Whey Protein-Based High Internal Phase Emulsion Gel Characterization and Its Effect on the Textural and Melting Properties of Processed Cheese

Some undesirable physical characteristics of processed cheese due to insufficient fat emulsification have prompted extra ingredients to be added to compensate. Whey proteins offer promising nutritional and emulsifying properties. In this study, whey protein and corn oil were applied to high internal phase emulsion gels with enhanced texture of processed cheese while offering additional functional ingredients. Emulsion gels were prepared after pre-emulsification of different levels of corn oil and milk fat and used in cheese. The gel strength, water holding capacity (WHC), rheology, and thermal stability properties of gel, as well as the texture and melting properties of cheese, were characterized. Corn oil could be pre-emulsified by heat-denatured whey protein forming a stable hexagonal arrangement structure at higher oil content, and the emulsion gels exhibited good viscoelasticity, WHC, and thermal stability. In contrast, the high crystallinity of milk fat conferred hardness to gel at higher oil content but was detrimental to the network structure of gel, with large gel particles and a rough network. The cheese made from high internal phase emulsion gels had a soft texture, and corn oil was more effective than milk fat in reducing the hardness of cheese, giving springness and cohesiveness to cheese, with a significant reduction in oil separation.