Synergistic Interactions of Acetan with Carob or Konjac Mannan

New experimental evidence has been obtained which demonstrates synergistic interaction of mixtures of acetan with carob or konjac mannan. These binary mixtures have been shown to form thermoreversible gels under conditions for which the individual components do not gel. The rheological properties of acetan−carob and acetan−konjac mannan mixtures have been studied at various concentrations above and below the threshold concentration for gelation. In dilute solutions, the synergisms manifested themselves as an enhancement of the viscosity, whereas at higher concentrations gelation occurred. The synergistic effects were much weaker for acetan−konjac mannan mixtures than for acetan−carob mixtures. Deacetylation of acetan enhanced the synergistic interactions, particularly for acetan−konjac mannan mixtures, and also altered the polymer ratio at which the maximum interactions were observed. The influence of the stability of the acetan helix on the gelation of the binary mixtures was investigated by varying the mixing (preparation) temperature and the level of salt added to the mixtures. These studies suggest that factors destabilizing the acetan helix favor gelation.