Caffeic Acid-Modified Mushroom Chitosan as a Natural Emulsifier for Soybean Oil-Based Emulsions and Its Application in β-Carotene Delivery

In this study, we developed a soybean oil-based emulsion system stabilized by caffeic acid-modified mushroom-derived chitosan, significantly enhancing its functional properties. The modification increased the grafting ratio from 5.02% to 8.26%, which greatly improved antioxidant activity and antimicrobial efficacy against Escherichia coli and Staphylococcus aureus. The modified chitosan exhibited superior rheological properties, including increased viscosity and elasticity, contributing to improved emulsification performance. Emulsions stabilized with caffeic acid-modified chitosan showed smaller and more uniform droplet sizes, along with greater stability, as indicated by a higher zeta potential (55.63 mV). These modifications resulted in enhanced β-carotene encapsulation efficiency (up to 87.46%) and improved bioaccessibility (up to 52.13%), highlighting the system’s potential as an efficient food-grade carrier for hydrophobic bioactive compounds. In conclusion, caffeic acid-modified mushroom chitosan is an effective natural emulsifier, enhancing stability, antioxidant activity, and nutrient delivery, and has promising applications in functional foods and nutraceuticals.