Interfacial Properties and Visualization of Emulsions Stabilized by Temperature-Triggered Bovine Bone High-Temperature Hydrolysate

Temperature is an important factor affecting the stability of emulsified products. This study explored how the typical temperatures in the industry (55, 70, and 85 °C) influence the stability of bovine bone high-temperature hydrolysate emulsion by modulating the interfacial properties. The results showed that heat treatment at 70 °C could improve the interfacial properties. In terms of structure, treatment at 70 °C facilitated the unfolding of the interfacial protein α-helix to the β-turn and β-sheet. Moreover, the interface was relatively smooth at 70 °C, while holes appeared at 55 and 85 °C. In addition, the disulfide bond promoted cross-linking, and the hydrogen bond strengthened the interfacial network. However, the cross-linking was seriously damaged at 85 °C. The most improved emulsion stability (the smallest droplet size, no aggregation) was observed at 70 °C. The lower interfacial protein concentration and layer thickness at 55 and 85 °C were insufficient to cover all oil-water interfaces, resulting in droplet aggregation. Our results demonstrated that heat treatment at different temperatures could change the interfacial properties, which was the main reason for the difference in emulsion stability.