Optimizing of the process of pistachio butter production

Pistachio butter (a paste of mashed pistachio and sugar) is one of the foodstuffs containing a thick oily pistachio paste in the formulation. The final product is highly nutritious. Organoleptic characteristics of pistachio butter depend on its formula and method of manufacturing. The most important factor affecting the quality of pistachio butter, be it from flavor, appearance and texture point of view, is oil separation in the product; therefore, leakage of oil from pistachio butter is an undesirable characteristic. In this investigation, the effect of two emulsifiers (lecithin and mono-di glycerides) in tree levels (0.0, 1.0 and 2.0%) on the oil leakage and the effect of one antioxidant (BHT) in tree levels (0.00, 0.01 and 0.02%) on the quality of pistachio butter were studied. Samples were stored at room temperature (25 C) for four months and then the volume of oil, which was separated, was measured by a measuring cylinder (10 mL volume; 1.3 cm in diameter). The experiment had a completely randomized design and the comparison between the means was done via Duncan's multiple range test (5% level). The results showed that the treatments containing 2% lecithin and 2% mono- di glycerides had the least leakage of oil. Also, the results showed that adding BHT antioxidant had a significant effect on peroxide value and shelf life of pistachio butter; but there was no significant effect between treatments.