المجلة الدولية للعلوم والتقنية

This study examines the impact of geographical location and harvest month on the chemical composition and quality of Libyan olive oil. Physicochemical properties, including density, water content, refractive index, absorption, acidity value (AV), peroxide number, and heavy metal content (copper and iron), were analyzed for oil samples collected from the Nafusa Mountain (NM) area (Gharyan (GR)& Al-Zintan (ZT)); and the Al-Jafara Plain (AJ) area (Al-Aziziyah (AZ)). Samples were taken at the start (November) and end (February) of the pressing season. Results showed notable variations in AC. At the beginning of the season, AV ranged from 0.22% to 1.6%, with the lowest values in ZT samples and the highest in AZ samples. At the end of the season, AV ranged from 1.62% to 3.03%, and the lowest values were found in GR samples, meeting international standards. Peroxide number results also showed notable variations. Values ranged from 3.97 to 6.7 mEq/kg at the start of the season, with the lowest values in AZ samples. At the end of the season, peroxide numbers ranged from 5.9 to 13.5 mEq/kg, with the lowest values recorded in GR samples. Despite an increase in peroxide values in ZT samples, they remained within permissible limits.An increase in copper and iron content was observed towards the end of the season. All olive oil samples from the 2022/2023 production year were edible and of high quality. To enhance export competitiveness against neighboring countries, the researchers recommend pressing olives early in the season (October to December). Key words: olives oil, harvesting time,physicochemical properties, peroxide value, acidity value.