## 4 PAH Occurrence and Formation in Processed Meat, Edible Oils, and Cereal-Derived Products
### Features Underlying PAH Formation in Edible Oils
Nonetheless, oil refining has the drawback of removing the antioxidant molecules in oil, which might lead to a rise in PAHs during storage [113]. In this regard, temperature settings are to be considered jointly with the storage period. A lower storage temperature is often linked to a decreased risk of PAH formation [7; 113]. For example, soybean and rapeseed oils were investigated over a 270-day storage period at 4 \({}^{\circ}\)C and 25 \({}^{\circ}\)C. Increases of 80.88% and 117.5% at 25 \({}^{\circ}\)C were registered, whereas only 14.77% and 27.07% increases were observed at 4 \({}^{\circ}\)C for crude and refined soybean oil, respectively. Similarly, the OPAH content increased by 72.69% and 82.35% at 25 \({}^{\circ}\)C and by 22.69% and 43.13% at 4 \({}^{\circ}\)C in crude and refined soybean oils, respectively [113]. Additionally, PAH levels in crude and refined rapeseed oils showed similar trends (89.51% and 98.14% increase at 25 \({}^{\circ}\)C; 61.13% and 55.09% increase at 4 \({}^{\circ}\)C), followed by OPAHs (65.85% and 429% at 25 \({}^{\circ}\)C; 19.66% and 212.9% at 4 \({}^{\circ}\)C) [113]. [PERSON] et al. (2008) also revealed a great increase of 14-23-fold in the PAH concentration of sunflower oil subjected to 112 months of storage at room temperature [184]. It is suggested that a number of processes, including polymerization, oxidation, degradation, and volatilization of unsaturated fatty acids, as well as the production of radicals throughout the storage period, might account for the elevated PAH concentrations [7]. Moreover, the fatty acid composition of the oil also affects PAH content [185], similar to the case of fatty acids from animal sources, where the number of carbon atoms and the respective degree of unsaturation influence PAH formation during processing [158]. The findings of [PERSON] et al. (2019) indicated that the increase in the fatty acid carbon number and unsaturation leads to a proportional rise in PAH levels [158]. In this respect, [PERSON] et al. (2022) reported that palm oil generated more particle-bound PAHs in comparison with soybean and olive oils. In addition, saturated fatty acids (SFAs) in general, and palmitic acid in particular, were found to contribute to PAH formation as a result of significant positive correlations between palmitic acid and acenapthtene (r = 0.74, \(p\) < 0.05) and benzo(e)pyrene (r = 0.79, \(p\) < 0.05), as well as between SFAs and chrysene (r = 0.86, \(p\) < 0.01) [185]. The replacement of the fat source in the final product may, for example, enhance monounsaturated fatty acids (MUFAs) when using olive oil or promote polyunsaturated fatty acids (PUFAs) when using sunflower oil and grape seed oil [159]. By substituting pork back fat with different vegetable oils, under the effect of temperature, sunflower and grape seed oils had a significant influence on PAH concentrations in pork patties owing to their lower smoking points (227 \({}^{\circ}\)C and 216 \({}^{\circ}\)C) compared to that of olive oil (242 \({}^{\circ}\)C), mainly due to the presence of PUFAs [159]. Model lipids or food lipids subjected to thermal treatment foster the production of cyclohexane or hydroperoxide through lipid oxidation and breakdown, which, upon further oxidation or cyclization, lead to the formation of naphthalene or naphthalene-like compounds [186; 187]. Specifically, the interaction of oleic and linoleic acids during heating might result in cyclic molecules, subsequently leading to the synthesis of PAHs or PAH derivatives through further polymerization [186]. The development of PAHs is also affected by the choice (type) of cooking oils employed when deep frying, pan frying, and pan grilling [7; 188]. At this stage, the use of air frying as an alternative might reduce PAH formation in French fries by up to 90% [189] and chicken meat by 20% [165]. Aside from adopting a cooking technique lacking oil, refined oil represents a suitable option for reducing oil-derived primary contamination [114].