Chemical changes during concentration processes

Chemical Changes in Citrus Juices During Concentration Processes... 

Table I. Chemical Changes during Processing of Tomato Juice (Concentrations in mmol/100 g dry matter)...

Previous production of pentachlorophenol, as well as the bleaching process in pulp and paper mills, has been shown to be a major source. Changes in industrial processes have resulted in a reduction of PCDD/PCDFs concentration in products. Whereas in the past the chemical industry and, to a lesser extent, the pulp and paper industry were considered to be the main sources of PCDD/PCDFs (and also the cause of many of today s contaminated sites in several industrialized countries), today s dioxin input is mainly due to thermal processes. There is still a considerable focus on waste incineration but, owing to requirements for dioxin reduction in stack gases set by several national authorities, the importance of this category has declined during the last years. Examples can be seen especially in the European emission inventories... 

The turnover of trace metals in organisms depends on dynamic processes of exchange with elements in the environment. Compartments of elements are identified from a mathematical analysis of the changes in concentration during accumulation or loss. The resolution of compartments is limited by experimental error, and the compartments that can be identified are those whose concentrations differ significantly in their exponential change. These compartments may be physiological, structural, or chemical entities, and their metabolic roles may not be known. 

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