Low Erucic Acid Research Articles

Flavor and oxidative stability of soybean, sunflower and low erucic acid rapeseed oils

AbstractThree samples each of soybean, sunflower and low erucic acid rapeseed (LEAR) oils were evaluated for flavor and oxidative stability. The commercially refined and bleached oils were deodorized under identical conditions. No significant differences were noted in initial flavor quality. After storage at 25°C or 60°C in the dark, soybean oils—with or without citric acid—were more stable than either sunflower or LEAR oils. However, in the presence of citric acid, soybean oils were significantly less stable to light exposure than either LEAR or sunflower oils. In contrast, in the absence of citric acid, soybean oils were significantly more light stable than LEAR oils. In either the presence or absence of citric acid, sunflower oil was significantly more stable to light than soybean oil. Analyses by static headspace gas chromatography showed no significant differences in formation of total volatile compounds between soybean and LEAR oils. However, both oils developed significantly less total volatiles than the sunflower oils. Each oil type varied in flavor and oxidative stability depending on the oxidation method (light vs dark storage, absence vs presence of citric acid, 100°C vs 60°C).

Relationship between lipid parameters and the occurrence and severity of lesions in the heart: a study on rats fed low erucic acid rapeseed oil.

Fifty-six male Wistar SPF rats were fed a diet containing low erucic acid rapeseed (LEAR) oil (15% by weight) as the only source of lipids for 18 wk. Lipid parameters (fatty acid composition and contents of lipid classes) and the occurrence and severity of focal lesions were both determined on the heart of each animal. Four groups were constituted according to the severity of cardiac lesions. Statistical analyses were applied to the data to find a relationship between the lipid parameters and the severity of heart lesions. None of the measured parameters (heart contents of neutral lipids, total phospholipids, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol, sphingomyelin and fatty acid composition of each phospholipid class) appeared to be related with the grading of the lesions. Therefore, we failed to find a direct support for the assumption that heart lesions, induced by LEAR oil, are mediated by changes in the lipid and/or fatty acid composition of heart membranes. However, this hypothesis can not be discarded.

Genetics of the Erucic Acid Content in Interspecific Hybrids of Ethiopian Mustard (Brassies carinata Braun) and Rapeseed (B. napus L.)

AbstractEthiopian mustard (Brassica carinata Braun) is a potential oil crop in which genes for low erucic acid content of the seed oil have not yet been found. In order to solve this problem the potential of rapeseed (B. napus L.) varieties as a source of these genes has been tested. Reciprocal F1 hybrids between B. carinata and a low erucic acid variety of B. napus, F2, and backcrosses with B. carinata were obtained. The fatty acid composition was determined in half seeds of F1 and segregating generations from reciprocal interspecific crosses. The genetic analysis indicated that the erucic acid content of the seed oil of B. carinata is controlled by two genes with no dominance and additive in action.

Dietary fats and lecithin-cholesterol acyltransferase activity in healthy humans.

We analyzed the effects of different types of dietary fat on the lecithin-cholesterol acyltransferase (LCAT) activity in 20 healthy women aged 26-49 years, consuming 6-week diets containing 54% of the calories as carbohydrates, 16% as protein and 30% as fat. The tested fats were successively: low erucic acid rapeseed (LEAR oil), sunflower oil, peanut oil and milk fats (butter and cream). The fractional and molar rates of LCAT were higher after sunflower and peanut oil diets and decreased significantly after LEAR oil and milk fat diets. The LCAT activity was independent of the P/S ratio of the diet, but positively correlated with the percentage of linoleic acid in serum phospholipids and cholesteryl esters, and negatively correlated with the percentage of oleic acid in the same fractions. Our results showed no relation between LCAT activity and the concentration of plasma cholesterol or triglycerides, no change in serum cholesteryl ester/total cholesterol ratio and confirmed that the distribution of high density lipoprotein subfractions is due to prerequisites other than LCAT.

Breeding for Improved Oil Quality in Winterrape by Means of Haploid Culture Techniques

AbstractFarmers growing oilseed rape are facing well defined demands on the quality traits of their product. Therefore their crops are regularly grown from seed with genetically low erucic acid and low glucosinolate content. But well adapted varieties with low linolenic acid content or yellow seed coat would fit further demands of seed crushers. Such genotypes exist, but in general they have poor agricultural habits. Breeders select for genotypes combining quality traits with good adaption to the farmers' need. The breeders' success is limited by genetical influences as segregation within the tested progenies and dominance of the traits, and non‐genetical influences on the expression of the traits. To eliminate the genetical influences would require very time consuming conventional breeding methods. The recently developed haploid culture techniques are alternatives to these conventional breeding methods. However, to develop a single testing unit is very expensive. The use of such methods therefore is only justified, if the magnitude of the former mentioned genetic effects hinders the efficient enhancement of the quality traits. Genetic effects estimated by various authors give no expectation of such influences. A clear advantage of the haploid techniques in enhancing the quality traits discussed here, is therefore not anticipated.

Low Density Lipoprotein Catabolism in Mononuclear Cells of Human Subjects Receiving Various Fat Diets

The effect of dietary fats on the low density lipoprotein (LDL) receptor activity of circulating blood mononuclear cells was investigated in 11 healthy women who consumed a 6-week normocaloric diet consisting of 54% of the calories as carbohydrate, 16% as protein, and 30% as fat. The tested fats were successively low erucic acid rapeseed (LEAR) oil, sunflower oil, peanut oil, and milk fats (butter and cream). Changes in total cholesterol levels according to the fat reflected changes in LDL-cholesterol but not in high density lipoprotein (HDL)-cholesterol. This effect was accompanied by modifications of the LDL receptor activity in freshly isolated blood mononuclear cells, quantified as the amount of [125I]LDL associated with cells: a negative correlation existed between total or LDL-cholesterol levels in plasma and LDL receptor activity (r=-0.35, p<0.05). Moreover, LDL receptor activity of cells was related to the daily intake of saturated fatty acids, particularly C16:0+C18:0. We conclude that a possible mechanism is a modification in the rate of endocytosis of LDL receptor due to changes in the membrane fluidity according to the dietary fat.

Development of Triazine Resistance in Crops by Classical Plant Breeding

The appearance of triazine resistance in a number of weed species has provided some opportunities for plant breeders to develop triazine-resistant crop varieties through classical breeding techniques. The sources of genes utilized by plant breeders for desirable characteristics are usually limited by the normal reproductive barriers that distinguish species. The occurrence of a triazine-resistant biotype of birdsrape mustard (Brassica campestris L. # BRSRA) has allowed for the development of commercially useful triazine-resistant varieties of canola (low erucic acid, low glucosinolate oilseed rape, B. napus L.). The cytoplasm of triazine-resistant birdsrape mustard was transferred interspecifically to oilseed rape, by a technique commonly known as back-crossing, in conjunction with selection for chromosome number. ‘OAC Triton′, the first triazine-resistant canola variety, appears to be finding commercial acceptance in Canada, in spite of some limitations in agronomic performance. Although it should be possible to transfer this triazine-resistant cytoplasm to other economic Brassica species including the cole crops and mustards, conventional plant breeding techniques cannot separate the gene conferring triazine resistance from other genes in the resistant weed biotype's cytoplasm. This problem may limit the utility of triazine-resistant cytoplasms from weed biotypes in classical crop breeding.

The Polymorphism of Low Erucic Rapeseed Oil with High Content of Palmitic Acid

AbstractA new type of low erucic acid rapeseed oil containing high amount (11%) of palmitic acid (C16‐LOBRA) was studied, both in labscale and in pilot‐plant equipment. The polymorphic behaviour of fat blends and margarine emulsions consisting of C16‐LOBRA, LOBRA and soybean oil and their hydrogenated fats were examined. The results clearly show the potential in the hydrogenated C16‐LOBRA. The time before the stable ß‐form is developed is much longer for the hydrogenated C16‐LOBRA compared with the hydrogenated LOBRA and in fact similar to a hydrogenated soybean oil. The hydrogenated C16‐LOBRA is therefore well suited to be used in e.g. margarine systems.

Influence of the fatty acid composition of high-density lipoprotein phospholipids on the cholesterol efflux from cultured fibroblasts

The purpose of this work was to determine whether the changes induced by dietary manipulations in the chemical composition of high-density lipoproteins (HDL) (particularly phospholipid fatty acid composition) modified their capacity to promote [ 3H]cholesterol efflux from cultured fibroblasts. Plasma HDL were obtained from subjects fed for six successive long periods on diets consisting of one predominant fat: peanut oil, corn oil, olive oil, soybean oil, low erucic acid rapeseed oil or milk fats. The [ 3H]cholesterol efflux from cells in the presence of plasma HDL was studied by means of normal adult human fibroblasts in culture. The [ 3H]cholesterol efflux from fibroblasts appeared to be independent of the overall composition of HDL and of the degree of saturation of the HDL phospholipid fatty acids, but it was correlated with the phospholipid fatty acid chain length. The [ 3H]cholesterol efflux from fibroblasts is highly and positively correlated with the sum of the HDL phospholipid C 20, C 22, C 24 fatty acids, and negatively correlated with the sum of the HDL phospholipid C 18 fatty acids.

Effect of Dietary Erucic Acid on the Utilization of Oils or Fats by Growing Chicks

Free erucic acid (EA) (C22 : 1) was blended with Cambra oil (CBO), sunflower oil (SFO), and animal lard (AL) at 45% (w/w). Six experimental diets were formulated to incorporate either CBO, SFO, AL, or EA blended oils (CBO plus EA, SFO plus EA), or fats (AL plus EA) at 8%. The adverse effects of dietary EA blended with various types of oils or fats were studied by feeding 180-day-old White Leghorn cockerels for a 4-week growing period.In general, adverse effects of dietary EA were clearly reflected in feed consumption, chick growth, and apparent digestibility of total lipids as well as individual fatty acids. The AL plus EA produced significantly greater adverse effects than with SFO plus EA. The diet containing CBO (low EA, 5.1% rapeseed oil) depressed chick growth and feed consumption, but no additive effect was manifested when EA was supplemented.The fatty acid profile of dietary SFO appears to counteract the metabolic burden of excess dietary EA. It was concluded that high linoleic acid content in SFO may be the major contributing factor in alleviating the adverse response to EA.

Influence of dietary partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets in the rat.

The aim of the present study was to investigate the influence of partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets with particular reference to the metabolism of linoleic acid and the production of arachidonic acid metabolites. Four groups of male weanling rats were fed linoleic acid supplemented diets containing 20% (w/w) of partially hydrogenated low erucic acid rapeseed oil (HLRSO), partially hydrogenated herring oil (HHO), olive oil (OO) and trierucin + triolein (TE) for 10 weeks. An additional two groups were fed partially hydrogenated low erucic acid rapeseed oil and partially hydrogenated herring oil without linoleic acid supplementation (HLRSO- and HHO-, respectively). Substantial amounts of trans fatty acids were incorporated into liver microsomes (12.6% in group HLRSO) and platelets (7.0% in group HLRSO-). This incorporation was not dependent on the dietary linoleic acid level. Hepatic microsomal delta5 -desaturase activity was significantly increased after HLRSO feeding compared to 00 feeding. Delta6 -Desaturase activity did not vary in the linoleic acid supplemented groups. Both delta5 -and delta6 -desaturase activities were significantly increased in groups without linoleic acid supplementation. Docosenoic acid was incorporated into platelet phospholipids in contrast to liver microsomes. In the platelet, docosenoic acid seemed to have a special preference for phosphatidylserine. Very small amounts were incorporated into platelet phosphatidylinositol. Feeding diets HLRSO, HHO and 00 did not influence rat platelet cyclooxygenase or 12-lipoxygenase activity. Platelets from rats fed TE, however, produced significantly less 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) than platelets from rats fed OO. Feeding of HLRSO- and HHO- resulted in a significantly diminished production of the arachidonic acid metabolites 12-HETE, 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 6-keto-prostaglandin F1alpha in stimulated platelets and aorta. Thus, high dietary levels of trans isomers of monoenoic acids do not interfere with platelet cyclooxygenase or lipoxygenase activity provided sufficient amounts of linoleic acid are available.

Effects of different dietary intake of essential fatty acids on C20:3 omega 6 and C20:4 omega 6 serum levels in human adults.

Four diets which differed in fatty acid composition were provided for five months each to a group of 24 healthy nun volunteers. The diets contained 54% carbohydrates, 16% proteins and 30% lipids. One-third of the lipid part remained unchanged during the whole study, and two-thirds were modified during each period. For this latter portion, one of the following dietary fats was used: sunflower oil, peanut oil, low erucic acid rapeseed (LEAR) oil or milk fats. This procedure allowed an evaluation of the effects of various amounts of dietary linoleic acid (C18:2 omega 6) and alpha-linolenic acid (C18:3 omega 3) on the serum level of their metabolites. A diet providing a large amount of linoleic acid (14% of the total caloric intake) resulted in low levels of dihomo-gamma-linolenic acid (C20:3 omega 6) and arachidonic acid (C20:4 omega 6) in serum phospholipids and cholesteryl esters. A diet providing a small amount of linoleic acid (0.6% to 1.3% of the total caloric intake) induced high levels of omega 6 fatty acid derivatives. Intermediate serum levels of C20:3 omega 6 and C20:4 omega 6 were found with a linoleic acid supply of about 6.5% of the total caloric intake. Serum levels of omega 6 metabolites were not different after two diets providing a similar supply of C18:2 omega 6 (4.5% to 6.5% of the total caloric intake), although in one of them the supply of C18:3 omega 3 was higher (1.5% for LEAR oil versus 0.13% for peanut oil).(ABSTRACT TRUNCATED AT 250 WORDS)

Choice of Simple Methods for Quality Control of Frying Fat during Deep Frying of Potato Products

AbstractStudies have been carried out to choice methods which could assess in best way the complex changes in fat during deep frying of French fries and potato crisps. A special emphasis was laid on the estimation of usefulness of simple and quick “methods” which could practically indicate the utilization time of fats (soybean oil, low erucic acid rapeseed oil, „Sofryt”︁ ‐hardened soybean oil), used in deep‐fat frying of potato products. Besides the oxidized fatty acid content, proposed by DGF (German Society for Fat Science) as a basic test for the quality assessment of used frying fats, following control tests during the deep‐fat frying of potato products have been appointed: colour tests with bromthymol blue and 2,6‐dichlorphenol‐indophenol, sensoric evaluation, dielectric constant and colour by iodine scale. For these tests suitable limits, qualifying the utility of oils and fats for further frying of French fries and potato crisps, have been estimated.

Book Reviews

Trichothecenes: Chemical, Biological and Toxicological Aspects. Ed. by Y. Ueno.Handbook of Indigenous Fermented Foods. Edited by K. H. Steinkraus.A Modern Introduction to Food Microbiology (Basic Microbiology, Volume 8). By R. G. Board.High and Low Erucic Acid Rapeseed Oils: Production, Usage, Chemistry and Toxicological Evaluation. Ed. by J . K. G. Kramer, F. D. Sauer and W. J . Pigden.Third International Symposium on Preharvest Sprouting in Cereals. Ed. by J . E. Kruger and D. E. LaBerge.Sanitation, Safety and Environmental Standards. By L. J . Minor.

Interspecific transfer of Brassica juncea-type high blackleg resistance to Brassica napus

Complete resistance to Leptosphaeria maculans, the cause of blackleg of oilseed rape (Brassica napus), was transferred from B. juncea to B. napus through an interspecific cross. B. juncea-type complete resistance (JR) was recognized first in one F3 progeny (OnapJR) by the absence of leaf-lesions on seedlings and canker-free adult plants. The commercially important characters of B. napus were retained in advanced lines of OnapJR, which combined JR with low erucic acid levels (<0.5%), high seed yield and variable maturity dates.

Effect of dietary supplementation with stearic acid on the severity of myocardial lesions

Histological studies were conducted on ventricular myocardium obtained from male rats of the Sprague-Dawley strain after 16 weeks of feeding diets containing 20 per cent (w/w) soybean oil, low erucic acid rapeseed oil or high erucic acid rapeseed oil. Additional groups of rats were fed similar diets supplemented with up to 8 g/kg of tristearin. Increasing dietary intake of stearic acid normalised the plasma ratio of C16:0 to C18:0 for rapeseed oil treatments to ratios analogous to that observed for rats fed soybean oil. Tristearin supplementation did not have a significant effect on myocardial lesion incidence but decreased the severity of lesions observed for rapeseed oil treatments.

Use of gas liquid chromatography for monitoring the fatty acid composition of canadian rapeseed

AbstractSince 1972, Canadian rapeseed has been changing from high erucic acid types to low erucic acid types. In 1970, the Canadian Grain Commission instituted a program to monitor the fatty acid composition of rapeseed at the farm level, in railway carlot shipments and in export cargo shipments. Initially, in order to process up to 20,000 samples per year, a combined extraction and methylation procedure was developed in which methyl esters were analyzed within 5 min by manual injection on a nonpolar column. Since conversion to low erucic acid rapeseed types has been completed, other details of fatty acid composition have received more attention. In the system presently used, the rapeseed oil methyl esters are analyzed on a mixedphase column which gives good resolution of all of the major fatty acids. Through the use of a microcomputer‐controlled autosampler, 50 samples can be analyzed per day. Reports are generated giving complete fatty acid composition as well as estimates of iodine value and saponification value.

Diet fat influences liver plasma-membrane lipid composition and glucagon-stimulated adenylate cyclase activity.

Rats were fed diets that differed in fatty acid composition or in the proportion of energy derived from fat to determine if alteration of dietary fat intake influences the structural lipid composition of liver plasma membrane and the expression of an associated hormone-receptor-mediated function. Weanling rats were fed 9% (w/w) or 20% (w/w) low-erucic acid rape-seed oil or 9% (w/w) soya-bean oil for 24 days. Plasma membranes were isolated and the effect of diet fat on the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol and sphingomyelin was determined. Diet fat significantly altered total saturated and (omega-9) and (omega-6)-unsaturated fatty acid composition in addition to the (omega-6)- to (omega-3)-unsaturated fatty acid ratio in these polar lipids. Feeding the high-fat diet increased the (omega-6)- to (omega-3)-unsaturated fatty acid ratio and the (omega-9)-unsaturated fatty acid content in all lipids except sphingomyelin. Assay of glucagon-stimulated adenylate cyclase activity at both high and low glucagon concentrations indicated that high-fat intake also decreased cyclic AMP formation. In a second experiment the fat intake was held constant (40% of energy) and oleic acid was substituted for linoleic acid by blending high- and low-linoleic acid-type safflower oils. This experiment established that a dose-response relationship exists between dietary intake of fatty acid and the fatty acid composition of plasma-membrane phospholipids. Specific diet-induced transitions in membrane phospholipid fatty acid composition were paralleled by changes in glucagon-stimulated adenylate cyclase activity. This study suggests that transitions in dietary fat intake can alter a hormone-receptor-mediated enzyme function in vivo by changing the surrounding lipid environment.

The Effect of Commercial Processing on the Nutritional and Cardiopathological Quality of Low Erucic Acid Rapeseed Oil

Vegetable oil was extracted from the same batch of low erucic acid rapeseed using a commercial extraction process or a specially designed pilot plant procedure. The latter method involved mild heat treatment and no subsequent refining and deodorization. A comparison of oils prepared by the two processes showed that the pilot plant extracted oil contained less sulphur and more colour, but the fatty acid composition was similar. Male rats fed diets containing the pilot plant extracted oil grew better, although the cardiopathogenic response to both oils was similar. The results appear to preclude the possibility that contaminants in the oil were the cause of the heart lesions. On the other hand, they provided further evidence that the formation of heart lesions in male rats was related to the fatty acid composition of the dietary fat or oil, since both the incidence of heart lesions and the fatty acid composition of the two oils were similar.

Effect of Canola Meal on the Sensory Quality of Turkey Meat

The sensory quality of 4 male and 4 female carcasses of 14-week-old broiler turkeys fed each level of 0, 73, 144, and 211 g Candle canola (low erucic acid, low glucosinolate rapeseed) meal (CM) per kilogram was evaluated by an experienced taste panel. Except for a slightly increased frequency of off-flavors at 73 g/kg diet, no differences in flavor or off-flavors were associated with level of CM in diet.