Spray-drying and rehydration on ß-carotene encapsulated Pickering emulsion with chitosan and seaweed polyphenol.

ABSTRACT

The spray-drying process to generate microcapsules from Pickering emulsions needs high temperatures, leading to instability of emulsions and degradation of encapsulated thermosensitive compounds (ß-carotene). However, these effects may be attenuated by the introduction of seaweed polyphenols into the emulsion interfacial layers, although the effects underlying this protective mechanism have not been explored. This study evaluates the effects of spray-drying/rehydration on the morphology, encapsulation efficiency, redispersibility, and stability of ß-carotene loaded Pickering emulsions stabilized by chitosan (PESC) and Pickering emulsions stabilized by chitosan/seaweed polyphenols (PESCSP). The encapsulation efficiency of ß-carotene in PESCSP microcapsules (61.13 %) was higher than PESC (53.91 %). Rehydrated PESCSP exhibited more regular droplet size distribution, higher stability, stronger 3D network morphology, and lower redispersibility index (1.5) compared to rehydrated PESC. Analyses of interfacial layers of emulsions revealed that chitosan covalently bound fatty acids at their hydrophobic side. Polyphenols were linked to chitosan at the hydrophilic side of emulsions through hydrogen bonds, providing 3D network between droplets and antioxidant activities to inhibit the degradation of ß-carotene. This study emphasized the role of polyphenols in the interfacial layers of Pickering emulsions for the development of efficient delivery systems and protection of ß-carotene and other thermosensitive bioactive compounds during spray-drying and rehydration.