Hydrophilic carotenoids: surface properties and aqueous aggregation of a rigid, long-chain, highly unsaturated dianionic bolaamphiphile with a carotenoid spacer.
The water dispersibility of astaxanthin was greatly enhanced by converting it to a disodium disuccinate salt. This carotenoid salt behaved as a bolaamphiphile in water; dynamic light scattering (DLS) revealed the formation of stable aggregates with an average hydrodynamic radius close to 1 microm. Larger aggregates were observed in solutions of increased osmolarity. Absorption spectra demonstrated that the aggregates could withstand the addition of 20% acetonitrile before disintegrating to monomers. The physicochemical properties of this astaxanthin derivative in solution were comprehensively studied by measuring surface tension, critical aggregate concentration, surface concentration, molecule area, free energy of adsorption and micellation, adsorption-aggregate energy relationship, and equilibrium constants, and then compared with similar compounds reported previously in the literature.
Foss
Bente Jeanette
BJ
Department of Chemistry, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
Sliwka
Hans-Richard
HR
Partali
Vassilia
V
Naess
Stine Nalum
SN
Elgsaeter
Arnljot
A
Melø
Thor Bernt
TB
Naqvi
K Razi
KR
O'Malley
Sean
S
Lockwood
Samuel F
SF
D002338:Carotenoids / Q000737:chemistry*; D005505:Food Coloring Agents / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water
D005505:Food Coloring Agents; D013501:Surface-Active Agents; D014867:Water; D002338:Carotenoids