Trường hợp như vậy đã dẫn đầu Liên đoàn dầu, hạt và chất béo Hiệp hội Ltd (FOSFA quốc tế) để nghiên cứu các phương pháp hợp đồng cho nội dung dầu hạt hướng dương và sửa đổi nó để bao gồm việc xác định độ ẩm, cả trước và sau khi xay trước khi bước khai thác dầu. FOSFA gốc | Chapter 2 Soxtec Its Principles and Applications Shirley Anderson Foss North America Eden Prairie MN 55344 Abstract The classical Soxhlet method provides the fundamental basis for a modern-day solvent extraction system the SoxtecTM. Using the Randall modification sometimes called the submersion method the Soxtec provides a faster approach to solvent extraction for the gravimetric quantitation of fat and oil. Typically the Soxtec methods require only 20-25 of the time required for traditional Soxhlet extraction. Sample preparation general extraction procedures method considerations and optimization are addressed. By definition the procedure to determine crude fat is an empirical method in which the result is determined by the conditions of the procedure. Several aspects of the extraction process such as solvent type time and temperature are explored. Several standardized Soxtec methods are discussed including the recently approved AOAC method for determining crude fat in feeds cereal grains and forages. Many Soxtec applications are routinely used in food feed industrial and environmental laboratories for the measurement of fats oils semivolatiles and other solvent extractables. For the determination of crude fat descriptions are given for various sample pretreatment and extraction procedures. Practical guidelines for handling challenging samples as well as general suggestions are presented. History The foundation of today s automated solvent extraction systems can be traced to 1879 to a German chemist Franz Von Soxhlet. He devised a liquid solid extraction apparatus in which a sample is placed in a cellulose thimble and stationed over boiling solvent. Condensed solvent would then drip into the sample solubilizing extractable material and then siphon back into the boiling solvent where this cycle would then repeat. After several cycles over many hours the apparatus is disassembled and the solvent now containing extract fat is evaporated off leaving the residue for .
