Multiscale Evaluation of Protein-Based Emulsion Gels: Impact of Gel Network Structure

Proteins are widely used as emulsifiers and gelling agents in emulsion gels to form a three-dimensional (3D) network structure, providing increased physical and chemical stability. Protein-based emulsion gels have versatile applications in the design of future food, such as precision, sustainable, and healthy food. Multiscale evaluation of protein-based emulsion gel systems is particularly important for developing future foods suitable for modern consumers. This study focuses on the effect of the protein gel network structure on the properties of emulsion gels, and the methods used to evaluate the gel network structure are described in detail. Texture profiles, gel strength, water and oil-holding capacities, rheological properties, freeze-thaw and oxidation stability, and sensory, digestive, and nutritional properties are commonly used to evaluate the characteristics of protein-based emulsion gels. The formation and quality of a 3D network structure significantly influence the aforementioned properties of protein-based emulsion gels. Compared with atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and X-ray, cryo-scanning electron microscopy (cryo-SEM) provides more reliable results of the gel network structure, helping to better clarify the mechanisms behind quality changes in protein-based emulsion gels. Future work should focus on standardizing the observation method for 3D network structures, establishing the relationship between network structure and gel properties, developing emerging technologies for 3D network observation, and creating sustainable protein-based emulsion gels.