Undenatured type II collagen nanofibrils with sodium alginate coating: Structural characterization, physicochemical properties and capability to load curcumin.

In this study, the structural design and physicochemical property enhancement of undenatured type II collagen (UC-II) nanofibrils with sodium alginate (SA) coating induced by calcium ions (Ca) were investigated. The research aimed to elucidate the impact of Ca concentration on the morphology, thermal stability, and digestive resistance, as well as to assess the potential of UC-II/SA nanofibrils as a delivery system for curcumin (Cur). A series of Ca concentrations (1-9 mM) were methodically applied to optimize the condition that maintains the triple-helical structure of UC-II, thereby enhancing its functional properties. It was found that the Ca level up to 5 mM effectively preserved the structural integrity and improved thermal stability of UC-II, with the added benefit of ensuring the substantial delivery of active fragment to small intestine (70.7 %), which was 3.43 times greater than that of uncoated UC-II. Moreover, incorporating Cur into the UC-II/SA nanofibrils resulted in a 300 times increase in Cur solubility and showcased the superior dispersion stability, antioxidant activity, and sustained release profile during simulated digestion. These findings underscored the dual functionality of the UC-II/SA system as both a stabilizing agent for UC-II nanofibrils and an efficient carrier for Cur delivery.