Metabolism of Nonesterified and Esterified Hydroxycinnamic Acids in Red Wines by Brettanomyces bruxellensis

Abstract

While Brettanomyces can metabolize nonesterified hydroxycinnamic acids found in grape musts/wines (caffeic, p-coumaric, and ferulic acids), it was not known whether this yeast could utilize the corresponding tartaric acid esters (caftaric, p-coutaric, and fertaric acids, respectively). Red wines from Washington and Oregon were inoculated with B. bruxellensis, while hydroxycinnamic acids were monitored by HPLC. Besides consuming p-coumaric and ferulic acids, strains I1a, B1b, and E1 isolated from Washington wines metabolized 40-50% of caffeic acid, a finding in contrast to strains obtained from California wines. Higher molar recoveries of 4-ethylphenol and 4-ethylguaiacol synthesized from p-coumaric and ferulic acids, respectively, were observed in Washington Cabernet Sauvignon and Syrah but not Merlot. This finding suggested that Brettanomyces either (a) utilized vinylphenols formed during processing of some wines or (b) metabolized other unidentified phenolic precursors. None of the strains of Brettanomyces studied metabolized caftaric or p-coutaric acids present in wines from Washington or Oregon.

Harnessing improved understanding ofBrettanomyces bruxellensisbiology to mitigate the risk of wine spoilage

“…HCA precursor less efficiently than coumaric and ferulic acids (Harris et al 2008, Cabrita et al 2012, Schopp et al 2013). Furthermore, the impact of 4-EC in wine may not be as significant as that observed for 4-EP and 4-ethylguaiacol (4-EG); in cider the detection threshold of 4-EC was more than tenfold higher than that of 4-EP (Buron et al 2012).…”

“…This discrepancy may be due to differences in biomass formation, reflecting relative capacity of strains to grow rather than relative capacity to metabolise HCAs (Vigentini et al 2008), or may be due to differences in strain catabolism of some HCA precursors. Tartrate HCA esters were not metabolised by B. bruxellensis strains growing in red wines (Schopp et al 2013) or model medium (Hixson 2012), whereas glucose esters and ethyl esters were partly metabolised to ethylphenols (Hixson 2012). Differences between strains were evident only for the ethyl esters; B. bruxellensis AWRI1613 was unable to catabolise ethyl coumarate or ethyl ferulate ).…”

Anti-Contamination Strategies for Yeast Fermentations

“…D. bruxellensis can metabolize free-form hydroxycinnamic acids (p-coumaric acid, caffeic acid, and ferulic acid) [33]. P-coumaric acid is converted to 4-ethylphenol, a volatile phenol, and unpleasant aromas occur as the concentration of 4-ethylphenol increases [34,35]. In the overall wine production process, D. bruxellensis can grow on damaged grapes in the vineyard to contaminate the grape juice, thus causing the production of volatile phenols (especially 4-ethylphenol) during fermentation (Table 1).…”

Determination of 4‐ethylcatechol in a Merlot wine using sensory evaluation and the electronic tongue

“…In South African Pinotage, higher levels of caffeic acid have been reported, suggesting that presence of 4‐EC is likely (de Villiers et al ., ). In Washington State red wine, the concentration of caffeic acid was also found to be in higher concentrations compared with the precursors for 4‐EP or 4‐EG (p‐coumaric and ferulic acids, respectively), suggesting that 4‐EC may be a contributor to ‘Brett’‐related aromas in these wines (Schopp et al ., ).…”