Determination of oxidative stability and characterization of oils obtained from different sesame seeds varieties by cold pressing

In this study, the characterization and oxidative stability of oils obtained by cold press method from six different native sesame seed varieties (Özberk-82, Gölmarmara, Muganlı-57, Batem Aksu, Batem Uzun and Baydar-2001) registered in Turkey were examined. As a result of the study, the highest brightness of cold pressed sesame oil varieties was Gölmarmara and as for the lowest was Baydar-2001. The refractive index values, free fatty acid (% oleic acid), saponification number iodine number, total phenolic content amount and DPPH antioxidant activity values of oils are ranged between 1.4724-1.4733, 0.23- 0.44 %, 214.52- 220.77 mg KOH/g, 104.75-115.84 g/100g, 52.29-115.66 mg GAE/100g, 2.50-4.70 µmol TE/100g, respectively. When the fatty acid composition of sesame oils was examined, it was seen that the most important fatty acids were palmitic (C16: 0), stearic (C18: 0), oleic (C18: 1) and linoleic acids (C18: 2). In addition, the amounts of these fatty acids were found as 9.23-9.83 %, 4.99-5.55 %, 42.08-45.28 % and 38.73-41.69 %, respectively. In all sesame varieties, β-sitosterol is the major sterol and determined between 316.25-498.06 mg/kg. The total carotenoid and total chlorophyll contents of sesame oils were found in the range of 0.13-1.07 mg/100g and 0.47-1.93 mg pheophytin a/kg. α- and γ- tocopherols were determined as the most dominant tocophero varieties and their amounts were found as 161.80-498.53 mg/100g and 3.95-19.22 mg/100g, respectively. In order to determine oxidative stability, Schaal oven test was performed on oils by keeping in incubator at 60˚ C for 21 days. In this context, peroxide, conjugated-diene, p-anisidine and Totox values of sesame oils were determined. According to the Schaal oven test, the oxidative stability of Muganlı-57 variety was highest and Batem Uzun variety was the lowest.