Nondestructive determination of fatty acid composition of husked sunflower (Helianthus annua L.) seeds by near-infrared spectroscopy

Determination of the fatty acid composition of sunflower (Helianthus annua L.) seeds by near-infrared (NIR) spectroscopy was examined. Sunflower seeds were husked (removed from their hulls by a husking machine or manually with a knife). NIR spectra of these seeds were scanned from 1100 to 2500 nm at 2-nm intervals in a whole-grain cell with a wideangle moving drawer for machine-husked seeds or in a single-grain cup for a manually husked single-grain seed. The extracted oils from machine-husked seeds also were scanned by sandwiching them between a pair of slide glasses to create a thin layer and by placing them on a syrup cup. For extracted oil, the absorption band around 1720 nm filled out to the shorter wavelength region in the NIR second-derivative spectra as the percentage of the linoleic acid moiety increased, because linoleic acid absorbs in this region. On the other hand, for husked seeds and for a single-grain seed, as the percentage of linoleic acid increased, the trough at 1724 nm where oleic and saturated acids absorb decreased in the second-derivative NIR spectra. Determination of the fatty acid composition of sunflower seeds could be carried out successfully according to the NIR spectral pattern for both extracted oil (r=−0.989) and kernel seed (r=−0.993). This is important, especially for a manually husked single-grain seed (r=−0.971), because it can still be germinated after such nondestructive analysis.     

Chemical composition and characteristics ofMoringa peregrina seeds and seeds oil

TheMoringa peregrina kernel contains 1.8% moisture, 54.3% oil, 22.1% protein, 3.6% fiber, 15.3% carbohydrate and 2.5% ash. The composition and characteristics of the extracted oil were determined. Gas liquid chromatography of methyl esters of the fatty acids shows the presence of 14.7% saturated fatty acids and 84.7% unsaturated fatty acids. The fatty acid composition is as follows: palmitic 9.3%, palmitoleic 2.4%, stearic 3.5%, oleic 78.0%, linoleic 0.6%, linolenic 1.6%, arachidic 1.8% and behenic 2.6%.     

Comparison of the composition and properties of canola and sunflower oil sediments with canola seed hull lipids

The phase transition behavior and chemical composition of sediments from Canadian and Australian canola oils, as well as from sunflower oil, were studied by differential scanning calorimetry, X-ray diffraction, polarized-light microscopy, and chromatographic techniques. Australian canola sediment was similar to Canadian canola sediment in both melting and crystallization behaviors and chemical composition. Compared to canola sediment, sunflower sediment underwent phase transformation (melting and crystallization) at lower temperatures, and the enthalpies associated with the phase changes were greater. The X-ray diffraction patterns for these materials were similar, indicating identical crystalline structures. Sunflower sediment contained mainly wax esters (99%), while canola sediment contained about 72–74% of waxes. Moreover, sunflower sediment consisted of shorter-chainlength fatty acids and alcohols than canola sediment. A hexane-insoluble fraction from Canadian canola hull lipids had fatty acid and alcohol profiles and X-ray diffraction pattern similar to the corresponding oil sediment.     

Factors affecting the composition of canadian oil seeds

Importance of climate, plant breeding, and economics to production of oil seeds in Canada is considered. The influence of temperature and rainfall on the oil content and fatty acid composition of linseed and rapeseed is discussed. Major changes in the fatty acid composition of rapeseed oil can be effected by modern techniques in plant breeding and selection, i.e. erucic acid content can be reduced from approximately 40% to 0. The impact on the oil meal market of continued selection for high oil in crops and varieties is discussed.     

Nondestructive single-kernel oil determination of maize by near-infrared transmission spectroscopy

The utility of near-infrared transmission spectroscopy (NITS) for the nondestructive prediction of oil content in single maize kernels was explored. Calibration models were developed from spectral information gathered between 850 and 1050 nm. Nuclear magnetic resonance (NMR) spectroscopy was employed as a reference method to determine the actual oil content of samples used for calibration development and testing. Various positionings of the kernels in the light path and calibration math treatments were explored. The best NITS calibration yielded a 1.2% standard error of cross validation, which was over four times the standard error of NMR reproducibility. Although not as accurate as NMR, NITS does have utility in selecting kernels with the highest oil content from a segregating population.     

Nondestructive single-seed oil determination of meadowfoam by near-infrared transmission spectroscopy

Near-infrared transmission spectroscopy (NITS) was explored for single-seed oil determination of meadowfoam. Two calibration sets were determined by principle component analysis of recorded spectra. Nuclear magnetic resonance (NMR) spectroscopy was used for oil content determination. The calibrations had standard errors of cross-validation of 3.6 and 4.4%, respectively, with an oil content ranging from 0.8 to 45.7%. This error is similar to that reported for NITS of single maize kernels, relative to the respective oil content ranges. Although not as accurate as NMR spectroscopy, NITS does provide a fast, efficient, and nondestructive method of predicting oil content of individual meadowfoam seeds.     

Oil stability index correlated with sensory determination of oxidative stability in canola oil

The usefulness of the Oil Stability Index (OSI) as an accelerated oxidative stability test for canola oil was studied by correlating the OSI with the induction period as determined by sensory analysis. Canola oil was treated by holding it for differing times (0, 1, 2, 3, 4, and 6 d) at elevated temperature (60°C) in the dark with agitation. The sensory induction period (SIP) was determined by storing the five treatments of oil and the control at 60°C in the dark with agitation and removing aliquots of oil for a nine-member sensory panel to evaluate over a 9-d period. The time it took for a treatment to reach an average sensory score of 5 (10-point scoring scale) was defined as the treatment’s SIP. OSI values were obtained on day 0 using a heating block temperature of 110°C and an air pressure of 6 psi. The relationship between SIP and OSI had a 0.89 coefficient of determination (r ²). This relationship may be sufficiently strong to warrant use of the OSI in industry applications but may not be ideal for more precise experimental studies of canola oil shelf life.     

Effect of sprouting on the quality and composition of canola seed and oil

Sprouting has been considered as a damage factor in grading canola. This project deals with the evaluation of the effect of sprouting on the quality and composition of canola seed and oil. Sprouted seeds had lower oil content than nonsprouted seeds as determined by exhaustive petroleum ether extraction. The difference, although statistically significant, was small, less than 0.1% oil at the maximum level of sprouting allowed in topgrade canola. There were no differences in chlorophyll contents or moisture contents between sound and sprouted seeds. Sprouted seeds had significantly higher levels of FFA and crude protein than sound seeds. Oxidation parameters (diene and aldehyde) were higher in oils from sound seeds than oils from sprouted seeds, but there was no statistically significant difference in PV. Sprouted seeds had higher levels of tocopherols and sucrose, but lower levels of raffinose, stachyose, and total sugars than sound seeds. There was no difference in overall FA composition of the oil between sound and sprouted seeds. The second extraction of the Federation of Oils Seeds and Fat Associations (FOSFA) extraction method, which allowed the extraction of more polar lipids, contained significantly more saturated FA. However, this was not significant in the overall FA composition of the oils because this fraction counted for about 2% of the total lipid content. The presence of sprouted seed had an effect on results for oil and crude protein determined by NIR as compared with results by FOSFA extraction, or pulsed NMR for oil and Dumas combustion for crude protein. Addition of sprouted seed samples to the NIR, calibration set overcame this problem. These results suggested that sprouting did not have a highly damaging effect on the quality and composition of canola seed and oil when less than 10% of the seeds in a sample were sprouting.     

Polymorphism of hydrogenated canola oil

The polymorphism of hydrogenated Canola oil was investigated using X-ray diffraction. The effects of hydrogenation conditions (selective: 200 C; 48 kPa hydrogen pressure, and nonselective: 160 C; 303 kPa) and degree of unsaturation on the transformation β′ → β are discussed. A densitometer was used to follow the changes in the relative density of the characteristic short spacings, in an attempt to present a semiquantitative measure of β′ « β transformation during storage. The samples studied were selectively and nonselectively hydrogenated Canola oils of iodine values (IV) 70 and 60, respectively. Among the 4 samples, the selectively hydrogenated sample with IV 70 was the most stable and the nonselectively hydrogenated sample with IV 60 the least stable.     

Rapid extraction of canola oil

The simultaneous size reduction and solvent extraction of canola seeds were studied using a laboratory blender and a small, pilot-scale Szego mill. The laboratory tests established that over 95% of the oil may be removed from the seed in a single contact stage. The effects of contact time and solvent-to-seed ratio were investigated. The extraction equilibrium favored the extraction of the oil at higher solvent-to-seed ratios. In all cases the extraction reached some 90% of the equilibrium value after 3 min. Runs in the Szego mill, which is a unique orbitalmill developed by one of us (O. Trass), confirmed that solvent grinding is an efficient extraction technique. In this equipment, contact times as short as 30 sec give significant extraction, with the system approaching equilibrium in one minute. The Szego mill appears to be suitable for the rapid extraction of edible oil seeds such as rapeseed.     

Scale-up of canola oil degumming

The chemical degumming of canola oil was optimized using citric acid and maleic anhydride as degumming agents. These chemicals were selected from a group of 54 degumming agents, reported previously. The effect of temperature, chemical addition level, water addition level and contact times was investigated. Best results were obtained at 40 C, using 10 min contact with the chemical, followed by the addition of 2% water and agitation for 20 min. Chemical degumming reduced the residual phosphorus level from 1049 mg/kg to 50 mg/kg using either maleic anhydride or citric acid. Refining tests gave excellent deodorized or hydrogenated products. The optimized reaction conditions were applied to 330 kg test batches of oil in the P.O.S. Pilot Plant. Results were identical to those obtained in the laboratory, indicating that the process may be scaled up readily for industrial application.     

Nondestructive estimation of fatty acid composition in seeds of Brassica napus L. by near-infrared spectroscopy

The feasibility of near-infrared (NIR) spectroscopy for the nondestructive determination of fatty acid composition in rapeseed was examined. NIR spectra were measured on extracted oil, intact rapeseed kernels, and an intact signle rapeseed with an InfraAlyzer 500 in a syrup cup or a single-grain cup. NIR spectra were scanned from 1100 to 2500 nm at 2-nm intervals. As the percentage of linoleic acid increased, the spectral values in the region 1696–1724 nm, where linoleic acid has its absorption band, became always stronger downward in second-derivative NIR spectra. As the percentage of erucic acid increased the spectral value at 1728 nm, where erucic acid has its absorption band, became always a little bit stronger downward in the second-derivative NIR spectra. On the basis of their NIR spectral patterns, linoleic acid and erucic acid could be successfully determined in both intact seed kernels and in a single seed of rape without damaging them.     

XRecent advances in canola oil hydrogenations

Rapeseed oil has been the source of edible oils in many parts of the world. In the last decade, Canadian plant breeders have developed new rapeseed cultivars which yield oil low in erucic acid and meal low in glucosinolates. These cultivars were named “canola” by the Canadian rapeseed industry. Literature on the hydrogenation characteristics of canola oil is limited; however, in recent years, several aspects of canola oil hydrogenations with commercial nickel catalysts have been reported including the formation ofrans-isomers, trisaturated glycerides and physical properties. In addition, as the methods for determination of sulfur compounds in canola oil developed, the effect of some isothiocyanates on the hydrogenation rate was further investigated to determine the relative catalyst poisoning ability of serveral of these sulfur compounds. However, during the last few years, most of the efforts were directed towards development of novel, selective and active catalysts for canola oil hydrogenations. These studies cover a wide range of homogeneous and heterogeneous catalysts including sulfur poisoned nickel, gold supported on silica, arene-Cr(CO)₃, RuCl₂(CO)₂(PPh₃)₂, palladium on carbon, palladium black and nickel and arene-Cr(CO)₃ mixtures. Effects of temperature, pressure, catalyst concentration and catalyst preparation procedure on the hydrogenation rate, selectivity, catalyst life and quality of the oil were examined and compared with that of commercial nickel catalysts. A brief discussion about continous hydrogenations of canola oil with commerical fixed bed catalysts is also included.     

Nondestructive quantitative determination of starch content in polyethylene by solid state NMR and FTIR

Fourier transform infrared spectroscopy (FTIR) and carbon-13 solid state nuclear magnetic resonance spectroscopy (NMR) were used quantitatively (and non-destructively) to determine the starch content in a series of starch filled polyethylene samples (nominal addition levels range from 3 to 6 wt%). Data acquisition times (including sample preparation and instrument analysis) were typically a few minutes for both techniques. Current methodologies for starch analysis in polyethylene are based upon wet chemical techniques (gravimetric or enzyme analysis). The proposed methods offer several advantages over these traditional methods: they are less labor intensive, do not require chemical reagents, are relatively insensitive to changes in the sample matrix, and are fast.     

Determination of total sulfur in canola oil

A rapid and sensitive chromatographic method for the determination of total sulfur in canola oil is described. All forms of sulfur in the oil are quantitatively converted to sulfate in an oxygen bomb. The sulfate is separated from other ions and measured using an ion chromatograph equipped with a conductivity detector. Standards containing different forms of sulfur were prepared and analyzed with this method. Recovery achieved on 11 compounds covering the concentration range from 9.3 to 143.5 mg/kg S ranged from 95.7% to 102.2%. The coefficient of variability of total sulfur in canola oils ranged from 1.0% to 2.9%. Values obtained on high sulfur content mustard oils when plotted vs the values determined by barium precipitation method showed a correlation coefficient of 0.997 and provided a slope of 1.0. This new method employing comparatively simple equipment requires less than 40 minutes for a complete analysis and is reliable for the determination of as little as 0.5 mg/kg S in canola oil.     

Mechanics of oil expression from canola

A laboratory-scale oilseed screw press was used to investigate the effects of shaft speed and choke opening and of seed pretreatments, including moisture conditioning, flaking and preheating, on the canola pressing performance. Maximum pressure increased, and press throughput and residual oil (RO) in presscake both decreased, with a reduction in choke opening and with lowering of shaft speed. When either whole seed or flakes were preheated in the range 40–100C, the pressure and throughput increased, and RO decreased. Press throughput and oil output both achieved maxima at a 5.0% moisture content in seed, while the RO showed a continuous increase with increasing seed moisture contents. The observed effects of choke opening and shaft speed on pressure, throughput, RO and press temperature could be explained with the aid of a simple equation representing the axial flow within the press. The same equation also served to explain the changes in pressure and throughput corresponding to the various seed pretreatments, when changes in viscosity of the oilseed mass were postulated. It was inferred that any seed pretreatment which increased viscosity would also increase throughput of the press. A further examination of the individual components of viscosity might explain the changes in the residual oil content and facilitate the development of improved or novel pretreatments of oilseeds.     

Phase transitions of canola oil sediment

Canola sediment was obtained from an industrial filter cake by solvent extraction. When heated in the differential scanning calorimeter (DSC) (5–100°C), the sediment exhibited a single narrow melting peak at around 74.8°C. No solid-state polymorphic transformation of the material could be detected over this temperature range. The X-ray powder diffraction pattern of canola sediment resembled waxes from other sources with an orthorhombic unit cell. The phase transition behavior of canola sediment in oil was studied by both DSC and polarizing microscopy. With increasing ratio of oil/sediment, a reduction in both melting temperature and transition enthalpy was observed. The shape of the supercooling curve resembled that of the melting curve. The induction time was determined by spectrophotometry and was used to calculate the interfacial free energyσ between sediment and oil; σ=4.71 erg/cm². The effect of temperature and sediment concentration on the clouding time of canola oil was studied; the clouding time was the shortest at 5°C.     

Use of NMR for predicting protein concentration in soybean seeds based on oil measurements

Increasing the level of protein in soybean seeds has been a major target for soybean [Glycine max (L.) Merr.] breeders. The objective of this study was to examine the potential of predicting soybean seed protein based on oil values as determined by NMR. Seed protein and oil concentrations were determined in an F₂ population generated from the cross between a G. max (NK, S08-80), and a G. soja (PI 458536) cultivar. The protein concentration in the population ranged from 40.4 to 52.6%. Protein-oil regression analysis was used to generate an equation for predicting seed protein concentration based on oil readings. The regression equation Protein=62.3–1.3 [Oil] (R ²=0.46) was developed, with a corresponding correlation of −0.69 between the traits. With this equation, the mean protein concentration of the selected 25% of the population (a simulated breeding pressure) was greater than the mean of the unselected population (46.1%, SE=0.13) by about 1.9%. Individual F₂ plants that exceeded the mean protein value of the population constituted 86.4% of the selected samples. Selection based on oil concentration, however, failed to include 27.1% of the plants that were among the top 25% for protein concentration. Selection of high-protein plants based on NMR oil measurement was reasonably effective in the test population and might offer a new and rapid method of selecting high-protein individuals in soybean populations derived from the wild soybean progenitor, G. soja. If further tested on other populations and samples, it might be used as an analytical alternative for an indirect measurement of protein concentration based on NMR measurements of the oil.     

Behavior of chlorophyll derivatives in canola oil processing

Chlorophyll derivatives in canola oil were analyzed quantitatively by reversed-phase high-performance liquid chromatography without any pretreatment. The main components were pheophytin (pheo) a and b and pyropheophytin (pyro) a and b. The factors affecting the types and concentration of chlorophyll derivatives in oil have been investigated during seed preparation, expelling, extraction, degumming and alkali-refining processes. Bleaching tests of alkali-refined canola oil with activated earth indicated the adsorption of each derivative to decrease in the following order: pheo a > pyro a >> pheo b > pyro b. In bleaching with activated carbon, however, the following order was observed: pyro b > pheo b > pheo a > pyro a.