Extraction of palm fatty acids from sterilized oil palm mesocarp by microwave technique: Optimization and kinetics

Abstract

Production of crude palm oil (CPO) from palm oil mill involves several processes such as sterilization, stripping, digesting, and pressing, all of which require great amount of water. Wastewater from these processes is collected in several ponds to produce palm oil mill effluent (POME). They are the main contributor of pollution in the industry and numerous researches have been carried out to reduce the production of POME. One of the methods used to extract oil palm mesocarp is microwave, as it has the advantage of short processing time. Microwave has also been used in the sterilization of oil palm fresh fruit and drying process. To date, limited studies have been conducted in the extraction of oil palm mesocarp by using microwave. Hence, this work investigates the best process conditions extraction of oil palm mesocarp and its kinetic and mathematical model based on heat transfer in the microwave. Temperature increment rate in the microwave was measured by determining the slope of linear regression equation obtained from its temperature profile. Steep slope describes how fast the extraction process occurs. A Box-Behnken design was applied to evaluate the effects of three independent variables of microwave power level (100–400 W), extraction time (20–30 min), and mass of mesocarp loading (80–120 g) on the responses, such as CPO yield and free fatty acids. The optimal extraction condition was found to be at 300 W, 30 min, and 80 g. From this result, based on the kinetics modeling done, it is found that a second-order kinetic model represents the palm fatty acid extraction by microwave-assisted extraction method.