Effect of process conditions, and component concentrations on the viscosity of κ-carrageenan and pregelatinised cross-linked waxy maize starch mixed fluid gels

The formation and characterisation of kappa-carrageenan and pregelatinised cross linked waxy maize starch mixed fluid gels on a Kinexus Pro rotational rheometer using vane geometry has been described. The viscosity of mixed fluid gels containing between 0.5 and 4% w/w starch was investigated and compared to fluid gels of kappa-carrageenan only. The dependence of the fluid gels initial and final viscosity on the application of shear rates between 1 and 600 s(-1), and cooling rate between 0.5 and 3 degrees C applied during hydrocolloid gelation was studied, along with the effect of altering the concentration of its components. The presence of pregelatinised cross linked waxy maize starch during fluid gel formation has been shown to decrease the onset gelling temperature by approximately 2 degrees C when compared to the kappa-carrageenan only fluid gel. The apparent 26 fold increase in the final fluid gels viscosity as a result of producing a 2% starch mixed fluid gels has the potential for composite fluid gels of this kind to be used as more effective thickening agent in fat replacement products than their kappa-carrageen only counterparts. (C) 2014 Elsevier Ltd. All rights reserved.