CONTAMINANTS ORIGINATING FROM HEAT PROCESSING OF FOODS
Graz University of Technology, Institute of Biochemistry, Petersgasse 12, 8010, Graz, Austria
Heating processes are important for food processing since these are necessary mainly for hygienic reasons to eliminate pathogenic and spoiling microorganisms. In addition, the bioavailability and digestibility of specific compounds (e.g. polymeric carbohydrates, proteins) is increasing and the palatability and the sensory properties improve significantly. However, during the heating a series of reactions are taking place that lead to compounds that can compromise the individual health. The main reaction types are the Maillard reaction and lipid oxidation. From both of these reactions carcinogenic compounds can arise. These are e.g. heterocyclic amines, furan derivatives, oil oxidation products. The temperatures that are necessary range from room temperature (e.g. oil oxidation) to temperatures of more than 150 °C which are necessary to form the heterocyclic amines or furan derivatives.
The precursors necessary for the formation of these compounds are present in the foods and comprise amino acids, carbohydrates, and creatin which is necessary for the formation of heterocyclic amines, asparagin in combination with reducing sugars as precursors for acrylamide and a variety of possible compounds (lipids, ascorbic acid, sugars) for furan and its derivatives like furfuryl alcohol, methylfurans, furfural.
For all of these reactions high temperatures are necessary for longer time. It is difficult to estimate the formation of these compounds just by judging the color or aroma, since this does not reflect completely the chemical situation behind the reactions.
In the case of oxidized oil – which might be related to colon cancer or the onset of non-alcoholic liver inflammation – the situation is more complex since no clear chemical background has been elucidated by the toxicologists.
Looking at the chemical background there is practically no possibility to eliminate these contaminants but with careful processing and heating or a selection of raw materials the concentrations can be reduced and a possible health risk minimized.
CV: 1959 geboren in Graz, Austria. 1985 Diplom in Technischer Chemie; 1989 Dissertation an der Technischen Universität Graz; Postdoktorand and der ETH Zürich/Schweiz. Arbeit: 1990-1993 F&E bei Biochemie Kundl/Sandoz; seit 1993 Mitarbeiter der Technischen Universität Graz; 2002 Habilitation in Lebensmittelchemie und a.o. Professor. Zurzeit am Institut für Biochemie als Leiter der Arbeitsgruppe “Chemie funktioneller Lebensmittel“. Vorsitzender der Studienkommission für Molekulare und Technische Biowissenschaften. Forschung: Die aktuelle Forschung konzentriert sich auf karzinogene Substanzen die beim Erhitzen entstehen, sowie auf die Gewinnung von funktionellen Stoffen aus Mikroalgen. Bibliographie: Publikation von mehr als 100 peer reviewed Manusktripten. Außerdem: Aktiv in der Gesellschaft Österreichischer Chemiker, sowie in der EUChemS (division of food chemistry), und nationaler Repräsentant der Global Harmonization Initiative.
CV: 1959 born in Graz, Austria. 1985 graduated in Technical Chemistry; 1989 Doctorate at Graz University of Technology; Post doctorate at ETH Zürich/Switzerland Working activities: 1990-1993 R&D at Biochemie Kundl/Sandoz; since 1993 employed at Graz University of Technology; 2002 habilitation in food chemistry and Associated Professor. Currently member of the Institute of Biochemistry leading the working group on functional foods. Chair of WG Curricular Committee for Field of Studies Molecular Biomedical Sciences and Biotechnology. Research: Current research activities comprise the investigation on carcinogenic compounds in foods originating from heating processes and functional ingredients from micro algae. Bibliography: more than 100 reviewed manuscripts. Additionally: Active in the Society of Austrian Chemists, EUChemS (division of food chemistry), and national representative of the Global Harmonization Initiative.