Mechanistic Insights into Myofibrillar Protein Oxidation by Fenton Chemistry Regulated by Gallic Acid

• Published in: Journal of agricultural and food chemistry 2023-08, Vol.71 (33), p.12587-12596
• Main Authors: Liu, Xue, Wang, Li, He, Bowen, Liu, Qiao, Zhu, He, Carrier, Andrew J, Oakes, Ken D, Zhang, Xu
• Format: Article
• Language: English
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.3c03284

Gallic acid (GA, 3,4,5-trihydroxybenzoic acid) is a widely used natural food additive of interest to food chemistry researchers, especially regarding its effects on myofibrillar protein (MP) oxidation. However, existing studies regarding MP oxidation by GA-combined with Fenton reagents are inconsistent, and the detailed mechanisms have not been fully elucidated. This work validated hydroxyl radical (HO ) as the primary oxidant for MP carbonylation; in addition, it revealed three functions of GA in the Fenton oxidation of MP. By coordination with Fe(III), GA reduces Fe(III) to generate Fe(II), which is the critical reagent for HO generation; meanwhile, the coordination improves the availability and reactivity of Fe(III) under weakly acidic and near-neutral pH, i.e., pH 4-6. Second, the intermediates formed during GA oxidation, including semiquinone and quinone, promoted Fenton reactivity by accelerating Fe catalytic cycling. Finally, GA can scavenge HO radicals, thus exhibiting a certain degree of antioxidant property. All three functions contribute to MP oxidation as observed in GA-containing meat.