## 3 Results and Discussion
### Physicochemical Characteristics of Cold-Pressed Camelina Oils  
3.2.1. Oxidative Status and Stability  
It is well known that the fatty acid profile is a crucial factor responsible for the cold-pressed oil's oxidative stability, which directly affects its overall quality. Due to the content of unsaturated fatty acids in CPCO samples being up to 80% (Table 3), these oils can be prone to oxidation during storage. Nevertheless, the other parameters can be taken under consideration to assess the state of oil deterioration, namely PV, AnV, and FFA. The PV is an indicator of the level of peroxides, which are intermediate products of oil oxidation. However, AnV measures the breakdown products of peroxides such as hydrocarbons, aldehydes, ketones, alcohols, esters, and acids, which cause the appearance of off-flavors and off-odors. Moreover, FFA produced by the hydrolysis of triacylglycerol is a widely used indicator of oil degradation. Significant differences in PV, AnV, and FFA results were observed between eight commercial CPCO samples (Duncan test, Table 4). However, the highest levels of peroxides (PV = 3.37 and 4.61 meq O\({}_{2}\)/kg) were determined in CPCO5 and CPCO1 samples, while these oils had the lowest content of secondary oxidation products (AnV = 0.15 and 0.25, respectively). The formation of lipid peroxide molecules (PV = 1.07-1.12 meq O\({}_{2}\)/kg) was similar in CPCO2, CPCO3, and CPCO4. Consequently, AnV data for CPCO1, CPCO3, CPCO4, and CPCO8, as well as CPCO2 and CPCO6, ranged between 0.25-0.34 and 1.58-1.60, respectively. Therefore, the development of rancidity in these oil samples did not differ significantly. On the other hand, the production of FFA in all commercial CPCO samples was low and varied from 0.42-0.98%, which is associated with better oil quality. Generally, oils with low amounts of peroxides (PV = 0.58 and 0.96 meq O\({}_{2}\)/kg for CPCO7 and CPCO8) had low FFA concentrations (0.42-0.56%). In contrast, the highest FFA (0.98%) was found in CPCO5, with high content of primary oxidation products (PV = 3.37 meq O\({}_{2}\)/kg). Therefore, a prooxidant effect of FFA was observed independently of oils' hydrolytic and oxidative alteration states. The oxidation of triacylglycerols probably leads to the formation of carboxylic acids that possess a glycerol backbone, which is calculated as acidity. Unexpectedly, lower amounts of FFA (0.64%) in CPCO1, the richest source of peroxides (PV = 4.61 meq O\({}_{2}\)/kg), indicated a lower magnitude of its hydrolytic deterioration. The reduction of FFA content in this oil can be attributed to lipase inactivation due to the thermal pretreatment of _Camelina sativa_ seeds before the mechanical pressing. Nevertheless, insignificant differences in FFA amounts were observed between CPCO1 and CPCO6, as well as CPCO3 and CPCO4 also having similar levels of primary oxidation products (Duncan test, Table 4). As can be seen in Table 4, the results of PV, AnV, and FFA of all the studied CPCO samples were well within limits specified by Codex Alimentarius (Codex Alimentarius, 2017), up to 15 meq O\({}_{2}\)/kg, 8, and 2%, respectively. In this way, amounts of oxidation products and the acidity of CPCO samples depend on several factors related to the freshness of _Camelina sativa_ seeds, their varieties, technological processes, composition, storage, and marketing conditions of the final oils. For comparison, cold-pressed amelina oils purchased from local grocery stores and small local manufacturers or directly pressed from _Camelina sativa_ seeds had similar oxidative status monitored by PV (0.79-4.88 meq O\({}_{2}\)/kg), AnV (0.22-1.60), and AV (0.25-1.90 mg KOH/g) or FFA (0.14-0.86%) ([PERSON] et al., 2016; [PERSON] et al., 2016; [PERSON] et al., 2016; [PERSON] et al., 2016). Although the contents of secondary oxidation products in amelina oils cold-pressed at a temperature below 50 \({}^{\circ}\)C from one winter cultivar (Luna) and two spring varieties (Omega and Smilowska) were comparatively lower; thus, AnV varied from 0.20-0.28 ([PERSON] et al., 2016).