Emulsion food is widely consumed in daily life, and natural protein stabilization emulsion is concerned. Myofibrillar protein is an important natural protein in muscle, and its emulsifying property affects the quality of emulsified meat products. Ultrasound-assisted emulsification, high pressure homogenization and high speed homogenization are commonly used to prepare myofibrillar protein emulsions. However, due to their different emulsification mechanisms, the emulsion properties are different.
The experimental materials included fresh pig back muscle, soybean oil and pure chemical reagents for analysis. Pig myofibrillar protein was extracted according to the literature method, and the protein concentration was determined by a kit.
Emulsion activity index and stability index of emulsion prepared by high pressure homogenization and ultrasonic assisted emulsification were higher than those prepared by high speed homogenization, and the emulsion activity index of emulsion prepared by ultrasonic assisted emulsification was significantly higher. The turbidity and whiteness of emulsions prepared by high pressure homogenization and ultrasonic assisted emulsification are higher, which is related to their smaller droplet size. The emulsion prepared by high speed homogenization has the highest apparent viscosity and shear stress, and the emulsion prepared by high pressure homogenization and ultrasonic assisted emulsification has lower yield stress and higher viscosity coefficient, which is more beneficial to emulsion flow.
The size of emulsion droplets prepared by ultrasonic-assisted emulsification is the smallest, and the size of emulsion droplets prepared by high-speed homogenization is the largest. Laser scanning confocal microscopy and cryo-scanning images showed that the emulsion droplets prepared by ultrasonic-assisted emulsification dispersed more evenly, and the emulsion droplets prepared by high-pressure homogenization were tightly connected by myofibrillar protein.
High pressure homogenization and ultrasonic-assisted emulsification increased the surface hydrophobicity and free sulfhydryl group content of myofibrillar protein, and the protein molecular development was higher. The emulsion prepared by high pressure homogenization and ultrasonic assisted emulsification has higher absolute zeta potential and better stability.
