Preparation of curcumin-loaded pectin-nisin copolymer emulsion and evaluation of its stability.

In the paper, Nisin was grafted onto native pectin by the 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC·HCl) method. Structure characterisation showed that the carboxyl group of pectin interacted with the amino group of Nisin and formed an amide bond. The highest grafting ratio of the modified pectin was up to 24.89 %. The emulsifying property of modified pectin, significantly improved, and emulsification performance improved with increasing grafting ratio. Emulsifying activity, emulsion stability, Zeta potential, and droplet morphology data demonstrate a notable enhancement in pectin's emulsifying properties due to Nisin's introduction, with the degree of grafting showing a direct correlation with the improvement observed. Pectin-based emulsion is utilized to load curcumin, enhancing its stability and bioavailability. Research findings highlight that the incorporation of Nisin-modified pectin significantly elevates curcumin encapsulation efficiency, while decelerating its release rate. Moreover, the stability of curcumin loaded in the modified pectin under light exposure, alkaline conditions, and long-term storage is also significantly improved. Ultimately, the bioavailability of curcumin escalates from 0.368 to 0.785.