Document Type : Research Paper

Authors

• Abuzar Hashempour ¹
• Ahmad Reza Dadars ²
• Rahmatollah Gholami ³
• Samaneh Asadi Sanam ⁴
• Mahmoud Azimi ⁵

¹ Department of Post-harvest Physiology and Technology, Citrus and Subtropical Fruits Research Center, Horticultural Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ramsar, Iran-

² Crop and Horticultural Science Research Department, Zanjan Agricultural and Natural Resources Research and Education Center, Education and Extention Organization (AREEO), Zanjan, Iran.

³ Crop and Horticultural Science Research Department, Kermanshah Agricultural and Natural Resources Research and Education Center, Education and Extention Organization (AREEO), Kermanshah, Iran

⁴ Medicinal Plants and By-Products Research Department, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extention Organization (AREEO), Tehran, Iran.

⁵ Crop and Horticultural Science Research Department, West Azarbayejan Agricultural and Natural Resources Research and Education Center, Education and Extention Organization (AREEO), Urmia, Iran

Abstract

     Background and Objective: Olive (Olea europaea L.) is one of the most important horticultural crops in Iran and worldwide. Its oil plays a key role in promoting human health because of its high content of unsaturated fatty acids, particularly oleic acid, and its unique phenolic compounds. Olive oil quality depends on various factors, including cultivar and climatic conditions. Because Iran has a diverse climate, this study evaluated the fatty acid profile, quality indices, and bioactive compounds of olive oil from the promising genotype Bn6 and the Konservolia cultivar in two regions: Tarom and Sarpol-e-Zahab.
Methodology: The research used a randomized complete block design with three replications in 2023 at two olive research stations in Tarom (Zanjan Province) and Sarpol-e-Zahab (Kermanshah Province). Olive fruits were harvested from genotype Bn6 and the Konservolia cultivar based on fruit color index, and oil was extracted at laboratory scale. Fatty acid composition was determined using gas chromatography (GC). We measured the following quality indices: acidity (as oleic acid percentage), peroxide value (milliequivalents of active oxygen per kg of oil), extinction coefficients K232 and K270, and total chlorophyll and carotenoid content. Total phenolic compounds were evaluated using the Folin–Ciocalteu method, and antioxidant capacity was assessed using the DPPH assay. Statistical analysis used a combined analysis of variance across locations in SAS 9.4 software, and means were compared using the LSD test.
Results: The combined analysis of variance showed that the genotype × environment interaction was significant for most fatty acids and some quality indices. Konservolia oil had higher oleic acid (63.47%), monounsaturated fatty acid (MUFA) (67.14%), MUFA/PUFA ratio (5.30), and oleic-to-linoleic acid ratio (5.44) than genotype Bn6. In contrast, genotype Bn6 had higher linoleic acid (36.73%) and a richer polyunsaturated fatty acid (PUFA) profile. The highest total phenol content (51.093 mg gallic acid per kg of oil) occurred in genotype Bn6 in Sarpol-e-Zahab, whereas the lowest (15.98 mg) occurred in the same genotype in Tarom. The highest antioxidant capacity (79.43%) occurred in Konservolia in Tarom and the lowest (13.54%) in the same cultivar in Sarpol-e-Zahab. According to International Olive Council (IOC) standards, Konservolia oil in both regions met the standard ranges for oleic acid (55–85%), palmitic acid (7–20%), and linoleic acid (2.5–21%). Genotype Bn6, however, did not meet the accepted standards for extra virgin olive oil in terms of oleic acid (below 55%) and linoleic acid (above 21%).
Conclusion: The Konservolia cultivar, with its stable phenolic compounds and compliance with IOC standards in both regions, is a more suitable option for producing oil with high oxidative stability and desirable nutritional value in both climates. Genotype Bn6 responds positively to heat stress by increasing phenolic compounds and therefore has special potential for warm regions. However, its oil does not comply with national and international standards regarding fatty acid composition. Therefore, given its high fruit yield and stable production in warm regions, it can be used in breeding programs and cultivar introduction for table olive production.

Keywords

• Olive
• oleic acid
• phenolic compounds
• antioxidant capacity
• IOC standard

Main Subjects

• Agriculture and horticulture