Exploring the potential of plant-based emulsion gels enriched with β-glucan and potato protein as egg yolk alternatives

Abstract

This study investigated the microstructure, physicochemical properties, and digestibility of plant-based egg yolk (PBEY) as a potential replacement for real egg yolk (REY). The PBEY consisted of oil-in-water emulsions containing β-carotene and vitamin D in the oil phase and β-glucan and potato proteins in the aqueous phase. The potato proteins were used as natural emulsifiers and gelling agents, the β-carotene was used as a natural yellow pigment, and the β-glucan, β-carotene, and vitamin D were used to improve the nutritional profile. In aqueous solutions, β-glucan was susceptible to aggregation and precipitation. However, it remained stable in PBEY during storage, which was attributed to non-covalent interactions between the potato proteins and β-glucan. β-glucan increased the apparent shear viscosity and shear thinning behavior of the PBEY, which was attributed to its polymeric nature. The thermal gelling properties of the PBEY were also affected by β-glucan addition, with a decrease in gelation temperature and final gel strength, indicating changes in gel structure. The addition of β-glucan also increased the hardness and resilience of the egg analogs, with 2.5 wt% yielding properties like REY in terms of springiness and chewiness. The color matching theory was used to match the color of the PBEY to REY. Optimizing the concentration of β-carotene in the PBEY allowed us to successfully match the yellow color of REY. The presence of β-glucan in the PBEY increased protein hydrolysis during simulated gastric and small intestinal digestion, but it decreased lipid hydrolysis and vitamin D bioaccessibility in the small intestine. This reduced bioaccessibility was attributed to the ability of the polysaccharide to inhibit the digestion of the protein-coated oil droplets. This study provides an improved understanding of how β-glucan affects the properties of nutrient-fortified PBEY. The PBEY developed in this study may be suitable for consumers seeking healthy and sustainable plant-based alternatives to REY. However, further research is required to test the sensory properties.