Matches in UGent Biblio for { ?s ?p Benzene has been classified as carcinogenic to humans (Group 1) by the IARC. The occurrence of benzene in food has been attributed to several potential sources. One of these sources is benzoate, a widely used preservative, which may decarboxylate in the presence of ascorbic acid and metal ions. At low pH, hydroxyl radicals are supposed to be the key intermediate for this oxidative mechanism. Since several other reactions in foods may give rise to the generation of hydroxyl radicals, their potential to decarboxylate benzoate were evaluated in a formate buffer system (0.5 M) at pH 3 and 4 and incubated at 50°C for 5 days under light. Neither photo-induced oxidation in the presence of riboflavin or lipid oxidation and combinations of thereof were able to induce benzene formation from benzoate. In the ascorbate-transition metal ion system, lipids seemed to reduce benzene formation. This can probably be explained due to the lower availability of benzoate in the aqueous fraction because of its lipophylic character. As a further elaboration of the ascorbate-transition metal ion oxidative decarboxylation mechanism, this reaction was studied in various other buffers at pH 3 and 4. Remarkably, a strong effect of the type of buffer on the amounts of benzene generated from benzoate was observed. Thus especially citrate and acetate buffers seemed to enhance the decarboxylation reaction when compared to formate. From results, it can be concluded that care should be taken in the formulation of foodstuffs with respect to acidifiers in the presence of benzoate and ascorbate. Acidifiers may affect the benzene formation to a significant extent.. }
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- aggregation abstract "Benzene has been classified as carcinogenic to humans (Group 1) by the IARC. The occurrence of benzene in food has been attributed to several potential sources. One of these sources is benzoate, a widely used preservative, which may decarboxylate in the presence of ascorbic acid and metal ions. At low pH, hydroxyl radicals are supposed to be the key intermediate for this oxidative mechanism. Since several other reactions in foods may give rise to the generation of hydroxyl radicals, their potential to decarboxylate benzoate were evaluated in a formate buffer system (0.5 M) at pH 3 and 4 and incubated at 50°C for 5 days under light. Neither photo-induced oxidation in the presence of riboflavin or lipid oxidation and combinations of thereof were able to induce benzene formation from benzoate. In the ascorbate-transition metal ion system, lipids seemed to reduce benzene formation. This can probably be explained due to the lower availability of benzoate in the aqueous fraction because of its lipophylic character. As a further elaboration of the ascorbate-transition metal ion oxidative decarboxylation mechanism, this reaction was studied in various other buffers at pH 3 and 4. Remarkably, a strong effect of the type of buffer on the amounts of benzene generated from benzoate was observed. Thus especially citrate and acetate buffers seemed to enhance the decarboxylation reaction when compared to formate. From results, it can be concluded that care should be taken in the formulation of foodstuffs with respect to acidifiers in the presence of benzoate and ascorbate. Acidifiers may affect the benzene formation to a significant extent.".