Physical, chemical, and thermal properties of Orychophagmus violaaceus seeds and oil

Authors: Evangelista, Roque; Moser, Bryan; Winfield, Demichael; Cermak, Steven - Steve

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 6/23/2024
Publication Date: 9/1/2024
Citation: Evangelista, R.L., Moser, B.R., Winfield, D.D., Cermak, S.C. 2024. Physical, chemical, and thermal properties of Orychophagmus violaaceus seeds and oil [abstract]. Association for the Advancement of Industrial Crops 35th Annual Conference & Meeting, Lisbon, Portugal, September 1-5, 2024.

Interpretive Summary:

Technical Abstract: Orychophragmus violaceus (Brassicaceae; common names: Chinese violet cress, February orchid) is widely distributed in northern and eastern China both as an annual and perennial plant. O. violaceus (Ov) is commonly used for erosion control and as an ornamental plant. The seed is rich in oil containing the very long chain dihydroxy fatty acids nebraskanic and wuhanic acids. It has been reported that the oil is accumulated in the seed as natural triacylglycerol (TAG) estolides. We report on the properties of Ov seeds and solvent-extracted oil. Based on thousand seed weight (TSW), Ov seeds (3.1 g) are larger than camelina (0.96-1.81 g) but smaller than rapeseed (~5.1 g). Ninety five percent of the seeds was retained on a 16 mesh (1.18 mm) screen. The bulk density (591 g/L) was lower than those of camelina (636 - 666 g/L) and rapeseed (623 g/L). The seed’s true density was 1.14 g/cc, hence the seed bed had a porosity (space between seeds) of 48%. The seed contained 44.3% oil and 23.9% protein on a moisture-free basis. No oil was recovered by cold-pressing the seed, but 39% crude oil was obtained from the press cake after 2 h of hexane extraction. The green-colored oil (CIE L a*b* = 41.9, 0.4, 70.8, respectively) contained 51 ppm chlorophyll and had an acid value of 6.6 mg KOH/g. The density of the oil at 15 deg. C was 0.954 g/mL, heavier than most vegetable oils (0.930). The oil exhibited a high oxidation onset temperature of 180 deg. C. Thermogravimetric analysis under nitrogen showed 10% mass loss when the temperature reached 333 deg. C. The high viscosity index (VI) of Ov oil (133) indicated good stability over a wide temperature range which is desirable in lubricant applications. Other natural hydroxy oils, like castor and lesquerella, have VIs of 89 and 123, respectively. The favorable properties of the seed and oil make Ov a prime candidate for domestication as an industrial oilseed crop.