| dc.description.abstract | Dragon fruits have been one of the most common tropical fruits cultivated in Vietnam.
Being a good source of nutrients, dragon fruits exhibit the ability to improve health
and prevent diseases. To increase its marketability, in this study, the qualities of
dragon fruit wine were evaluated in terms of chemical compounds and antioxidant
properties. The effects of species (Hylocereus undatus and Hylocereus polyrhizus),
peel addition, and fermentation temperature (20, 25 and 30oC) on these components
and characteristics of the wines were also investigated. The result showed that all the
studied samples had the acceptable final alcohol content of 8.7-10.9% (v/v), pH value
of 3.8-4.2 and titratable acidity of 4.5-5.5 g malic acid/L, suggesting that these
factors did not significantly affect the wine fermentability. On the other hand, the
changes in antioxidant content and activities were obviously observed. The wines of
H. polyrhizus species contained much higher total phenolic content (1.4-1.6 times),
betacyanin content (75-81 times), and vitamin C content (2.8-3.8 times) as well as
higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (1.2 times)
than the wines of H. undatus. Although fermentation process led to the degradation
of betacyanins, it increased total phenolic content (up to 17%), vitamin C (up to 24%)
and DPPH scavenging activity (up to 19%) when the fermentation was carried out at
25oC, which was found to be the most suited fermentation temperature to produce
wines with the highest quality in terms of antioxidant contents and activity. At this
temperature, the inclusion of the peel also helped to increase these values as
compared to the wines made without it in the same species. The study may provide
insights in fruit winemaking with higher health benefits.
Keywords: fermentation; dragon fruits; peel inclusion; chemical compositions;
antioxidants; betacyanins; phenolic content; vitamin C | en_US |
