Designing W1/O/W2 double emulsions stabilized by protein-polysaccharide complexes for producing edible films: Rheological, mechanical and water vapour properties

Rheological properties and the droplet mean volume-surface diameter of water-in-oil-in-water double emulsions ELMP-WPI and ECMC-WPI, stabilized with low-methoxyl pectin (LMP)-whey protein isolate (WPI) or sodium carboxymethylcellulose (CMC)-WPI complexes were determined. ELMP-WPI emulsions showed smaller droplet diameter (2.47 mu m) than ECMC-WPI emulsions (10.68 mu m), and higher values of apparent viscosity, storage modulus and loss modulus. Microstructure and mechanical properties of the FLMP-WPI and FCMC-WPI films were affected by the type of the stabilizing biopolymer complex used in the formulation of the ELMP-WPI and ECMC-WPI double emulsions from which were prepared. The FLMP-WPI films microstructure consisted of a biopolymer mainframe relatively compact, interrupted by small emulsion droplets. The FCMC-WPI film mainframe had an open and oriented structure, in which relatively large emulsion droplets were packed. FLMP-WPI films presented higher values of transparency, tensile strength and Young's modulus, but lower elongation percentage and comparable water vapour permeability than FLMP-WPI films. (C) 2010 Elsevier Ltd. All rights reserved.