Study of phenolic and volatile composition of white wine during fermentation and a short time of storage

The phenolic composition including hydroxybenzoic acids, hydroxycinnamic acids and flavan-3-ols was identified and quantified in all studied samples by using a reversed-phase high-performance liquid chromatography (HPLC) system coupled with diode array detection. Gallic, protocatechuic, p-coumaric and vanillic acids were the major phenolic substances in grape juice, whereas caffeic acid was the most abundant phenolic acid in the wine after a short time of storage. For more reliable results, the antioxidant activity of grape juice and wine was measured by beta-carotene bleaching (BCB) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging methods. The content changes of volatile compounds in the grape juice and wine were determined by using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography (GC/FID and GC/MS). Hexanal, (E)-2-hexenal, 2-ethyl-1-hexanol, 1-hexanol, (Z)-nerol-oxide and linalool were the most representative compounds determined in grape juice, whereas ethyl esters of hexanoic, octanoic, decanoic and dodecanoic acids, hexyl acetate, isoamyl acetate, as well as isobutanol, isoamyl alcohol and 1-hexanol were identified as the main compounds.