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Bioconservazione enzimatica degli alimenti.
Biokonservierung von Lebensmitteln durch Enzyme
By using enzymes for biopreservation, the thermal damage and the addition of preservatives to food can be avoided or reduced. Enzymatically catalysed reactions exhibit several advantages compared to currently used preservation methods, for example low incubation temperature and minimal interfering or side reactions. Another important point is that the velocity of the reaction is dependent on external parameters, and therefore the desired effect in the product can be influenced by controlling the reaction conditions. The example of milk demonstrates that nature has already developed some partly enzymatic mechanisms which show antibacterial effects. The lactoperoxidase-system, lactoferrin, glucoseoxidase and lysozyme are good examples which have been discussed in detail in this paper. For the food industry, several reasons exist for choosing glucoseoxidase as an additive (mostly in combination with other enzymes) as it can be deduced from the substrates used and from the productsformed in this enzymatic reaction. The essential objectives are the removal of oxygen or glucose from the food, the production of the toxic peroxide, and the lowering of the pH-value in the medium. Another important group of antimicrobially active enzymes are those with cell wall disrupting specificities, such as lysozyme, glucanase and chitinase. Our lab has obtained a considerable amount of results and experience in the area of enzymatic biopreservation using lysozyme. In vitro experiments demonstrated that the heat resistance of spores of the genus Bacillus can be significantly decreased by pretreatment with lysozyme. The shelf life of salads with a mild acidification can be significantly prolonged, as was shown in various addition experiments under praxis relevant conditions.