The Oil Composition of Brassica napus and Brassica juncea: A Comparison

Brassica juncea (Indian mustard) has been identified as a potentially important crop for commercial production in low rainfall areas of Australia, as it has greater tolerance to heat and water stress than B. napus (canola). It is also more resistant to blackleg fungal disease and shattering. The success of B. juncea as a commercial crop will, to a large extent, depend upon its suitability for processing as an alternative form of canola, and ability to market it for the same applications that currently use canola oil. This requires a similar chemistry between the two species. This study investigated the chemical composition of four high oleic acid B. juncea breeding lines and three B. napus lines grown in two environments within the 2003 season. The oil content was significantly affected by environment, but not by species. The B. juncea lines tested contained slightly lower levels of oleic acid (average 58.2 %) compared to B. napus (average 63.1 %). In addition, higher levels of linoleic (20.6 % and linolenic acid (12.6 %) were observed in comparison to B. napus (18.6 and 8.65 %, respectively). Neither species contained significant levels of erucic acid. No differences were observed between species for tocopherol content. The average tocopherol levels (B. juncea and B. napus) were 154 g/g -tocopherol, 38.4g/g -tocopherol and 650g/g -tocopherol. Marginal species-related differences were observed in phytosterol content, with B. juncea containing slightly lower levels of brassicasterol, campersterol and -sitosterol (190, 354, and 66 g/g, respectively) than B. napus (248, 369, and 723 g/g, respectively). The compositional data suggests that there is potential to process and use B. juncea oil in the same way as B. napus. The 2003 season results indicate a strong move towards canola quality oil, however lines used in this study will not be commercially released. More recent studies on 2004 and 2005 Indian mustard trials indicate an even closer alignment of chemical characteristics, with respect to fatty acid profile.