Efficacy of Chitosan in Inhibiting the Oxidation of (+)-Catechin in White Wine Model Solutions

Abstract

The efficacy of chitosan and sulfites in inhibiting the oxidation of (+)-catechin in aerated model white wines has been compared by monitoring the browning development and the generation of oxidized phenolic compounds. In addition, the protecting effects of these two additives toward the oxidative decay of varietal thiols were investigated. Chitosan effectively contrasted the browning onset in model solutions all along the entire duration of the experimentation. Color development was limited and comparable in both the sulfite and chitosan added samples. Thanks to its polyelectrolyte behavior, chitosan adsorbed up to 80% of the more hydrophilic oxidized phenolic species and chelated 70 and 30% of Fe and Cu added to the solutions, respectively. Thiol oxidation was significantly lowered by chitosan, suggesting that this additive could contribute to maintain the varietal character of wines coming from aromatic grapes and vinified with reduced sulfite amounts.

Physico-Chemical Features of Sangiovese Wine as Affected by a Post-Fermentative Treatment with Chitosan

“…To evaluate the effect of chitosan on the color of red wines, in a first approach the optical density at 420, 520 and 620 nm was measured ( Table 1). As also already described elsewhere [23,26], chitosan addition resulted in a reduction of the absorbance related to yellow nuances (420 nm) regardless the physical form of addition (dissolved or solid). Lower values of optical densities at 520 and 620 nm on KT and KTS were also recorded.…”

“…As displayed in Table 1, both treatments with chitosan drove to a significant reduction of total phenolic index of wines. Other authors also observed a diminution of this parameter after addition of 1 g/L chitosan in white or model wines [23][24][25] due to absorption onto the polymer surface. Data reported by Milheiro et al [10] and Filipe-Ribeiro et al [9] after treating red wines with different chitosans at 0.1 g/L revealed no differences when compared to untreated samples.…”

Chitosan as an antioxidant alternative to sulphites in oenology: EPR investigation of inhibitory mechanisms

“…It is therefore possible that part of the effect of chitosans found in the above EPR experiments may be due to Fe(II) chelation properties. Chelation capacity of chitosan in oenology has already been reported (Bornet & Teissedre, 2008;Chinnici et al, 2014;Colangelo et al, 2018). Since for these compounds metal removal is based on the formation of a complex involving amine or hydroxyl groups (Fig.…”

“…3A). Furthermore, chitosan can adsorb polyphenols into its matrix, decreasing their level in wine (Chinnici et al, 2014;Spagna et al, 1996). Hence, such a decrease in the 4-MeC (model wine) or oxidizable polyphenols (real wine) contents would indirectly inhibit spin adduct formation by lowering H 2 O 2 levels.…”

“…(EC Regulation No 53/2011). Since its early introduction as anti-browning agent in white wines (Spagna, Pifferi, Rangoni, Mattivi, Nicolini & Palmonari 1996) chitosan has stimulated wine researchers as a substitute for SO 2 (Chinnici, Natali & Riponi, 2014) and is gaining popularity in winemaking (Colangelo, Torchio, De Faveri & Lambri, 2018;Filipe-Ribeiro, Cosme & Nunes, 2018;Castro-Marín, Buglia, Riponi & Chinnici, 2018). In the present work established EPR spin trapping and wine oxidation relevant techniques were applied for the first time, to obtain a deeper understanding of the mechanisms of how an approved, insoluble chitosan protects against white wine spoilage in winemaking conditions.…”