Feasibility of Application of Microwave Pretreatment to Improve Oil Extraction Efficiency from Cucurbita pepo (Cucurbita pepo subsp. Pepo var. Styriaca) Seed

In this study, the feasibility of application of microwave radiation as a pretreatment technique was investigated to increase the extraction yield of Cucurbita pepo seed oil. Seeds were pretreated at different power (180, 450, 600 and 900 W) and radiation time (30, 60, 90 and 120 sec) and then the oil was extracted by conventional Soxhlet method using n-hexane. According to the results, even at the lowest microwave pretreatment variables applied (180 W and 30 sec) the oil yield (27.22 ± 0.02%) was higher compared with those obtained from untreated seeds (26.88 ± 0.04%). Maximal oil yield (35.19 ± 0.04%) was obtained by Soxhlet extraction with microwave pretreatment at 600 W and 120 sec. Under these conditions of microwave pretreatment, the extraction time was shortened from 360 to 300 min. A shorter extraction time resulted in higher ability of oil for scavenging DPPH and HO free radicals. Furthermore, the fatty acid profile of samples was detected using gas chromatography- mass spectrometry. Linoleic acid was the most abundant fatty acid in C.pepo seed oil. Microwave pretreatment showed negligible effect on the fatty acid composition of samples. From the results, microwave pretreatment could be a promising technique to increase the quality and quantity of oil extracted from C.pepo applying conventional Soxhlet method.