손바닥선인장 약주의 pH 변화는 발효가 진행됨에 따라 감소하는 경향을 나타내었으나, 총산 함량은 증가 하는 경향을 보였다. 환원당 함량은 발효 2일에는 모든 시료구가 증가하였으나 발효 4일 경과후 감소하는 경향을 나타냈으며, ethanol은 발효 2일째부터 함량이 급속히 증가하여 발효 6일 부터는 완만한 증가를 보였고 발효 종료 시점인 14일에는 16.23~17.10%의 최대치를 나타냈다. 약주에서 확인된 유리당은 sucrose, maltose,

Fermentation characteristics of yakju prepared with addition of Opuntia ficus indica were examined, with respect to the nature and concentration of additional added materials. The pH level began to decrease after the secondary brewing stage and the total acid content increased during fermentation. The level of reducing sugars in yakju prepared with Opuntia ficus indica increased at the first brewing stage and then slowly decreased after 4 days of fermentation. The ethanol content of supplemented yakju rapidly increased during the initial 6 days of fermentation, to a maximum content of 17.1% after 14 days. The free sugar content was higher in yakju fermented with Opuntia ficus indica stem compared with fruit. The level of organic acids increased as the amount of Opuntia ficus indica material increased. Organic acid level increased during fermentation and lactic acid was the main organic acid in yakju fermented with Opuntia ficus indica. Sixteen volatile compounds were found by GC-MS in supplemented yakju. The most prominent volatile component was iso-amyl alcohol, followed by butyl alcohol and methyl esters. The DPPH radical-scavenging activity of yakju fermented with Opuntia ficus indica stem was higher than when yakju was prepared with fruit. Sensory scores of yakju fermented with 20% (w/v) fruit and 10% (w/v) stem were greater than those of yakju prepared by other treatments.

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