Crop description. Brassica carinata, commonly known as Ethiopian mustard, is an adequate oil-bearing crop that is well adapted to mar­ginal regions (see Fig. 4.15). This crop, which is originally from Ethiopia, is drought-resistant and grown in arid regions [127, 128]. Ethiopian mustard presents up to 6% saturated hydrocarbon chains. It is native to the Ethiopian highlands, is widely used as food by the Ethiopians, and pre-sents better agronomic performances in areas such as Spain, California, and Italy. This makes B. carinata a promising oil feedstock for cultivation in coastal Mediterranean areas, which could offer the pos­sibility of exploiting the Mediterranean marginal areas for energetic pur­poses [129]. Its fatty acid composition includes palmitic acid (3.6%), stearic acid (1.3%), oleic acid (14.8%), linoleic acid (12.2%), gadoleic acid (10.3%), and erucic acid (45.4%) [123].

Main uses. It is widely used as food in Ethiopia. Oil from wild species is high in erucic acid, which is toxic, although some cultivars contain little erucic acid and can be used as food. The seed can also be crushed and used as a condiment [127]. There is a genetic relationship among

B. carinata genotypes based on oil content and fatty acid composition. Genet et al. have generated information to plan crosses and maximize the use of genetic diversity and expression of heterosis [130]. Dorado et al. found negative effects of singular fatty acids, such as erucic acid, over alkali-catalyzed transesterification reaction [39]. These researchers described a low-cost transesterification process of B. carinata oil. An oil-methanol molar ratio of 1:4.6, addition of 1.4% of KOH, a reaction tem­perature in the range of 20-45oC, and 30 min of stirring are considered to be the best conditions to develop a low-cost method to produce biodiesel from B. carinata oil [39, 131]. Biodiesel from Ethiopian mustard oil could become of interest if a fuel tax exemption is granted [30]. When com­pared with petroleum diesel fuel, Cardone et al. have found that engine test bench analysis did not show any appreciable variation of output engine torque values, while there was a significant difference in specific fuel consumption data at the lowest loads. Biodiesel produced higher levels of NOx concentrations and lower levels of particulate matter (PM), with respect to diesel fuel. Biodiesel emissions contain less soot [132].