The effect of microwave pretreatment on some physico-chemical properties and bioactivity of Black cumin seeds' oil

In the current study, different processing times including 90, 180 and 270 s and microwave powers including 180, 540 and 900 W were applied for optimizing of the extraction process. After microwave pre-treatments, the oil seeds were extracted with screw press with different rates (11, 34 and 57 rpm), then parameters including extraction efficiency, oxidative stability, peroxide and acidity index, DPPH free radical scavenging activity as well as the refractive index of the extracted oil were studied. Statistical analysis and process optimization was performed with the use of response surface methodology (RSM). The results revealed that enhancement in the microwave power and the processing time increased extraction efficiency, acidity index and oil peroxide value, but it decreased the oxidative stability value of the achieved oil. The achieved results also showed up that the studied parameters had no significant impacts on the refractive index; moreover the extraction efficiency was reduced with an enhancement in the rotational rate of the screw press. According to the process optimization results, it might be stated that with applying processing time for about 185.44 S, microwave pretreatment of 718.65 Wand screw-rotation speed of the press of 11 rpm, the desired outcomes are reached.