Focused microwave-assisted Soxhlet extraction: an expeditive approach for the isolation of lipids from sausage products

A prototype of extractor based on the conventional Soxhlet principles but assisted in the cartridge zone by focused microwaves is proposed for accelerating the extraction of lipids from sausage products. The extraction process has been optimised using a multivariate design involving the main variables influencing the performance of the prototype (namely, irradiation power P, irradiation time T and number of cycles C). Under the optimum working conditions (P=160 W, T=10 s and C=14), the extraction of lipids from different Spanish sausage products is complete in 45 min. The extracts thus obtained have been compared with those provided by conventional Soxhlet extraction for 8 h by development of chromatographic analyses (namely, quantification of polar lipids by thin-layer chromatography, determination of free fatty acids by gas chromatography and quantification and distribution of total polar compounds by high-performance size exclusion chromatography), and not qualitative or quantitative differences have been found.