SYNERGISTIC INTERACTIONS OF ACETAN WITH CAROB OR KONJAC MANNAN

New experimental evidence has been obtained which demonstrates synergi stic interaction of mixtures of acetan with carob or konjac mannan. Th ese binary mixtures have been shown to form thermoreversible gels unde r conditions for which the individual components do not gel. The rheol ogical properties of acetan-carob and acetan-konjac mannan mixtures ha ve been studied at various concentrations above and below the threshol d concentration for gelation. In dilute solutions, the synergisms mani fested themselves as an enhancement of the viscosity, whereas at highe r concentrations gelation occurred. The synergistic effects were much weaker for acetan-konjac mannan mixtures than for acetan-carob mixture s. Deacetylation of acetan enhanced the synergistic interactions, part icularly for acetan-konjac mannan mixtures, and also altered the polym er ratio at which the maximum interactions were observed. The influenc e of the stability of the acetan helix on the gelation of the binary m ixtures was investigated by varying the mixing (preparation) temperatu re and the level of salt added to the mixtures. These studies suggest that factors destabilizing the acetan helix favor gelation.