Chemical composition and oxidative stability of kernel oils from two current subspecies of Pistacia atlantica in Iran.

摘要

Pistacia atlantica subsp. mutica (PAM) and kurdica (PAK) kernel oils showed significantly lower unsaturated to saturated fatty acid ratios (6.39, 6.33, respectively) and calculated oxidizability (Cox) values (3.99, 4.13, respectively) than those of the P. vera L. cv. Ohadi (PVO) kernel oil (8.91, 4.41) samples. The highest peroxide value was observed for the PAK oil (4.07 mequiv kg-1) (PAM, 1.94; PVO, 0.37) samples. Iodine values for the PAM, PAK, and PVO oils were 104.26, 104.77, and 110.66, respectively. The saponification number of the PVO oil was significantly greater than the PAM and PAK oils, which were statistically not different. The unsaponifiable contents, which were composed mainly of sterols, ranged from 5.63 to 6.14%. Statistically the total tocopherols contents of the PAM (818.58 mg ?-tocopherol kg-1) and PVO (815.90 mg ?-tocopherol kg-1) oils were significantly higher than that of the PAK oil (499.91 mg ?-tocopherol kg-1). Total phenolics contents differed significantly, the greatest concentration was for the PAM oil (81.12 mg gallic acid kg-1), followed by the PVO (62.84 mg gallic acid kg-1) and PAK (56.51 mg gallic acid kg-1) oil samples. The wax contents of the oil samples were statistically in the same range, namely 5.67-6.48%. Oxidative stability data indicated that the PAM oil is the most resistant to the formation of lipid oxidation products, followed by the PAK and PVO oil samples.