Fast quality monitoring of oil from prefried and fried foods by focused microwave-assisted Soxhlet extraction

A new method for fast quality monitoring of fat from prefried and fried treat and fish is proposed. Prefried and fried samples were extracted with a focused microwave-assisted Soxhlet extractor. The main factors contributing to the extraction efficiency, namely microwave irradiation power. number of cycles rind microwave irradiation time were optimized by means of a central composite design based on two level-three factors factorial design. This method has allowed us to carry out the extraction of lipids from prefried and fried samples with qualitative and quantitative results similar to those provided by the usual methods (both manual and conventional Soxhlet extraction). A drastic reduction of the procedure time (55 min versus 8 h) is achieved with similar reproducibility to that provided by the conventional method. In addition. the proposed method is cleaner than conventional Soxhlet as 75-80% of the extractant is recycled. (C) 2002 Elsevier Science Ltd. All rights reserved.