Effects of sesame dehulling on physicochemical and sensorial properties of its oil

At present, sesame oil is extracted from un-hulled white sesame seeds by using cold press lubrication machines in local stores in Iran. This study aimed to evaluate the physicochemical properties and safety parameters of the hulled and un-hulled white sesame oils. The fatty acid composition, antioxidant activity, oxalates content, total phenolic content, carotenoid content, acid value, peroxide value, p-anisidine value, value total oxidation value (TOTOX), aflatoxins and pesticides residue, smoke point, color, relative density, and refractive index of oil sample were examined immediately after extracting the oil. The peroxide, p-anisidine, and TOTOX value of the hulled and un-hulled sesame oil samples were also examined periodically. After 7 months, the quality parameters were high and the oil samples were not consumable. Linoleic and oleic acids were the predominant fatty acids in the hulled and un-hulled sesame oils. The results of this study showed that the oil extracted from raw un-hulled sesame had a lower initial quality than hulled sesame oil and was oxidized more rapidly than it during the storage period. Virgin oils contained impurities acting like prooxidants and reduced their stability and shelf life. In addition, the un-hulled sesame oil contained higher amounts of antinutrient compounds (e.g., oxalate and pesticide residues) than the hulled sesame oil. Aflatoxin was not detected in our oil samples.