selected as optimal combination, and the optimizing process conditions for koji to produce more GABA were studied. The results suggested that Aspergillus oryzae 3. 800 was cultured for 6 days at 30℃ in PDA medium, and then put into steamed rice with 40mg/100g spore amount after rices were soaked in the water with 7. 5mg/mL vitamin C and 2. 0mg/mL sodium glutamate overnight, and more GABA was obtained after the koji was cultivated in the variable temperatures, just 30℃ for 20h, 32℃ for 4h, 35℃ for 14h, 38℃ for 8h. 6. 936mg/g and 0. 439mg/mL GABA were got in the koji and sake respectively in the above conditions.