Study on the Pistachio Oil Oxidative Stability Increase Using Monoglyceride Emulsifier and Carotino Oil at 60°C

Background and Objectives: Stability of the products made from pistachios depends on stability of the oil. Oxidized oil includes unpleasant taste and thus its quality and shelf-life decreases. The aim of this study was to assess pistachio oil oxidation stability alone and in combination with Carotino oil and monoglyceride emulsifier using method of accelerated temperature (60 °C).  Materials & Methods: Qualitative factors (including free fatty acids, peroxide value, anisidine value, TOTOX value, 2,4-decadienal, color and sensory analysis) of the stored samples were evaluated on Days 0, 5, 10, 15, 20 and 25. Results: In all treatments, including pure pistachio oil, pistachio oil with Carotino and pistachio oil with Carotino and monoglyceride emulsifier, free fatty acids, peroxide value, anisidine value, Totox value, 2,4-decadienal and a-value increased during storage with the highest increase seen on Day 25. In contrast, L* and b* values and fresh odor decreased during storage with the lowest value observed on Day 25 of storage. On Day 25 of storage, free fatty acids, peroxide value, anisidine value, TOTOX value and 2,4-decadienal were higher in pure pistachio oil than pistachio oil containing Carotino alone and pistachio oil containing Carotino and emulsifier. The 2,4-decadienal was not detected in samples on Day 0 but on Day 25 with a higher quantity in pure pistachio oil than other oils. This was not significantly different between pistachio oil containing Carotino and pistachio oil containing Carotino and emulsifier. Conclusion: Addition of Carotino and emulsifier either alone or in combination to pistachio oil affected the oil stability. Based on the TOTOX value, this addition increased the oil oxidative stability from 15 to 20 days at 60 °C. High quantities of oleic acid and palmitic acid in Carotino and stabilizing effects of emulsifier resulted in a higher stability for a combination of pistachio oil, Carotino and emulsifier, compared to other oils.