Increasing the shelf life of pistachio oil using mentha piperita essential oilEffect of using mentha piperita essential oil on the shelf life of pistachio oil

In this study, the antioxidant effect of mentha piperita essential oils in the concentrations of 1500 and 3000 ppm (and synthetic antioxidant BHT in concentration of 100 ppm on oxidation stability of pistachio oil was investigated. To evaluate the oil oxidative stability, some quality specifications of oils such as peroxide value (PV), oxidation stability index and the fatty acid composition of oil were measured during the interval of each 20 days. The results showed antioxidant components were effective on the oxidation rate of pistachio oil during storage. There was no significant difference among concentrations of 0 (control), 750, 1500 and 3000 ppm in terms of flavor. The peroxide value showed increasing rate in all treatments. The highest PV was belong to control, Mentha piperita (1500 ppm), BHT, and Mentha piperita (3000 ppm) at the end of storage time, respectively. The highest increase of PV was observed in control (51.17). The treatments containing Mentha piperita (3000 ppm) and BHT showed significant difference (p ≤ 0.05). OSI indicator reached to lowest amount in day 80 due to oxidation acceleration. The control and Mentha piperita showed the lowest and highest OSI (5.1 and 12.1 hr), respectively. Natural essence of Mentha piperita showed much better performance in all measured parameters than BHT. It can be concluded that Mentha piperita is a good alternative agent for pistachio oil storage compare to synthetic antioxidant. In concentration of 3000 ppm it has no unfavorable effect without affecting on taste.