COMPOSITE MECHANICAL-BEHAVIOR OF CARRAGEENAN GUM MIXED GELS - INFLUENCE OF COMPOSITION

A comparative study of the evolution of values of 18 mechanical parameters obtained by subjecting carrageenan-locust bean gum and carrageenan-locust bean gum-guar gum gels of different composition to compression, penetration and cutting tests was carried out. The study was performed in two series of 15 samples of 0.5 and 0.75% total hydrocolloid concentration, the proportion of gum varying from 0 to 70%. Information on the composite mechanical behaviour of the gels was obtained with only eight parameters, selected by cluster analysis. Influence of composition on the composite mechanical behaviour defined by the selected parameters was also studied. The effects of type of gum and gum proportion and their interaction on mechanical behaviour were significant (p less-than-or-equal-to 0.05). Canonical representations showing how far apart the classes were and quantitative measures of distances among populations were obtained. Slight changes of type and proportion of gum produced differences in mechanical behaviour and the extent of these differences depended on total concentration of hydrocolloids in the gel.