Characterization of chitosan-ferulic acid conjugates and their application in the design of β-carotene bilayer emulsions with propylene glycol alginate

Abstract

The current study investigated the formation of chitosan-ferulic acid (FA) conjugates (CFC), and the application of CFC and propylene glycol alginate (PGA) in designing β-carotene bilayer emulsions. CFC was synthesized based on the carbodiimide-mediated coupling reaction, which was confirmed by FITR and 1H NMR analysis. The resulting CFC could have a high ratio of FA grafted onto chitosan (83.20 ± 0.81 mg/g) and exhibited stronger antioxidant activity than FA, and better water solubility than chitosan alone. Being oppositely charged, PGA and CFC formed bilayer interface covering the oil droplets of β-carotene emulsions through electrostatic attraction. The results showed that the concentration of CFC affected the interfacial content of FA, particle size, and surface charge of the droplets in β-carotene emulsions. Compared to chitosan or chitosan-FA mixture (CFM) stabilized bilayer emulsions with PGA, CFC stabilized bilayer emulsions showed better creaming stability against different environmental stresses (i.e., pH, heat and ionic strength) and higher β-carotene stability when exposed to thermal treatment and UV light. The knowledge obtained in the present study could be useful in designing bilayer emulsions for bioactive compounds with improved performance.