Abstract:

Yacon juice with added sucrose and milk powder was fermented by Lactobacillus bulgaricus and the formula and processing conditions for production of the fermentation beverage were optimized by orthogonal test design. Results showed that browning of yacon juice was effectively prevented by boiling in water for 1 minute and then ascorbic acid was added to adjust the pH of the yacon syrup within the range of 4.0 to 4.5. The optimum conditions fermention by Lactobacillus bulgaricus in the yacon juice (60 ml-scale) were: temperature of 41 ℃, inoculation amount of 10 % and with the contents of sucrose and milk powder 4 g and 4 g, respectively. The optimum formula of the fermented yacon beverage was that sucrose (4 g) and xanthan gum (0.2 g) were mixed with the fermented yacon juice (100 ml).

Key words: yacon, browning, lactic acid bacteria, fermentation beverage