RHEOLOGICAL PROPERTIES OF MIXED GELS OF KAPPA-CARRAGEENAN WITH GALACTOMANNAN

The rheological properties of 1-1.5% kappa-carrageenan gels mixed with galactomannan, i.e., locust bean gum, tara gum, and guar gum, in rati os of 7:3 and 1:1 were investigated by measuring the temperature depen dence and the courses of dynamic viscoelasticity and static viscoelast icity. The addition of small amounts of locust bean gum and tara gum t o kappa-carrageenan changed the rheological properties of the original to a firmer and more elastic gel. Measurements of the storage modulus (G') and loss modulus (G'') showed that kappa-carrageenan formed the basic network structure of the gel, while locust bean gum and tara gum strengthened this network structure. kappa-Carrageenan showed a syner gistic effect with locust bean gum and tara gum, but not with guar gum , which was caused by the difference of the constituent ratio of galac tose to mannose in the three gums. Significant differences in the netw ork structures of mixed gels of kappa-carrageenan and the three gums w ere apparent by observing with a scanning electron microscope.