LAUSR

BACKGROUND Flavor is a key element affecting the popularity of French fries (FFs). When oil is heated, the changes in oil quality can directly affect the flavor of the food. RESULTS The flavor of FFs showed three crucial stages, including break-in (3.0% to 6.8% of total polar compounds (TPC)), optimum (7.0% to 19% of TPC), and degrading (above 19.5% of TPC) stages. To discriminate the key aroma compounds among the three stages, the FFs prepared in PO at TPC of 3.0% (FF3), 7.5% (FF8), 19.5% (FF20), and their relevant oils (PO3, PO8, PO20) were selected for molecular sensory science analysis. The results indicated that the concentration of (E, E)-2,4-decadienal linked with the deep-fried odor was low in FF3, which lead to lower sensory score in FF3 sample. FF8 sample had a high content of (E, E)-2,4-decadienal and obtained a high sensory score. Besides, FF20 sample possessed high contents of hexanoic acid, heptanoic acid (sweaty odor), benzaldehyde (stale odor), octanoic acid (sweaty odor), (E)-2-undecenal (fatty odor), and trans-4,5-epoxy-(E)-2-decenal (metallic odor), thus leading to the undesirable flavor of FFs. In addition, PO20 showed a high content of hexanoic acid and heptanoic acid, contributing to a lower sensory score in PO20. CONCLUSION The flavor of FFs became undesirable when TPC was above 19.5% due to significant influences of some off-flavor compounds. Therefore, it is essential to prevent the generation of rancid substances in order to prolong the optimum stage during frying. This article is protected by copyright. All rights reserved.