Structural characteristics of gels formed by mixtures of carrageenan and mucilage gum from Opuntia ficus indica Article uri icon

abstract

  • Sol-gel and gel-sol transitions of mixtures formed by mucilage gum from Opuntia ficus indica and either κ-carrageenan or ι-carrageenan were studied using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). A total polymer concentration of 2%25 (w/w), a mucilage concentration in the interval between 0 and 80%25 (w/w), and KCl or CaCl 2 concentrations of 12 or 60 mM, were used. Results from DSC showed that gelation was independent of the presence of mucilage gum in the mixtures. SEM results showed the non-gelling characteristic of mucilage gum from O. ficus indica. However, when mixed with κ-carrageenan a synergistic effect was observed only at the 80/20 κ-carrageenan/mucilage gum ratio. The DSC and SEM results indicated that the mucilage gum gets adsorbed onto the i-carrageenan structure in an interaction controlled by electrostatic charges. Regarding the i-carradeenan/mucilage mixtures no clear interaction at structural level was observed.

publication date

  • 2006-01-01