Biomass Lignin Stabilized Anti-UV High Internal Phase Emulsions: Preparation, Rheology, and Application As Carrier Materials

Biomass enzymatic hydrolysis lignin (EHL) was used as emulsifier to produce oil-in-water high internal phase emulsions (HIPEs) with the assistance of sodium dodecyl sulfate (SDS). The effects of EHL concentration, SDS dosage, oil/water ratio, and pH of water phase on the microstructure, stability, and rheological properties of the HIPEs were investigated via optical microscopy and rheometer. The results showed that HIPEs with internal phase of 80 vol % had smaller diameter and tighter droplets packing when emulsified by 5.0 wt % EHL and 1.0 wt % SDS, which were very stable and displayed no significant change over a period of one month. EHL/SDS costabilized HIPEs with smaller droplets had higher viscosity, yield stress, complex viscosity, and storage moduli values (G′). The experimental G′ values of the HIPEs were compared with the values predicted from the Princen and Kiss model and from the modified Mougel model, giving insight into the critical effects of nonideality induced by polydispersity in highly viscous emulsions. In addition, the HIPEs exhibited an outstanding protection on UV-induced degradability of curcumin. The residual level of curcumin encapsulated in the HIPEs reached 60.3% after 72 h of UV irradiation. Meanwhile, the curcumin loaded HIPEs displayed rapid drug release and thermal stability in the PBS buffer solution.