산머루과즙을 이용한 발효산형음료 개발

Development of Fermented Acidic Beverage using Wild Grape Juice

산머루과즙으로 새로운 산형음료 개발을 위해 tea fungus로부터 분리한 G. hansenii TF-2 균을 이용하여 발효하였다. 과즙배지는 11~17%(v/v)의 산머루과즙에 초기 당도를 $10^{\circ}Brix$로 조정하였다. G. hansenii TF-2에 의한 발효는 과즙 배지에 활성화시킨 seed gel의 5%(w/v)를 첨가하여 $29{\pm}1^{\circ}C$에서 15일 동안 배양하였다. 발효동안 발효 액 표면에 막을 생성시키고 산(acids)을 생성하였다. 산머루과즙 발효액의 유기산은 succinic acid와 malic acid가 acetic acid 보다 우위를 차지하였으며, 발효 15일째 측정에 의하면 WGB의 succinic acid는 WGB11이 49.6 ppm, WGB17은 77.4 ppm이 검출되었다. 배양기간 동안 WGB의 유리당은 fructose, glucose, sucrose가 확인되었으며, 발효 15일째에는 fructose 만이 1063.6~1082.5 mg/mL 검출되었다. 발효음료의 음용시 식중독 유발균에 대해 WGB17이 34.46~88.00%의 저해율을 나타내었으며 그람 양성균보다는 음성균에서 더 효과적인 것으로 나타났다.

Wild grape juice was fermented by Gluconacetobacter hansenii TF-2 isolated from tea fungus, to develop a new acidic beverage (fermented wild grape beverage, WGB). Broth was prepared by fermentation of 11~17% (v/v) juice, and sweetened with sucrose (initial sucrose level: $10^{\circ}$ Brix). Fermentation was initiated by addition of 5% (w/v) seed gel (the pellicle of the tea fungus) which had been previously cultured in the same medium (freshjuice broth), and fermentation proceeded in the dark at $29{\pm}1^{\circ}C$ for about 15 days. The major acids produced were succinic acid, malic acid, and acetic acid. After 15 days of fermentation, the organic acid content (principally succinic acid) was 49.6 ppm in WGB 11 and 77.4 ppm in WGB 17. The free sugar content of WGB was 1063.6-1082.5 mg/mL, composed of unfermented fructose, glucose, and sucrose, in that order. The microbial inhibitory effects of the fermented beverage were most apparent when Gram-negative bacteria (Escherichia coli and Salmonella typhimurium) were tested; the inhibition rate was 34.46-88.00%. The new fermented beverage thus displays effective antimicrobial activity against some species of bacteria.