Fucoidan extracted by different methods and bound to zein loaded curcumin nanoparticles: Preparation, physicochemical stability, and in vitro functions

In this study, fucoidan (Fuc) extracted from kelp by water (WFu) and acid (AFu) was combined with zein to prepare nanoparticles. Its potential application as a curcumin (Cur) delivery system was also investigated. The results of chemical composition analysis showed that the sulfate content of AFu (26.44%) was significantly higher than that of WFu (19.65%). The molecular weight (Mw) and monosaccharide composition of WFu and AFu were also different. The anti-solvent precipitation method was used to prepare the nanoparticles. The analysis of nanoparticles with different mass ratios showed that the nanoparticles with a mass ratio of Fuc/zein of 1.5:1 had uniform particle distribution, good stability and the best encapsulation effect. Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and fluorescence spectroscopy showed that hydrogen bonds and electrostatic interaction were the main forces responsible for the formation of the nanoparticles. Moreover, Fuc enhanced the thermal and storage stability of zein nanoparticles (ZNP). An in vitro digestion experiment using nanoparticles revealed that Fuc-ZNP had strong tolerance to the gastrointestinal tract and could be used for colon-specific Cur delivery. In addition, antioxidant experiments showed that Fuc significantly increased the antioxidant activity of ZNP (P < 0.05). In conclusion, Fuc-ZNP have potential as a Cur delivery system.