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Three sulfur-heterocyclic fatty acids (SHFA) had been tentatively identified in rapeseed oil in the late 1980s. In this study we aimed to enrich and verify the presence of potential SHFA in one sample of native rapeseed oil, refined rapeseed oil and mustard seed oil. Fifty-gram samples of the three oils were individually saponified and converted into methyl esters. The resulting samples were hydrogenated and subjected three times to urea complexation. The resulting extracts of native rapeseed oil and mustard oil contained 21 different SHFA with 18, 20, 22 or 24 carbons. The refined rapeseed oil contained only nine C18-SHFA. Structure investigation of the SHFA was performed by gas chromatography with mass spectrometry (GC/MS) using methyl esters and also 3-pyridylcarbinol esters. A direct screening of non-enriched samples by GC/MS in the selected ion monitoring mode and by GC with flame photometric detector (sulfur-selective) verified that the SHFA were native compounds of the oils and no artefacts of the sample preparation. Similar abundances of the four isomer groups of SHFA with monoenoic fatty acids of the same carbon number in these and five further rapeseed and mustard samples indicated that these could be the precursors of the SHFA.

Seed roasting is practiced in the mustard oil industry in some areas of the world, and can affect the physicochemical properties of the oil for further applications. This research studied the differences in oxidative stability, tocopherols, and carotenoids during heating at 160 °C between oil extracted from roasted mustard seeds and that from unroasted seeds. The content of free fatty acids, polar compounds (PC), and lutein were not significantly different between the roasted and unroasted seed oils before heating. The fatty acid compositions of both oils were also similar, with high amounts of erucic, linoleic, and oleic acids, moderate amounts of linolenic and eicosenoic acids, and low amounts of palmitic and stearic acids. However, the levels of tocopherols and conjugated dienoic acids (CDA) were higher in the roasted seed oil. Heating increased the content of CDA and PC in both oils, but decreased tocopherols and lutein. The rates of increase in CDA and PC and the degradation rates of tocopherols and lutein during heating were lower in the roasted than in the unroasted seed oil. Overall, the increased thermo-oxidative stability of the mustard oil by roasting the seeds before oil extraction was highly correlated with improved heat stabilities for both tocopherols and lutein.

The effects of genotype and growing environment on the tocopherols and fatty acids (FA) of experimental Brassica juncea and B. napus breeding lines were investigated. For both species, with the exception of a few genotypes, the concentration ratio of γ-tocopherols to α-tocopherol was practically constant. The genotype influenced the tocopherol concentration in B. napus, and to a lesser degree, B. juncea. The environment also had a similar effect, and a positive correlation existed between the daily maximum temperature and the α-tocopherol concentration in B. napus. Genotype effects on the FA composition were significant for the conventional but not for Clearfield or triazine tolerant traits of B. napus. The genotype had no effect on the FA of the B. juncea genotypes. In contrast, the growing environment had a significant influence on the FA composition of both species with apparent influence from temperature and rainfall. For both species, the concentration of γ-tocopherol as well as total tocopherols was inversely related to the 18:3 concentration, which could have resulted from opposite and independent effects of temperature on the two variables. No relationship existed between the concentrations of tocopherol and the remaining unsaturated FA 18:1 and 18:2. The positional distribution of unsaturated FA within the oil triacylglycerol was a function of their total concentration.

A membrane-based process to produce protein isolates from seeds of oriental mustard (Brassica juncea) was developed by modifying a method originally developed for rapeseed. The optimized process consisted of extraction at pH 11, ultrafiltration with concentration factor 4, diafiltration with diavolume 3, and precipitation at pH 5. The process, based on defatted oriental mustard seed containing 45–50% protein, recovered 81% of the protein in useful products: 47.3% in precipitated protein isolate (PPI), 3.8% in soluble protein isolate (SPI), and 13% in meal residue. Mass yields were 21.9% in PPI, 2.8% in SPI, and 38.4% in meal residue. The losses in the system included ∼10% loss of nonprotein nitrogen, and

Prediction of the content of water, oil, and protein in rape and mustard seed was examined by a combination of low-field 1H nuclear magnetic resonance (LF-NMR) and chemometrics, enabling utilization of the entire relaxation curves in the data evaluation. To increase the range of relative contents, the untreated seeds were wetted and dried; each treatment was followed by NMR analysis. The chemometric results are compared to traditional evoluation by multiexponential fitting of the relaxation curves. For this purpose a new jackKnife validation procedure was developed to evaluate the number of exponential components objectively. Classification of the two kinds of seeds was easily performed by LN-NMR. Partial least squares regression to oil content in untreated rape and mustard seed yielded models with correlation coefficients of r=0.88 and 0.89 with root mean square error of cross-validation (RMSECV) of 0.84 and 0.45, respectively. The rapeseed model was based on one component, wheres the mustard seed model was based on two components. If the seeds were dried, the predictive performance improved to r=0.98 and RMSECV=0.38 for rapeseed and to r=0.95 and RMSECV=0.38 for mustard seed. Upon drying, prediction of protein content in mustard seed improved, whereas the prediction of protein for rapeseed deteriorated. Global models, including the combination of untreated, wet, and dry seeds, all resulted in a robust and good predictive performance with RMSECV in the range 0.8–1.3% to water, oil, and protein content. It was demonstrated that drying the seeds to simultaneously determine water and oil content was not necessary when chemometrics was applied on the relaxation curves.

Aqueous enzymatic extraction was investigated for recovery of oil from mustard seed and rice bran. The extraction process was reproducible based on statistical analysis of extraction data under different extraction conditions. The most significant factors for extraction were the time of digestion with enzymes, seed or bran concentration in water, volume of hexane added before recovery, and amount of enzyme(s) used. The pretreatment steps of each material before enzyme digestion influenced oil yield.

This work reports on the dry adhesion strength of wood adhesives formulated with fractions of an alkaline extract obtained from wastewater activated sludge, a renewable and abundant resource. The extract was fractionated and desalted using ultrafiltration techniques. The effect of molecular weight and composition (protein and carbohydrate content) on the extract’s adhesion strength was assessed, as well as the effect of crosslinking using glutaraldehyde. The dry adhesion strength of adhesives formulated with soluble mustard seed protein isolate, a protein-rich alkaline extract, is also reported. In the presence of glutaraldehyde, an extract fraction with high protein content and low salt and hydroxide content showed adhesion strength close to that of the mustard protein adhesive and a commercial wood adhesive. It was further determined that the adhesion strength of the extract and its fractions was strongly correlated with their protein content.

The recent development of combustion-type nitrogen analyzers capable of handling relatively large samples with semi automatic operation offers a potential replacement for the Kjeldahl method for direct determination of nitrogen. Nitrogen analyses for canola seed, flaxseed, sunflower seed, mustard seed and soybeans on a LECO (St. Joseph, MI) FP-428 Nitrogen Analyzer were evaluated against results from the Grain Research Laboratory's (GRL) Kjeldahl system. The nitrogen analyzer gave significantly higher values than the Kjeldahl method, resulting in a correction of low values in the GRL Kjeldahl, caused by the inability to use mercury as catalyst. The standard error for results from the analyzer was comparable to that for the Kjeldahl method. The nitrogen analyzer also was faster than the Kjeldahl method and had less environmental impact. The combustion method has replaced the Kjeldahl method for routine nitrogen determinations in oilseed surveys conducted by the GRL.

Defatted meals and protein concentrates from five varieties of mustard seeds (four Brassica spp. and one Sinapis alba) were analyzed for polypeptide composition and functional properties. Nonreducing gel electrophoresis showed that Brassica seeds lacked the 135- and 50-kDa polypeptides that were present in the seeds of the S. alba variety. On the other hand, the 29-kDa polypeptide found in the Brassica seeds was absent from the seed of the S. alba variety. Under reducing conditions, the 135 kDa was not detected in the S. alba variety and the intensity of the 50-kDa polypeptide was severely reduced; in contrast, the intensity of the 29-kDa polypeptide in the Brassica seeds was not affected. Meals from yellow seeds had significantly higher (P≤0.05) protein contents than meals from the brown seeds. The emulsifying activity indexes (EAI) of meals and protein concentrates from the Brassica seeds were significantly higher (P≤0.05) than those obtained for similar products from S. alba sees. It was concluded that the disulfide-bonded 50- and 135-kDa polypeptides may have contributed to increased rigidity of S. alba meal proteins, which resulted in poor EAI when compared to the Brassica meals, which do not contain these polypeptides.

Recent investigations into the processing of oriental mustard seed for production of livestock feed and of lipid-containing erucic acid have stimulated interest in the composition of the by-product essential oil. The development of a method for analysis of this oil by gas-liquid chromatography has led to the demonstration of an equilibrium reaction between the two main constituents. A similarity in composition and response to heat is shown between the natural essential oil and oils prepared synthetically. These observed similarities should lead to a better understanding of the enzymatic reaction responsible for release of this oil from the seed.

Processed mustard seed contains a considerably higher content of reducing sugar than other oilseeds. During processing, the natural reducing sugar is supplmented with glucose released by enzyme hydrolysis of the thioglucoside, and this total content reaches a value of more than 3% of the defatted mustard meal. This quantity of reducing sugar in mustard seed is three times more than that in soybean meal. Consequently, the browning reaction, which degrades protein, presents a greater problem in processing oilseeds containing thioglucosides than oilseeds free of thioglucosides. In developing the processing of mustard seed, the degree of heat treatment given the protein meals had to be determined. Several indirect methods were developed for following the effects of heat treatment on protein quality. Nitrogen solubility index, optical density of aqueous extracts, and reducing sugar content correlated well with degradation of heat-labile amino acids, such as lysine, arginine, and histidine, and gave an index of protein quality.

The oils from yellow mustard seed (Brassica alba), black mustard seed (Brassica nigra) of Indian origin, and rapeseed (Brassica Compestris) of unknown origin have been analyzed for their fatty acid composition without preliminary resolution of fatty acids by lead-salt-alcohol or fractional crystallization methods. The results compare very favorably with those determined by other recently developed methods. It may be concluded therefore that this method can be favorably employed for the determination of fatty acid composition of fats containing higher unsaturated acids.

Rapeseed is number five among the oilseeds of the world. During the last 10 years the crop has increased more in per cent than any other oilseed crop. In the FAO prospects an annual rate of increase of 4.7% is foreseen. The fatty acid composition will change during the next years so that erucic acid will be practically removed. The content of glucosinolates will also be reduced dramatically, and consequently the meal will be accepted much more readily.

A modified cooking and extraction process for mustard seed is reported in which the pungent factor, allyl isothiocyanate, is separated from the seed to yield triglyceride oil and protein meal. Although removal of the pungent factor from the oil and meal products was previously reported, investigations were continued to develop critical improvements in the process. A reduction in conversion time, combined with steam stripping and shorter heating preiods, resulted in quantitative recovery of the essential oil and in improved protein quality, as measured by the basic amino acids. Biological testing with rats showed the processed meals to be free of toxic and goitrogenic factors and to be well utilized nutritionally. Preliminary estimates indicate that process costs are nearly the same as for a comparable soybean plant.

Mustard seed like rapeseed is characterized by the presence of glucosides, which are readily hydrolyzed under certain conditions by enzymes in the seeds to produce pungent “mustard oils”. This property is utilized in the preparation of condiments from some varieties of mustard, but when the seed is processed to yield a palatable oil and feed meal, this pungent factor must be removed. This was accomplished in bench-scale studies at the Northern Laboratory by converting the mustard glucoside enzymatically and removing the converted product, allyl isothiocyanate, during a subsequent cooking step before filtration-extraction of the meal.

24-Methylcholesta-5,E-22-dien-3β-ol (C28 Δ5,22-sterol) was separated from the unsaponifiable matters of the following eight seed oils of Brassica species:Brassica campestris (candle I and II and torch),B. napus (tower and midas),B. juncea (brown and oriental mustards), andB. alba (yellow mustard). The configuration at C-24 methyl group of the respective sterols was evaluated by13C NMR spectroscopy. All the C28 Δ5,22-sterols in the Brassica seed oils were found to contain the C-24 epimer of brassicasterol,trans-22-dehydrocampesterol, in the range of ca. 10–30%.

Seed oils from most of the known species and varieties ofLimnanthes were analyzed for their fatty acid content. Each contained at least 95% acids with more than 18 carbon atoms. The major component acid,cis-5-eicosenoic, ranged 52–77% of the acids present. Seeds of all species examined contained thioglucosidic precursors of volatile isothiocyanates, liberated by the action of mustard seed enzymes on the meal. One species also yielded a small amount of an oxazolidinethione-like compound of the type associated with enzyme-treated rapeseed meal.

Because crambe, mustard seed, and rapeseed oils, like soybean oil, contain linolenate ester, they have been examined and compared with soybean oil for flavor stability after accelerated storage and after exposure to fluorescent light. Tests showed that the Cruciferae oils did have similar flavor characteristics and that the addition of citric acid did improve their stability. When exposed to light, the citric acid-treated Cruciferae oils differed from soybean oil; they developed a rubbery flavor, whereas soybean oil developed a grassy flavor. Oxidative stability determined by the active oxygen method confirmed results of oven storage tests. This work supports the belief that if linolenic acid is present in an edible oil, it is a precursor to typical off-flavor development.

Argemone mexicana plant, a good natural source of nonedible oil in India can be used for beneficial use if the toxic alkaloids present in the oil are removed. The author suggests purification by acid treatment of the hexane extract of Argemone seeds, then passing the solvent through bone-charcoal column. The toxic yellow-colored alkaloids are adsorbed in the column. The colorless oil is obtained on recovery of the solvent.