engleski

Effect of wine ageing in oak barrels on the phenolic content and antioxidant capacity of red wine

INTRODUCTION During the ageing of wine the complexity of the phenolic components is increased due to the condensation and polymerization among certain compounds present in wine. Phenolic compounds contribute directly or indirectly to wine organoleptic characteristics such as colour, astringency, bitterness and aroma. The objective of this study was to determine concentrations of phenolic compounds and antioxidant capacity of red wine made from Croatian native grape variety Teran (Vitis vinifera L.) during the six months ageing in oak barrels. MATERIALS AND METHODS This study was performed on samples of wine produced from native grape variety (Vitis vinifera L.) Teran, vintage 2006. The wine was maturated from January 2007 to June 2007 in oak barrels. The content of total phenolic compounds in wine samples was determined by the Folin-Ciocalteu's reagent. Anthocyanins were determined by HPLC with UV-Diode Array detection. The total antioxidant capacity of wine was measured by three different analytical methods: 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, 2, 2'-azinobis(3-ethylbenzothialozine-6-sulfonic acid) radical cation (ABTS۰ +) and ferric reducing antioxidant power (FRAP). RESULTS AND DISCUSSION The amount of total polyphenol content in the period of ageing was slightly decreased (1514 mg/L to 1399 mg/L GAE). As a result of anthocyanins analysis of all the wines studied a total of eleven different anthocyanins compounds were detected and determined quantitatively. Significant differences were found in the concentrations of all the anthocyanins compounds identified due to ageing time. The concentrations of identified anthocyanins diminished during the six months ageing in barrel, possibly due to typical oxidation and condensation reactions occurring in barrels. In Teran wine malvidin-3-O-glucoside was the major anthocyanin, with concentrations up to 358.23± 1.53. After six month of ageing the concentration of malvidin -3-O-glucoside was 198.34± 3.42. During the ageing of wines the antioxidant capacity was constantly decreasing and was found to be the highest in the beginning of ageing in oak barrels.

anthocyanins; antioxidant capacity; phenolic composition; Teran

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