Application of different pre-fermentation techniques in the winemaking using Guankou table grape (Vitis vinifera × Vitis labrusca)

Abstract

The study produces white wines with the table grape (Guankou grape, Vitis vinifera × Vitis labrusca) using different pre-fermentation techniques to reduce bitterness and enhance aroma. Pre-fermentation techniques included pressing levels, low-temperature maceration, ultralow temperature freezing, hyperoxidation, and their different combinations. The compounds were analyzed by ultraperformance liquid chromatography (UPLC) and solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometric (GC-MS) analysis. The results shown that different pre-fermentation techniques influence the extraction of phenolic and aroma compounds, further forming different sensory qualities. The more damaging process increases the bitter phenols and unpleasant aroma compounds. Flavonoids, tartaric acid esters, and gallic acid esters caused bitterness, and 2,5-bis(1,1-dimethylethyl)-phenol mainly generated aromas of stone fruits. Finally, the results of the comprehensive evaluation of the sensory analysis suggested that after destemming and maceration (4 ± 1 °C, for 24 h), the most aromatic wines are fermented with pressed juice (pressure from 0.5 to 1.0 bar),and the most harmonious wines are fermented with free juice. The study provides a strong basis for winemaking with table grapes.