Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement.
In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.
Jaime
Laura
L
Sección Departamental de Ciencias de la Alimentación, Universidad Autónoma de Madrid, Spain.
Mendiola
José A
JA
Ibáñez
Elena
E
Martin-Alvarez
Pedro J
PJ
Cifuentes
Alejandro
A
Reglero
Guillermo
G
Señoráns
Francisco J
FJ
D000975:Antioxidants / Q000032:analysis; D002245:Carbon Dioxide; D000460:Chlorophyta / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D025924:Chromatography, Supercritical Fluid; D019207:beta Carotene / Q000032:analysis*
D000975:Antioxidants; D019207:beta Carotene; D002245:Carbon Dioxide