Pectin-whey protein complexes vs. small molecule surfactants for stabilization of double nano-emulsions as novel bioactive delivery systems

Water-in-oil-in-water (W1/O/W2) double emulsions are one of the most efficient nutraceutical delivery systems. Our main objective was to compare some emulsion properties of double nano-emulsions loaded with gallic acid in W1 phase. Polyglycerol polyricinoleate (PGPR), and pectin-WPC or/Tween 80 were applied as emulsifiers in W1-O and O-W2 interfaces, respectively. Our results revealed that complex of pectin-WPC had the same resistance against sedimentation and creaming as Tween 80. The particle size of double emulsions produced by Tween 80 and pectin-WPC were in the range of 98–577 and 100–1520 nm, respectively. Z-potential of double emulsions prepared with pectin-WPC were more negative than −30 mV; so they were more stable during the long term storage. The optimum conditions for preparing WPC-pectin stabilized delivery systems were determined as 5, 75 and 20 (wt. %) PGPR, soybean oil and deionized water, respectively for internal W1/O nano-emulsion; and 1, 4, 79 and 16 (wt. %) pectin, WPC, deionized water, and internal nano-emulsion, respectively for the W1/O/W2 emulsions. Student's t-test analysis revealed that except for z-potential, there were no significant differences between emulsifiers (pectin-WPC and Tween 80). The present study demonstrates that pectin-WPC complex can be used as an appropriate emulsifier comparable with Tween 80 for stabilizing double emulsions.