Quantification of seed oil from species with varying oil content using supercritical fluid extraction.
BACKGROUND
The quantity and composition of seed oil affects seed viability and storability and hence the value of a species as a resource for nutrition and plant conservation. Supercritical fluid extraction with carbon dioxide (SFE-CO2) offers a rapid, environmentally friendly alternative to traditional solvent extraction.


OBJECTIVE
To develop a method using SFE-CO2 to quantify the seed oil content in a broad range of species with high to low oil contents.


METHODS
Seed oil was extracted using SFE-CO2 from four crop species representing high, medium and low oil content: Helianthus annuus, Asteraceae, with ca. 55% oil; Brassica napus, Brassicaceae, with ca. 50% oil; Glycine max, Fabaceae, with ca. 20% oil; and Pisum sativum, Fabaceae, with ca. 2% oil. Extraction pressures of 5000, 6000 and 7500 psi and temperatures of 40, 60 and 80 degrees C were examined and a second step using 15% ethanol as a modifier included. Oil yields were compared with that achieved from Smalley Butt extraction. The optimised SFE-CO2 method was validated on six species from taxonomically distant families and with varying oil contents: Swietenia humilis (Meliaceae), Stenocereus thurberi (Cactaceae), Sinapis alba (Brassicaceae), Robinia pseudoacacia (Fabaceae), Poa pratensis (Poaceae) and Trachycarpus fortunei (Arecaceae).


RESULTS
The two-step extraction at 6000 psi and 80 degrees C produced oil yields equivalent to or higher than Smalley Butt extraction for all species, including challenging species from the Brassicaceae family.


CONCLUSIONS
SFE-CO2 enables the rapid analysis of seed oils across a broad range of seed oil contents.
Seal
Charlotte E
CE
Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH176TN, UK.
Kranner
Ilse
I
Pritchard
Hugh W
HW
D000704:Analysis of Variance; D029688:Brassica napus / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D006368:Helianthus / Q000737:chemistry; D018532:Pisum sativum / Q000737:chemistry; D010938:Plant Oils / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry
D010938:Plant Oils; D002245:Carbon Dioxide