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

Antonio Castro Marín (1, 2) , Marcel Culcasi (1) , Mathieu Cassien (1) , Pierre Stocker (1) , Sophie Thétiot-Laurent (1) , Bertrand Robillard (3) , Fabio Chinnici (2) , Sylvia Pietri (1)

1 ICR - Institut de Chimie Radicalaire
2 UNIBO - Alma Mater Studiorum Università di Bologna = University of Bologna
3 IOC - Institut Oenologique de Champagne

The efficacy against oxidative degradation in model and sulphite-free white wines of two commercial, in soluble chitosans (one being approved for winemaking) were investigated by electron paramagnetic resonance (EPR). Both compounds at various doses significantly inhibited the formation of ∝- (4-pyridyl-1-oxide)-N-t-butylnitrone (4-POBN)-1-hydroxyethyl adducts under normal wine storage conditions. Pre-incubation with 2 g/L chitosan followed by filtration had a better effect than adding 50 mg/L sulphur dioxide to the experimental Chardonnay wine on the release of 4-POBN adducts after 6 days of incubation with 100 μM iron(II). In a relevant photo oxidative system acetaldehyde formation was significantly reduced after 6 days of incubation. Parallel EPR tests were performed to assess the importance of metal chelation (iron and copper) versus direct scavenging of hydroyl radicals on the effect of chitosan. The present data support the potentiality of using biocompatible chitosan as a healthier complement and/or alternative to sulphur dioxide against white wine oxidative spoilage.

Mots clés: Photooxidation; Sulp h ur dioxide - free wines; Antioxidant; Chitosan; EPR s pin trapping; Hydroxyl radical scavenging activity; Metal chelation

Domaines: Chimie analytique

Antonio Castro Marín, Marcel Culcasi, Mathieu Cassien, Pierre Stocker, Sophie Thétiot-Laurent, et al.. Chitosan as an antioxidant alternative to sulphites in oenology: EPR investigation of inhibitory mechanisms. Food Chemistry, 2019, ⟨10.1016/j.foodchem.2019.01.155⟩. ⟨hal-02004026⟩