The mechanism of molten-globule-state conformation transition from bulk phase to oleogel interface.

Oleogels have potentials as fat substitutes to improve emulsification stability, and unsaturation degree of oleogels affect molecular conformation transition and stability of oleogel-myofibrillar protein (MP) interface. The adsorption behavior and transition mechanism of molten-globule (MG)-state proteins were investigated at the oleogel interface, considering unsaturation degree of oil phase. Results indicated that β-sheets, hydrophobic interaction and active sulfydryls of bulk and interfacial MPs gradually decreased as adsorption time prolonged, in which MG-state conformation was transformed into unfolding conformation. As the unsaturation degree of triglyceride-type fatty acids in the oleogels increased, MG-state conformation was kept longer. Interfacial pressure and adsorption capacity significantly increased along with unsaturation degree. Moreover, oleogels with high unsaturation degree were conducive to penetration and film-forming as well as increment in Ed, Ev and E values. The oleogel interface with C20:5 and C22:6 facilitated to reach equilibrium state faster and to form a thicker interfacial adsorption layer with high elasticity compared C18:2 and C18:3. Hence, highly unsaturated triglycerides delayed MG-state conformation transition and enhanced the stability of oleogel-MP interface.