Pickering emulsions by combining nanocellulose/nanochitin and silk fibroin: Silk fibroin as a stabilizer or an emulsifier

Silk fibroin (SF) was considered as emulsifier due to its inherent amphiphilicity. Nevertheless, SF was also speculated to act as a stabilizer in emulsions because of its self-assembly in the interfaces and formation of viscoelastic surface or interfacial layers. Here, the emulsions were produced by mixing SF with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized nanocellulose (TOCN) or partially-deacetylated nanochitin (DEChN) as a continuous phase. The performance of emulsions was examined in regard to the concentrations of TOCN, DEChN, and SF. And comparative emulsions stabilized by conventional surfactants alongside TOCN or DEChN were prepared. Emulsion stability and droplet size were influenced by TOCN or DEChN concentration, while SF concentration played a minor role. SF exhibited stability enhancement compared to conventional surfactants. Overall, emulsions remained highly stable over 30 days with substantial TOCN, DEChN, and SF (>= 0.4%) concentrations. This work provides valuable insights into choosing stabilizers or emulsifiers for use in the emulsion.