## 4 PAH Occurrence and Formation in Processed Meat, Edible Oils, and Cereal-Derived Products
### Features Underlying PAH Formation in Meat and Meat-Derived Products
Antioxidants and antioxidant-rich ingredients have been shown to reduce the generation of PAHs in processed food [7; 162]. For example, the addition of either garlic (15 g/100 g of meat) or onion (30 g/100 g of meat) was shown to reduce PAH levels in pan-fried pork meat by up to 54% and 60% on average, respectively [163]. Similarly, [PERSON] et al. (2018) detected the PAH inhibitory effects of onion, garlic, red chili, paprika, black pepper, and ginger addition (5 g/kg) to deep-fried beef meatballs (65%, 57%, 65%, 87%, 47%, and 98%) and chicken meatballs (86%, 86%, 79%, 74%, 97%, and 97%), respectively [97]. The reduction in PAH levels under the influence of antioxidant molecules has been attributed to the free radical species scavenging capacity, which may interfere with the fragmentation and cyclization reactions involved in PAH formation [97; 163]. However, different scavenging potencies may be observed depending on the chemical structure of the antioxidant [97]. Correspondingly, antioxidant compounds may exert a scavenging effect on the free radicals formed during thermal decomposition and result in decreased lipid peroxidation (TBARS), accompanied by decreased PAH levels in the food product [164]. A further influence is exerted by water content, with its rise leading to reduced PAH contents [7; 15]. Variations in the water retention rate have a crucial role in minimizing the incomplete combustion of organic compounds during meat cooking [148; 165]. In this regard, chicken thawed in the fridge prior to air frying or deep frying resulted in lower PAH levels compared to microwave or water immersion defrosting [165]. In addition, [PERSON] et al. (2018) described a decreasing rate of PAH levels when water was added in an equal proportion (50%) to minced meat, depending on the cooking temperature, which ranged from 80 \({}^{\circ}\)C to 200 \({}^{\circ}\)C [148]. Aside from water content, pH has been documented to affect PAH formation [7]. The Maillard reaction promotes aromatization and dehydroxylation, caramelization, and the breakdown of fats and sugars [100]. With higher pH values promoting the Maillard reaction, a subsequent rise in PAH levels is expected [6; 95; 161]. The use of acid marinade on raw food material seems to be a potential way to prevent PAH development, despite the limited research investigating the impact of pH on the PAH formation rate in processed food [7; 166]. Casings act as an effective barrier to mitigate PAH contamination. To this end, the characteristics of the casing surface, such as smoothness and material porosity, can contribute to inhibiting PAH penetration, implying reduced adsorption by the product [7; 143; 167]. For example, [PERSON] et al. (2016) noted a 78% reduction in PAH content when replacing the original sheep intestine with a cellulose casing for smoked beef sausages [168]. Similarly, collagen is also a suitable alternative to natural animal intestinal casings in suppressing PAH contamination in sausages [108; 143; 169]. The effect of PAH penetration inhibition was also evidenced for banana leaves (40%) and aluminum wrapping (46%) in grilled beef meat. On the other hand, grilled chicken meat showed a reduction of 80% irrespective of the wrapping [170], emphasizing the importance of casing removal before consumption [143]. Other features bearing additional weight on PAH content cover the storage settings and operational circumstances [7; 15]. Depending on the type of food, the storage period has varying effects on the PAH concentration. For example, the maximum PAH concentration in smoked sausages is detected just after smoking [168; 171]. Nevertheless, during storage, PAHs may migrate inside the product and become less readily decomposable, or may interact with other substances, such as antioxidants, and undergo photochemical oxidation [171].