Engineering heat-resistant high internal phase emulsions via Gelatin/soy protein isolate heterogeneous protein...

This study addresses the limited thermal stability of gelatin (GA)-stabilized high internal phase emulsions (HIPEs), which restrict their application in heat-processed food systems. To overcome this challenge, heterogeneous protein complexes based on type A GA and soy protein isolate (SPI) were engineered at varying ratios through thermal assembly, and their structural, interfacial, and rheological characteristics were systematically investigated. The formation of GA-SPI complexes was driven by intermolecular hydrogen bonding and electrostatic attraction, with increasing SPI proportion leading to smaller complex particles, enhanced surface hydrophobicity, and improved thermal stability. HIPEs stabilized by GA-SPI complexes demonstrated remarkable heat resistance, particularly at a GA:SPI ratio of 5:5, showing minimal droplet coalescence, increased apparent viscosity, and superior viscoelastic properties after heating (P < 0.05). The enhanced performance was attributed to SPI-induced hydrophobic adsorption and the formation of thermally cross-linked viscoelastic networks. Overall, this work presents a practical approach for designing heat-resistant, GA-based HIPE systems that serve as promising reduced-fat and thermally stable food matrices.