Improving emulsifying properties of carboxylated microcrystalline cellulose by calcium bridging to hydrophobic peptides

Abstract

This study aimed to improve the emulsifying properties of microcrystalline cellulose by carboxylating (CC) and bridging to hydrophobic oat globule peptides (HP) via Ca²⁺ (CC-Ca-HP). FTIR and XRD spectra analysis proved the successful attachment of HP to CC through a salt bridge. The Ca²⁺-bridging significantly changed the particle characteristics of CC-Ca-HP, including particle size, ζ-potential, and wettability. The Ca²⁺-bridged composite CC-Ca-HP demonstrated remarkable emulsifying stability compared with the nonbridged blend (CC-HP). Further analysis of the steady flow characteristics and dynamic viscoelastic properties revealed a network structure formed in the CC-Ca-HP emulsion. Moreover, the CC-Ca-HP emulsion showed a marked release of free fatty acids, increased bioaccessibility of zeaxanthin in the simulated gastrointestinal digestion, and less oil oxidation under the accelerated oxidation condition, indicating that the stable structure of CC-Ca-HP imparted by Ca²⁺-bridging prevented the aggregation of oil droplets as collision occurred under the harsh gastric conditions.

Keywords: Bioaccessibility; Hydrophobic peptides; Microcrystalline cellulose; Pickering emulsion; Rheological property; Zeaxanthin.