Der Einfluß der Raffination auf die Konzentration von Spurenmetallen in Ölen und Fetten

Effect of Refining on the Concentration of Trace Metals in Oils and Fats The published concentrations of trace metals in edible oils and fats vary considerably. This is probably not only caused by samples being of different origin but also by different methods of analysis. Values determined by us for lead and mercury in crude oils and fats are relatively frequently above the limits featuring in German draft legislation dating from May 1974. Refining, as normally done for oils and fats, reduces the lead contents to or below the draft limit of 0.15 ppm. Even after refining the draft limit of 0.025 ppm mercury is sometimes exceeded. The neutralisation step is primarily responsible for the reduction of the lead content.     

Einfluß der Struktur und der Morphologie von Bleicherden auf die Bleichwirkung bei Ölen und Fetten

Influence of the Structure and Morphology of Bleaching Earths on Their Bleaching Action on Oils and Fats In the manufacture of highly active bleaching earths from bentonite, the acid activation causes alterations in the chemical composition and structural as well as morphological properties of bentonite, depending on the concentration of acid, temperature, time etc. This has been demonstrated by changes in specific surface, volume of the micropores, particle size distribution and proportion of soluble silicic acid, and the impact of these alterations on the bleaching of vegetable oils is discussed. The results are supported by electron optical and X-ray investigations. Studies on repeated removal of silicic acid formed by acid treatment of bentonite as well as repeated acid activation indicate that the bleaching action of these earths depends not only on specific surface, but also, to a considerable extent, on the volume of micropores.     

Die kontinuierliche Hydrierung von Ölen und Fetten

Continuous Hydrogenation of Oils and Fats The processes described till now for the continuous hydrogenation of glycerides are reviewed. The various systems are classified from the viewpoint of the reactor involved and their advantages and disadvantages are discussed. As an example of a modern plant for continuous hydrogenation, the reactor of BUSS AG, Basel, is described in details and its operational characteristics in the selective hydrogenation of fish oil are reported. The effect of pressure, temperature and catalyst concentration on the dilatation properties of the products at various temperatures and iodine values is given. Pressure was found to be the most important factor governing the selectivity. Finally, the consumption figures of a 150 to and a 250 to per day plant are presented.     

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.     

Veränderung der Sterine durch industrielle Verarbeitungsprozesse von Fetten und Ölen I: Einfluß der Raffinationsbedingungen auf den Steringehalt und die Sterinzusammensetzung

Alteration of Sterols by Industrial Processing of Fats and Oils I: Influence of Refining Conditions on the Sterol Content and Sterol Composition Action of bleaching earths on cholesterol was studied, both as solution in a neutral synthetic triglyceride and in hexan. The influence of reaction conditions on the amount and qualitative composition of the derivatives formed was investigated. The acidity of both the bleaching earth and the substrate are significant for the reaction. Furthermore, the type and amount of steryl esters as well as the concentration of bleaching earth and sterol in the fat play a role. By gas chromatography and thin-layer chromatography of the sterol derivatives formed it was found that the artefacts formed are qualitatively always the same although their proportions vary.     

Bestimmung von Schwermetallen in Ölen,Fetten und Futtermitteln

Determination of Heavy Metal Traces in Oils, Fats and Feeding-Stuffs Atomic absorption spectroscopy has proved to be the best method for the determination of lead, cadmium and mercury in fats, oils and feeding-stuffs, whereas colorimetry is best for the determination of arsenic. For each substrate the most suitable digestion method is described. Recoveries and detection limits of the determination methods are shown.     

Schnelle atomabsorptionsspektrometrische Bestimmungen von Spurenelementen in Ölen und Fetten

Fast Atomic Absorption Measurements of Trace Elements in Oils and Fats by Reduced Sample Preparation Atomic absorption measurements of trace elements in oils and fats can be performed either in aqueous solutions after wet digestion or directly inorganic solutions of the samples. But wet digestions are time-consuming and may cause contamination. Direct measurements are fast but are influenced in uncontrolled manner by the matrix or the state of the trace elements in the sample. Such possible errors can be widely reduced if the samples are treated with concentrated formic acid before being measured directly in an organic solution. With formic acid the organic standards can also be prepared from aqueous solutions.     

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.     

Einfluß der Prozeßparameter auf die Tocopherolbilanz bei der Gewinnung von pflanzlichen Ölen

Effect of Process Parameters on the Balance of Tocopherols in the Production of Vegetable Oils. The influence of process parameters on the balance of tocopherols is investigated in five plants for the production of rapeseed oil with mechanical and extractive deoiling of the seed followed by physical or chemical refining. The state of the seed has an unexpectedly strong effect on the concentration of tocopherols in mechanically pressed oil. Warm pressing of the press cake results in twice as high concentration of tocopherols in the oil as cold pressing of the whole seed corn. With respect to the balance of tocopherols deodorizing is the most important refining step. Tocopherols are partly transferred into deodorizer condensates by distillation. Mathematical modelling of the continuous deodorizing shows the effect of temperature in good correspondence with measured results at a production plant. Enrichment of tocopherols from deodorizer condensates by means of high pressure extraction with supercritical carbon dioxide results in high concentration of more than 90% and high yield of about 70%.     

Erfahrungen bei der Hydrierung von einigen Ölen und Fetten mit einem Kupferkatalysator

Experiences on the Hydrogenation of Fats with a Copper Catalyst Soybean oil, rapeseed oil and lard were hydrogenated using a copper catalyst. The products of hydrogenation were refined after the removal of copper following a new technique. The aforesaid oils were also hydrogenated with a nickel catalyst to the same iodine value and then refined. The products of hydrogenation using copper showed a better stability towards oxidation than those obtained with nickel.     

Schnellmethode zur Isolierung der Sterine aus Fetten und Ölen

Rapid Method for Isolation of Sterols from Fats and Oils Isolation of sterols from fats and oils mostly takes place by the very time-consuming solvent extraction of the unsaponifiable from the soap solution. The time required can be reduced to about 1 hour by a new developed procedure which makes possible to separate soaps and polar components of the fats from the saponified sample by aluminium oxide columns. The use of 250 mg of fat is sufficient for a following sterol examination by gas chromatography.     

Separation von Feststoffen aus Fetten und Ölen durch Elektrophorese

Separation of Solids from Fats and Oils by Electrophoresis The development of PETRECOR ELECTROFILTER^TM SEPARATOR provides the food industry with plants that enable the separation of solid particles, including those in the submicron region (< 0.5 μm), from fats and oils with the aid of high-voltage electrical field. The most important commercial application is the removal of bleaching earth and nickel catalyst; a final polishing filtration becomes unnecessary. Results of pilot plant operation show, for example in the removal of nickel catalyst from hydrogenated soybean oil, a continuous reduction of nickel from 500 ppm to < 0.15 ppm. These plants are completely closed systems under slight pressure with a definite precalculated capacity for solids; the latter can be removed by a simple regeneration process involving rinsing with the product to be treated. This regenerating liquid is a pumpable suspension containing ca. 5% solids; it is subjected to further treatment. Plants of various sizes with respect to maximum flow rate and capacity are available. The layout is always done for the specific application.     

Die polarographische Bestimmung von Tocopherolen und Tocopherylchinonen in Ölen und Fetten

Polarographic Determination of Tocopherols and Tocopherylquinones in Oils and Fats A method for the polarographic determination of α-, γ-, and δ-tocopherols and the corresponding tocopherylquinones in oils and fats was worked out. After saponification of the samples and extraction of unsaponifiable matter with ether, the tocopherylquinones originally present in oils and fats are directly determined polarographically. Tocopherols present in the sample are oxidized quantitatively with cerium(IV) sulfate to the corresponding tocopherylquinones and latter are then likewise polarographed. The presence of substances accompanying tocopherols in the unsaponifiable matter does not interfere with the determination of tocopherols or tocopherylquinones. The tocopherol contents of different oils and fats are given.     

Monoglycerid und Lecithin als Ursache von Fehlern bei der Atomabsorptionsanalyse von Metallspuren in Ölen und Fetten

Monoglyceride and Lecithin as Cause of Errors in the Atomic Absorption Analysis of Trace Metals in Oils and Fats Presence of monoglycerides and lecithin can at times cause considerable errors in the atomic absorption analysis of trace metals in oils and fats. This has been shown in test analyses of copper and iron. Errors can be avoided by applying a method, in which standard amounts of copper or iron are added to the sample.     

Die Anwendung der Norm DIN ISO 9001 bei der Beschaffung von Ölen und Fetten

Practical Application of the ISO 9001 Requirements for the Purchasing of Oils and Fats Close cooperation between supplier and customer offers the best opportunity for further quality improvement. The ISO requirement for purchasing has precisely and clearly started that: “The supplier shall establish and maintain documented procedures to ensure that purchase product confirms to specified requirements, evaluate and select subcontractors on the basis of their ability to meet subcontract requirements including quality system requirements, establish and maintain quality records”. For the oleochemical manufacturing industries engaged in the ISO certification process, this was regarded as a mean to stronger involve the supplier in the quality idea. Following steps are necessary for the implementing of an efficient quality management system: 1. to specify exactly all purchased products, 2. to define the criteria for the supplier rating, appraisal and selection, 3. to sign quality agreements with the supplier, 4. to perform supplier audits. This lecture refers to the experience of an oleochemical company and describes how to fulfill the ISO 9001 requirement with less effort and paper work.     

Quantitative Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen in Fetten und Ölen

Quantitative Determination of Polycyclic Aromatic Hydrocarbons in Fats and Oils A method, based on liquid-liquid partition and column as well as thin-layer chromatography, for the qualitative and quantitative UV-spectrophotometric determination of 13 polycyclic aromatic hydrocarbons present in fats and oils, is reported. The limit of detection lies between 0.1 to 0.5 μg/kg, the recovery between 55 and 60% and the relative standard deviation between 5 and 20%. A determination in duplicate requires about 3 days. Another procedure, requiring a few hours for the determination of groups of the polycyclic aromatic hydrocarbons in 20 g fat or oil, which provides only semi-quantitative results, is reported as well.