Optimization of Fermentation Process of Grapefruit Whole Fruit Wine and Analysis of Its Antioxidant Activity and Volatile Components

Fresh grapefruit was used as raw material to brew fruit wine, and the effects of sugar content, potassium bisulfite amount, yeast inoculation amount and initial pH on the volume fraction of ethanol in grapefruit wine were studied. The brewing process of grapefruit wine was optimized by orthogonal design method, and its antioxidant activity and aroma components were determined. The results showed that the optimal fermentation parameters of grapefruit wine were 22% sugar content, 40 mg/L potassium bisulfite, 1.0% yeast inoculation, and initial pH4.0. Under this technological condition, the alcohol content of grapefruit wine was 14.4%vol. With the extension of fermentation time, the in vitro antioxidant activity of grapefruit wine gradually decreased, and the DPPH free radical scavenging rate and iron ion reduction ability decreased by 5.01% and 13.99 mmol Fe²⁺/L, respectively. A total of 23 aroma substances were detected in grapefruit wine, of which esters accounted for about 1/2 of the total aroma substances, including phenethyl alcohol, ethyl n-hexanoate, 3-methyl-1-butanol acetate, acetic acid, caprylic acid ethyl ester, linalool, and ethyl caprate, etc. This experiment optimizes the brewing process of the whole grapefruit wine, and provides a reference for the industrial production of Guanxi Miyou honey grapefruit wine.