Quantitation of Furan and Methylfuran Formed in Different Precursor Systems by Proton Transfer Reaction Mass Spectrometry

Abstract

Furan has recently received attention as a possibly hazardous compound occurring in certain thermally processed foods. Previous model studies have revealed three main precursor systems producing furan upon thermal treatment, i.e., ascorbic acid, Maillard precursors, and polyunsaturated lipids. We employed proton transfer reaction mass spectrometry (PTR-MS) as an on-line monitoring technique to study furan formation. Unambiguous identification and quantitation in the headspace was achieved by PTR-MS/gas chromatography-mass spectrometry coupling. Ascorbic acid showed the highest potential to generate furan, followed by glyceryl trilinolenate. Some of the reaction samples generated methylfuran as well, such as Maillard systems containing alanine and threonine as well as lipids based on linolenic acid. The furan yields from ascorbic acid were lowered in an oxygen-free atmosphere (30%) or in the presence of reducing agents (e.g., sulfite, 60%), indicating the important role of oxidation steps in the furan formation pathway. Furthermore, already simple binary mixtures of ascorbic acid and amino acids, sugars, or lipids reduced furan by 50-95%. These data suggest that more complex reaction systems result in much lower furan amounts as compared to the individual precursors, most likely due to competing reaction pathways.

Furan in food - a review

“…Only recently, Märk et al (2006) studied furan formation using three main furan precursors, i.e. ascorbic acid, Maillard precursors, and polyunsaturated lipids.…”

Application of Gas Chromatography in the Analysis of Flavour Compounds in Field Peas

“…Relative peak area (%) = Peak area of total hydrocarbons/ Total peak area of volatile compounds x 100. In general, hydrocarbons are derived from oxidation of unsaturated fatty acids in foods (Märk et al, 2006;Oomah & Liang, 2007). Trichloromethane (chloroform), produced on exposure to chlorinated organic compounds, is a natural compound in plants (Lovegren et al, 1979).…”

On‐Line Monitoring of Flavour Processes

“…Monitoring specific chemical reactions in coffee using on-line direct mass spectrometry has also been reported (Muller et al, 2006). Acrylamide formation has also been studied using on-line techniques Channell et al, 2008) as have the formation of food contaminants (furan and methyl furan; Mark et al, 2006) and aromas .…”

“…For acrylamide, it was found that gas-phase contents were directly related to amounts in the solid phase and a calibration curve could be constructed although it was temperature dependent . On-line mass spectrometry for following chemical reactions is a relatively new technique although there are some published examples in the literature on non-food applications (see for example Brum and Dell'Orco, 1998;Dell'Orco et al, 1999;Brum et al, 2001;Mark et al, 2006). It is a powerful tool for studying real foods as well as the dynamics of individual reaction steps in the Maillard reaction.…”