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.     

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 Fütterung unterschiedlicher Öle und Fette auf das Fettsäurenmuster des Abdominalfettes von Broilern

Influence of Feeding of Different Oils and Fats on the Fatty Acid Pattern of the Abdominal Fat of Broilers The fatty acid pattern of the abdominal fat of broilers depends to a high degree on the fatty acid pattern of the ratio. It can be absolutely reasonable to change the fat component during the fattening period. But the exchange should have taken place at last till the end of the 3rd life week, because afterwards a sufficient alteration of the fatty acid pattern can not longer be achieved because of the increased embedment. Besides, there are fatty acids which are embedded only to a small amount. Erucic acid and stearic acid, as well as caprylic and capric acid belong to them. These fatty acids are obviously mostly transformed to oleic acid.     

Über die mechanische und dielektrische Zerkleinerung von Getreide- und Ölsaaten

Mechanical and Dielectric Disintegration of Cereal- and Oilseeds After dealing with the fundamental theories of mechanical and thermal disintegration the author explains the microstructures (microcells, micropores, microcapillaries) occuring in cereal- and oilseeds, and the alterations taking place in these microstructures by the action of dielectrically generated heat. It is shown that dielectrically generated heat causes the evaporation of water in the microstructures. The resulting increase in pressure leads to disintegration of the material.     

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%.     

Der Einfluß der Fütterung und Haltung auf die Qualitätsmerkmale von Nahrungsmitteln tierischer Herkunft

Influence of Feeding and Management on Quality Characteristics of Feed of Animal Origin Food of animal origin are milk and eggs as well as meat products, which are special parts of the carcass. Besides water which is the main component in most of these products, protein and fat are very important contents. The content of these main components could be influenced by regulation of the daily feed intake. For milk-composition also the type of diets, More roughages or more concentrates, is important. But these effects are also dependent on species of animals, breed and sex. Feeding systems do not affect the composition of these contents in eggs burs the weight of eggs, Which is also an important characteristic of quality.     

Hochdruck-Extraktion von Ölsaaten

High Pressure Extraction of Oil Seeds In recent times it is more and more reflected whether oil seed processing by high pressure extraction could be advisable. As a contribution to answer this question results from pilot plant trials of direct and press cake extraction of rape seed are presented. The obtained data, concerning yield per time and oil quality are discussed. Besides that different process circuits including the conventional hexane extraction are compared with respect to energy consumption. Finally the development of continuous oil seed processing by high pressure extraction is reported.     

Einfluß der mechanischen spannung und der temperatur auf die photooxidation von polyethylen

The tensile stress and temperature effects on the Polyethylene photooxidation kinetics have been investigated. Subjects are light stabilized and not stabilized high density Polyethylene films. The tensile stress used were 10% and 20% of the breaking stress. Temperatures of 50°C, 30°C, 5°C were realized in a chamber for an artificial climate with an irradiation source mercury ark lamp type ??PK-2. The duration of exposure was up to 1500h. The oxidation degree has been appreciated by the carbonyl index determined by means of a IR spectrophotometer. It was established that the photooxidation process rate depends on the temperature as well as on the mechanical stress. At the tensile stress used it was found a decrease of the oxidation rate in comparison with the unloaded samples. The mechanical stress influence was stronger when testing unstabilized Polyethylene.     

Mischungen von Fetten und Ölen im internationalen Lebensmittelrecht und Einfluß der Harmonisierung in der EWG auf bundesdeutsches Recht

Blends of Fats and Oils in International Food Legislation and the Influence of EEC Harmonisation on German Federal Law Blends of fats and oils are of particular interest in terms of food legislation when milk fat is incorporated. In contrast to the existing standards of the Codex Alimentarius, the national legislation of each EEC member state contains far-reaching restrictions on this point which, however, are being or have been given up under the influence of the Cassis de Dijon judgement of the European Court of Justice. In 1988 France was the first EEC country to change its laws, the Federal Republic of Germany followed suit in 1990. At EEC level, the umbrella organisations of the dairy industry and the margarine industry have put forward suggestions for structuring the market for yellow fat spreads, which is to form a basis for EC legislation. In anticipation of EF legislation of this kind, Germany now permits, by virtue of an Order concerning margarine and mixed fat products of 31.8.1990, the production of mixed fat products consisting of fats fit for human consumption and a proportion of milk fat. The total fat content of these products must be 20–62% or at least 80%. The milk fat content must be between 15 and 25%, 45 and 55%, or 65 and 75% of the total fat content, but must account for at least 8% of the product weight.     

Einfluß von Fettreduktion und Substitution mit einem Fettersatzstoff auf den Vitamin E-Gehalt im Plasma und auf die Oxidierbarkeit der LDL

Effects of Fat Reduction and Replacement with a Fat Substitute on Vitamin E Content in Plasma and on LDL Oxidation Ten healthy obese volunteers (Broca + 136) were supplemented with α-tocopherol 140 mg/d and retinol-acetate 50000 IU/d for 2 weeks. Then they were observed during 4 weeks on a conventional 1000 kcal diet, with fat providing 30% of the energy intake. During the following 4 weeks 30% of the dietary fat were replaced by a protein based fat substitute (Simplesse). At the end of the supplementation with vitamins, and at the ends of the two reduction diets, fasting blood samples were drawn for determinations of plasma lipids, α-tocopherol, retinal and β-carotene and for measurements of LDL-oxidation. After supplementation the average concentration of α-tocopherol in plasma was 37 ± 16.5 μmol/1; the conventional diet decreased this vitamin to 28 μmol/1, no further effect of the fat substitute was observed on this parameter. The individual values varied between 19 – 70 μmol/1, the low values corresponded to a high oxidation rate of LDL and vice versa. Copper induced LDL-oxidation was inversely correlated to the α-tocopherol concentrations. Compared to preexperimental values, it was significantly increased at the end of the conventional 1000 kcal diet, and even more by the fat substitute.     

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.     

Die markt- und umweltgerechte Erzeugung von Ölsaaten in Mitteleuropa

Rapeseed Production in Middle Europe-Meeting market and Environment Demands The European oilseed production allows a considerable economical increase in value because of its successful adaptation to the demands of the market during the last decades. Oilseeds are mainly used in highly nutritious products, but mroe and more also for non-food purposes. The most important oilseed crop is rapeseed; its oil is appreciated worldwide with increasing demand because of its dietetic value. Middle Europe has excellent positions for oilseed production. They favour a production, thereby meeting environmental and economical aims, unless the agricultural politics secure the relative preference to the other agricultural market crops. The restriction of the oilseed production in the European Union, forced by the “Blair-House-Compromise”, can lead to supply shortfalls of the demanded quality in the world market.     

Einfluß der Zweiphasenströmungsbereiche auf die Trenneigenschaften von Siebböden

Influence of binary phase flow regimes on the action of sieve plates . Recognition of various flow regimes on sieve plates has greatly enhanced our understanding of the mode of action of these plates. When vapour flow dominates the liquid is dispersed into drops; this is the so-called ?droplet regime”?. In a second principal regime, liquid flow predominates and the vapour is dispersed into small bubbles; this is the ?emulsion regime”?. A transition region exists between these two principal regimes; it is called the ?mixed regime”?. The present paper attempts to demonstrate the relations between the flow regimes and the characteristics of sieve plates. It considers the structure of the binary phase layer, flow over the weir, axial mixing, entrainment of liquid, maximum loading (flooding), and efficiency.     

Perspektiven für Ölsaaten und deren Verarbeitung aus Sicht der Europäischen Gemeinschaft

Perspectives for Oilseeds and Oilseeds Processing in the European Community Oils from European oilseeds, in particular sunflower oil and rapeseed oil, are very useful to create added value. The enormous increase of the consumption of sunflower oil during the last years has its main reason in concrete and demonstrable health aspects. Additionally, sunflower oil has an excellent application performance. Rapeseed oil has also a wide spectrum of usability and good properties for industrial application. It has to be noted that these valuable raw materials which have been created by the European agriculture have become subject of fierce political battle. Following recent changes in the market organisation, the absence of any longer-term concept is quite noticeable. All this happens in the absence of any production surpluses for oilseeds in the world. To the contrary: taking into account the expected increase of the world population, there will be a world-wide deficit in supplies. The regions of surplus, this is also true for the European Community, must fulfil supply functions. For this, completely new instruments of financing have to be found. A new system of coordinated export credits may be one alternative. The global perspectives for European oilseeds are relatively positive. Agricultural policy must, however, define clear objectives for agriculture in order to exploit the existing potential.