Effects of citrus fiber on the emulsifying properties and molecular structure of mutton myofibrillar protein: An underlying mechanisms study

The effects of water-soluble citrus fiber (SCF) and water-insoluble citrus fiber (ICF) on emulsifying properties and molecular structure of the mutton myofibrillar protein (MP) were studied. The emulsifying activity index and emulsifying stability index of MP emulsion, treated with 5% SCF significantly improved to 36.80% and 65.27%, respectively. The droplet size of the emulsion significantly reduced, forming smaller and more uniformly dispersed droplets. SCF promoted the unfolding of MP, and showed a significant increased (p < 0.05) in total sulfhydryl content and fluorescence intensity, but a significant decreased (p < 0.05) in surface hydrophobicity. Besides, SCF treatment showed a significant reduction (p < 0.05) in α-helix content and a significant enhancement (p < 0.05) in β-turn content of the MP secondary structure. The EAI, ESI, and solubility of MP significantly decreased after the addition of ICF, but there was no significant change in the secondary structure. These data demonstrated that, the addition of the appropriate amount of SCF could improve the emulsifying properties and molecular structure of MP.