A chemometrics-guided lipidomics approach may offer a more detailed way to assess how vegetable oils degrade during repeated deep-frying.
In the study, researchers evaluated four widely used edible vegetable oils – soybean, rapeseed, sunflower, and palm oil – across 40 consecutive frying cycles to examine how their lipid profiles changed under prolonged heat exposure. Using a chemometrics-guided lipidomics workflow, the team monitored molecular-level changes in triglycerides and related lipid species that arise during thermal oxidation and hydrolysis.
The analysis revealed progressive degradation of triglycerides with increasing frying cycles, accompanied by the formation of oxidized triglycerides (oxTGs), diglycerides, and free fatty acids. Triglyceride concentrations decreased substantially after extended frying, dropping by roughly 55 percent in soybean oil and sunflower oil, around 50 percent in rapeseed oil, and about 45 percent in palm oil after 40 cycles.
These changes reflect the oxidative breakdown of triglycerides into smaller molecular species and oxidized derivatives that accumulate as oils are repeatedly heated. Oils with higher degrees of unsaturation – including soybean and sunflower oil – were more susceptible to thermo-oxidative degradation, whereas palm oil showed greater oxidative stability under the same frying conditions.
To interpret the complex lipidomic data, the researchers applied chemometric analysis to distinguish patterns of molecular change associated with oil deterioration. The approach enabled the identification of several lipid species that showed strong predictive performance as potential markers of frying-induced degradation.
Among the candidate indicators were several oxidized triglyceride species and modified triglycerides whose abundance increased consistently during repeated frying cycles. Statistical modeling suggested that these markers could help distinguish oils with different levels of thermal deterioration, with predictive performance reaching area-under-curve values of 0.778 or higher.
Conventional physicochemical measurements – including acid value, p-anisidine value, and thiobarbituric acid value – also increased steadily with frying cycles, confirming progressive oxidative and hydrolytic degradation. However, the lipidomics workflow provided a more detailed view of molecular transformations occurring during frying.
By combining lipidomics with chemometric modeling, the approach may offer a more sensitive way to monitor oil degradation during repeated frying and identify molecular markers that could support quality control in food production.
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