Naringenin-loaded nanoparticles based on sodium caseinate and carboxymethyl chitosan for filled starch gels: Characterization, texture, stability, bioactivity, and digestion

Although naringenin exhibits a wide range of biological activities, its practical use is limited by its poor water solubility and bioavailability. In this study, a pH-driven method utilizing sodium caseinate and carboxymethyl chitosan (CMCS) was employed to prepare protein-polysaccharide composite nanoparticles (N/NC NPs) for naringenin delivery. These nanoparticles were formed through hydrogen bonds, hydrophobic bonds, and weak electrostatic interactions. The physicochemical stability of nanoparticles improved after the surface modification of CMCS, compared to sodium caseinate nanoparticles loaded with naringenin (N/N NPs). The water solubility and bioactivities of naringenin, including its in vitro hypoglycemic and hypolipidemic effects, inhibition of erythrocyte oxidative hemolysis, and antimicrobial qualities, and its release rate (63.55%) during digestion were all greatly improved after encapsulation. When used as an active filler in starch gels (N/NC-SG), the nanoparticles softened the textural properties and conferred bioactivity to the gel. Moreover, the reticular structure within the gel encapsulated the nanoparticles, providing a physical barrier and effectively regulating the delivery of naringenin. The bioaccessibility of naringenin in N/NC-SG (53.49%), N/NC NPs (44.59%), and N/N NPs (42.80%) is significantly higher than that of free naringenin (23.05%). Consequently, N/NC NPs improved the usability of naringenin. The preparation of N/NC-SG broadens the application potential of N/NC NPs in the food industry, and the nanoparticle-starch gel composite could serve as a new and efficient bioactive substance delivery system.