## 3 Results and Discussion  
### Quality Parameters  
Quality parameters, including free fatty acids, PV, K232, and K270 measured in Arbeitina variety EVOO subjected to five storage conditions of light and temperature for 12 months are reported in Table 1. A slight increase in free fatty acids (%FFA) over time was observed in C1 (\(-\)23 \(\pm\) 2 \({}^{\circ}\)C in darkness), C2 (23 \(\pm\) 2 \({}^{\circ}\)C with light), and C3 (23 \(\pm\) 2 \({}^{\circ}\)C in darkness) storage conditions, however, values between 0.17-0.20% of oleic acid were relatively stable. The %FFA of samples stored at C4 (30 \(\pm\) 2 \({}^{\circ}\)C) and C5 (40 \(\pm\) 2 \({}^{\circ}\)C) conditions, both in darkness, increased beginning after 6 months, reaching a statistically higher value (\(p\) < 0.05) of 0.32 % of oleic acid in the C5 condition compared to all other storage conditions. The increase in %FFA at higher temperatures might be due to higher hydrolytic activity of lipase enzymes on triacylglycerglycerols that remain in the oil after extraction [5], which could be further influenced by the moisture levels in the oil [30]. In all conditions, the %FFA did not reach 0.8%, the maximum allowed by IOC for EVOO category [2], and were lower than those reported by [PERSON] et al. [5] when olive oil was stored at 37 \({}^{\circ}\)C without oxygen in darkness. Peroxide value (PV) is an indicator of initial oxidation and is considered to be a relevant quality index because it detects the oxidation before it is perceived organoleptically [31]. As shown in Table 1, the fresh EVOO yielded a low peroxide value (2.9 \(\mathrm{meq\,O_{2}/kg}\)), indicating that the oil was processed in good manufacturing conditions. The C1 condition (control) showed little to no change during storage time, reaching a value of 3.3 \(\mathrm{meq\,O_{2}/kg}\) of oil. The highest PV was reached in the C2 condition after 12 months of storage (8.2 \(\mathrm{meq\,O_{2}/kg}\) of oil), compared with the C3, C4, and C5 conditions with values of 5.9, 5.3, and 4.4 \(\mathrm{meq\,O_{2}/kg}\) of oil, respectively. The largest increases in PV were observed during the first 3-4 months of storage when hydroperoxides were formed with the remaining oxygen in the oil. In the C5 condition, a decrease in PV from the third month of storage was observed, which could be explained by the decomposition of hydroperoxides and subsequent formation of products of secondary oxidation. Similar results were published by [PERSON] et al. [26], who attributed a low PV accumulation to the rapid conversion of hydroperoxides to related products, such as C7-C11 volatiles, responsible for rancid defect in oil. Furthermore, [PERSON] et al. [5] observed a decrease in the PV of olive oil stored without oxygen in darkness, particularly when stored at 37 \({}^{\circ}\)C.  
The higher level of the hydroperoxides formed in the C2 condition during storage could be explained by the action of light on the oils chlorophyll, or photooxidation. Light-activated chlorophyll would act on oxygen at fundamental state to generate singlet oxygen, which would then react with unsaturated fatty acids to form hydroperoxide [31]. The darkness conditions C3, C4, and C5, would follow the classic autoxidation mechanism with the formation of free radicals from an unsaturated fatty acid, such as linoleic acid. In this study, light appeared to have more impact than temperature on PV, suggesting that photooxidation is more effective than autoxidation in the formation of hydroperoxide in olive oil.