Preparation, rheological properties, and in vitro digestibility of starch-based hydrogel beads for curcumin delivery

Curcumin (CUR) possesses notable health benefits but suffers from poor solubility, instability, and low bioavailability. To address these limitations, this study developed a novel starch-chitosan composite cross-linked with citric acid (CA). The modified starch was employed in the fabrication of emulsion and emulsion gel beads, which were systematically evaluated based on rheological properties, texture, moisture distribution, and in vitro digestibility. The starch-based emulsion exhibited higher storage modulus and loss modulus compared to the emulsion. Texture analysis revealed that the hardness and adhesiveness decreased to 1.89 ± 0.13 N and 0.66 ± 0.05 N, respectively, while cohesion, elasticity, and chewiness were increased. The LF-NMR results indicated that the CA combined CS modified starch-based emulsion beads (CA/CS-SEB) had a diminished proportion of free water and a correspondingly greater proportion of bound water compared to starch-based emulsion beads (SEB). The encapsulation efficiency of the CUR-loaded beads reached 86.50 ± 0.25 %. In simulated gastrointestinal digestion, CA combined CS modified starch-based emulsion beads loaded with curcumin (CA/CS-SEB-CUR) exhibited the slowest release ratio, which decreased from 23.20 ± 0.03 % to 17.03 ± 0.77 %. These findings provide a theoretical basis for the use of modified starch and propose a viable strategy for curcumin delivery.