Preparation, characterization, and application of composite oleogels based on whey protein isolate and sodium alginate.

Oleogels with solid-like properties can serve as substitutes for fats, thereby avoiding the consumption of high levels of saturated fatty acids. In this study, we developed a protein-polysaccharide composite network oleogel using whey protein isolate (WPI) and sodium alginate (SA) through an emulsion-templated method. Analysis with Fourier Transform Infrared (FTIR) spectroscopy confirmed the presence of hydrogen bonds and van der Waals forces between WPI and SA, which bolstered the oleogel's structure. The enhanced oxidative stability and oil binding capacity of the WPI-SA composite oleogels were attributed to these interactions, as compared to the WPI single-network oleogel. Large-amplitude oscillatory shear testing demonstrated that the WPI-SA composite oleogels exhibited good plastic behavior and irreversible shear thinning, whereas the WPI single-network oleogel displayed more viscous behavior and shear-thinning characteristics. In applications, replacing pork fat entirely with the WPI-SA composite oleogel in Harbin red sausage resulted in a product with similar texture and sensory qualities to the original sausage. These results suggested that the WPI-SA composite oleogel could be a potential suitable fat substitute in the food industry, particularly for meat products.