RESUMO
This study evaluates and relates the molecular and rheological characteristics of native carrageenan obtained from Kappaphycus alvarezii seaweed. Native carrageenan was extracted by a differentiated methodology by atomization drying process, which reduces the time for obtaining carrageenan dry powder and minimizes costs and environmental damages. Rheological properties of native carrageenan were compared with a commercial carrageenan grade. Molecular properties were performed by SAXS and GPC analysis and the rheological properties by DMTA and stress relaxation tests. Molecular analysis proved a folded and compact molecular structure and indicated the presence of chains with different molecular weights for native carrageenan. The results obtained showed that the helix-coil transition occurs at temperature about 50 °C. The native and commercial grade carrageenan presented the characteristic of viscoelastic materials and their gel properties show a higher contribution from solid elastic component, and the initial force (F(0)) was higher in commercial carrageenan than native one.