Low Erucic Acid Research Articles

Development of Resynthesized Rapeseed (Brassica napus L.) Forms with Low Erucic Acid Content Through in ovulum Culture

Development of Resynthesized Rapeseed (Brassica napus L.) Forms with Low Erucic Acid Content Through in ovulum Culture

Temporal gene expression of 3-ketoacyl-CoA reductase is different in high and in low erucic acid Brassica napus cultivars during seed development

The membrane-bound acyl-CoA elongase complex is a key enzyme responsible for erucoyl-CoA synthesis. Among the four putative genes encoding the four moieties of this complex in Brassica napus seeds, only one has been characterized, the Bn-fae1 gene, which encodes the 3-ketoacyl-CoA synthase. The genes encoding the other enzymes (3-ketoacyl-CoA reductase, 3-hydroxyacyl-CoA dehydratase and trans-2,3-enoyl-CoA reductase) have not been identified. We cloned two 3-ketoacyl-CoA reductase cDNA isoforms, Bn-kcr1 and Bn-kcr2, from B. napus seeds. Their function was identified by heterologous complementation in yeast by restoring elongase activities. The comparison of Bn-kcr mRNA expression in different B. napus tissues showed that the genes were preferentially expressed in seeds and roots. We also investigated the regulation of gene expression in High Erucic Acid Rapeseed (HEAR) and in Low Erucic Acid Rapeseed (LEAR) cultivars during seed development. The co-expression of Bn-fae1 and Bn-kcr observed in HEAR cultivar during seed development was different in LEAR cultivar, suggesting that expression of both genes was directly or indirectly linked.

Capillary gas chromatography analysis of Ethiopian mustard to determine variability of fatty acid composition

AbstractEthiopian mustard (Brassica carinata A. Braun) is an oil crop grown in Ethiopia. However, the oil is considered low quality, as it contains long chain monounsaturated fatty acids, mainly erucic acid. High erucic acid content is beneficial for the polymer industry, whereas low erucic acid is recommended for food purposes. Both linoleic and linolenic acids are essential fatty acids; however, less than 3% linolenic acid is preferred for oil stability. The objectives of this study were to determine fatty acid composition of Ethiopian mustard to determine the range of genetic diversity for these traits. The genotypes were analysed by capillary gas chromatography (CGC). Twenty‐six fatty acids were identified. In all accessions, the predominant fatty acids were erucic, linoleic, α‐linolenic and oleic, followed by gadoleic and palmitic. To a lesser extent stearic, vaccinic, nervonic and behenic acids were found in all accessions. Significant correlations were found between palmitic acid and stearic acid (positive), between erucic acid and palmitic, stearic, vaccinic, oleic, linoleic and α‐linolenic acids (negative) and eicosenoic acid (positive). Selection and hybridization techniques can be applied to modify the oil content of Ethiopian mustard, considering the variability observed. Copyright © 2004 Society of Chemical Industry

Food intake, growth rate, food conversion and food choice in broilers fed on diets high in rapeseed meal and pea meal, with observations on sensory evaluation of the resulting poultry meat

1. Experiments were done to measure the effects of 100 and 200 g/kg of either pea meal or low glucosinolate, low erucic acid rapeseed meal on food intake and growth, food choice and meat organoleptic quality in broiler chickens. 2. The test diets were formulated to be iso-energetic and iso-nitrogenous with a soy–wheat control diet. In all diets, lysine was fixed at 11·0 g/kg and all other indispensable amino acids were present in excess of requirements. 3. Food intake was little affected by the inclusion of 100 g/kg of pea meal in the diet but 200 g/kg of peas caused a decrease. Rapeseed produced a decrease in food intake at both dietary concentrations. 4. Weight gain was similarly affected, but food conversion from d 0 to d 42 was little affected by the inclusion of either peas or rapeseed. 5. Absolute breast muscle weight was affected by diet but there was no significant difference in breast weight as a proportion of total body weight. 6. From d 7 onwards, selection against the pea-containing diet approached statistical significance. Between d 7 and d 14, birds ate almost twice as much of the control as of the pea-containing diet. Birds offered a rapeseed meal diet ate similar amounts of that and the control diet. 7. The breast meat from birds given 200 g rapeseed/kg was the only meat identified as different but no strong aversion was expressed by the tasting panel.

Effect of genetic background on the target fatty acids of acyl‐ACP thioesterase transgenes in Brassica napus

AbstractAcyl‐acyl carrier protein (ACP) thioesterase (TE) is involved in the biosynthetic fatty acid pathway of plants. Conventional canola lines transformed individually with the bay‐TE (Uc FatB1), elm‐TE (Ua FatB1), nutmeg‐TE (Mf FatB1) or Cuphea‐TE transgene (Ch FatB1), produce seed oil with modified fatty acid compositions. This study assessed the effects of genetic background, cytoplasm, maternal parent, and interaction of different TE transgenes, on the target fatty acids using F1 seeds and double haploid (DH) lines. The F1 seeds were produced by crossing four TE transgenic parental lines and three non‐transgenic cultivars with distinct fatty acid compositions. The DH lines were developed from microspores of F1 plants. DH lines from different crosses showed that genetic background does not have an effect on the relative levels of the target fatty acids of the same TE, indicating the stability of the substrate specificity of the TE within canola. However, significant effects of genetic background on the content of the major target fatty acids, lauric acid (C12:0) or palmitic acid (C16:0) depending on the TE, were observed. Expression of the TE in low erucic acid (C22:1) genotypes resulted in higher target fatty acid levels than expression in high C22:1 genotypes. Reciprocal crosses showed maternal effects, but not cytoplasmic effects. In addition, co‐expression of two different TE transgenes in the same seeds was observed. These results indicate the importance of selection for appropriate genetic backgrounds in order to maximize the expression of the target fatty acids of TE transgenes, and also indicate potential uses of TE co‐expression in modifying canola seed oil.

Flesh quality of raw and smoked fillets of Atlantic salmon as influenced by dietary oil sources and frozen storage

The aim of this study was to evaluate the effects of dietary oil source and frozen storage on flesh quality characteristics of Atlantic salmon. Four diets containing either 100% of Peruvian fish oil (PO), capelin oil (CO), soybean oil (SO) or low-erucic acid rapeseed oil (RO) as supplemental oil were fed to triplicate groups of salmon for 135 days. After slaughter, half of the fish were smoked while the rest were analysed when raw. For smoked and raw fish, the left fillet was analysed as fresh fillet while the right fillet was frozen and stored at −20 °C for two or four months before analyses. Fish fed SO and PO diets had firmer texture than fish fed RO diet. Liquid holding capacity (LHC) and colour evaluation were influenced by dietary oil source. Colour of fish fed fish oil-diets had significantly higher colour than fish fed vegetable oil-diets. Frozen storage decreased the firmness of raw fillets and the LHC of raw and smoked fillets. Colour evaluation was affected by frozen storage by increasing L *, a * and b * values whereas muscle carotenoid concentrations slightly decreased. Lipid oxidation was more pronounced in fish fed high levels of n-3 fatty acids and increased with frozen storage.

Influence of SFC, microstructure and polymorphism on texture (hardness) of binary blends of fats involved in the preparation of industrial shortenings

Several binary blends of vegetable oils commonly used in industrial shortenings (i.e., palm oil (PO), hydrogenated palm oil (HPO), soybean oil (SO), hydrogenated soybean oil (HSO), low-erucic acid rapeseed oil (LERO), hydrogenated low-erucic acid rapeseed oil (HLERO)) were studied for their physical properties such as solid fat content (SFC) by nuclear magnetic resonance (NMR) and textural properties (hardness). Microstructure was also observed by microscopy in order to explain the variability in hardness for samples having the same SFC values. The blends studied by microscopy were the following: HSO, HPO and HLERO diluted in LERO. For these three blends which had the same SFC, the level of network structure was different. HSO diluted in LERO had more crystals, closer to each other and overlapped. This can explain that HSO has a higher hardness than HPO or HLERO, for a same SFC value, when diluted in LERO. Polymorphism was also observed by powder X-ray diffraction. The variability in hardness for samples having the same SFC is due to various crystal types and/or network structures that are formed upon crystallization of hard fats. This work demonstrates that for binary blends of studied oils, changes in the hardness are controlled mostly by the SFC, polymorphism and also by the material’s microstructure.

Blending of hydrogenated low‐erucic acid rapeseed oil, low‐erucic acid rapeseed oil, and hydrogenated palm oil or palm oil in the preparation of shortenings

AbstractTwo ternary systems of fats were studied. In the first system, low‐erucic acid rapeseed oil (LERO), hydrogenated lowerucic acid rapeseed oil (HLERO), and palm oil (PO) were blended. In the second system, hydrogenated palm oil (HPO) was used instead of PO and was blended with LERO and HLERO. The blends were then studied for their physical properties such as solid fat content (SFC), melting curves by DSC, and polymorphism (X‐ray). HPO showed the highest melting enthalpy after 48 h at 15°C (141±1 J/g), followed by HLERO (131±2 J/g), PO (110±2 J/g), and LERO (65±4 J/g). Binary phase behavior diagrams were constructed from the DSC and X‐ray results. Iso‐line diagrams of partial‐melting enthalpies were constructed from the DSC results, and binary and ternary isosolid diagrams were constructed from the NMR results. The isosolid diagrams demonstrated formation of a eutectic along the binary blend of PO/HLERO. However, no eutectic effect was observed along the binary lines of HPO/HLERO, PO/LERO, HPO/LERO, or HLERO/LERO. The same results were found with the iso‐line diagrams of partial‐melting enthalpies. As expected, addition of PO or HPO increased polymorphic stability in the β′ form of the HLERO/LERO mixture.

Formation of modified fatty acids and oxyphytosterols during refining of low erucic acid rapeseed oil.

Formation of trans fatty acids and cyclic fatty acid monomers was investigated during refining of low erucic acid rapeseed oil. The first steps of the refining process, that is, degumming, neutralization, and bleaching, hardly modified the fatty acid profile. In contrast, deodorization produced substantial quantities of trans fatty acids (>5% of total fatty acids) and small amounts of cyclic fatty acid monomers (650 mg of cyclic fatty acid monomers/kg of oil) when severe conditions (5-6 h at 250 degrees C) were used. Alpha-linolenic acid was the main precursor of cyclic fatty acid monomers. The influence of deodorization on the chemical composition of low erucic acid rapeseed oil was studied additionally. Whereas free fatty acids, peroxides, and tocopherols decreased, neither total polar compounds nor oxyphytosterols changed during deodorization. Oxyphytosterols were identified by GC-MS. Three oxyphytosterols not yet observed in oil were tentatively identified as 6beta-hydroxycampestanol, 6beta-hydroxysitostanol, and 6beta-hydroxybrassicastanol. Brassicasterol oxides were the most abundant oxyphytosterols.

Cereal Grain and Dockage Identification using Machine Vision

Algorithms were written to extract a total of 230 features (51 morphological, 123 colour, and 56 textural) from the high-resolution images of kernels of five grain types [barley, Canada Western Amber Durum (CWAD) wheat, Canada Western Red Spring (CWRS) wheat, oats, and rye] and five broad categories of dockage constituents [broken wheat kernels, chaff, buckwheat, wheat spikelets (one to three wheat kernels inside husk), and canola (rapeseed with low erucic acid content in the oil and low glucosinolate content in the meal)]. Different feature models, viz. morphological, colour, texture, and a combination of the three, were tested for their classification performances using a neural network classifier. Kernels and dockage particles with well-defined characteristics ( e.g. CWRS wheat, buckwheat, and canola) showed near-perfect classification whereas particles with irregular and undefined features ( e.g. chaff and wheat spikelets) were classified with accuracies of around 90%. The similarities in shape and size of some of the particles of chaff and wheat spikelets with the kernels of barley and oats affected the classification accuracies of the latter, adversely.

Effects of prepress-solvent extraction on the nutritional value of canola meal for broiler chickens

The objective of the experiment was to determine if standard prepress-solvent extraction of canola (low glucosinolate, low erucic acid rapeseed) affects the nutritional value of the resulting meal for broiler chickens. Three sets of samples were collected from all stages of prepress-solvent extraction at a commercial crushing plant and examined for nutritional value. Except for cystine and serine, processing stages up to and including solvent extraction did not affect coefficient of apparent ileal digestibility (CAID). However, the desolventization/toasting process reduced ( P<0.05) lysine content (6.03–5.50 g/16 gN), crude protein CAID (0.81–0.77), lysine CAID (0.87–0.79) and the CAID of all the other amino acids except glutamine, leucine, methionine and serine. Desolventization/toasting increased the coefficient of variation (percent CV) for the CAID of lysine over the solvent extracted meal (5.6% versus 1.4%) and all the other amino acids except glutamine, histidine, leucine, and serine. As expected, apparent metabolizable energy (AME) content decreased ( P<0.05) with expelling and solvent extraction due to the reduced oil content, but was not affected by other processing stages. In conclusion, commercial desolventization/toasting can reduce the content and CAID of many amino acids in canola meal and increase the level of variability in nutritional value between canola meal samples.

Restoring enzyme activity in nonfunctional low erucic acid Brassica napus fatty acid elongase 1 by a single amino acid substitution.

Genomic fatty acid elongation 1 (FAE1) clones from high erucic acid (HEA) Brassica napus, Brassica rapa and Brassica oleracea, and low erucic acid (LEA) B. napus cv. Westar, were amplified by PCR and expressed in yeast cells under the control of the strong galactose-inducible promoter. As expected, yeast cells expressing the FAE1 genes from HEA Brassica spp. synthesized very long chain monounsaturated fatty acids that are not normally found in yeast, while fatty acid profiles of yeast cells expressing the FAE1 gene from LEA B. napus were identical to control yeast samples. In agreement with published findings regarding different HEA and LEA B. napus cultivars, comparison of FAE1 protein sequences from HEA and LEA Brassicaceae revealed one crucial amino acid difference: the serine residue at position 282 of the HEA FAE1 sequences is substituted by phenylalanine in LEA B. napus cv. Westar. Using site directed mutagenesis, the phenylalanine 282 residue was substituted with a serine residue in the FAE1 polypeptide from B. napus cv. Westar, the mutated gene was expressed in yeast and GC analysis revealed the presence of very long chain monounsaturated fatty acids (VLCMFAs), indicating that the elongase activity was restored in the LEA FAE1 enzyme by the single amino acid substitution. Thus, for the first time, the low erucic acid trait in canola B. napus can be attributed to a single amino acid substitution which prevents the biosynthesis of the eicosenoic and erucic acids.

Erucic acid heredity in Brassica juncea ‐ some additional information

AbstractGenetic studies were undertaken to reassess erucic acid heredity in Brassica juncea. Analysis of segregation in F2 and BC1 generations from two zero × high erucic acid crosses indicated that higher erucic acid in B. juncea was controlled by two dominant genes with additive effects, whereas segregation in a cross involving ‘CCWF 16′, a genotype having intermediate erucic acid (25.6%), and a zero erucic acid strain, indicated monogenic dominant control for intermediate erucic acid content. The B. juncea strain ‘CCWF 16’ was developed by hybridizing high‐erucic acid B. juncea cv.‘WF‐1’ with a ‘0’ erucic B. rapa cv.‘Candle’ followed by backcrossing with ‘WF‐1’ and half‐seed selection for low erucic acid in each backcross generation. This strategy resulted in substitution of the high erucic acid allele present in the A genome of B. juncea (AABB) by the zero erucic acid allele associated with ‘A’ genome of ‘Candle’. The intermediate erucic acid content in ‘CCWF 16’ was thus attributed to a gene present in the ‘BB’ genome. Experimental data clearly suggested that the gene (E2) associated with the A genome had a greater contribution to the total erucic acid content in B. juncea than the gene (E1) located on the B genome. This provided experimental evidence for a previous suggestion of unequal contributions of two dominant genes (E1= 12%, E2= 20%) to high erucic acid content in conventional digenomic Brassica species.

Oxidative stability and minor constituents of virgin olive oil and cold-pressed rapeseed oil

The oxidative stability and minor constituents of three cold-pressed low erucic acid rapeseed oils and three virgin olive oils were compared. The rapeseed oils were more easily oxidized, in part due to their higher contents of polyunsaturated fatty acids. The rapeseed oils were rich in γ-tocopherol and had low initial peroxide values (PVs), but their hydrophilic phenol content was low, only 3–4 ppm. Olive oils contained α-tocopherol and 40–100 times more hydrophilic phenols compared to the rapeseed oils. The initial PVs of fresh olive oils were much higher than those of rapeseed oils. Lutein and β-carotene were present in all oils but chlorophylls (pheophytin a) only in the olive oils. The phenolic extract from the olive oils protected both bulk and emulsified methyl linoleate (MeLo) from oxidation at the 100 ppm level. The extracts obtained from the rapeseed oils had either moderate or no antioxidative effect in MeLo. Testing of the extracts for their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity yielded similar results. We conclude that phenolic compounds contribute significantly to the oxidative stability of cold-pressed oils.

Correlation studies on oil content and fatty acid profile of some Cruciferous species

Mean individual fatty acid concentration among differentspecies of the family Cruciferae are not similar because of the presence ofdifferent kind of significant relationship among the individual fatty acids.Brassica napus L., Sinapis alba L.,Raphanus caudatus L.f. Raphanus sativusL. and B. nigra (L.) Koch arecomparatively low erucic acid (<40%) containing species. Crambeabyssinica Hochst. ex. R. E. Fries collections gave as high as 60%erucic acid. Low erucic acid concentration was found associated with thepresence of high level of palmitic and oleic acid concentrations. Erucic acidconcentrations were found varied within the range of 42 to 57% among thecollections of Brassica rapa L. and B.carinata A. Braun. All the collections ofB. nigra (L.) Koch were found to havehigher proportion of linoleic acid than the corresponding oleic acidconcentration. Linolenic acid concentrations of B.nigra (L.) Koch was also higher in comparison to otherspecies of the Cruciferae. Raphanus collections were foundto contain higher levels of total saturated fatty acids as well as eicosenoicacid. Oil content of the total collections under present study did not show anysignificant relationship either with linolenic acid or with erucic acidconcentration. But significant positive relationship was observed between totaloil and erucic acid level within the collections of B.juncea Czern. & Coss. Similarly significant negativecorrelation was observed between total oil and linolenic acid content inBrassica rapa L. ssp. trilocularis (Roxb.) Hanelt, yellow sarson.

Cloning and molecular characterization of the FattyAcidElongase 1 ( FAE 1) gene from high and low erucic acid lines of Brassica campestris and Brassica oleracea

Brassica campestris (sarson) and B. juncea (mustard) are the major sources of edible oils in India. Modification of the Brassica oil for the desired fatty acid profile through genetic manipulation necessitates isolation and characterization of genes involved in the fatty acid biosynthesis. We report the cloning of the Fatty Acid Elongation 1 ( FAE 1) genes from two species of Brassica with an objective of characterizing the differences responsible for variation in the erucic acid levels. The product of this gene, β-ketoacyl-CoA synthase (KCS) is the key enzyme in erucic acid biosynthesis. Consensus primers were used to amplify the target locus from B. campestris, (low and high erucic acid lines), and vegetable B. oleracea. The putative gene from Low and High Erucic Acid B. campestris and lines of B. oleracea were sequenced for further analysis. Proteins of 458 (HEAC Fae 1) and 459 (LEAC Fae 1 and BO Fae 1) were deduced from their respective nucleotide sequences. Clustal analysis revealed a high similarity (98%) at both nucleotide and amino acid sequence level among the clones. Nucleotide sequence similarity of our FAE 1 clones with FAE 1 from Brassica napus was as high as 98%. Likewise, sequence similarities of 86, 84 and 58% were obtained on comparison with FAE 1 from Brassica juncea, Arabidopsis thaliana and Simmondsia chinensis, respectively. The FAE 1 genes from LEAC and HEAC differed at 13 positions at amino acid sequence level. These were mainly localized in the central part of the protein sequence. We propose that the altered amino acid sequence is responsible for low level of erucic acid in LEAC as also speculated by earlier reports. The clones can be used to map the region in Brassica species and engineer plants for modified oil composition.

Acyl-CoA elongase expression during seed development in Brassica napus

The Bn-FAE1.1 and Bn-FAE1.2 genes encode the 3-ketoacyl-CoA synthase, a component of the elongation complex responsible for the synthesis of very long chain monounsaturated fatty acids (VLCMFA) in the seeds of Brassica napus. Bn-FAE1 gene expression was studied during seed development using two different cultivars: Gaspard, a high erucic acid rapeseed (HEAR), and ISLR4, a low erucic acid rapeseed (LEAR). The mRNA developmental profiles were similar for the two cultivars, the maximal expression levels being measured at 8 weeks after pollination (WAP) in HEAR and at 9 WAP in LEAR. Differential expression of Bn-FAE1.1 and Bn-FAE1.2 genes was also studied. In each cultivar the same expression profile was observed for both genes, but Bn-FAE1.2 was expressed at a lower level than Bn-FAE1.1. Secondly, VLCMFA synthesis was measured using particulate fractions prepared from maturating seeds harvested weekly after pollination. The oleoyl-CoA and ATP-dependent elongase activities increased from the 4th WAP in HEAR and reached the maximal level at 8 WAP, whereas both activities were absent in LEAR. In contrast, the 3-hydroxy dehydratase, a subunit of the elongase complex, had a similar activity in both cultivars and reached a maximum from 7 to 9 WAP. Finally, antibodies against the 3-ketoacyl-CoA synthase revealed a protein of 57 kDa present only in HEAR. Our results show: (i) that both genes are transcribed in HEAR and LEAR cultivars; (ii) that they are coordinately regulated; (iii) that Bn-FAE1.1 is quantitatively the major isoform expressed in seeds; (iv) that the Bn-FAE1 gene encodes a protein of 57 kDa responsible for the 3-ketoacyl-CoA synthase activity.

Variation and inheritance of erucic acid content in Brassica carinata germplasm collections from Ethiopia

AbstractEthiopian mustard possesses a number of agronomic advantages over other oilseed crops with similar ecological adaptation in Ethiopia. However, its high erucic acid content is undesirable for a vegetable oil. Although efforts have been made to improve its quality, much has to be done to use natural variations that might exist within the species for fatty acid contents. This project was undertaken to study the variability of fatty acid contents, primarily erucic acid, in germplasm collections of Ethiopian origin, with an attempt to develop low (zero) erucic acid genotypes. The study used inbred lines as well as F2 populations of 10 crosses between six parental lines. A wide variation in fatty acids was found. Oleic acid content varied from 5 to 34% and erucic acid content from 6 to 51%. Linoleic and linolenic acid contents were less variable. The high‐oleic genotypes exhibited not only low erucic but also higher linoleic (25%) and considerably lower linolenic acid (8%) contents. It was possible to classify the F2 populations with the lowest erucic acid into three distinct classes. While the first class had an erucic acid content of 6–12%, the second and third classes had contents of 18–32% and 36–42%, respectively. The existence of a multiple allelic series of erucic acid in Ethiopian mustard would enable its fixation at zero levels without necessarily going into interspecific crossing.

Low-erucic acid rapeseed oil and platelet function

La composition d'un regime alimentaire en acides gras a des incidences sur les cardiopathies ischemiques. Elle n'est pas seulement un determinant important de la concentration du serum en cholesterol mais aussi influence les facteurs hemostatiques. Les thrombocytes sont les plus petites particules cellulaires du sang, ils arretent le saignement des plaies par agregation. Cette analyse rapporte differentes etudes ou des regimes alimentaires ont ete modifies en remplacant les sources d'apport d'acides gras satures par des margarines et des huiles de colza et de tournesol. Les donnees obtenues ne sont pas tres concluantes et des etudes sur les effets des composes mineurs de l'huile de colza comme les antioxydants et les phytosterols sont a envisager.

Low-erucic acid rapeseed oil and platelet function

Low-erucic acid rapeseed oil and platelet function