Location: Bio-oils Research Unit
Title: Fuel properties of methyl esters of borage and black currant oils containing methyl-gamma-linolenate Author
Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 3, 2013
Publication Date: August 8, 2013
Citation: Knothe, G.H. 2013. Fuel properties of methyl esters of borage and black currant oils containing methyl-gamma-linolenate. European Journal of Lipid Science and Technology. 115:901-908. Interpretive Summary: Biodiesel is an alternative to petroleum-derived diesel fuel. Biodiesel is commonly produced from vegetable oils such as soybean oil or other sources such as animal fats and waste frying oils. Advantages of biodiesel has advantages such as renewability, domestic origin, biodegradability, safer handling, lower sulfur content and reduced exhaust emission when compared to petroleum diesel. However, problems related to behavior at low temperatures and storage stability affect biodiesel. In this work, biodiesel fuels derived from two oils, black currant and borage, enriched in a specific component called methyl gamma-linolenate were studied to compare them to other biodiesel fuels. Biodiesel from these oils had not been studied previously. The results show that these biodiesel fuels meet most specifications in biodiesel standards. Only the so-called cetane number, which is related to combustion was below specifications, however, only slightly in one case. For the biodiesel fuels to be stable towards air under long-term exposure, adding other materials is necessary but this is the case with other biodiesel fuels, too.
Technical Abstract: Additional or alternative feedstocks are one of the major areas of interest regarding biodiesel. In this work, two oils enriched in gamma-linolenic acid (6Z,9Z,12Z-octadecatrienoic acid) were investigated as biodiesel feedstocks. One oil is black currant in which gamma-linolenic and alpha-linolenic (9Z,12Z,15Z-octadecatrienoic acid) are relatively evenly distributed, and the other oil is borage oil which mainly contains gamma-linolenic acid as C18:3 species. The cetane number of neat methyl gamma-linolenate was also determined for the first time as 29.2, which is slightly higher than that of the more common methyl alpha-linolenate. The methyl esters (biodiesel) from these oils meet most fuel property specifications in biodiesel standards with the exception of feedstock restrictions on highly unsaturated fatty acid chains, although cetane numbers are lower and antioxidants are required for oxidation stability. The 1H- and 13C-NMR spectra of black currant and borage methyl esters are also reported.