Probleme beim Pelletieren von Mischfutter mit hohen Fettanteilen

In the steam conditioning with subsequent pressing mixed feed passes considerable temperature ranges, which depend on the processing abilities. By maturation or sweating during long term conditioning up to 30 min cohesion and absorption of fats and molasses can be improved. Free added fats lower the friction and reduce the pellet firmness. Here technical limits are set especially with broiler feed. Trials with various lengths of the press canal indicate the influence on firmness and energy consumption. The fat is extracted from meal and pellets after the processing steps and investigated by its characteristic values w. r. t alterations by the process. A subsequent storage makes the influence of the fat alterations by the press process more obviously.     

Verfahrenstechnische und apparative Möglichkeiten zum Einbringen von Fett während des Mischfutterherstellungsprozesses

Processing and Plant Feasabilities for Fat Addition during the Production Process of Mixed Food In the production of high energy containing mixed food fats play an important role. However limits are set by processing. Thus the content of free added fats before pressing is even under favourable conditions only between 3 and 5%. Investigation showed that long time conditioning did not give the expected effect. Only by addition of molasse a higher increase is achieved. If a higher fat content in the mixed food product is desired, additional technical measures are demanded. Spraying of fats on a continuous pellet flow belongs in this connection to the most common methods. The results of the in the meantime closed research project are reported. Technical perspectives from the industrial practice indicate on further possibilities of the addition of fat in food.     

Die Aktivität von Lipoxigenasen in Getreide sowie Möglichkeiten der Enzymhemmung

Activity of Lipoxygenase in Cereals and Possibilities of Enzyme Inhibition In different feed components the activity of the enzyme lipoxigenase was determined. In cereals the enzyme activity predominantly decreases in the following order: barley, wheat, corn, oats and rye. During the malt process the activity of barley lipoxigenases increases to a very high level. During storage ungerminated grains are showing increasing (barley) or decreasing (wheat) variations in enzyme activity. The addition of propionic acid decreases the activity of lipoxigenases in cereals. The peroxide value of added fat in mixed feed was not influenced by lipoxigenases. For wheat products positive relations between the content of crude protein as well as crude fat and the enzyme activity were ascertained. Heat treaments with temperatures exceeding 100% C lowered the lipoxigenase activity to values below 10% of the untreated sample. The usual temperatures during feed processing, e.g. after conditioning and pelleting, are sufficient to inhibit the enzyme activity almost completely.     

Verwendung von Futterfetten in der Tierernährung sowie ihr Einfluß auf die Qualität der Schlachtkörper

Use of Feed Fats for Animal Nutrition and their Influence on the Quality of the Slaughtered Bodies For about 40 years fats have become an important feed component in rations of agricultural working animals. An increase of fat use in compound feed up to forty times was noted in the period from 1955 to 1984. But still today there are signs of uncertainty concerning quality assessment and selection of fats for feeding the various working animals. Today the quality of feed fats can be determined by analysis methods which enable a relatively quick assessment. Unfortunately there is no official control so that at last the compound feed factories have to fulfil this task. As fats have in comparison to carbohydrates an energy value which is 2.3 times higher, the energy amount of the compound feed increases by their addition. Thus the improved genetic ability of putting on weight of the working animals can completely be made use of. A greater fattiness of slaughtered bodies is not caused by fat addition in balanced rations. Because of their variety of different fatty acids and above all by their differences in the consistency and oxidation stability fats are of great influence on the performance of the animals and their slaughtered body quality. Depending on the content of polyenic acids and their oxidation degree lower increases of weight and damages in the organism are possible. High amounts of multiple unsaturated fatty acids cause a worse fat consistency in the slaughtered body and the from that produced products. Furthermore the suitability for storage declines by the lacking stability of the polymeres. Higher additions of vitamin E, Selenium or also of technical antioxidants show positive effects.     

Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods – Chemical properties

In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25 °C for 12 wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by the conventional methods (chemical interesterification and physical blending) and to selected commercial margarines. The changes in the chemical properties of the products, including peroxide values (PV), tocopherols, free fatty acids, volatile oxidation products, and sensory evaluation, were examined during storage. It was observed that the margarine produced from the chemically interesterified fat had higher PV in weeks 4, 8 and 10 than the margarines produced from the enzymatically interesterified fats and the physically blended fat. These differences were not caused by different contents of tocopherols in the hardstocks. The differences between the processes for chemical and enzymatic interesterification, including further treatment stages, might be responsible for the development of a high PV in the margarine produced from the chemically interesterified fat. However, the contents of volatiles did not show the same tendency as observed for PV for the margarines stored at 25 °C during 12 wk. Storage at 25 °C accelerated oxidation compared to storage at 5 °C. The content of δ‐ and γ‐tocopherols decreased faster than the content of α‐ and β‐tocopherols during storage. This phenomenon was only affected by storage time, not by storage temperature. Sensory analysis did not show consistent differences between the produced margarines and commercial margarines, and no hydrolysis occurred for these four margarines during storage. The margarines produced from the enzymatically interesterified fats had low PV and a similar taste and smell compared to the margarine produced from the chemically interesterified fat.     

Über Oxysäuren zur Beurteilung erhitzter Fette

Oxy Acids in the Assessment of Thermally Treated Fats The usual characteristic values such as peroxide, aldehyde and epoxide values are mostly insufficient for the assessment of the degree of oxidation of thermally treated fats. Characteristics such as acid value and especially colouration with alkali and oxy acids offer a good insight into the degree of oxidation of a fat. According to the investigations carried out till now a good correlation exists between the alkali colouration and the oxy acids so that the determination of either of the two suffices. The measurement of alkali colouration is preferred, since it is simple and rapid, and permits the simultaneous assessment of oxy acids.     

Einfluß von Futterfetten auf die Qualität tierischer Veredlungsprodukte

Effects of Feed Fats on Quality of Animal Product At the same level of energy supply intake of fats/oils do not lead to a higher fat deposition in the carcass. Additionally, fats are carrier of fat soluble vitamins A, D, E, K and improve their absorption from the intestinal tract. The fatty acid profile of fat deposited in the organism, as for example in egg yolk is influenced by the intake of fatty acids provided by feed. This especially concerns linoleic- and linolenic acid as well as lauric- and myristic acid, High contents of polyunsaturated fatty acids negatively influence oxidative stability as well as consistency of body fat and therefore quality of animal products. An improved oxidation protection can be carried out by supplementation of antioxidants. Medium-chain, saturated fatty acids reveal positive effects on both criteria.     

Changes in a fat with prolonged storage and the palatability of doughnuts cooked in the fat

Summary The storage for 2.5 years did not appreciably affect the smoke point, nor did storage for 3.5 years cause appreciable changes in the iodine value or the refractive index. There was a perceptible change, in the free fatty acid content after storage for 3.5 years, but none after 2.5 years. The peroxide value was higher after 2.5 years' storage than at 6 months, but unaccountably was lower after 3.5 years than after 2.5 years' storage of the fat. The chemical and physical constants, of the fats were changed appreciably and, in general, consistently during the use of the fat for cooking 24 lots of doughnuts. The rapidity with which chemical changes took place in the fats during their use for cooking was not influenced by the length of time the fat had been stored previous to use. In general, the constants of the fat extracted from the doughnuts closely paralleled the corresponding samples of fat in which the doughnuts were cooked. Iodine values of extracted fats tended to be lower than the kettle fats for the first two storage periods and about the same after 3.5 years. The free fatty acid content was slightly higher in the extracted fat than in the kettle fat at the 6-month period, and slightly lower at the 3.5-year period. Volatile acids were higher in extracted than in kettle fats. The desirability of doughnuts fried in the fat was not affected by storage of the fat 2.5 years prior to use, but was lowered after the fat was stored for 3.5 years. Approved for publication by the director of the Iowa Agricultural Experiment Station as Journal Paper No. J-1388, Project 761.     

Zur Kenntnis schwefelhaltiger Fette und ihres Härtungsverhaltens

Information about Fats Containing Sulfur and their Behaviour During Hydrogenation Commercial marine oils - whale oil and fish oil - can contain combined sulfur, which cannot be eliminated by means of the normal refining and therefore causes considerable difficulties during the hydrogenation. An analytical method for the determination of sulfur in fats is described. This method allows the quantitative determination of 0.5 to 100 μg sulfur per g fat with an exactness of 0.2 μg sulfur per g fat. Semi-refined fats to be hydrogenated, containing more than 2 μg sulfur, should be subjected to a hydrogenating desulfurization with nickel contacts at 120° to 130° C. By means of the method described a complete desulfurization is attained without any noticeable hydrogenation or isomerisation of the unsaturated fat constituents. Such pretreated fats can be hydrogenated as usual. Also rapeseed oil, sometimes containing sulfur constituents not easily to be eliminated, can be desulfurized in the same way.     

Zusammenhänge zwischen Fettoxidation und Antioxidantienzulagen im Mischfutter

Relations Between Fat Oxidation and Antioxidative Additives in Mixed Feeding Stuff Storage experiments with various mixtures of feeding stuffs were carried out. The influence of single factors on fat stability in test mixtures should be tested. The type of fat (refined soya bean oil, free fatty acids from soya bean oil raffination) fat content (3, 6, 9%), antioxidants (BHA, TBHQ), amount of anti oxidants (0 - 50 - 100 - 150 mg/kg feeding stuff), storage temperature (4, 14, 24°C) and storage period (6 - 12 - 24 weeks) were varied. The peroxide value (POZ) and the remaining amounts of antioxidants were used as parameters for the determination of the fat oxidation. The test results showed a some what enlarged stability of the fatty acids of soya bean oil raffination compared with refined soya bean oil in presence of anti oxidants. The stabilising effect of TBHQ was higher than that of BHA, but the consumption of antioxidants was lower with BHA than with TBHQ. With increasing amounts of antioxidants the stability of the fat was enlarged. The stability was lowered with rising storage temperature. Increasing storage period gives rise to a considerable increase in oxidation.     

Die Pulverisierung von Fetten im Kaltluftstrom - Anwendungsmöglichkeiten und Wirtschaftlichkeit

Pulverization of Fats in Cold Air Flow - Feasibilities of Application and Economy Because of the great importance of fats and oils for human nutrition a procedure is necessary which produces stable products from fat and solid materials by methods most favourable from the energetic point of view which keep their natural properties. The pulverization of fats is discussed and the influence of particle size during spraying is shown. Pressure nozzles have proved true for this use. Because of the globular shape of the fat particles and of the increased presence of the saturated fatty acids at the surface of the pulverized fats, an improved stability exists. Beyond antioxidants can be added without any problem. The whole plant consists of a mixing part for the solid material, a mixing part for the fat which has to be used, and of the plant for cristallization of the fats and the coating of fats with the solid material and filling the finished product in bags. The economic aspect is considered and it is found that the economy is essentially influenced by the degree of utilization of the plant, as more than 50 % of the total expenses occur because of capital costs. The amount of energy costs with respect to the total expenses comes to 10 %.     

Ernährungsphysiologische Wirkung unterschiedlicher Gemische von Öl-, Linol- und Linolensäure bei wachsenden Schweinen. 2. Einfluß auf Depotfette und Blutlipide

Physiological Effect of Various Mixtures of Oleic, Linoleic and Linolenic Acids on Growing Pigs: 2. Influence on Depot Fats and Blood Lipids At the end of the feeding trials described extensively in the first contribution, from all animals saddle bacon and leaf fat as well as serum lipids have been investigated on effects of the various food fats. Earlier results have been confirmed according to which the increased supply of unsaturated fatty acids results in an increase of the content in depot fat and in a decrease of palmitic and stearic acid. The storage of linoleic and linolenic acids is linked to the consumed amount of these acids in a linear way. Some hints have been found for the occurrence of yellow fat desease that besides the deficiency of vitamin E an enzyme activating effect of higher amounts of linolenic acid may be responsible. Furthermore the attacked animals showed a linear dependence of the fat content in the yellow tissue from its peroxide value. As well linolenic acid as oleic acid led to a significant decrease of the serum triglycerides. Besides, linolenic acid lowered the content of serum cholesterol, whereas linoleic acid caused a significant increase of the HDL content.     

Auswirkungen oxidierter Fettsäuren des Mischfutters auf die Carotinoideinlagerung im Eidotter

Effects of Oxidized Fatty Acids of Mixed Feed on Interstitial Carotinoids in Egg Yolk It was the target of investigations to test whether a different degree or course of oxidation of the fat/oil contained in mixed feed influences the deposit of carotinoids in egg yolk. The results show a significant influence of fat oxidation on carotinoid deposit in egg yolk. The yolk colour decreases with increasing peroxide value and is improved at lower peroxide values. Especially oils with high contents of unsaturated fatty acids cause a diminished carotinoid deposit in egg yolk. By addition of antioxidants the fatty acid oxidation can be delayed. Basic feed components among others bad tapioca meal with high lipoxygenase activity can have an important influence too on peroxide formation and with that on yolk colouring.     

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.     

Tierische Fette in der Tierernährung

Animal Fats in Animal Nutrition Intensive feeding of several types of farm animals is unthinkable without the use of fats in feed formulations. Animal fats are, however, considered inferior to plant oils with respect to quality and energy utilization. In the practical application, only mixed fat formulations are used. Therefore, there is little chance that the absorption of fat from the gastro-intestinal tract is inhibited by the presence of relatively high proportions of saturated C₁₆ and C₁₈ fatty acids. Large proportions of fat are used in feeds for broilers and calves. Moreover, from nutritional viewpoint, the fat content of feeds for swine and laying hen could be increased, if technical devices for restricted feeding are used, which prevent excessive intake of energy. A higher content of fat in ruminant feed is also to be recommended. Since in monogastric animals the consistency of fatty tissues is influenced by unsaturated fatty acids of dietary fat, the use of animal fats having low content of unsaturated fatty acids is favorable for the quality of slaughtered products.     

Quality and consumption of oxidized lipids from deep-frying fats and oils in New Zealand

Samples of beef dripping and plant oil-based deep-frying fat were obtained from fast-food premises in Christchurch, New Zealand, as well as samples of deep-fried battered fish and potato chips. The fat in these samples was analyzed for level of oxidation by measuring acid value, peroxide value, polar compounds, thiobarbituric acid-reactive substances (TBARS), and conjugated dienes. The acid and peroxide value results were contradictory when compared with limits set in the New Zealand Food Regulations 1984, but the levels of polar compounds were generally below 25%, indicating that the fats were well maintained. The TBARS and conjugated diene levels were compared with those for oxidized corn oil used in a feeding trial and indicated a similar oxidation level, although the amount of fat consumed in the feeding trial would be 30–50% higher. These results show that well-maintained deep-frying fat has oxidation levels sufficient to cause elevation of plasma lipid oxidation levels as observed in a human feeding trial.     

Consumption of cholesterol oxides from fast foods fried in beef fat in New Zealand

Samples of beef dripping and plant oil-based deep-frying fat were obtained from fast-food premises in Christchurch, New Zealand, as well as samples of deep-fried battered fish and potato chips. The fat in these samples was analyzed for level of oxidation by measuring acid value, peroxide value, polar compounds, thiobarbituric acid-reactive substances (TBARS), and conjugated dienes. The acid and peroxide value results were contradictory when compared with limits set in the New Zealand Food Regulations 1984, but the levels of polar compounds were generally below 25%, indicating that the fats were well maintained. The TBARS and conjugated diene levels were compared with those for oxidized corn oil used in a feeding trial and indicated a similar oxidation level, although the amount of fat consumed in the feeding trial would be 30–50% higher. These results show that well-maintained deep-frying fat has oxidation levels sufficient to cause elevation of plasma lipid oxidation levels as observed in a human feeding trial.     

Über das Lagerverhalten von Kartoffelchips bei Belichtung und im Dunkeln I Analyse der durch Licht ausgelösten Veränderungen des Röstöls

Storage Behavior of Potato Chips Exposed to Light and in the Dark I: Analysis of Alterations of the Frying Oil Caused by Light Two aspects should be considered in evaluating potato chips produced commercially: quality control within the production plant at the time of manufacture, and detection of alterations on storage during the period of circulation. Currently, these products are packaged without taking protective measures to eliminate light and atmospheric oxygen. The investigations in the first part of this study were therefore devoted towards the determination of the action of these two parameters on the oxidation of the frying oil. Since the fat content of such products is as high as 45%, one might assume that the state of oxidation of the fat determines the quality of the entire product. Based on the kinetics of peroxide formation and oxygen uptake it is shown that the light sensitivity of refined peanut oil increases with increasing thermal stress in the frying equipment. A common consideration of the oxygen uptake as measured physically, the peroxide formation, the absorption at 232 nm, and the carbonyle content gives a deep insight into the course of the reaction. Due to the tocopherols present in the oil conjugated hydroperoxides are predominantly formed in a wide region of the oxidative process. The parallel reaction of peroxide decomposition, which yields carbonyls having intense taste, occurs to such a small extent that methods suitable for routine analysis are unable to differentiate the samples. Addition of antioxidants was found to be of little use for the quality retention under the action of light. Exact knowledge of the storage behavior might enable to draw consequences for the practice. For example, one might use a packaging, which not only fulfils the technical requirements but also justifies economic considerations.     

Solid Fat Content Estimation by Differential Scanning Calorimetry: Prior Treatment and Proposed Correction

The objective of this work was to develop a corrected method for solid fat content estimation by differential scanning calorimetry (DSC), as important differences are usually observed between the results given by DSC and pulsed nuclear magnetic resonance (NMR). Cold storage after full melting of fats was necessary to avoid the appearance of exothermic peaks in the modulated temperature DSC thermograms, in order to make an appropriate estimation of melting energy. Different fats were analyzed by NMR and DSC, obtaining considerably higher solid fat content values with the latter, uncorrected method. These differences were attributed to the fact that consumed energy per unit of melted mass tends to increase with the increase of the melting temperature of each fraction of the fats. A linear correlation between melting enthalpy and melting point of different triglycerides was used to estimate the energy per unit of mass consumed at each temperature. From these data, an estimated transformation of melting energy into melted mass was performed and new solid fat content values were calculated. The results obtained from this correction were much closer to the measurements made by NMR, in comparison to the uncorrected DSC method.     

Zur Ernährungsphysiologie der Schlachttierfette

Nutritional Properties of Animal Fats Dietary fat plays two roles, as a carrier of energy, and, in the form of essential fatty acids, as an indispensable component of food. Animal fats can meet both requirements. Since fats are greatly accepted by the people due to their taste, the fat consumption by the entire population has been very high. High fat consumption are believed to have resulted in increased level of cholesterol and premature occurrence of coronary diseases. Increase in the incidence of deaths by coronary diseases has drawn attention to the nutritional properties of dietary fats, which affect the level of cholesterol. It has been established that saturated fatty acids in foods raise the level of serum cholesterol, whereas polyunsaturated fatty acids lower it. However, with diets of relatively low fat content the ratio of saturated to polyunsaturated fatty acids is not so significant with regard to level of serum cholesterol as with high-fat diets.