# Physicochemical Properties and Oxidation Status of Pork from Three Rearing Systems
## 4 Discussion
### Oxidation Status  
Lipid oxidation is one of the main causes of meat deterioration, leading to the formation of compounds that are potentially harmful to human health. The initiation and propagation of lipid oxidation may occur due to the imbalance between pro- and antioxidant substances that occurs during the conversion of muscle into edible meat after slaughter [44]. The notable presence of elevated TBARS levels and correspondingly diminished antioxidant capacity observed in organic pork specimens provides insights into biochemical dynamics at play. These distinctive observations may be attributed to the organic production system's inherent challenge of achieving and sustaining a delicate equilibrium between pro-oxidant and antioxidant factors, wherein the intricate interplay between these opposing forces becomes disrupted, potentially leading to an imbalance that manifests as the higher TBARS levels and reduced antioxidant capacity witnessed within our experimental framework. [PERSON] et al. [31] indicated that the higher TBARS levels in meat from organic pigs may be related to the lack of vitamin E (lipid oxidation inhibitor) for antioxidant protection of PUFA. The higher TBARS levels and lower antioxidant (vitamin E) content in meat from organically raised pigs corresponded to the higher intake of polyunsaturated fatty acids reflected in the meat [16]. Free fatty acids may have a pro-oxidant effect on lipid substances, which have a catalytic effect for the carboxyl group in the formation of free radicals during the decomposition of hydroperoxides [45; 46]. According to the results of FFA in our study, meat from organic pigs was more susceptible to lipid oxidation than meat from traditional and conventional pigs. High oxidative stability of the meat required low TBARS and FFA values [46; 47]. However, a higher lipid oxidation was observed in organic meat by [PERSON] et al. [11] and [PERSON] et al. [14]. Results of higher lipid oxidation of organic meat in this study were expected due to greater physical activity of animals and high peroxididability index [25]. More oxidation stability of pork from traditional systems in comparison with organic pork was observed. Differences in oxidation stability between the pork from traditional and organic rearing systems may be related to the level of kinetic activity of these pigs (in outdoor areas) on one side and feeding regimen (pasture grazing is the source of antioxidant substances) on the other side [25; 34; 35]. The lower antioxidant capacity observed in meat from organic pigs in this study may be due to its involvement in controlling oxidation processes in the body of a live animal, thus depleting its reserves in the meat after slaughter. [PERSON] et al. [48] found that the low level of antioxidants (vitamin E) in pig tissues containing high concentrations of PUFA was due to the use of antioxidants to control oxidative processes. However, it should be underlined that important factors affecting oxidative stability are also the diet, sex and breed of the animal, as well as the storage temperature and fat composition of the meat. This statement emphasizes the complexity of meat properties, including oxidative stability, that can be affected by multiple external and internal factors [46; 47].