Comparative study of extraction methods for pistachio hull antioxidants by multiple assays

In recent years, the use of natural antioxidants extracted from agricultural and industrial by-products hasbeen increased because of sustainability, high and stable antioxidant activity, absence of toxicity. theseextracts can be used as substitute of synthetic antioxidants for food products, color and oxidativestabilization. in this study, experimental design and response surface methodology (rsm) were used tooptimize experimental variables such as sample weight (g), irradiation power and time (s) in microwaveassistedextraction (mae) of antioxidants from pistachio hull. effect of sample weight was found to besignificant on total phenolic content (tpc), ferric reducing antioxidant power (frap), scavenging activityof 1,1-diphenyl-2-picrylhydrazyl (dpph) radical and extraction yields. the optimal conditions were wateras solvent, particle size of 0.25 mm, microwave power 600 w, sample weight 0.2 g, irradiation time of 150s. finally, comparison of extraction methods was shown that mae method gave better results thanultrasonic-assisted extraction (uae) and conventional methods with the optimum operating conditions liketime and energy consumption.