Influence of ionic strength and thermal pretreatment on the freeze-thaw stability of Pickering emulsion gels

Salt addition and thermal pretreatment were used to improve the freeze-thaw stability of Pickering emulsion gels (PEGs) stabilized by compound proteins. Thermal pretreatment with the presence of salt could promote the formation of gel-like structure and alter the interactions between the emulsion droplets of PEGs, sequentially increase the resistance of the PEGs to water separation, creaming, and oiling-off during freeze-thaw cycles (freeze at -20 degrees C for 22 h and thawing at 37 degrees C for 2 h), especially at higher salt levels (200 and 500 mM). Microstructures indicated that the presence of high salt concentration and heat pretreatment could help to maintain the gel-like structures of PEGs during freeze-thaw cycles. Overall, our results showed that novel viscoelastic food materials with good freeze-thaw stability can be produced by controlling the electrostatic interactions between the emulsion droplets and the gelation of emulsion gels. These materials may be useful for application in frozen food products.