Isolation and selection of yeast for wine fermentation from red dragon fruit (Hylocereus polyrhizus)

Abstract

The research was implemented with the aim of isolating and selecting of yeast strains with high fermentation efficiency from red dragon fruit (Hylocereus polyrhizus) for the fermentation of red dragon fruit wine. The result of isolation showed that 29 strains of yeast were isolated from 12 red dragon fruit samples in Can Tho, Hau Giang, Vinh Long, Dong Thap, and Ben Tre provices. Based on the classification of yeast (morphological, physiological, biochemical characteristics), the characteristics of the yeast strains isolated from the red dragon fruit samples were determined. The yeast strain BT2.1 isolated from the red dragon fruit in Cho Lach district (Ben Tre province) was selected based on the highest content of ethanol (11.17% v/v) and the lowest content of residual sugar (8.33o Brix). Fermentation of red dragon fruit wine with the strain BT2.1 was conducted with red dragon fruit juice (22°Brix, pH 4.5, and cell density of 106 cells/ml) at room temperature for 7 days. The highest concentration of ethanol was achieved at 12.15% v/v. The yeast strain BT2.1 was identified to have the similar genetic characteristics as Saccharomyces cerevisiae.