Three-leaved Cayratia, a perennial climber, is widely distributed in India, Asia, Africa, and Australia. In Vietnam, it is found in the Mekong Delta with a specific aroma, dark purple berries, and contains an abundant source of bioactive compounds (yellow waxy oil, steroids/terpenoids, flavonoids, and tannins) in whole plants. Taking advantage of the raw source might enhance various fermented juice drinks and increase income for denizens. The initial parameters were pH 3, 4, and 5 with the total soluble solids (TSS) of 18, 20, 22, and 24 °Bx, respectively, to determine the appropriate Cayratia cider making condition. The yeast concentration (0.1, 0.15, 0.2, and 0.25% [w/v], respectively) and fermentation time (24, 48, and 72 h, respectively) at room temperature (28 ± 2°C) were also surveyed. Thereafter, the final product was analyzed for the sensory quality and microbiological and chemical criteria. The fresh Cayratia juice has a pH of 3.2 and 6 °Bx, and the juice recovery efficiency was 74%, equivalent to 0.74 L/kg of the fruit juice amount after squeezing. The low alcoholic juice has 4.62% v/v ethanol content which meets the Vietnam National Standard (TCVN 3215:79, and QCVN 6-2: 2010/BYT) after 72 h of fermentation time. The TSS of 22 °Bx, pH value of 4, and yeast concentration of 0.2% (w/v) are appropriate initial conditions for Cayratia juice with low ethanol content. Cayratia cider with 4.6% (v/v) ethanol content was produced by Saccharomyces cerevisiae HG 1.3 at room temperature 28 ± 2°C with initial TSS of 22 °Bx, pH 4, and inoculation yeast rate of 0.2% w/v. The quality analysis meets Vietnamese standards for food consumption.
Key words: Fermented juice, three-leaf cayratia, Saccharomyces cerevisiae, fermented conditions
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