Effect of polyethylene terephthalate packaging and storage temperature on the characteristics of edible oils

The stability of edible vegetable oils is strongly affected by packaging. Plastics such as polyethylene terephthalate (PET) are widely used due to cost-effectiveness and practicality, yet their protective capacity under stress conditions is limited. This study examined the degradation of extra-virgin olive oil (EVOO), olive oil (OO), and refined rapeseed oil (RO) stored in PET at 20 °C, 40 °C, and 60 °C, over six weeks, with dark-glass storage at 20 °C as control. Quality changes were assessed using physicochemical, sensory, and antioxidant indicators, including free fatty acids (FFA), peroxide value (PV), UV extinction coefficients (K 232 , K 268 ), sensory analysis (descriptive and via a potentiometric electronic tongue used as a taste device), oxidative stability (Rancimat), and antioxidant potential (DPPH, ABTS, FRAP, and total phenolics). Significant quality degradation was observed with up to a 44 % increase in FFA, a 53 % reduction in TPC, and a 44 % reduction in FRAP. Sensory defects emerged in RO samples, while EVOO retained positive sensory attributes. Oils stored in PET containers exhibited greater susceptibility to oxidation at high temperatures, whereas samples stored in dark glass showed enhanced stability. Predictive discrimination models showed high sensitivity (99 ± 4 % to 100 %) in accurately classifying edible vegetable oils according to storage conditions when combining physicochemical and sensory data, while E-tongue fingerprints alone achieved satisfactory discrimination (87 ± 13 % to 96 ± 8 %). Antioxidant activity also declined with thermal stress. Overall, findings highlight that temperature significantly compromises oil stability in PET packaging, underscoring the importance of optimized storage strategies to ensure product safety and quality preservation. • Thermal exposure alters physicochemical and sensory quality of oils in PET bottles • EVOO retained higher oxidative stability and antioxidant capacity than refined oils • Storage at 40 °C–60 °C sped up degradation, especially in rapeseed and olive oils • Electronic tongue accurately classified oils according to storage conditions • Integrating sensory and physicochemical data enhanced predictive quality modelling