Soxtec Extraction Method for Crude Fat

Crude fat extraction protocol was adapted from Yeo et al. (27 (link)) using Soxtec extraction method (Soxtec™ 2055, Foss™, Denmark). Dried sample (2.5–3 g) was weighed in duplicates into individual thimbles and covered with de-fatted cotton, before oven dried at 103°C for 2 h and cooled for 30 min in a desiccator. Corresponding thimbles and sample cups were set into the apparatus with 80 ml of petroleum ether added to each sample cup. Crude fat was extracted at 135°C at a boiling time of 20 min, rinsing time of 40 min for recovery and drying time of 10 min, respectively. After extraction, sample cups were dried in an oven at 103°C for 30 min to evaporate the remaining solvent before weighing of cups and quantification of crude fat. Crude fat was stored at −80°C before derivatisation for fatty acid identification.