Changes in furan and other volatile compounds in the headspace of sliced carrot (Daucus carota ssp. Sativus) during air-drying were studied using selected ion flow tube-mass spectrometry. Drying temperatures of 93 to 133C were applied to study how the volatiles change during heat treatment. Furan concentration did not change significantly until the moisture content was below 40%. At less than 7% moisture content, the furan content increased with increasing drying temperature and decreasing moisture content. Furan concentration tended to increase exponentially with drying temperature and Hunter L-value. Changes in some major volatiles during drying were monitored. Many aldehydes, alcohols and terpenes decreased 60–90% during the early stages of drying; however, significant increases in (E)-2-octenal, 2,3-butanedione, 2-methylbutanal, acetone, bornyl acetate, butanal, butanone, furfural, furaneol and sotolon, hexanal, methyl acetate, monoterpenes, norfuraneol, undecane, β-caryophyllene, β-ionone, p-cymene, and p-cymenene were found at the end of drying.


Furan is a possible carcinogen, but data in dried fruits and vegetables are limited. Furan was formed in the headspace of dehydrated carrots, but it only formed significantly at higher temperatures of 113 to 133C, especially at moisture content less than 4%, so typical commercial drying conditions, at temperatures below 100C, will not be a concern for significant furan formation. Some volatile flavor compounds were formed and others lost during drying, which could be used to aid processors in limiting major flavor changes.