Effects of catechin on the stability of myofibrillar protein-soybean oil emulsion and the adsorbed properties of myosin at the oil–water interface

•10 μmol/g of catechin did not affect the stability of emulsion.•Catechin (50–200 μmol/g) decreased the stability of emulsion.•Catechin (50–200 μmol/g) caused excessive expansion and aggregation between myosins.•Catechin (50–200 μmol/g) hindered the myosin adsorption at the oil–water interface.•Catechin (50–200 μmol/g) reduced the elasticity of interfacial protein film. The effects of different concentrations of catechin on the stability of myofibrillar protein-soybean oil emulsions and the related mechanisms were investigated. Adding 10 μmol/g catechin had no obvious effects on the emulsion stability and myosin structure, but 50, 100 and 200 μmol/g catechin decreased the emulsion stability. The microstructure observations showed that 10 μmol/g catechin caused a dense and uniform emulsion to form, whereas 50, 100 and 200 μmol/g catechin induced the merging of oil droplets. The addition of 50, 100 and 200 μmol/g catechin caused a decline in both the total sulfhydryl content and surface hydrophobicity, suggesting protein aggregation, which decreased the adsorption capacity of myosin and the elasticity of interfacial film. These results suggested that higher concentrations of catechin were detrimental to the emulsifying properties of myosin and that the dose should be considered when it is used as an antioxidant.