چكيده انگليسي :
Due to the increasing demand for vegetable oils, finding new sources of desirable quality as edible oils and increasing extraction efficiency by using new extraction methods are among the most important points for research for oil industry. Therefore, in this study, the effect of microwave and ultrasound pretreatments as new procedure on the extraction efficiency and quality of watermelon seed kernel oil as one of the agricultural wastes in cold press extraction was investigated. Physicochemical properties of oil from pretreatments, including refractive index, specific gravity, iodine value, saponification value, unsaponifiable materials, acid value, peroxide value, total phenolic content, color, fatty acid composition, and oxidative stability of the oil were measured and compared with the non treated sample that extracted with cold press. To optimization, the process, the response surface methodology was used with two independent power and time in three different levels (300, 400, and 500 W) and (2, 4, and 6 min) respectively for microwave pretreatment ultrasound pretreatment, two independent power and time parameters in three levels of (100, 150, and 200 W) and (10, 20, and 30 min) respectively based on initial tests and obtaining the kinetics of oil extraction efficiency. In both pretreatments, three parameters including extraction efficiency, microwave, and ultrasonic electrical power consumption, and an acid value of extracted oil were determined as the process response. The optimum extraction conditions were 388 W and a duration of 3.27 min of microwave pretreatment. Under optimal process conditions, the extraction efficiency, acid value, and consumed power were 38.89%, 0.86 mg / g oil, and 45.14 Whr respectively which increased the extraction efficiency by 3.67% compared to the control sample. As well as the optimum extraction conditions of ultrasonic pretreatment were, 100 W and a duration of 21 min were determined, in which the extraction efficiency, acid value, and consumed power were 39.76%, 1.12 mg / g of oil, and 25.33 Whr respectively which increased the extraction efficiency by 4.54% compared to the control sample. Among the extraction variables, irradiation time had the most significant effect on extraction efficiency. The Fat, fiber, moisture, ash, and protein content of watermelon seed kernel were, 49.58%, 4.82%, 4.92%, 3.56%, and 32.69% (w)respectively. By comparing the physicochemical properties of extracted oil from microwave and ultrasonic pretreatments with the control sample, it was found that there was no significant difference observed between these treatments in terms of specific gravity, refractive index, saponification value, unsaponifiable materials and oil peroxide value
