A comparative investigation of anionic polysaccharides (sulfated fucan, ?-carrageenan, ?-carrageenan, and alginate) on the fabrication, stability, rheology, and digestion of multilayer emulsion

In this study, four important marine polysaccharides (sulfated fucan, iota-carrageenan, kappa-carrageenan, and alginate) were selected and tailored to a similar molecular weight using heterologously overexpressed enzymes. These "standardized " polysaccharides were firstly used to elucidate the effect of anionic polysaccharides on the for-mation, stability, rheology, and digestion of the multilayer emulsions. Results showed that the four poly-saccharides were all capable of adsorbing to the surfaces of lipid droplets at the pH values of 5, 4, and 3. iota-Carrageenan could adsorb to the surface of the droplet at a higher pH (pH 6) than the other three poly-saccharides (pH 5). Stable multilayer emulsions were formed at a higher polysaccharide concentration (0.05 wt %) for kappa-carrageenan compared with sulfated fucan, iota-carrageenan, and alginate (0.04 wt%). The emulsion containing alginate was susceptible to flocculation at low pH (pH 3) and high polysaccharide concentration (> 0.1 wt%). Multilayer emulsions fabricated by iota-carrageenan were stable under all the examined NaCl con-centrations (0-400 mM). Multilayer emulsion fabricated by sulfated fucan showed less aggregation in the stomach stage, which is a good choice to encapsulate acid-intolerant substances. Multilayer emulsions fabricated by kappa-carrageenan and alginate showed higher apparent viscosity, and the rheological curves of multilayer emulsions fabricated by FUC or ICA were quite similar. Moreover, multilayer emulsions fabricated by kappa-carra-geenan showed the fastest digestion rate and the highest digestion extent. These findings would facilitate the targeted design of multilayer emulsions by selecting suitable polysaccharides.