Hydroxymethylfurfural contents in foodstuffs determined by HPLC method

Abstract

34 © 2006 VUP Food Research Institute, Bratislava The technological processes used in food production fundamentally impact on the nutritional and biological value of food and, in most cases, also on its sensory quality. Hydroxymethylfurfural (HMF, 5-hydroxymethyl-2-furaldehyde) is a recognized indicator of reduced quality in numerous foods that contain carbohydrate [1]. This cyclic aldehyde is formed through the dehydration of hexoses and hexuloses in an acidic environment, or as the result of Maillard reactions and caramelisation. In acidic environments, HMF partly decomposes to levulinic acid (4-oxopentanoic acid) and formic acid [2, 3]. However, HMF formation is not li mited to foodstuffs with a high content of reducing carbohydrates or proteins. FALLICO et al. [4] have shown a correlation between HMF formation and the content of lipids and their oxidative products in roasted peanuts. ROCHA et al. [5] have even demonstrated HMF formation in the cork stoppers of food glass containers owing to the degradation of their cellulose content due to the technological process. The presence of HMF in foods is the result of excessive temperatures during heat treatment and inappropriate and long-term storage. HMF re duces the nutritional value of foods [1, 6-13]. Opinions on the cytotoxic, genotoxic and carcinogenic effects of HMF vary [8, 14]. The U. S. Public Health Service, National Toxicology Program has HMF on the list of toxicological studies to be conducted – SCHMIDT and RODRICK [15]. The presence of HMF in honey has been known and monitored for a long time. The Czech legislation (Decree No. 76/2003 Coll. [16], as amended by Decree No. 43/2005 Coll. [17]) sets a maximum to the permitted concentration of this crucial parameter (40 mg.kg-1; this does not apply to honeys from tropical regions and mixtures of such honeys). The same limit value has also been defined in the international legislation for honey, namely by the European Honey Directive [18] and Codex Alimen tarius [19]. However, HMF can also be present in other foods containing carbohydrates in an acidic environment, and its concentration can reach considerable values. The objective of our study was to determine the HMF content in selected vegetable and fruit Hydroxymethylfurfural contents in foodstuffs determined by HPLC method