Effect of green tea on interaction of lipid oxidation products with sarcoplasmic and myofibrillar protein homogenates extracted from bovine top round muscle

•Aldehydes with longer carbon-chain length were bound stronger to the proteins.•Binding aldehydes to sarcoplasmic proteins was stronger than with myofibrillar.•Aldehydes bind to myoglobin surface with less favorable affinity than tea phenols.

The interaction between lipid oxidation products and bovine sarcoplasmic (SP) and myofibrillar protein (MP) homogenates in the presence of green tea was investigated. To monitor the effect of green tea on lipid oxidation, aldehydes were measured while effect on protein was monitored via changes in myoglobin, thiols, and tryptophan fluorescence over nine days of refrigerated storage. The presence of SP and MP decreased free aldehydes in the buffers. Sarcoplasmic homogenates bound aldehydes to a greater degree than MP. The tea compounds exhibited more favorable binding energies than aldehydes near histidine 64 close to the heme moiety of myoglobin. Addition of tea lowered tryptophan fluorescence and thiol content. The results suggested that green tea enhances the binding of bovine SP and MP to lipid oxidation products. The results also suggested that green tea can decrease rancidity by directly binding lipid oxidation products.