In Situ Fabrication of Starch-Based Hydrogels for Co-Encapsulation and Delivery of Vitamin D and Calcium

Hydrogels based on starch–fatty acid salt complexes were developed for targeted substance delivery. X-ray diffraction analysis confirmed that all complexes exhibited the typical V-type crystalline structure. Differential scanning calorimetry revealed structural differences between the complexes: the normal maize starch–sodium laurate complex formed a less ordered VI-type structure, whereas the maize starch–sodium palmitate samples displayed a coexistence of both VI- and VII-type inclusion complexes. This discrepancy is likely attributable to the difference in hydrophobicity between sodium laurate and sodium palmitate. Following calcium ion-induced gelation, oscillatory frequency sweep measurements revealed that the storage modulus (G′) exceeded the loss modulus (G″) for all hydrogel samples during detection, indicating that the hydrogels maintained a predominant elastic network structure. During simulated gastrointestinal digestion, a substantial portion of the released calcium ions and vitamin D was observed in the intestinal phase, suggesting that this starch–fatty acid salt complex-based hydrogel system holds promise as a viable carrier for the targeted delivery of bioactive compounds in food applications.