Method for analysis of fatty acid distribution and oil content on a single lesquerella fendleri seed

Authors: Isbell, Terry; Mund, Melissa; Evangelista, Roque; Dierig, David

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2008
Publication Date: 7/28/2008
Citation: Isbell, T.A., Mund, M.S., Evangelista, R.L., Dierig, D.A. 2008. Method for analysis of fatty acid distribution and oil content on a single lesquerella fendleri seed. Industrial Crops and Products. 28(2):231-236.

Interpretive Summary: Lesquerella fendleri is a developing oilseed crop suitable for temperate growing regions in the U.S. The seed oil is rich in hydroxy fatty acids (lesquerolic acid) and could serve as a domestic source of these hydroxy fatty acids. Hydroxy fatty acids are used in a wide range of consumer products that encompass greases, lubricants and cosmetics. Currently, all hydroxy fatty acids consumed in the U.S. are imported as castor oil. Thus, development of a domestic source of hydroxy fatty acids is important to the U.S. economy. One key to development of a new crop is the ability to select plants that have desirable characteristics, like high oil and hydroxy fatty acid content. We have developed a method to access these traits in single or one half of a lesquerella seed. This allows the breeders to grow the remaining portion of the seed. As a result, a rapid increase in the development of a crop is possible by identifying the genetic information in the half seed and ramping its desirable traits under isolation. Before development of this method, multiple generations would need to be grown before a homogeneous population with the desired chemical composition could be obtained.

Technical Abstract: Lesquerella fendleri is a developing oilseed crop suitable for temperate growing regions in the U.S. The seed oil is rich in lesquerolic acid (57%) and could serve as a domestic source of hydroxy fatty acids. A method for the analysis of fatty acids and total oil content of a half or single lesquerella seed was developed. Lesquerella seeds are small with 1,000 seed weights around 0.6 g (half seed mass of 200 to 500 µg). Conventional analytical balances provide mass accuracy to ± 40 µg which fails to provide sufficient accuracy/precession (4 – 40% mass error) for the initial seed mass. A micro balance which measures to ±2 µg provided good reproducibility in initial seed weights, but was not suitable for mass balance of the extracted oil. A normal phase HPLC coupled to an evaporative light scattering detector gave good response for oil in the mass range of 22 µg – 110 µg/mL. Therefore, micelle concentrations from single or half seed extractions could be determined with good reproducibility. This method was then evaluated on bulk seed that had been fractionated on a gravity table. Gravity table fractionation of L. fendleri seeds obtained from a large field plot provided 7 fractions with increasing bulk density. These fractions were then analyzed in sets of 30 individual seeds and as an aggregate of 50 seeds. Oil content for individual seeds varied widely (15.6 – 44.2%) as did lesquerolic acid content (42.2 – 63.7%). The mean oil content increased (27 – 33%) with increasing bulk density (684 – 745 g/L). The mean lesquerolic acid content did not correlate with bulk density.