Experiment 60 Fat Extraction and Determination

Since all triacyglycerols (fats) are hydrophobic, they may be extracted from food samples using hydro-phobic solvents such as various ethers. Also, since fat content in processed foods is of critical concern to consumers, this technique has considerable real-world significance. Rubber gloves should be worn, and it is very important that there be no open flames in the laboratory. 

Assemble a boiling water bath in a fume hood using a hot plate and a 250-mL beaker filled halfway with distilled water. 

Obtain samples of various foods and weigh approximately 1 g of each on a top-loading balance. Record and label each weight (as to the type of food) in your notebook Also in your notebook, give each an identifying number. Place each sample in a 100-mL round-bottom flask labeled with the identifying number. 

Place the flask in the water bath without the stopper and add 10.0 mL of concentrated hydrochloric acid to the flask. Heat for 45 min at a gentle boil and shake the flask at 10-min intervals. The HCl-heat combination breaks up the food sample, releasing free fatty acids, monosaccharides, amino acids, etc., thus making extraction easier. 

After 45 min, remove the flask from the water bath and add 10 mL of distilled water. Then cool the flask by running water over its exterior. Stopper the flask and place it in a freezer for 30 min. This aids in the separation of the fat. 

---