Читать книгу Foods and Their Adulteration - Harvey Washington Wiley - Страница 144

—It is evident that a beef extract is only a soup or a soup stock specially prepared from beef. Beef extract first became known by the researches of the celebrated chemist Liebig, and has passed from a mere local preparation to an article which is important in commerce. Factories have been established in localities far removed from the principal markets of the world, but where cattle are extremely plentiful, as in South America, and the preparation of beef extract is carried on on a large scale, the meat of the animal being thrown away after the preparation of the extract. The method of preparing beef extract is practically that described for making a soup stock under pressure. Instead of using only the trimmings and refuse of the animal, however, usually the whole of the flesh is employed. The bones are sometimes used in the making of a beef extract. The sound, fresh meat is cut into small pieces and extracted under pressure as already described. After cooking and filtering the product it is brought, in vacuo, to a proper consistence. Meat extract is, therefore, simply a concentrated soup stock. It requires about thirty-four pounds of meat to yield one pound of concentrated extract, and this extract may be diluted for consumption so as to make from six to seven gallons of beef tea. The composition of the ordinary beef extract of commerce shows that it contains from 15 to 20 percent of moisture, from 17 to 23 percent of ash and from 50 to 60 percent of meat bases, that is, the soluble nitrogenous contents of meat. The bones and tendons are not used in making beef extract on account of the introduction of considerable quantities of gelatine into the material. Liebig does not recommend the presence of gelatine in beef extract because, being cheaper in quality, it is an adulteration of the genuine article, which should contain only the pure bases and not the gelatinous principle of the meat in the tendons and bones.