NaCl addition increased the stabilization ability of Pickering emulsion stabilized by tannic acid-crosslinked silver carp spine bone pepsin enzyme hydrolyzed gelatin nanoparticle conjugates

Polyphenol crosslinking is a promising method to improve the properties of a protein. Herein, the effects of tannic acid-crosslinking and NaCl addition on the properties of silver carp spine bone hydrolyzed gelatin nanoparticles were explored. PEHG was extracted with pepsin (6 U/g silver carp spine bone) and then self-assembled into nanoparticles (named as PEHG6). Tannic acid-crosslinked PEHG6 nanoparticle conjugates (named as PEHG6-TA) were synthesized by covalently crosslinking ≥ two PEHG nanoparticles with one TA molecule. The effects of NaCl addition and heating pretreatment on the Pickering emulsion stabilization ability of PEHG6-TA were studied. The results suggested that PEHG6-TA induced faster droplet coalescence, slower liquid-gel transition, and lower creaming stability of Pickering emulsions than PEHG6 did. NaCl addition delayed the liquid-gel transition and decreased the creaming stability of PEHG6-stabilized Pickering emulsions, whereas it speeded the liquid-gel transition and increased the creaming stability of PEHG6-TA-stabilized Pickering emulsions. PEHG6-TA induced more stable Pickering emulsion droplets against coalescence after the heating pretreatment than PEHG6 did. Heating pretreatment promoted the liquid-gel transition of PEHG6-TA-stabilized Pickering emulsions. Heating pretreatment temperatures had no obvious effect on the creaming stability of both PEHG6-stabilized and PEHG6-TA-stabilized Pickering emulsions. This work provided useful information to understand the effect of polyphenol crosslinking on the properties of protein nanoparticles.