A combined microwave pretreatment/solvent extraction process for the production of oil from palm fruit: optimisation, oil quality and effect of prolonged exposure.

Background: Conventional palm oil milling involves multiple stages after fruit collection; in particular, oil clarification introduces water into the pressed oil, which results in a large quantity of wastewater.

Results: A combined process of microwave pretreatment and solvent extraction to mill crude palm oil, without introducing water or steam, is described. An excellent yield (up to 30%) of oil was obtained with pretreatment in a 42 L, 1000 W and 2450 MHz microwave oven followed by hexane extraction.