The gelling of κ-carrageenan in light and heavy water.
Gels of κ-carrageenan were prepared in H₂O and D₂O. Rheological measurements revealed that in heavy water the elastic modulus is substantially higher. From the rheological view point, this result indicates the formation of a higher number of physical-crosslinking points in the structure of the gel. These crosslinking points are mainly associated with the aggregation of the double-helix of the κ-carrageenan, which is enhanced in D₂O. The thermal stability of the gels in both solvents (relative to the sol-gel transition) was also investigated by using polarimetric measurements (to measure the relative fraction of helix-coil) and micro-differential scanning calorimetry (micro-DSC). The results obtained using these techniques are very consistent and allow us to propose a model to explain the differences for the gels formed in light and heavy water based on the degree of double-helix aggregation.
Cardoso
Marcus Vinícius Cangussu
MV
Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, UNICAMP, PO Box 6154, 13084-862, Campinas, SP, Brazil.
Sabadini
Edvaldo
E
D002236:Carbohydrate Conformation; D002351:Carrageenan / Q000737:chemistry*; D017666:Deuterium Oxide / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D012212:Rheology; D012997:Solvents; D013696:Temperature; D014867:Water / Q000737:chemistry*
D005782:Gels; D012997:Solvents; D014867:Water; D002351:Carrageenan; D017666:Deuterium Oxide