Abstract

The effect of solvent polarity, polar and non-polar solvents, on pumpkin (Cucurbita maxima) seed oil yield and quality based on selected physicochemical properties was investigated. Five different solvents, like petroleum ether, hexane, cyclohexane, acetone and ethanol were used on a laboratory scale in this study. Results showed that both physicochemical properties and oil yield extracted from the pumpkin seed were influenced by solvent polarity. Oil yield ranged from 4.12 to 27.93%, with higher yield registered in petroleum ether and lowest in ethanol. Results on the physicochemical properties were as follows: Refractive index ranged from 1.437 (cyclohexane) to 1.466 (hexane), acid value, in mg KOH/g oil, ranged from 1.80 (cyclohexane) to 43.54 (ethanol), Peroxide value ranged, in meq O2/kg, from 6.70 (hexane) to 58.11 (ethanol), Iodine value, in g I2/g, ranged from 1.20 (petroleum ether) to 36.73 (ethanol), Saponification value, in mg KOH/kg, ranged from 30.54 (hexane) to 121.14 (acetone). The findings have demonstrated that solvent polarity significantly influenced physicochemical properties and oil yield extracted from pumpkin seed and therefore can assist in selecting solvents required in oil extraction to maximize yield and enhance or maintain oil quality.

Key words: Cucurbita maxima, dielectric constant, oil, polarity, phytochemical properties, soxhlet extraction.