Summary
Researchers measured levels of the toxic lipid oxidation product 4-hydroxy-2-trans-nonenal (HNE) in French fries from six fast-food restaurants. HNE forms when oils rich in polyunsaturated fats—especially linoleic acid—are repeatedly heated during frying.
French fries purchased at different times of day contained varying amounts of HNE, ranging from about 7.8 to 32 µg per 100 g of fries, and 0.9 to 4.9 µg per gram of extracted fat. Restaurants using oils with higher linoleic acid content consistently produced fries with higher HNE levels.
The study shows that HNE forms during normal frying operations and becomes incorporated into the food itself. Because HNE is a reactive and toxic aldehyde linked to inflammation, cardiovascular disease, neurodegeneration, and other health problems, the presence of measurable amounts in commonly eaten foods like French fries represents a potential public health concern.
DOI: 10.1007/s11746-015-2699-z
Abstract
The toxic lipid peroxidation product, α,β,4-hydroxy-2-trans-nonenal (HNE) concentration, was measured in French fries (FF) from six local fast food restaurants. FF were purchased between 2 and 3 pm from all six restaurants. FF were also purchased at 12, 2, 4, 6 pm from one and at 1, 3, 5, 7 pm from another restaurant. Samples were analyzed for total fat, fatty acid distribution and for HNE by high performance liquid chromatography (HPLC). HNE was confirmed by HPLC/MS. HNE concentrations in FF from the 6 fast food restaurants were between 7.83 and 32.15 µg HNE/100 g FF and between 0.9 and 4.9 µg HNE/g extracted fat. HNE concentrations in FF purchased at 12, 2, 4, 6 pm were between 19.07 and 32.15 µg/g of FF and purchased at 1, 3, 5, 7 pm were between 7.47 and 10.21 µg HNE/100 g of FF. Differences in FA distribution were observed in the samples from some restaurants. FF which contained higher levels of linoleic acid (LA) also contained more HNE. It is clear that HNE is produced during the heating process of the frying oils and is incorporated into FF. Frequently consumed foods containing considerable amounts of HNE, a toxic aldehyde, may be a public health concern since HNE toxicity is related to a number of common pathological conditions.
Yash Shah, Pawan Singh Takhar, Predicting the quality changes during microwave frying of food biopolymers by solving the Hybrid Mixture Theory-based unsaturated transport, and electromagnetics equations, Current Research in Food Science, 10.1016/j.crfs.2025.101264, (101264), (2025).
