Comparative analysis of aroma compounds in <scp>F</scp>rench fries and palm oil at three crucial stages by <scp>GC/MS</scp>‐olfactometry, odor activity values, and aroma recombination
Lirong Xu, Jiarui Chang, Xue Mei, Youfeng Zhang, Gangcheng Wu, Qingzhe Jin, Xingguo Wang
Abstract
BACKGROUND: Flavor is a key element affecting the popularity of French fries (FFs). When oil is heated, the changes in oil quality can affect the flavor of the food directly. RESULTS: The flavor of FFs showed three crucial stages: the 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 distinguish the key aroma compounds in the three stages, the FFs, prepared in palm oil (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 led to a lower sensory score in the FF3 sample. The FF8 sample had a high (E, E)-2,4-decadienal content and received a high sensory score. The FF20 sample possessed high 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) content, thus leading to FFs having an undesirable flavor and PO20 showed high hexanoic acid and heptanoic acid content, contributing to a lower sensory score in PO20. CONCLUSION: The FFs' flavor became undesirable when TPC was above 19.5% due to significant influences of some off-flavor compounds. It is therefore essential to prevent the generation of rancid substances to prolong the optimum stage during frying. © 2021 Society of Chemical Industry.