Reaction of Acetaldehyde with Wine Flavonoids in the Presence of Sulfur Dioxide

Abstract

Acetaldehyde is responsible for many of the beneficial changes that occur in red wine as a result of oxidation. Ethylidene bridges are formed between flavonoids upon their reaction with acetaldehyde, which can contribute to improvements in color stability and SO-resistant pigments. In the present study, the reactions between acetaldehyde and various flavonoids (catechin, tannins from grape seed extract, and malvidin-3-glucoside) were examined in a model wine system. Lower pH conditions were seen to significantly increase the rate of reaction with acetaldehyde, whereas dissolved oxygen did not affect the rate. In systems containing SO, the rate of reaction of acetaldehyde with catechin was slowed but was not prevented until SO was in great excess. Significant improvements in color stability were also observed after treatment with acetaldehyde, despite the presence of equimolar SO. These results demonstrate that acetaldehyde is reactive in its sulfonate form, which is contrary to widely held assumptions. In addition, the products of the reaction of flavonoids with acetaldehyde were characterized using MALDI-TOF MS in this study. Ethyl-bridged catechin nonamers were observed, as well as anthocyanin and pyranoanthocyanin derivatives of catechin and tannin oligomers. The results of this work illustrate the significance of acetaldehyde reactions in forming stable pigments in wine and the reactivity of acetaldehyde from its sulfonate form.

The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

“…Acetaldehyde is known to react to anthocyanins, flavanols and tannins to form ethyl-bridged polymeric pigments which have less astringency (Cheynier, Duenas-Paton, Salas, Maury, Souquet, Sarni-Manchado, et al, 2006;Vidal, Francis, Noble, Kwiatkowski, Cheynier, & Waters, 2004) and which become resistant to sulfite bleaching (Sheridan & Elias, 2015). According to recent data acetaldehyde may react not only to anthocyanidins, but to phenolic acids and flavonols (Aleixandre-Tudo, Lizama, Alvarez, Nieuwoudt, Garcia, Aleixandre, et al, 2016) or to catechin itself (Sheridan & Elias, 2016). The reaction of some of these ARPs with acetaldehyde is much faster than previously expected and takes places, albeit at lower rates, even in the presence of equimolar amounts of SO 2 (Sheridan & Elias, 2016).…”

Effect of grape juice composition and nutrient supplementation on the production of sulfur dioxide and carboxylic compounds bySaccharomyces cerevisiae

“…Musts contain several constituents that mainly come from the pulp, such as water, carbohydrates, proteins, organic acids, lipids, mineral elements and vitamins. The reaction between acetaldehyde and bisulfite is known to be fast (98% bound in 90 min at pH 3.3) and the resulting adduct is strongly bound, although it has been recently demonstrated that acetaldehyde remains reactive in the presence of bisulfite (Sheridan and Elias 2016). Some serve as a food source for S. cerevisiae, such as sugars or amino acids (AA), and therefore may influence the development of the fermentation and the release of fermentation by-products in the wine.…”

“…The presence of SO 2 in red wine can also inhibit polymerisation reactions among anthocyanins and flavonoids because sulfite occupies the same C4 position that could be occupied by flavonoids to form new condensed pigments and larger structures by ethyl-flavanol units (Rivas-Gonzalo et al 1995, Escribano-Bailón et al 2001, Tao et al 2007). Furthermore, the rate of reaction of acetaldehyde with catechin is slow in systems containing SO 2 and may be prevented by excess bisulfite (Sheridan and Elias 2016). For instance, pyruvic acid reacts with malvidin 3-glucoside to form pyranoanthocyanins, which are resistant to bleaching by SO 2 (De Freitas and Mateus 2011).…”

“…Sulfur dioxide either inhibits aldehyde dehydrogenase (so acetaldehyde is not converted to ethanol) or binds directly with acetaldehyde and thus reduces the amount of acetaldehyde that can be transformed to ethanol (Frivik and Ebeler 2003). The reaction between acetaldehyde and bisulfite is known to be fast (98% bound in 90 min at pH 3.3) and the resulting adduct is strongly bound, although it has been recently demonstrated that acetaldehyde remains reactive in the presence of bisulfite (Sheridan and Elias 2016).…”

“…For instance, pyruvic acid reacts with malvidin 3-glucoside to form pyranoanthocyanins, which are resistant to bleaching by SO 2 (De Freitas and Mateus 2011). Furthermore, the rate of reaction of acetaldehyde with catechin is slow in systems containing SO 2 and may be prevented by excess bisulfite (Sheridan and Elias 2016). The presence of acetaldehyde in proanthocyanidin polymerisation and precipitation reactions could also lead to modification of the astringency of wines.…”