Regenerated silk fibroin for the stabilization of fish oil-loaded Pickering emulsions

Abstract

Protein nanofibril-stabilized Pickering emulsion is a promising emulsion in the field of food emulsion. However, no microscale protein fibrils have been applied as emulsifiers for the stabilization of food emulsions. In this work, regenerated silk fibroin (RSF) was prepared and applied to stabilize fish oil-loaded Pickering emulsions. RSF could form a microfiber-microfiber-nanofilm interconnection network at the oil/water interfaces to stabilize the emulsions. Fish oil-loaded RSF-stabilized Pickering emulsions showed low creaming (0% ≤ creaming index < 10%) during the 31-day storage at room temperature, which was lower than the creaming index values (10–47%) of the emulsions in previous report. Moreover, RSF is an excellent emulsifier to prepare semigel and gel of fish oil-loaded RSF-stabilized Pickering emulsions. For the RSF-stabilized Pickering emulsions, a lower oil/water volume ratio might induce lower initial droplet size, slower droplet coalescence, slower liquid-gel transition, and lower creaming stability. In addition, higher homogenization energy input (speed and time) and RSF concentration might induce lower initial droplet size, slower droplet coalescence, faster liquid-gel transition, and higher creaming stability for Pickering emulsions. Therefore, RSF could have good emulsion stabilization ability by adjusting preparation parameters and is a promising emulsifier to prepare emulsion semigel and gel in the field of food emulsions. This work provided useful information to understand the effects of preparation parameters on the formation and stability of RSF-stabilized emulsions.