Determination of the effects of maceration time and fermentation conditions on the aroma and phenolic compounds of wine

ABSTRACT MASTER THESIS DETERMINATION OF THE EFFECTS OF MACERATION TIME AND FERMENTATION CONDITIONS ON THE AROMA AND PHENOLIC COMPOUNDS OF WINE HAKAN DURSUN TOKAT GAZIOSMANPASA UNIVERSITY GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES DEPARTMENT OF FOOD ENGINEERING (SUPERVISOR: Assoc. Prof. Dr. MUSTAFA BAYRAM) This study aims to identify the aroma and phenolic compounds of wines produced from Okuzgozu grapes in different maceration durations (5, 10 and 15 days) and under different fermentation conditions [fermentation without the inoculation of commercial wine yeast (DF) and fermentation with the inoculation of commercial wine yeast (TF)] and to demonstrate the effects of aroma and phenolic compounds on quality. Total acid, water soluble dry matter, pH, reducing sugar, free and total SO2, density, alcohol, volatile acid, total phenolic compound, total monomeric anthocyanin, and some individual phenolic and aroma compounds were analysed in the wines. Total amount of phenolic matter in wines were identified as 1496.2 mg GAE/L, 1533.75 mg GAE/L and 1652.50 mg GAE /L in DF5, DF10 and DF15 wines and 1517.08 mg GAE/L, 1552.5 mg GAE/L and 2008.67 mg GAE/L in TF5, TF10 and TF15 wines, respectively. The amount of monomeric anthocyanin in wines were identified as 69,67 mg/L, 82.12 mg/L. and 73.11 mg/L in DF5, DF10 and DF15 wines and 66.46 mg/L, 77.32 and 75.62 mg/L in TF5, TF10 and TF15 wines, respectively. The highest amount of phenolic compound was determined as quinic acid, gallic acid and (+) – catechin in wines. The amount of gallic acid were identified as 7.46 mg/L, 12.77 mg/L and 24.71 mg/L in DF5, DF10 and DF15 wines and 8.45 mg/L, 12.85 mg/L and 20.65 mg/L in TF5, TF10 and TF15 wines, respectively. The amount of (+)-catechin in wines were identified as 7.54 mg/L, 10.43 mg/L and 25.34 mg/L in DF5, DF10 and DF15 wines and 8.38 mg/L, 11.28 mg/L and 25.31 mg/L in TF5, TF10 and TF15 wines, respectively. It was determined that as the duration of maceration increased, total amount of phenolic compounds increased, total amount of monomeric anthocyanins decreased, and as for individual phenolic compounds the amount of catechin and gallic acid increased in wines. 2019, 73 Pages KEYWORDS: Okuzgozu, natural, commercial, fermentation, maceration, phenolic, aroma