Identification of Adducts between an Odoriferous Volatile Thiol and Oxidized Grape Phenolic Compounds: Kinetic Study of Adduct Formation under Chemical and Enzymatic Oxidation Conditions
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- 作者：Maria Nikolantonaki ; Michael Jourdes ; Kentaro Shinoda ; Pierre-Louis Teissedre ; St茅phane Quideau ; Philippe Darriet
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：March 14, 2012
- 年：2012
- 卷：60
- 期：10
- 页码：2647-2656
- 全文大小：363K
- 年卷期：v.60,no.10(March 14, 2012)
- ISSN：1520-5118
文摘
HPLC鈥揗S and 1H, 13C, and 2D NMR analyses were used to identify new addition products between 3-sulfanylhexan-1-ol (3SH) and o-quinones derived from (+)-catechin, (鈭?-epicatechin, and caftaric acid. The kinetics of formation of these adducts were monitored in a wine model solution and in a must-like medium by HPLC鈥揢V鈥揗S with the aim of understanding the chemical mechanism involved in reactions between volatile thiols and o-quinones. One o-quinone-caftaric acid/3SH adduct, three o-quinone-(+)-catechin/3SH adducts, and three o-quinone-(鈭?-epicatechin/3SH adducts were characterized. Caftaric acid was oxidized faster than (鈭?-epicatechin and (+)-catechin when these phenolic compounds were incubated in a one-component mixture with polyphenoloxidase (PPO) in the presence of 3SH. Consequently, o-quinone-caftaric acid formed adducts with 3SH more rapidly than o-quinone-(+)-catechin and o-quinone-(鈭?-epicatechin in the absence of other nucleophilic species. Furthermore, o-quinone-(鈭?-epicatechin reacted faster than o-quinone-(+)-catechin with 3SH. Sulfur dioxide decreased the yield of adduct formation to a significant extent. Under chemical oxidation conditions, the rates and yields of adduct formation were lower than those observed in the presence of PPO, and o-quinone-caftaric acid was slightly less reactive with 3SH, compared to oxidized flavan-3-ols. The identification of o-quinone-caftaric acid/3SH and o-quinone-(+)-catechin/3SH adducts in a must matrix suggests that the proposed reaction mechanism is responsible for 3SH loss in dry wines during their vinification and aging process.