Enhancing emulsion stability to environmental stresses using whey protein-tragacanthin interfacial complexes: Comparison of layer-by-layer and mixing methods

International Conference on Food Chemistry & Hydrocolloids

August 11-12, 2016 Toronto, Canada

Soleiman Abbasi, F Azarikia, M G Scanlon and D J McClements

Tarbiat Modares University, Iran
University of Manitoba, Canada
University of Massachusetts, USA

Posters & Accepted Abstracts: J Exp Food Chem

Abstract :

Electrostatic interfacial complexes can be formed around the oil droplets in oil-in-water emulsions using either layer-by-layer (LBL) or mixing methods. The LBL approach involves forming the interfacial complexes after homogenization, whereas the mixing approach involves forming them before homogenization. The objective of this research was to compare the stability of emulsions prepared using these two approaches to environmental stresses when the oil droplets were coated by whey protein isolate (WPI) and tragacanthin (T) complexes. In the mixing approach, the emulsion was prepared by homogenizing an aqueous phase containing WPI-T complexes (0.4:1% w/w) with an oil phase using sonication. In the LBL method, an emulsion containing WPI-coated droplets was formed by sonication; then, it was mixed with a tragacanthin solution to form a final emulsion containing droplets coated by WPI-T complexes (0.4:1 % w/w). The effect of heating, salt addition (50mM NaCl or 17 mM CaCl2), and freezing-thawing on the stability of the emulsions was investigated. The presence of tragacanthin improved the thermal stability of both mixed and LBL emulsions at pasteurization but not sterilization temperatures. LBL emulsions were also stable against salts. Emulsions containing CaCl2 had higher apparent viscosity than those containing NaCl, which suggested that the calcium ions induced droplet flocculation. However, the emulsions were still stable to gravitational separation. Moreover, the presence of tragacanthin improved the stability of the LBL emulsions against freezing-thawing. The better stability of the LBL emulsions than the mixed emulsions may be attributed to the depolymerization of the tragacanthin during sonication.

Biography :

Email:sabbasifood@modares.ac.ir