Optimization of fermentation technology for composite fruit and vegetable wine by response surface methodology and analysis of its aroma components.

Fruit wine has certain health care functions, but fruit wine made from a single fruit or vegetable does not have a good enough color, flavor or nutrient composition. Therefore, this study used fresh carrot (Daucus carota subsp. sativus) and pomegranate (Punica granatum) as raw materials to explore the brewing process of carrot and pomegranate compound wine. The fermentation technology of the composite carrot and pomegranate wine was optimized by a single-factor experiment and Box-Behnken design (BBD), which provided a theoretical foundation for the fermentation of this wine. As per the results, the alcohol content of this composite carrot and pomegranate wine was 12.35% vol. under the optimum fermentation conditions of 28 °C initial temperature, 24% initial sugar content, and with the addition of 64 mg L-1 sulfur dioxide (SO2). In the fermented fruit and vegetable wine, a total of 30 aroma components were detected; 21 composites (such as bornyl acetate, caryophyllene and 3-(2-nitrophenylmethyl)-2-thiazolidinone) were newly generated. The relative content of alcohol flavor composites (such as propionic acid 2-methyl-3-hydroxy-2,2,4-trimethylpentan-1-ol, 2-methyl-2-ethyl-3-hydroxycyclohexyl propanoate and terpinene-4-ol) showed an upward trend, and the relative content of alkene components increased significantly after fermentation. The findings of this study provide an experimental foundation for optimizing fermentation technology and for improving the product quality of composite carrot and pomegranate wine.