TAILIEUCHUNG - Correlation between browning degree and composition of important Turkish white wine grape varieties
This study was undertaken to investigate the correlation between browning degree and composition of important Turkish white wine grape varieties during the 2006 and 2007 seasons. Large seasonal and cultivar variations were found in all measured variables. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2016) 40: 62-67 © TÜBİTAK doi: Correlation between browning degree and composition of important Turkish white wine grape varieties 1, 2 Mustafa Ümit ÜNAL *, Aysun ŞENER Department of Food Engineering, Faculty of Agriculture, Çukurova University, Adana, Turkey 2 Department of Food Engineering, Faculty of Engineering, Adıyaman University, Adıyaman, Turkey 1 Received: Accepted/Published Online: Final Version: Abstract: This study was undertaken to investigate the correlation between browning degree and composition of important Turkish white wine grape varieties during the 2006 and 2007 seasons. Large seasonal and cultivar variations were found in all measured variables. The highest browning degree was found in the Narince cultivar in both years, followed by Emir and Sultaniye, with Narince being the most susceptible to browning and Sultaniye being the least. No correlation (P < ) was found between browning degrees and cysteine, glutathione, polyphenol oxidase activity, or total phenolic contents. Effects of harvest year and variety on all measured parameters, except total phenolics, were statistically significant (P < ). Key words: Browning, composition, grape, polyphenol oxidase, white wine 1. Introduction Oxidative browning encountered during the vinification of white wine adversely affects quality attributes of wine, such as color, flavor, and aroma. Therefore, it is considered undesirable in young table and sparkling wines. The initiating mechanism of browning of wine can be enzymatic or nonenzymatic. Enzymatic browning is initiated by the action of polyphenol oxidase (PPO, EC ) when grapes are crushed or pressed during vinification of white wine. Nonenzymatic browning can occur both in grape must and wine (Macheix et al., 1991; Cheynier et al., 1994; Li et al., .
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