Quantification of seed oil from species with varying oil content using supercritical fluid extraction.

Introduction: 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. Methodology: 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°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°C produced oil yields equivalent to or higher than Smalley Butt extraction for all species, including challenging species from the Brassicaceae family. Conclusion: SFE-CO₂ enables the rapid analysis of seed oils across a broad range of seed oil contents. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]