Effect of Storage period and Antioxidants treatment on Physiochemical Characteristics and Stability of Cottonseed and Canola oils
The Journal of Environmental studies (JES)
Vol.I: 55-64 (1), 10 pages
This work was carried out to investigate the stability of cottonseed and canola oils as well as the effect of some commercial antioxidants. The obtained results indicated that the viscosity increased gradually in all oil samples during storage. The lowest increase in the viscosity was found in oil samples stored for three months and treated with 0.02 % of either B.H.A. or B.H.T. The refractive index was decreased gradually as storage period increased. The acid value increased gradually in all oil samples during storage. The lowest increase in acid value was found in oil samples stored for three months and treated with 0.02 % B.H.A. The oil samples treated with the concentration 0.01 % of antioxidants showed a little higher increase in acid value than oil samples treated with 0.02 %. The P.V. and T.B.A. values were increased gradually in all oil samples during storage; the rate of increase was higher in the oil samples stored for three months. Also, the rate of increase in P.V. and T.B.A values were higher in oil samples (either cottonseed or canola) treated with 0.01 % concentration of antioxidants than those treated with 0.02 % concentration. The iodine value (I.V.) of all oil samples was decreased during storage. The highest decrease in iodine value was recorded in control oil samples stored for either three or six months. The rate of decrease in iodine value of the oil samples treated with 0.01 % concentration of antioxidants was higher than those oil samples treated with 0.02 % either stored for three or six months. The saponification value (S.V.) increased gradually in all oil samples as storage period increased. The highest increase in S.V. was recorded in control oil samples stored for six months. The values of fatty acids; C10, C12, C14, C16, C18, C20, TSFA and ratio of C18:2: C18:1 were increased with increasing the storage period in all oil samples. In contrast, the values of C16:1, C18:1, C20:1, C22:1, TMFA, C18: 2n-6, C18:3n-3, TPUFA, TUFA and ratio of TUFA: TSFA were decreased. Finally, the storage of cottonseed and canola oils for long period at room temperature causes undesirable changes in their physical and chemical properties. Furthermore, it reduced the nutritive value of the stored oils through the reduction of their unsaturated fatty acid contents.
Antioxidants, Cotton, Canola oils.