Artificial aging of wines using oak chips P. Arapitsas, A. Antonopoulos, E. Stefanou, V.G. Dourtoglou * Department of Oenology and Beverage Technology, Technological Educational Institute (T.E.I.) of Athens, Ag. Spyridonos Str., Egaleo, Athens 12210, Greece Received 7 March 2003; received in revised form 2 October 2003; accepted 2 October 2003 Abstract Wine treated with oak chips was analysed for its contents of furfural, vanillin, guaiacol, oak lactone, eugenol and syringaldehyde. These wood-originated volatiles were released into the wine and their levels were measured by gas chromatography, at different time intervals, for fourteen days. The amounts measured were compared to those found in barrel-aged wine. Statistical analysis of the data indicates that syringaldehyde, primarily, and then vanillin, guaiacol and furfural can be used to discriminate artificially aged from barrel-aged wine. Two different sizes of oak chips were used for this study. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Wine; Furfural; Vanillin; Guaiacol; Oak lactone; Eugenol; Syringaldehyde; Oak chips 1. Introduction Oak wood is mainly composed of three large insol- uble polymers – cellulose, hemicellulose and lignin. It also contains other compounds of lower molecular weight, such as volatile and non-volatile acids, sugars, steroids, terpenes, volatile phenols, and lactones which can be extracted in wine or hydroalcoholic solvents (Maga, 1984; Nykanen, 1983). Although aging condi- tions, such as the wine cellar temperature and humidity and the length of time in barrel, affect the characteristics of wine (Dubois, 1989; Towey & Waterhouse, 1996a, 1996b), the most important factor is the raw material of the barrel – oak – and its treatment (Towey & Water- house, 1996b; Miller & Howell, 1992), as these two factors determine the wood compounds extracted in wine. Studies carried out on the contributions of oak to the olfactory characteristics of wine have shown that these are mainly influenced by compounds such as furfural, guaiacol, whisky lactone, eugenol, vanillin, and syring- aldehyde (Pollnitz, Jones, & Sefton, 1999; Mosedale, Puech, & Feuillat, 1999; Perez-Coello, Sanz, & Cab- ezudo, 1999; Spillman, Iland, & Sefton, 1998; Spillman, 1997; Chatonnet, Cutzach, Pons, & Dubourdieu, 1999). More specifically, furfural (2-furancarboxaldehyde) originates from degradation of monosaccharides pro- duced by partial hydrolysis of hemicellulose. It con- tributes the character of dried fruits, and particularly that of burned almonds (Sauvageot & Feuillat, 1999; Spillman et al., 1998; Chatonnet et al., 1999). Guaiacol (o-methoxyphenol) is produced by the lig- ninÕs breakdown during wood toasting and it is re- sponsible for the burn overtones of wine aroma (Aiken & Noble, 1984; Guymon & Crowell, 1972; Hale, McCafferty, Larmie, Newton, & Swan, 1999; Chaton- net, 1998). Oak lactone (cis and trans isomers of b-methyl-c- octalactone), which is often referred to as whisky lac- tone, since it was discovered in bourbon (Suomalainen & Nykanen, 1970), originates from oak lipids and di- rectly influences the character of wine (Mosedale et al., 1999). That is why the concentration of this compound in wine significantly determines quality, as well as, ac- ceptance by the consumer (Spillman, 1997). Whisky lactone mainly attributes a woody and coconut charac- ter (Pollnitz et al., 1999; Chatonnet, 1995; Boidron, Chatonnet, & Pons, 1988; Perez-Coello et al., 1999; Spillman et al., 1998; Spillman, 1997), while some studies have shown that high concentrations of this Food Chemistry 86 (2004) 563–570 www.elsevier.com/locate/foodchem Food Chemistry * Corresponding author. Tel./fax: +30-210-9327047. E-mail address: dourt@ath.forthnet.gr (V.G. Dourtoglou). 0308-8146/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2003.10.003