Glycation improved the oxidative stability of myofibrillar protein emulsion: Effect of pH

Emulsions rich in unsaturated fatty acids are susceptible to oxidation under environmental stress. Glycation has been regarded as an effective strategy to improve oxidative stability of emulsions. This study investigated the pH-dependent antioxidant mechanisms of protein-glucose conjugates in myofibrillar protein (MP) emulsions during storage. Results showed that the glycated MP exhibited greater radical scavenging activity (DPPH: 7.88%-32.08%, ABTS: 16.37%-50.91%) over a wide pH range (3.0-11.0). The interfacial protein adsorption of glycated MP is increased to 97.22% (pH 11.0) from 50.10% (pH 3.0), thereby providing a thicker layer of oxidized protection under alkaline conditions. Protein oxidation analysis revealed that glycation inhibited the production of carbonyl compounds (only 43.21% increase) and oxidation of sulfhydryl groups (only 18.51% decrease). Meanwhile, fewer lipid oxidation products were detected in the glycated MP emulsion with the lowest POV and TBARS values. These findings confirm that glycated MP improved emulsion stability mainly by reducing protein/lipid oxidation of emulsions during storage. Meanwhile, the influence of pH on the oxidative stability of MP emulsions is achieved by altering the free radical scavenging activity and the interfacial adsorption capacity. Overall, glycated MP shows potential applications in developing stable emulsified meat products. • Oxidative stability of glycated MP emulsion was revealed during storage. • DPPH/ABTS radical scavenging activity of GMP reached 32.08% and 50.91%. • Interfacial adsorption of GMP was enhanced with increasing pH, up to 97.22%. • Glycation decreased the protein/lipid oxidation of MP emulsion during storage.