Kinetics of the extraction of pumpkin seed oil (Cucurbita pepo L) by supercritical CO2

This paper deals with the supercritical carbon dioxide extraction of pumpkin seed oil (Cucurbita pepo L). Supercritical fluid extraction (SFE) has been used to obtain total lipid extracts from other oilseeds, and it has also proved successful in the isolation and enrichment of sterols from oilseeds. The SFE of pumpkin seed oil on a laboratory scale was investigated in thus paper, with special interest in the influence of the extraction pressure on the overall yield of pumpkin seed oil. Extractions were carried out at the pressures of 15, 25 and 30 MPa and at 313 K, and at a pressure of 30 MPa and the temperatures 313, 323, and 333 K. The yield of the extractions conducted at 15 MPa was rather low, 0.1814 g oil per 1g of seed feed (18.4%) for an extraction time of 14 h. However, extractions at higher pressures yielded greater quantities of the oil; at 22.5 MPa for 9 h, 36.3% of the oil and at 30 MPa for 6 h, 41.0% of the oil. For comparison, hexane extraction of the seed material yielded less than 40% of the oil. Temperature did not influence the extraction yield. At a pressure of 30 MPa, the color of the fractions yielded during successive extraction time intervals varied greatly, from pail yellow (the first 2 h), through orange-yellow (from 2-4 h) to red (after 4 h). The experimental results of the oil yields were compared with the data obtained by the mathematical model of Hong et al., presented in the literature.