Evaluation of the Physicochemical Properties and Aflatoxin Levels of Industrial and Non-industrial Sesame Oil

The present study aimed to evaluate the physicochemical properties (refractive index, acid value, peroxide value, conjugated dienes, Fatty acid composition) and level of aflatoxins (AFB1, AFB2, AFG1, and AFG2) in the sesame oils (cold press) consumed in Iran. In total, 30 sesame oil samples were collected from factories (n=20; industrial) and traditional mills (n=10; non-industrial). No significant differences were observed between the industrial and non-industrial sesame oil samples in terms of the physicochemical properties and AF contamination and therefore, it is not possible to prefer the consumption of one of the oils (industrial or non-industrial) to another. According to the physicochemical examination, the mean peroxide value was 2.93±1.59 and 1.95±1.24 meq/kg, the acid value was 0.86±0.82 and 1.12±0.58 mg KOH/g, the refractive index was 1.4,706±0.0002 and 1.4,705±0.0001 at 28°C, and the conjugated diene value was 12.13±3.25 and 10.02±1.43 μmol/g in the industrial and non-industrial sesame oil, respectively. In addition, the fatty acid profile of the industrial and non-industrial sesame oil indicated high levels of unsaturated fatty acids (84.5% and 83.49%, respectively), with the main fatty acids determined to be oleic acid and linoleic acid. The fatty acid profile of the sesame oil samples indicated no adulteration with other vegetable oils. The mean contamination with AFB1, AFB2, and AFG1 in the non-industrial sesame oil was estimated at 0.06±0.26, 0.02±0.67, and 0.15±0.18 µg/kg, while the mean contamination with AFB1, AFB2, and AFG1 was 0.04±0.84, 0.03±0.61, and 0.17±0.16 µg/kg in the industrial sesame oil. Moreover, the AFB1 and AFs levels in all the sesame oil samples were significantly lower than the Iranian legislation limits (5 and 15 µg/kg, respectively) and the European Union (2 and 4 µg/kg, respectively). Risk assessment based on the margin of exposure revealed the risk of AFB1 and AFG1 exposure through industrial and non-industrial sesame oil consumption and AFB2 exposure through industrial sesame oil consumption.