A course in food analysis / by Andrew L. Winton.

  • Andrew Lincoln Winton
Date:
[1917]
Catalogue details

Licence: Public Domain Mark

Credit: A course in food analysis / by Andrew L. Winton. Source: Wellcome Collection.

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    be needed later in the determination of the crude fat in vege- table products. In boring holes in the corks (which should first be rolled until soft), be sure that the borer (Fig. 16) has a keen edge, secured by means of a u cork borer sharpener ” (Fig. 17), and that it bores a smooth hole into which the tube fits without danger of leaking. Do not use a rat-tail hie; it will be found that one of the borers in a good set, properly sharp- ened, will cut a hole into which, without further treatment, a given tube will fit accurately When the apparatus is set up, place an identification mark on the extraction flask. This is best done with a lead pencil on an etched or ground spot. The etching fluid, known as “ diamond ink/’ applied with a brush, or a few strokes with the flat surface of a file moistened with water, gives the desired surface. In using any hydrofluoric acid preparation be careful not to get any on the skin, as it makes serious wounds. Weigh the flask without drying in a desiccator, and without a stopper. If special accuracy were important a counter- poise flask of the same size but slightly less weight could be used, thus obviating the slight error due to the variable amount of moisture which condenses on the surface. Attach the flask to the lower end of the extractor and place the dried and weighed perforated cylinder with asbestos and milk solids in the extractor. Pour 8 to 10 cc. of anhydrous alcohol-free ether through the cylinder, attach the extractor to the condenser, run water through the latter, and heat the flask cautiously. Ether free from water and alcohol is required, as these would extract sugars and other substances from the residue. The ether in the form of vapor passes up through the extractor, is liquefied in the condenser, and is returned drop by drop through the asbestos into the extraction flask. The fat gradually ex- tracted from the milk solids remains in the flask, but the vaporiza- tion and condensation of the ether continue without intermis- sion as long as the heat is applied. After two hours—the end of the laboratory period—the extraction is complete. Turn out the lamps, remove the flask, and allow to stand until the next day, when the ether should be
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