Risks for public health related to the presence of furan and methylfurans in food

EFSA wishes to thank the hearing experts: Diana Doell and Ruud Woutersen and EFSA staff member: José Cortinas Abrahantes for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data on furan and methylfurans in food, and supported the data collection for the Comprehensive European Food Consumption Database. Adopted: 20 September 2017Peer reviewedPublisher PD

Furan formation in food model systems

Since furan has been classified as “possibly carcinogenic to humans” (group 2B) by the International Agency for Research on Cancer (IARC) (1995), its presence in foods has acquired significant attention. Many studies on furan formation have been performed mainly in simple model systems (buffered or dry mixtures of furan precursors) which do not fully represent food. Therefore, the main goal of this research was to investigate furan generation in more realistic starch-based model systems containing various furan precursors, such as vitamin C (ascorbic and dehydroascorbic acid), carbohydrates, lipids (vegetable oils as a source of polyunsaturated fatty acids) or mixtures of lipids and antioxidants, all either alone or in the presence of proteins. In addition, the interactions between various furan precursors were studied. The quantitative determination of furan was performed by solid-phase microextraction-gas chromatography-mass spectrometry. The results indicated that ascorbic acid and lactose at pH 6.0 with and without proteins were particularly vulnerable to furan formation upon heating when incorporated in a starch-based model system. Interestingly, starch itself showed an enhancing effect on furan formation from ascorbic acid as compared to buffered solutions of this vitamin heated under the same conditions. Fresh oils were nearly unable to generate furan. However, oils, such as soybean, rapeseed and linseed oil, containing α linolenic acid, generated considerable amounts of furan, but only when highly oxidized. Remarkably, generation of furan in emulsions containing fresh and oxidized oils was significantly enhanced in the presence of ascorbic acid, which indicated a synergistic effect between oils and vitamin C. This phenomenon was probably due to an enhanced degradation of this vitamin in the presence of lipids. These results illustrated the importance of the interactions between furan precursors, e.g. oils and ascorbic, in real foods which were currently neglected in the literature. In conclusion, this research contributed to a better understanding of furan formation in food. It indicated the most relevant sources of furan and the most important factors influencing furan generation, which can be useful for the food industry in order to mitigate the formation of furan

Mechanistic insights into furan formation in Maillard model systems

Furan has recently received considerable attention as a possibly carcinogenic compound occurring in thermally processed foods. Although several food constituents have been identified as furan precursors, multiple formation pathways remain unclear. Therefore, the mechanisms of furan formation in Maillard model systems were studied by means of the carbon module labeling (CAMOLA) technique. Under both roasting and pressure-cooking conditions, furan was formed from glucose via the intact skeleton, and its formation pathways from glucose alone were not amino acid-dependent. However, some amino acids, especially alanine and serine, did influence the furan production by providing an additional formation pathway. Furthermore, most amino acids enhanced the furan production from glucose. Roasting conditions produced 25-100 times higher amounts of furan as compared to pressure-cooking conditions. Surprisingly, in the alanine/glucose model systems, the relative importance of furan production from glucose alone and from the combination of a glucose-derived and an alanine-derived fragment changed completely over a limited time course of 60 min

Furan Formation from Lipids in Starch-Based Model Systems, As Influenced by Interactions with Antioxidants and Proteins.

The formation of furan upon sterilization of a lipid-containing starch gel was investigated in the presence of various antioxidants, namely, alpha-tocopherol, beta-carotene, and ascorbic acid, with and without proteins. Results indicated that alpha-tocopherol did not significantly influence furan formation from oxidized lipids. beta-Carotene, suggested previously to be a furan precursor itself, did influence the generation of furan in a concentration-dependent manner, although to a limited extent. Surprisingly, the presence of lipids seemed to limit the furan generation from beta-carotene. Interestingly, the addition of ascorbic acid to the emulsions containing soybean or sunflower oils considerably enhanced the formation of furan from these oils. This was also the case when fresh oils were applied, shown previously to be nearly unable to generate furan. This observation can be explained by an intensified ascorbic acid degradation stimulated by the presence of lipids

Furan formation in starch-based model systems containing carbohydrates in combination with proteins, ascorbic acid and lipids

Formation of the ‘‘possibly carcinogenic’’ furan during thermal treatment of a starch-based model food system containing selected sugars alone and in the presence of proteins, ascorbic acid and lipids, respectively, was investigated. The results showed that in starch gels containing various sugars significantly more furan was formed at pH 6 than at pH 4. Moreover, addition of whey proteins enhanced the generation of furan considerably at both pH values tested. In acidic conditions, no significant difference was observed between the amounts of furan found in a starch–carbohydrate–ascorbic acid model system and those formed in a starch-based samples containing only ascorbic acid. Addition of fresh lipids did not affect furan formation. However, when oxidised soybean oil was applied, the generated amounts of furan were higher than expected from the sum of furan found in the separate starch–carbohydrate and starch–lipid samples. Interestingly, the most efficient carbohydrate in furan generation, among the sugars tested, at pH 6, was lactose, especially when heated in the presence of proteins. This is the first report on the generation of furan from lactose