تأثیر شرایط مختلف منطقه کشت بر خصوصیتهای فیزیکوشیمیایی و پایداری اکسایشی روغن زیتون بکر رقم روغنی

In this research, physicochemical properties and oxidative stability of Roghani virgin olive oil grown in two regions of Roodbar and Kazeroon, located in north and south of Iran respectively, with differences in pedoclimatic conditions, altitude and soil were investigated. To determine the physicochemical properties, acidity, peroxide value, spectrophotometric indexes at 232 and 270 nm, smoke point, specific gravity and refractive index as well as the total contents of phenolic compounds, alpha tocopherol, chlorophyll, carotenoid, and fatty acid composition were evaluated. To evaluate the oxidative stability, the effect of heat treatment at 180 °C for 8 hours on indicators such as conjugated diene value, carbonyl value, polar compounds and oxidative stability index were tested. Results indicated the differences in the structural properties and oxidative stability of the oil obtained from two regions. As the oil from Roodbar region with lower altitude, lower average annual temperature, higher average annual rainfall, and specific geographical conditions, contain higher phenolic compounds, alpha tocopherol and oleic acid and also showed higher oxidative stability during heat treatment. But the oil of Kazeroon region with higher altitude, higher average annual temperature, and lower average annual rainfall, had higher linoleic and linolenic acids and exhibited lower oxidative stability during thermal treatment. Therefore the results of this study can be used as a description of physicochemical properties and oxidative stability of Roghani olive oil from two regions of Roodbar and Kazeroon.