Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/8/2005
Publication Date: 9/10/2005
Citation: Fan, X. 2005. Formation of furan from carbohydrates and ascorbic acid following exposure to ionizing radiation and thermal processing. Journal of Agricultural and Food Chemistry. 53:7826-7831. Interpretive Summary: Furan is classified as “reasonably anticipated to be a human pathogen” by the U. S. Department of Health and Human Services, and as “possibly carcinogenic to humans” by the International Agency for Research on Cancer. A recent FDA survey found furan was present in a large number of thermally processed foods. Our recent study suggested that ionizing radiation, a nonthermal processing technology, induced furan formation in orange and apple juices. The mechanism of furan formation was, however, unclear. This study was conducted to investigate the formation of furan from simple sugars, vitamin C and organic acids as affected by ionizing radiation and thermal treatments. Results showed that both thermal treatments and irradiation induced formation of furan from simple sugars and vitamin C. Little furan was produced from organic acids. The pH and concentration of sugars and vitamin C solutions had profound influences on furan formation. The results are useful for food industry and scientists to develop and optimize treatments and food formulations in order to minimize formation of this toxic compound.
Technical Abstract: This study was conducted to investigate the formation of furan from sugars, ascorbic acid and organic acids as affected by ionizing radiation and thermal treatments. Results showed that both thermal treatments and irradiation induced formation of furan from ascorbic acid, fructose, sucrose, or glucose. Little furan was produced from malic acid or citric acid. The pH and concentration of sugars and ascorbic acid solutions had profound influences on furan formation due to either irradiation or thermal treatment. The rate of irradiation-induced furan formation increased with decreasing pH from 8 to 3. Approximately 1600 times less furan was formed at pH 8 as apposed to pH 3. At the same pHs, the amounts of furan formed from irradiation of ascorbic acid, fructose, and sucrose were always higher than from glucose. An increase in thermally induced furan as a result of pH decrease from 7 to 3 was observed for sucrose and ascorbic acid solution, but for glucose solution, less furan was formed at pH 3 than pH 7. The levels of sugars commonly found in fruits and fruit juices, upon irradiation, would be high enough to potentially produce a measurable amount of furan. The concentration of ascorbic acid at which a maximum of furan was produced upon irradiation was about 0.5 mg/ml, a level commonly found in some foods. Five furan derivatives were tentatively identified in thermally treated ascorbic acid solution while one furan derivative was tentatively found in both irradiated and thermally treated samples.