Chemometric properties of wines treated with natural extracts as an alternative of sulphur dioxide

Ege University, Department of Food Engineering, 35100 Bornova, Izmir, Turkey

Abstract

Sulphur dioxide (SO₂) is commonly used as an antioxidant and antimicrobial compound during wine production. Phenols naturally existence in plant extracts have been reported to possess antioxidative, antimicrobial activities, and as anti-inflammatory activities. Since few consumers preferred foods treated with natural preservatives, the aim of this study was to determine the effects of different natural plant extracts as an alternative of sulphur dioxide used in wines. Wine production was done according to the accepted conventional method for red wines (Cabernet sauvignon). The experimental design was achieved by using different plant extracts (grape pomace, rosemary, black blueberry) at different concentrations. As controls were used wine samples produced without natural extracts and second group samples produced without addition of sulphur dioxide (SO₂). At the end of production basic analyzes (total acidity, volatile acidity, pH, dry matter, ash, free and total SO₂), and colorimetric wine analyses (TWP, WC, CD, CI, %R, %Y, %B, Abs280, Abs420, Abs520, Abs620, %dA and tint values) were performed. Analyses on n-dimensional scale demonstrated that each used plant exact have different effects on required SO₂ and wine quality parameters. The lowest concentrations of grape pomace extract caused reduction of SO₂ and maintaining the required wine properties. The highest value of the end of first month of storage for TWP, WC, Abs280, Abs520, %R values were determined for grape pomace treatment wines. The highest value of the TPW were determined for samples treated with grape pomace (1 ml/L extract), rosemary (1 ml/L extract), and blue berry (1 ml/L extract with 25 mg/L SO₂) 2.710, 2.550 and 2.520 respectively. Results emphasized the importance of used plant extracts and their concentrations. The study demonstrated the possibilities of SO₂ optimization on the base of used natural plant extracts.