Regulation mechanism of ionic strength on the ultra-high freeze-thaw stability of myofibrillar protein microgel emulsions

The regulation mechanism of ionic strength (0-1000 mM) on the freeze-thaw (FT) stability of emulsions stabilized by myofibrillar protein microgel particles (MMP) was systematically investigated. High ionic strength emulsions (300-1000 mM) exhibited stability after five FT cycles. With ionic strength increasing, the repulsive force between particles gradually reduced, the flocculation degree (20.72 ∼ 75.60%) and apparent viscosity of emulsions gradually rose (69 ∼ 170 mPa·s), promoting the formation of protein network structures in the continuous phase. Concurrently, the interfacial proteins rearranged (18.8 ∼ 104.2 s-1) and aggregated rapidly, facilitating the formation of a stable interface network structure, ultimately improving its stability. Besides, scanning electron microscopy (SEM) images revealed that the interfacial proteins gradually aggregated, further forming a network with the MMP in the continuous phase, allowing MMP emulsions with enhanced FT stability at high ionic strength (300-1000 mM). This study was beneficial to produce emulsion-based sauces with ultra-high FT stability.