Effect of maturity stages on triglyceride and fatty acid profiles in olive oil from Zaity and Kaissy varieties grown in Syria

Syria is recognized as one of the earliest cradles of olive cultivation. Olive oil is not only an agricultural product in Syria, but it is a symbol of national culture and identity that dates back over 6000 years. Olive oil composition and quality are influenced strongly with fruit maturity and variety. Understanding these effects is essential for optimizing harvest time and ensuring oil originality. This study focused on two Syrian olive varieties, Zaity and Kaissy, to assess how different maturity stages affect on triglyceride and fatty acids profiles in their oils. Fruits from Zaity and Kaissy trees in Aleppo were taken at three maturity stages (green, colored (turning) and black) every 15 days. Oils were extracted using the ABENCOR method. Physical parameters and maturity are assessed by tensile strength, coloration index, and tissue resistance. Oil content, free acidity, peroxide value, fatty acid, and triglyceride composition were measured using standard analytical techniques, including GC and HPLC. Zaity olives had a higher oil contents than Kaissy 30.8% and 21.2% respectively, with both increasing as fruit matured. Free acidity and peroxide values remained low across all stages, indicating that good oil quality. Oleic acid content decreased while linoleic and linolenic acids increased with maturity, especially in Kaissy. Triglyceride analysis revealed that LLL content rose with maturity, particularly in Kaissy, while OOO and POO peaked at intermediate stages and then declined. Significant correlations were found between fatty acid and triglyceride profiles, varying by variety and maturity. Both olive variety and fruit maturity stage significantly affect on the triglyceride and fatty acid composition of olive oil. Zaity is best harvested in November to maximize oil yield and quality, while Kaissy allows for later harvesting without compromising oil properties. These findings provide valuable guidance for harvest timing and authenticity assessment of Syrian olive oils.