Chemical analysis of polymerization products in abused fats and oils

For more than a decade, numerous analytical methods have been proposed for the detection and measurement of polymers in vegetable fats and oils. Many of the methods have been little more than laboratory curiosities, either because they were concerned with only very specific compounds or were too cumbersome and time consuming to become very popular. More recently, a number of methods in common use for analysis of fats and oils has been shown to be useful for indirectly measuring polymeric materials in heat abused oils. The present report shows, by the use of gel filtration chromatography, the validity of two of the indirect methods of estimating polymeric products of abused fats and oils. These methods are: the estimation of polymers through changes in the iodine value and the measurement of retention materials on a gas liquid chromatographic column. A new simplified internal standard gas liquid chromatographic procedure utilizing triglyceride standards also is presented. This latter method permits estimating the degree of degradation of vegetable fats and oils by any laboratory capable of determining the fatty acid composition of a sample by gas liquid chromatography. Presented at the AOCS Meeting, Ottawa, Canada, September 1972.     

Determination of sulfur contents of vegetable and marine oils by ion chromatography and indirect ultraviolet photometry of their combustion products

A simple method for the determination of total sulfur content in vegetable and marine oils is described. The method involves combustion of the oil sample in an oxygen bomb to convert all forms of sulfur to sulfate ions with subsequent determination of the sulfate by ion chromatography and indirect ultraviolet detection. The ultraviolet system described is more sensitive than conductivity detection and enables the method to be applied more widely. Application of the method to a variety of vegetable and marine oils showed the general occurrence of sulfur in fats and oils, albeit often at a low level. Among the samples examined, crude Canola oil had the highest sulfur content (25.0 mg/kg) followed by the marine oils (5.8-15.2 mg/kg) and the non-Cruciferae vegetable oils (2.0-6.1 mg/kg). To whom correspondence should be addressed.     

Quantification of free and esterified steryl glucosides in vegetable oils and biodiesel

Steryl glucosides (SG) are minor components that dramatically modify the low temperature performance of fatty acid methyl esters (FAME) used as biodiesel. SG are naturally present in vegetable oils but they may also be the result of the transesterification of esterified steryl glucosides (ESG). These are present in vegetable oils at a level of a few hundred milligrams per kilogram, depending on the nature of the feedstock. We developed an analytical method to quantify SG and ESG in vegetable oils and in FAME. The purification of SG and ESG was performed by liquid chromatography on silica gel, and the analysis of the trimethylsilyl derivatives was achieved by gas chromatography and flame ionization detection. The filterability of biodiesel is affected when the SG content is higher than 20 mg/kg. Therefore, the sensitivity of this new method is adapted for this purpose since the quantification limit is 10 mg/kg of SG and ESG. The recoveries are acceptable, between 75% and 90% depending on the species and content, and the reproducibility relative standard deviation, evaluated at 10%, is comparable to other studies.     

Spurennachweis von mehrfach verzweigten Fettsäuren in Fetten

Detection of Traces of Polybranched Fatty Acids in Fats A method for the detection and quantitative determination of saturated polybranched fatty acids in animal and vegetable fats is described. The method is based on gas-chromatographic determination of polybranched fatty acid methyl esters in the methyl esters which do not form urea adducts. The following amounts of polybranched fatty acids were determined in animal fats: whale oil 15 000 ppm., fish oil 6000 ppm., butter fat 4000 ppm., beef tallow 2000 ppm. and lard 110 ppm. In different vegetable oils and fats upto 200 ppm. of polybranched fatty acids were found. Not only the difference in total content of polybranched fatty acids but also differences in their percentage composition and retention volumes in gas-chromatograms were found. This method therefore offers the possibility of identification of some of the animal fats.     

Über den Nachweis von Wärmeträgerölen in Fetten

Detection of Heat-Transfer Oils in Fats The use of heat-transfer oils in place of high pressure steam for heat transfer of fats from the discontinuous high temperature deodorization presumes analytical methods for the identification of traces of this oils in fats. In this paper two semi-quantitative rapid methods and one quantitative method applicable as an arbitrational analysis are described. A detection limit of ≤ 0.001% can be achieved.     

What correlation is appropriate to evaluate biodiesels and vegetable oils higher heating value (HHV)?

The heating value is one of the most important properties of animal fats, vegetable oils and biodiesels for their use as fuels in stead of petroleum.There are lots of formulae or correlations encountered in the literature to evaluate biomass fuels’ higher heating value (HHV). Lots of them are not specially established for vegetable oils, animal fats and their derivatives. In this paper, some correlations previously published and based on ultimate analysis or fatty acid composition are applied to some bio oils samples collected from the literature. The aim of this article is to investigate what of them can be used to estimate animal fats, biodiesels, vegetable oils and their derivatives HHV with a high accuracy. With an absolute average error inferior to 4%, the results show that the formulae of : Channiwala and Parikh, Boie and Vondracek, Boie, Vondracek, Fassinou et al. Milne, IGT, Demirbas and Dulong can be used at this purpose with a high accuracy by comparison to the bomb calorimetric method.     

The antioxidant properties of gallic acid and allied compounds

Summary The differences between animal fats and common vegetable oils as regards their protection by antioxidants are briefly reviewed; in general, the former can be stabilized by di- and poly-phenolic inhibitors and by inhibitols, the latter by acid-type inhibitors such as tartaric, phosphoric and other acids; these acids reinforce the action of the inhibitols which occur naturally in vegetable oils or which may be added to animal fats. A study has been made of the antioxygenic action of the polyphenols on both kinds of fats. The trihydric phenols, gallic acid and ethyl gallate are effective stabilizers in animal and vegetable fats and enhance the antioxygenic activity of inhibitols; they thus demonstrate the properties of both phenolic and acid inhibitors. The possible mechanism of this synergistic action is briefly discussed.     

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

The advantages and disadvantages of various approaches to the capillary-gas liquid chromatography (GLC) of sterols in fats and oils with internal standards are discussed. The German method F-III 1²(,3) for sterol analysis in fats and oils, which uses betulin as an internal standard, was reformulated and translated. A number of further improvements and alterations were also made, and the procedure used is described more precisely below in English in order to give detailed explanations, e.g. regarding the role of the aluminium oxide column and of the internal standard betulin. The method is applicable to a wide range of oils and fats, including mixtures of vegetable and animal fats, cereal lipids, and partially hydrogenated fats.     

Antioxidant activity of tocopherols,ascorbyl palmitate,and ascorbic acid and their mode of action

In the quest to use antioxidant compounds occurring in nature or related compounds, extensive studies have been made on vegetable oils, animal fats, apocarotenal, and vitamin A as substrates with ascorbyl palmitate, tocopherols, and ascorbic acid as antioxidants. Antioxidant efficiency varies with the substrate. Ascorbyl palmitate at a level of 0.01% provides a useful increase in the shelf-life of vegetable oils. Alone it is better than butylated hydroxytoluene and butylated hydroxyanisole and in combinations with other known antioxidants improves the shelf-life of all vegetable oils, as well as potato chips. Solubility problems with ascorbyl palmitate and other esters of ascorbic acid are discussed. The tocopherols have their greatest effect in protection of animal fats, carotenoids, and vitamin A. Experiments utilizing tocopherols and tocopherol combinations are presented. The activity of ascorbic acid, an excellent scavenger of oxygen, is reviewed. Quenchers of singlet oxygen do not inhibit the direct oxidation of fats and oils under the conditions used.     

红外分光光度法测定动植物油方法的改进

介绍了以CCl4萃取水体中的动植物油,通过红外分光测油仪测定其浓度的方法,并对动植物油矿物油混合标准曲线及其加标回收率、动植物油测定方法检出限进行测定.结果表明,红外分光光度法测定动植物油方法可靠、准确、成熟,达到了一定的技术水平,可以用于环境污染的监测分析.     

Antioxidants for vegetable oils

Several chemical compounds having antioxidant efficacy in food fats and oils and cleared for food use by governmental regulatory agencies are available for such use by vegetable oil processors in many nations of the world. These antioxidants are reviewed with particular attention to major benefits and possible shortcomings they may afford when added to vegetable oils. Some guidelines in selecting antioxidants to achieve optimum results are offered. Also, precautions to be observed in adding antioxidants to fats and oils are discussed.     

Determination of Mineral Oil-Saturated Hydrocarbons (MOSH) in Vegetable Oils by Large Scale Off-Line SPE Combined with GC-FID

A method based on an off-line large-scale solid phase extraction (SPE) approach combined with conventional gas chromatographic-flame ionization detection (GC-FID) was developed to determine the mineral oil-saturated hydrocarbons (MOSH) in vegetable oils. A large-scale SPE column loaded with 10 g of activated silica gel impregnated with 1% silver nitrate which was used to retain lipids and olefins in vegetable oils and the MOSH in the oil samples was eluted with hexane. Then 2 μL concentrated solution was splitlessly injected into a common GC-FID instrument. The quantification limit reached 2.5 mg/kg when the MOSH fraction was concentrated to 0.1 mL. The accuracy of this procedure, as assessed by measuring the recoveries from spiked oil samples, was higher than 80%. This procedure was applied to analyze the MOSH in 38 commercial vegetable oils from Chinese market, which was the first survey of mineral oil contaminant in Chinese edible oils. The oil samples contaminated with different levels of MOSH, among which, 15 samples contained no mineral oils and 3 samples were contaminated with more than 50 mg/kg of MOSH. The highest contamination level was found in one of rice oils, in which the concentration of MOSH was up to 713.36 mg/kg. Of the 9 types of oils analyzed, camellia oil contained MOSH ranging between 6.76 and 78.49 mg/kg, averaging 46.72 mg/kg, indicating a higher contamination level than other types of oils. The results suggested that it is necessary to routinely detect mineral oil contamination in vegetable oils for food safety.     

Formation of headspace volatiles by thermal decomposition of oxidized fish oilsvs. oxidized vegetable oils

To understand the reasons for differences in oxidative stability among edible oils, the temperature dependence was investigated for the development of volatile lipid oxidation products in fish oils and in vegetable oils. A rapid headspace capillary gas chromatographic method was developed to determine volatile oxidation products of omega-6 (n-6) polyunsaturated fats (pentane and hexanal) and omega-3 (n-3) polyunsaturated fats (propanal) at different decomposition temperatures. Headspace gas chromatographic analyses of partially oxidized menhaden, bonita and sardine oils could be performed at 40°C, whereas soybean, canola, safflower, high-oleic sunflower and high-oleic safflower oils required temperatures greater than 100°C. Volatile formation by thermal decomposition of oxidized oils had lower apparent activation energies in fish oils than in vegetable oils, and significantly higher apparent activation energies in high-oleic oils than in polyunsaturated oils. The activation energy data on headspace volatiles provided another dimension toward a better understanding of the thermal stability of flavor precursors in unsaturated fish and vegetable oils. Presented at the ISF/AOCS joint meeting, Toronto, Canada, May 10–14, 1992.     

Applicability of the stamm reaction for rancidty

Summary The Korpaczy modification of the Stamm reaction for detecting rancidity in fats has been applied to a variety of fats and oils, including hog and beet fat, cottonseed oil, a number of other vegetable and seed oils, and a group of marine oils. This reaction has been shown to be generally inapplicable to vegetable, seed and marine oils but applicable to lard and beef fat.     

Fats and oils as feedstocks for oleochemicals

The approximate quantity of 3 million tons estimated to be required at present for the production of oleochemicals is to be covered from a total production of more than 60 million tons of vegetable and animal fats. While the quantity of eleochemicals produced has nearly doubled in recent years, vegetable oil production alone has increased from 25 to 40 million tons in the same period. More than half the feedstocks required for oleochemicals are acid oils and other fats and oils which are unsuitable for human food. The demand for fats and oils for oleochemicals will certainly grow for price and technological reasons, but only the use of large quantities of oils and fats for diesel engines could shift this balance drastically and endanger the world supply of edible fats. A bottleneck may arise in the supply of fatty acids of medium chain length, although the use of coconut and palm kernel oil by the food industry in the highly developed countries has been on the decline. The green revolution goes on and the fat supply grows faster than the population. In addition, new approaches to plant breeding and agriculture, and biochemical processes as well, might help circumvent any conceivable shortage in the supply of oils and fats in general, and in the supply of special fatty acids in particular.     

Fate of dietary sterols in hydrogenated oils and fats

Samples of table margarines, so-called polyunsaturated table margarines, hydrogenated vegetable oils, and so-called polyunsaturated hydrogenated vegetable oils were shown by infrared spectroscopy to contain hydrogenated components. Examination of the sterols from these oils by argentation thin layer chromatography and gas liquid chromatography did not reveal campestanol, stigmastanol, or Δ²²-stigmastenol, the expected hydrogenation products of the natural sterols. The sterol compositions of the above samples, animal fats, and blends of hydrogenated vegetable oils and animal fats were determined. The compound 24-methyl cholest-7-en-3β-ol was identified tentatively in sunflower and safflower oils.     

油脂市场走势分析

对世界油脂市场状况及中国油脂市场的现状进行了阐述,对中国的棕榈油市场及大豆油市场进行了分析。中国油脂消费量已经达到一定水平,中国已成为食用油消费、进口主要国,中国油脂市场的发展对世界油脂市场具有很大的影响力。2008年-2009年中国植物油产量提高较快,直接进口保持稳定。中国将努力扩大大豆和油菜籽等主要油料作物生产,大力发展芝麻和胡麻等油料作物的生产。论述了中国政策调控对国内油脂市场的影响。     

Determination of triacylglycerol composition in vegetable oils using high-performance liquid chromatography: a collaborative study

Triacylglycerol (TAG) composition in vegetable oils was collaboratively analyzed in 9 laboratories using high-performance liquid chromatography (HPLC) equipped with a refractive index detector. Dococyl (C22) and triacontyl (C30) silica columns were used for analysis. The TAG molecular species in soybean, rapeseed, and palm oils were individually separated on the chromatogram. The collaborative study demonstrated that TAG composition in vegetable oils could be analyzed based on partition numbers (PN) between 38 and 50. In conclusion, the HPLC method using C22 and C30 silica columns would be useful for determining the TAG composition (%) in vegetable oils.     

Refining,bleaching and hydrogenating meat fats

Meat fats are most often steam refined. This has been the accepted practice for at least 35 years. Meat fats are caustic refined for a few specialized products. The caustic refining conditions differ from those used for vegetable oils primarily in the amount of mixing used after the addition of caustic. Bleaching of meat fats is accomplished easily. Most meat fats are light in color and require clarification more than bleaching. The green color of tallows containing large amounts of chlorophyll is easily removed with activated earth. Meat fats are hydrogenated to develop the SFI curves needed for various products and also are hydrogenated to saturation for use as plasticizing agents. The hydrogenation of lard and tallow is not as complicated as that of most vegetable oils, because the original fat is more saturated and the reaction has fewer possible routes to follow.     

The analysis of sterol degradation products to detect vegetable fats in chocolate

A method for the detection of hydrocarbon sterol degradation products (sterenes) has been adapted for the analysis of noncocoa butter vegetable fats in chocolate. The method involves solvent extraction of the fat separation of the sterene fraction, and analysis of individual sterenes with mass spectrometric detection. The sterene composition of refined noncocoa vegetable fats was determined in samples of cocoa butter, and retail chocolates. The presence of known sterenes was confirmed for all of the refined vegetable fats and for a single sample of cocoa butter, the processing history of which was not known. Detection of vegetable fat added to chocolate at the 5% level was demonstrated. Sterenes were detected only in chocolates labeled as containing vegetable fats. This technique has potential use as a screening method for the detection, but not quantification, of refined vegetable fat in chocolate.