Emulsion stabilizing properties of various chitosans in the presence of whey protein isolate

The emulsion stabilizing potential of chitosans (CN) with various molecular weights and degrees of deacetylation (CNI = 1494 kDa, 78.1%DD; CNHI=694kDa, 78.5%DD; CNH12=319kDa, 78.5%DD; CNHK=749 kDa, 67.7%DD) was compared in the presence of whey protein isolate. Phase separation evolutions revealed minimal stabilizing concentrations against syneresis from 0.1 to 0.125% in most CN preparations, except CNH12 where it was higher (0.225%). Those stabilizing concentrations are the result of interfacial coadsorption saturation of CN with proteins, favouring interfacial electrostatic and steric stabilizing mechanisms. The emulsion characteristics (droplet size, limiting low-shear viscosity, and surface net charge), mostly distinctive at 0.1%CN, revealed the following order of stabilizing potentials: CN1 approximate to CNHI > CNHK > CNHI2, which is in agreement with respective phase separation evolutions. The lower stabilizing potential of CNH12 is explained by lower interfacial coadsorption efficiency with protein. In spite of a higher interfacial load of CNHK vs. CNI and CNHI, its lower stabilizing potential is essentially explained by a lower surface net charge. (c) 2004 Published by Elsevier Ltd.