Bestimmung von Tocopherolen in Ölen und Fetten: Einfluß des Tocopherol-Gehaltes von Erdnuß- und Sojaöl auf den Oxydationsverlauf dieser Öle beim Erhitzen I

Determination of Tocopherols in Oils and Fats: Influence of the Tocopherol Content of Ground-nut and Soybean Oils on the Course of Oxidation of these Oils on Heating I A sensitive method for the quantitative determination of α, γ and δ tocopherols in edible oils and fats was worked out. The tocopherols are isolated from unsaponifiable matter by thinlayer chromatography and ultimately each of them was determined photometrically from the red colour formed with iron chloride and bathophenanthroline. The effect of reduction in tocopherol content, resulting from the heating of oils, on the course of the oxidation of oil was followed, among others, with the help of 4-hexylresorcin. The blue dyestuff formed by this reaction was synthesized and identified as trimethin dye.     

Die Entsäuerung von Pflanzenölen mit Ammoniak Eine umweltfreundliche Raffinationsmethode

Deacidification of Vegetable Oils with Ammonia – An Environmentally Safe Refining Method Compared to conventional deacidification of vegetable oils using sodium hydroxide, neutralization with aqueous ammonia has the advantage of being safe to environment, because the deacidification agent can be repeatedly reused. Oils, especially soybean oil with low degree of oxidation, can be fully deacidified only with the help of ammonia. A post-refining with 0.5 N sodium hydroxide at 95-100° C reduces the residual phosphorus content to 1-4 ppm. The same effect can be frequently achieved by a preliminary desliming with 5% formic acid or citric acid. Deodorization at 210° C of oils that have been deacidified with ammonia and washed with water yields bland and pale edible oils having good keepability.     

Dünnschicht-chromatographische Untersuchung oxydierter Fette und Öle

Thin-Layer Chromatographic Analysis of Oxidized Fats and Oils The oxidation stage of fats and oils can be estimated rapidly with the help of silica gel or aluminium oxide thin-layer chromatography. The presence of different oxidation products in the chromatographically separated fractions was examined by chemical and spectrophotometric methods. The quantitative portion of each fraction, after elution, was determined with the help of hydroxamic acid method. The suggested method is suitable for pure fats and fat containing foodstuffs.     

50 Jahre Technologie pflanzlicher Öle und Fette - ein Erfahrungsbericht

50 Years Technology of Vegetable Oils and Fats - a Report of Experiences In a survey about the development of the technology of vegetable oils and fats between 1932 and 1982 above all those areas are dealt, in which the author could contribute to the optimization of technological process steps and to the quality improvement of final products. It is described in detail: influence of solvent composition on benzine losts and on hydrocarbon retention in the oil seed extraction, improvement of the lecithin removal process, the entire desliming of extracted oils and its influence on raffinate quality, methods for determination of refining lost and for estimation of quality of raw and refined oils, comparison between various alkali-neutralization methods, relations between bleaching earth activity and oxidation stability of the oils, recovery of oil from used bleaching earth, distillative neutralization and determination of optimal deodorising conditions. The report is finished with hints on the importance of special fats for the fat processing industry obtained by hydrogenation, interesterification or fractionation.     

Die Weiterentwicklung der Codex Alimentarius Standards für Öle und Fette

Further Development of Codex Alimentarius Standards for Oils and Fats A report is given on the further development of Codex Alimentarius Standards for oils and fats, which was discussed in the 9th meeting of the Codex Committee on Fats and Oils from 28th November to 2nd December 1977 in London. Topics discussed were a collaborative report by FAO and WHO on the role of fats in human nutrition, the general standard for oils and fats, and standards for reduced fat margarine, low erucic acid rapeseed oil, coconut oil, palm oil, palm kernel oil, babassu oil, grape seed oil as well as marine oils. Furthermore, the limits of fatty acid composition as criteria for identification of specific oils and fats were discussed.     

Gekoppelte LC-GC für die Analyse von Olivenölen

Coupled LC-GC for the Analysis of Olive Oils The analysis of the so-called sterol fraction of fats and oils can be strongly improved by the application of on-line coupled LC-GC. LC replaces saponification, the (difficult) extraction of the non-saponifiable and the clean-up by preparative thin layer chromatography. The proposed method eliminates most of the manual sample preparation work, is more accurate, and provides more information at the same time, since the free and esterified components are analyzed separately. Analyzing olive oils, mostly small admixtures of other oils can be detected. For the determination of solvent extracted oil in “extra virgin” or “pure” olive oils, the method is more suitable than the conventional determination of the triterpenedialcohols erythrodiol and uvaol. Finally pressed oil of first quality (“extra virgin”) can be distinguished from that of second quality (“pure” olive oil). Oils of second quality are usually the result of pression with an excessive delay after harvesting the olives.     

Isomere Monoensäuren in Pflanzenölen

Isomeric Monoenoic Acids in Vegetable Oils In the scope of systematic studies the fatty acids of oils from seed and fruits of 38 plants are investigated for presence of isomeric monoenoic acids with 16, 18 and 20 C-atoms. All analyzed oils contain between 2 and 4 hexadecenoic, octadecenoic and icosenoic acids with different position of the double bound. Vaccenic acid, the cis-11-octadecenoic acid, is always found in low quantities. Its share depends within certain limits on the content of the oils of cis-9-hexadecenoic acid, the so-called palmitoleic acid. Petroselinic acid, cis-6-octadecenoic acid, is found in apiaceae oils and also in the seed oil of some other plant families. Besides, 14 of the investigated oils contain low quantities of ω5-monoenoic acids.     

Tocopherole — Antioxidative Wirkung bei Fetten und Ölen

Tocopherols — Antioxidative Effect on Oils and Fats The main reason for the deterioration of fats and oils is a chemical reaction between the oxygen and the double bonds which are contained in the unsaturated fatty acids. In the course of the autoxidation intermediate peroxides affect the vitamines sensitive to oxidation. They lower the content of physiologically valuable essential fatty acids. The oxidation stability of oils and fats depends on the natural content of tocopherols as well as on the composition of the fatty acid. The effect of the added tocopherols depends on the natural content of tocopherols. Lipids with lower contents can be stabilized very well with antioxidants consisting of tocopherols. Here animal fats as well as synthetical lipids are considered which in particular are used in cosmetic industry and in the field of pharmacy but also in food industry. Vegetable oils contain, due to their nature, high contents of tocopherols which are partly removed or oxidised during raffination and storage. Therefore adding antioxidants containing tocopherols is adviseable. Also an addition of reducing substances as for instance ascorbylpalmitate is recommended. Moreover antioxidant systems should consist of heavy metal chelating substances.     

Qualitätsmerkmale kaltgepreßter Speiseöle

Quality Characteristics for Cold Pressed Edible Oils The determination of steradienes, trans fatty acids and free fatty acids together with the UV absorption at 232 and 270 nm leads to quality characteristics for cold pressed edible oils. Two methods, a GLC and a HPLC method, are both valid for the determination of steradienes. In addition with the determination of trans fatty acids they are a powerful tool for the determination of adulterations of cold pressed native edible oils with refined oils. The amount of free fatty acids and the UV absorption provide only ambiguous informations for the characterization of cold pressed oils.     

Palmöle und Palmöl-Fraktionen und ihre analytische Differenzierung

Palm Oils and Palm Oil Fractions and their Analytical Differentiation Due to the increasing production of palm oils and the correlating production of palm oil fractions there is a need to differentiate analytically between palm oils and palm oil fractions. The analytical differentiation of these products on the one hand and the detection of unwanted additions and mixtures on the other hand is intended to be achieved. Palm oils of different origin and palm oil fractions, fractionated by different procedures, were examined in this context. The composition of total fatty acids, fatty acids in 2-position of the triglycerides, slip point, iodine value, composition of triglycerides by gaschromatography as well as saturated triglycerides were determined. The slip point, which can easily be determined, and the palmitic acid content in 2-position of t he triglycerides proved to be most suitable for the analytical practice.     

Säulen-chromatographische Bewertung der Oxydationsstufe von Fetten und Ölen

Column Chromatographic Estimation of the Extent of Oxidation of Fats and Oils Oxidized fats and oils can be separated into oxidized and unoxidized fractions by column chromatography with aluminium oxide as adsorbent and benzene and ethanol-diethyl ether mixture as eluting solvents. The method is suitable for the evaluation of advanced oxidation where chemical methods can lead to false results.     

Über den Einfluß von Licht auf den oxydativen Verderb von Speiseölen IV: Abhängigkeit der Oxydationsgeschwindigkeit von der Wellenlänge des eingestrahlten Lichts

Influence of Light on Oxidative Deterioration of Edible Oils IV: Dependence of Rate of Oxidation on Wave-Length of Incident Light A distinct decrease in the rate of oxidation with increasing wave-length is observed for soybean, sunflower and peanut oils when these oils are irradiated with various coloured lights having the same quantum-density. While studying the causes of this behaviour, pure absorption curves for the aforesaid oils were determined. Light of short wave was completely absorbed, whereas long-wave light was barely absorbed to any measurable extent. A considerable increase in quantum yield during oxidation occurs with increasing wave-length. Inspite of this, the oxidation of oils is catalysed most strongly by short-wave light, because the influence of pure absorption exceeds the increase in quantum yield. Pure absorption is therefore considered as the decisive factor with regard to the dependence of photooxidation on wave-length. Finally, the rate of oxidation, as determined in darkness, was found to increase with decreasing wave-length of light used for pre-oxidation of the oil.     

Bestimmung coplanarer polychlorierter Biphenyle in Mineral- und Altölen

Determination of Coplanar Polychlorinated Biphenyls in Mineral Oils and Waste Oils Due to insufficient waste management polychlorinated biphenyls (PCB) are often found in waste oils and in recycled mineral oil products. Because of their structure coplanar PCBs are more toxic than other congeners and insofar possibly comparable to polychlorinated dioxins and furans (PCDD/F). Known analytical methods for PCBs in mineral oils do not distinguish between the different toxic congeners. This paper describes a method of selective measurement of eleven coplanar PCBs from mineral oils. The complexity of the matrix and the very low concentration of the analytes require a laborious clean-up procedure: Solid phase extraction (SPE) on silica impregnated with sulfuric acid, gel permeation chromatography, direct treatment with conc. sulfuric acid and chromatography on alumina. After separation of the co-planar congeners from the other PCBs by chromatograpy on activated charcoal and on basic alumina they are determined by GC/high-resolution-MS.     

Quantitative chromatographische Analyse Petroselinsäure-haltiger Öle

Quantitative Chromatographic Analysis of Oils Containing Petroselinic Acid A method is described for the analysis of the component fatty acids of oils containing petroselinic acid, based on columnar partition chromatography of the natural acids and of their oxydation products, obtained after E. von Rudloff. The method is illustrated by the analysis of the seed oils of Foeniculum vulgare L., Coriandrum sativum L. and Pimpinella anisum L. of Bulgarian origin.     

Der Futterwert von Fetten und Ölen aus Verarbeitungsprozessen bei Geflügel

Feeding Value of Fats and Oils from Finishing Processes for Poultry Altogether two trials with 22 different fats/oils have been carried out. In the first trial the interesterification and the digestibility of the fatty acids of seven fats and oils from the finishing processes with different contents of polymeres have been determined with broilers, aged 2–3 and 5–6 weeks as well as adult cocks. The age of the animals and the shares of the fatty acids were of high influence on the feeding value. In the second trial the fattening performance of broilers that had got ratios of 13 different frying oils, bleaching earth oils or distillation residues, was determined. The results with frying oils were successful, those with bleaching earth oils were moderate and with distillation residues extremely bad. A dependence between the content of polymeres and the feeding value of fat and oils could not be found out.     

Die Notwendigkeit,neue Qualitätsanforderungen für rohes Sojaöl einzuführen

Necessity for the Introduction of New Quality Requirements for Crude Soybean Oil Crude degummed soybean oils of good and inferior quality were refined in semi continuous scale and the refined oils were investigated with respect to colour and flavour stability. The results showed that the colour and flavour stability of the end product are dependent on oxidation characteristics, i. e. p-anisidine value, peroxide value and UV absorbence, and from iron and phosphorus content of the crude oil. Therefore, it is necessary, in addition to current quality requirements, that the maximum values of oxidation characteristics and iron content should be specified.     

Die Analyse von Raffinationsfettsäuren zur Charakterisierung von Futterölen für Kleintiere

Analysis of Feeding Oils for Small Animals Fatty acids used as feeding oils in small animal keeping are mainly acids, which are obtained as by-products during the neutralisation step of edible fats refining process. However, up to now often products with sub-optimal or even low quality were offered in the market. Therefore, the characterization of feeding oils by means of suitable analytical data becomes more important. Up to now used quality criteria are critically investigated especially considering modern methods of analysis and possible alternatives. Among others a method for determination of oxidized fatty acids is reported.     

Farbe von Ölen

Colour of Oils For many products, particularly edible oils and fats, color is an essential indicator for quality. Today instruments are used to measure the color in oils, fats, fatty acids or other substances. The Tintometer is a subtractive colorimeter, which used red, blue and yellow glass standards. Almost everywhere in the world, the Lovibond color scale is nowadays considered as an accepted means of assigning precise color values to edible oils and fats. But there are also, of course, alternative ways and techniques of determining or measuring color. In recent years, the development of microprocessor-controlled colorimeters has made it possible to automatically measure and compare Lovibond color scale and correlating international standard values pursuant to the CIE System.