The effect of interfacial interactions on the rheology of water in oil emulsions oleogelled by candelilla wax and saturated triacylglycerols

The effects of water-oil interfacial activity of candelilla wax (CW), glycerol monopalmitate (GMP), glycerol monooleate (GMO) and polyglycerol-polyricinoleate (PGPR) on the microstructure and rheology of W/O emulsions oleogelled with CW and fully hydrogenated soybean oil (FH) was investigated. The emulsifier with the highest interfacial activity was PGPR, followed by GMO, and GMP. Polar compounds of CW (CW-PC) also displayed interfacial activity. Interfacial interactions of the continuous lipid crystal network with the CW-PC and PGPR in W/O emulsions decreased the elastic modulus (G ') as the aqueous phase (AP) increased, indicating the water droplets behaved as inactive filler due to a weak interaction with the continuous phase. In contrast, the CW-PC and the monoglycerides had a cooperative interaction on the interfacial tension reduction. W/O emulsions produced with monoglycerols maintained or increased their G ' as the AP increased, denoting a strong interaction of water droplets and the continuous phase (i.e., active filler behavior). At constant content of AP and FH, G ' of emulsions tended to decline as the PGPR content increased, while the opposite was observed with emulsions produced with GMO. Adding 10% FH to the emulsions magnified both the active and inactive filler effects produced by GMO and PGPR, respectively.