Comparison of oil-in-water emulsions prepared by ultrasound, high-pressure homogenization and high-speed homogenization

This study was designed to compare the properties of myofibrillar protein (MP) stabilized soybean oil-in-water emulsions fabricated by ultrasound-assisted emulsification (UAE), high-pressure homogenization (HPH) and high-speed homogenization (HSH). The emulsion properties, droplet characteristics, interfacial proteins, protein exposure extent, microrheological properties, multiple light scattering results, and 7 d storage stabilities of the three emulsions were specifically investigated. Our results indicate that UAE and HPH were better emulsification methods than HSH to obtain high-quality emulsions with higher emulsifying activity index (UAE 20.73 m(2).g(-1), HPH 11.76 m(2).g(-1) and HSH 6.80 m(2).g(-1)), whiteness (UAE 81.05, HPH 80.67 and HSH 74.09), viscosity coefficient (UAE 0.44 Pa.s(n), HPH 0.49 Pa.s(n) and HSH 0.22 Pa.s(n)), macroscopic viscosity index (UAE 2.31 nm(-2).s, HPH 0.38 nm(-2).s and HSH 0.34 nm(-2).s), and storage stability, especially for the UAE. Furthermore, UAE was a more efficient emulsification method than HPH to prepare the fine MP-soybean oil emulsion. The protein-coated oil droplets were observed in the three emulsions. The emulsion droplet size of the UAE-fabricated emulsion was the lowest (0.15 mu m) while the interfacial protein concentration (93.37%) and the protein exposure extent were the highest among the three emulsions. During the 7 d storage, no separation was observed for the UAE-fabricated emulsion, while the emulsions fabricated by HPH and HSH were separated after storage for 5 d and 2 h. Therefore, this work suggests that UAE could be a better method than HPH and HSH to fabricate MP soybean oil emulsion.

Automated summary

This study compared the properties of myofibrillar protein stabilized soybean oil-in-water emulsions fabricated by ultrasound-assisted emulsification, high-pressure homogenization, and high-speed homogenization. The results showed that ultrasound-assisted emulsification and high-pressure homogenization were superior methods for emulsification, with ultrasound-assisted emulsification being more efficient. Furthermore, the emulsion fabricated by ultrasound-assisted emulsification had smaller droplet size, higher interfacial protein concentration and protein exposure extent, and better storage stability.