The impact of reducing fatty acid desaturation on the composition and thermal stability of rapeseed oil.

Harjeevan Kaur,Raymond Sloan,Peter Eastmond,Natalia Stawniak,Lihong Wang,Ian Bancroft,Harrie Van Erp

doi:10.1111/pbi.13263

Harjeevan Kaur, Raymond Sloan + Show 5 more

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https://doi.org/10.1111/pbi.13263

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Abstract

SummaryOilseed rape (Brassica napus) is the third largest source of vegetable oil globally. In addition to food uses, there are industrial applications that exploit the ability of the species to accumulate the very‐long‐chain fatty acid (VLCFA) erucic acid in its seed oil, controlled by orthologues of FATTY ACID ELONGASE 1 (Bna.FAE1.A8 and Bna.FAE1.C3). The proportion of polyunsaturated fatty acids (PUFAs) in rapeseed oil is predicted to affect its thermal stability and is controlled by orthologues of FATTY ACID DESATURASE 2, particularly Bna.FAD2.C5. Our aim was to develop rapeseed lines combining high erucic and low PUFA characters and to assess the impact on thermal stability of the oil they produce. The new type of rapeseed oil (high erucic low polyunsaturate; HELP) contained a substantially greater proportion of erucic acid (54%) compared with high erucic rapeseed oil (46%). Although the total VLCFA content was greater in oil from HELP lines (64%) than from high erucic rapeseed (57%), analysis of triacylglycerol composition showed negligible incorporation of VLCFAs into the sn‐2 position. Rancimat analysis showed that the thermal stability of rapeseed oil was improved greatly as a consequence of reduction of PUFA content, from 3.8 and 4.2 h in conventional low erucic and high erucic rapeseed oils, respectively, to 11.3 and 16.4 h in high oleic low PUFA (HOLP) and HELP oils, respectively. Our results demonstrate that engineering of the lipid biosynthetic pathway of rapeseed, using traditional approaches, enables the production of renewable industrial oils with novel composition and properties.

Highlights

Oilseed rape (OSR) is the world’s third largest source of vegetable oil, after palm and soybean (FAO, 2018)
Rapeseed oil is an edible oil, but due to the presence of very-long-chain fatty acids (VLCFAs, carbon chain length ≥20), erucic acid, it has a wide range of industrial applications (Ro€bbelen, 1991; Zanetti et al, 2012)
We combined low polyunsaturated fatty acids (PUFAs) and high erucic acid seed oil traits by crossing the low PUFA donors K0472 and K0047 (which had been generated by chemical mutagenesis of the low erucic acid variety Cabriolet as reported by Wells et al (2014)) onto the current high erucic acid rapeseed cultivar Maplus

Summary

Introduction

Oilseed rape (OSR) is the world’s third largest source of vegetable oil, after palm and soybean (FAO, 2018). It is a crop type of Brassica napus, which is a polyploid species (AACC, 2n = 38) formed by the spontaneous hybridization of B. rapa (AA, 2n = 20) and B. oleracea (CC, 2n = 18) (Nagaharu, 1935; Palmer et al, 1983; Parkin et al, 1995). Rapeseed oil is an edible oil, but due to the presence of very-long-chain fatty acids (VLCFAs, carbon chain length ≥20), erucic acid, it has a wide range of industrial applications (Ro€bbelen, 1991; Zanetti et al, 2012). Other species have been evaluated for the production of erucic acid, the main source remains OSR (Hebard, 2016; Lalas et al, 2012; Sanyal et al, 2015)

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