Influence of whey protein isolate-chitosan oligosaccharide micro gel pickering emulsion on reducing fat bioaccessibility and physicochemical features of cheddar cheese

This study investigated the feasibility of protein/chitosan-based Pickering emulsions as a fat replacer in low-fat cheddar cheese. It compared the chemical composition, functional properties, and microstructure of full-fat cheese (FFC) with reduced-fat cheese (RFC) and low-fat cheese (LFC), both utilizing a whey protein isolate-chitosan oligosaccharide (WPI-COS) microgel-stabilized emulsion as a fat substitute. The results indicated that cheese yield decreased following the substitution with fat replacers, although the cheese had higher protein and moisture contents, and lower fat content. Color analysis revealed that WPI-COS microgels significantly mitigated color defects in low-fat cheese. The use of WPI-COS microgels as matrix fillers resulted in a denser cheese structure, but simultaneously observing cheese collapse associated with poor meltability and denser structure. This observation corresponded to increased hardness, elasticity, and G′, thus demonstrating improved chewiness. Scanning electron microscopy observations demonstrated that the microstructures of RFC and LFC were more uniform and smoother. Confocal laser scanning microscopy revealed smaller and more uniform fat globules in RFC and LFC groups, preventing quality issues caused by fat aggregation. Compared to FFC, RFC and LFC groups had higher levels of fatty acid, especially caproic, nonanoic, and capric acids, providing a rich fatty flavor. Hydrocarbons, aromatic, and heterocyclic compounds also contributed to cheese flavor, as well as the fruity taste produced by toluene. Additionally, nonanal compounds were detected due to the action of WPI-COS which imparted a greasy and citrus flavor to the low-fat cheese. These findings suggested that WPI-COS microgel-stabilized Pickering emulsions could be a feasible way as fat substitutes of cheddar cheese, offering potential benefits for reducing fat bioaccessibility in dairy products. This approach may have significant implications for the dairy industry, particularly in the development of healthier low-fat cheese options, as well as for public health by offering a viable strategy to reduce saturated fat consumption.