Establishment of tannin enhancement conditions for development of high quality wild grape wine

Abstract

Wild grapes contain lots of organic acids, vitamins and inorganic salts compared to other fruits. Also, it has known to have excellent effects on preventing cancer and heart disease. Wild grapes are supposed to be superior material for fermentation of wine. Tannin contents of wine, which is an important functional factor in flavor of wine, were enhanced to develop quality of Korean wild grape wine. In this study, we investigated tannin extraction conditions and analyzed quality properties of tannin-enhanced wild grape wine. The most suitable tannin extraction condition for enhancing tannin of wild grape wine was extraction of tannin from green tea using spirits at 4°C. For producing high quality wild grape wine, added concentration and time of tannin extract were 6.5 mg/mL before wild grape wine fermentation. Tannin contents of tannin-enhanced wild grape wine was 7.4±0.05 mg/mL. Quality properties of tannin-enhanced wild grape wine fermented under optimized fermentation conditions were analyzed. pH, acidity and alcohol contents were 3.69±0.01, 0.95±0.01% and 12.2±0.03%, respectively. Total sugar, tannin, polyphenol and resveratrol contents of tannin-enhanced wild grape wine were 60.00±1.15 mg/mL, 79.50±0.55 mg/mL, 7.40±0.05 mg/mL and 5.00±0.11 mg/mL, respectively showing significantly higher value than that of commercial wine. Production of high quality wild grape wine is expected with the establishment of optimum fermentation condition and tannin-enhancing process of wild grape wine.