Gelation of globular protein in presence of low methoxyl pectin: effect of Na~+ and/or Ca~(2+) ions on rheology and microstructure of the systems

摘要

The present investigation aimed at understanding how the type of cations (Na~+ and/or Ca~(2+)) influences heat-induced gelation of globular protein/LM pectin mixtures in comparison to the globular protein only. Two globular proteins (β-lactoglobulin or bovine serum albumin) were compared. On the basis of viscoelastic and microscopic observations (CLSM), it has been shown that the two cations play a major role in gelation of the individual biopolymers and, therefore, influence strongly the properties of the mixture. These differences are related to a competition between gelation of the protein (in absence of Ca~(2+)) or of both biopolymers (if Ca~(2+) is added) and phase separation processes taking place before the mixed system is entirely gelled.