Impact of solid-to-liquid lipid ratio on the gelation and emulsion properties of lamb myofibrillar protein gels

The effects of different olive and coconut oil ratios on the physicochemical and rheological properties of lamb myofibrillar protein emulsion gels were investigated. Solid fat index and viscosity analyses revealed that optimal solid-to-liquid fat ratios enhanced gel strength and emulsion stability by forming dense protein-fat interfacial layers. Medium-chain triglycerides of coconut oil contribute to increased viscosity at lower temperatures, whereas excessive amounts (>60 % of total lipid) disrupt the protein matrix and weaken the gel strength. Fourier-transform infrared spectroscopy analysis showed that moderate coconut oil levels promoted α-helix formation, improving protein stability and water-holding capacity, whereas excessive incorporation led to random coil formation and lower water retention. Rheological analysis confirmed the highest storage modulus at 40 %–60 % coconut oil, supporting the strongest gel network. The morphological analysis revealed smaller and more uniformly distributed pores at optimal ratios, corresponding to superior mechanical strength and stability. These findings demonstrate the critical role of the oil composition in determining the structural and functional properties of emulsion gels.