Chemie der Fischlipide

Chemistry of Fish Lipids The muscle (‘meat’) of freshwater fishes and marine fishes contains 1–25% lipids which are predominantly triglycerides; phospholipids are generally present in rather small proportions. The lipids in the muscle of typical freshwater fishes contain considerable proportions of oleic and linoleic acids, whereas the lipids of most marine fishes contain relatively large amounts of highly unsaturated fatty acids having 20 and 22 carbon atoms. The fatty acid patterns of lipids in the muscle of freshwater predatory fishes resembles to a greater extent that of marine fishes than herbivorous freshwater fishes. In the meat of sharks, alkyldiacylglycerols occur in addition to small amounts of alk-1-enyldiacylglycerols (neutral plasmalogens). In the muscle lipids of marine fishes from depths of more than 1000 m, wax esters predominate. As a rule, the liver of marine fishes, especially of sharks, is rich in alkoxylipids, wax esters, steryl esters, vitamin A esters and hydrocarbons.     

Nutzen und Risiken der Chemie

Benefits and risks of chemistry . The benefits of chemistry for mankind are undisputed. Without the discovery and invention of artificial fertilizers the rapidly growing population of the world could not be fed. A fourth of our foodstuffs is currently preserved and improved by crop protection. Besides, an agricultural worker now produces thirty times the amount of agricultural products than was usual fifty years ago. Many developments, such as synthetic fibers and numerous dyes have been made possible only by advances in chemistry; there was a time when dyes were worth their weight in platinum. But what are the risks which chemistry introduces? The basis of chemistry is the conversion of materials. The use of chemical products can lead to interactions with nature, and excessive or uncontrolled usage can in turn endanger life. This biological aspect is the major reason for a wide section of the population being apprehensive about the increasing use of chemical products. An isolated accident involving an explosion leads to a feeling of uncertainty among the populace. One feels that one might be involved oneself at some future date. Thus one of the chief aims in the chemical industry, compared to other branches of industry, is to ensure a very high standard of safety. But the citizen must also be kept well-informed. There is always room for improvement in this direction, and false notions and allegations should be repeatedly corrected. Reasonable legislation which allows chemistry to play its important and positive role in the service of mankind will always be welcomed.     

Aromastoffe aus der Lipidperoxidation

Aroma Compounds Formed by Peroxidation of Lipids A complex of volatiles results from the peroxidation of unsaturated lipids in foods. Among these volatiles some carbonyl compounds, showing low odour and taste thresholds, were identified. On the basis of their sensory properties they cause distinct notes in the aroma profile of many foods and, in some cases, also off-flavours. Problems in the analysis of aroma compounds are mentioned at the introduction. In particular the differentiation of potent aroma compounds from the other components of the volatile fraction is discussed. The contribution of aroma compounds derived from lipid peroxidation to the aroma of some foods of plant origin and of cooked meat is discussed. As example of an off-flavour, the aroma compounds which cause the reversion flavour of soya-bean oil are reported.     

Die wirtschaftliche Bedeutung der thermischen Verfahrenstechnik in der Chemie

Development of thermal process technology within the chemical industry . The paper reviews the historical development of thermal process technology within the chemical industry and in particular its rapidly increasing utilization during the last 20 years. A decisive factor in this development was the establishment of thermal process technology as an exact science. Emil Kirschbaum is regarded as one of the principal founders of this science. The paper portrays the importance of thermal process technology by examining a series of processes, utilizing investment figures and energy consumption data. Future development efforts in this area will be concentrated on the supply of the chemical industry with energy and raw materials, on process cost reduction, and on environmental protection.     

Einige Erkenntnisse aus der Kurzbewitterung

Some Findings from the Accelerated Weathering The authors have drawn a comparison between the findings, which were obtained by the short weathering of TiO₂-pigmented paints. Different lighting sources (xenon lamp, arc lamp) were used. Special importance was ascribed to the effect of humidity in definite cycles, purity of water and the arrangement of the test objects in the short weathering apparatus. All the results are relative, just as a comparison between short and free weathering.