Microwave drying combined with magnetic stirring for quick analysis of oil content of fresh palm bunch

Abstract

The oil content of a fresh palm bunch (OCB) is a crucial factor in deciding the price of oil palm between the farmers and the oil palm mill owners. The mill owners usually use visual inspection and their experience to estimate the oil content, which does not provide an accurate estimate. The chemical extraction method (traditional oven drying combined with automated Soxhlet extraction) is the only method that is recommended as a standard for oil content analysis and practical use in Thailand. This method provides reliable results, but is time consuming. This study investigated the feasibility of a quick test to determine the oil and moisture content of the mesocarp using microwave drying to replace oven drying, and magnetic stirring to replace automated Soxhlet extraction. The results showed that the time required for the microwave drying technique was 6 min, while the time for the oven method was 24 h. Using magnetic stirring could also reduce the oil extraction time from 2 h to 10 min compared to automated Soxhlet extraction. Based on validation data, the method of microwave drying combined with magnetic stirring for OCB analysis gave a good correlation with the standard method and is thus recommended for a quick OCB analysis.