FoodNet

Elements of the theory and practice of cookery

1901

Page 68

Presented as published in 1901. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Experiment. — A. Test beef-juice for albumin. If albumin is shown to be present, observe the form in which it appears. Com- pare with pure white-of-egg cooked, and with white-of-egg mixed with water and heated. AVhat besides albumin do you think beef- juice contains ? Note that heating destroys the red color of beef- juice. What gives it this color ? 256. Nitric acid added to beef-juice clots it and turns it yellow. What does this prove? What other nitrogenous substance is coagulated by acid ? Human flesh, too, is stained yellow by nitric acid. How do you explain this? 257. Beef-juice contains albumin and other proteids, mineral salts, and extractives, dissolved in water ; boil- ing coagulates the albumin into a brownish jelly. In the bits of beef we have pressed there remains some albuminous juice ; what besides may be shown by an- other experiment ? Experiments. — B. Observe the fibrous appearance of a piece of round of beef. Can you see any fat among the fibres? Scrape with a knife first one side, then the other, of one of the pieces of meat from which the juice has been squeezed, until only the fibres are left. Pick some of them apart with a needle. Try to break or tear them. C. Heat the mass of fibre, and note the effect. Each fibre is a bundle of tube-shaped cells filled chiefly with proteid substance. These tubes are cov- ered and bound together with a web cf white connec- tive tissue, threaded by tiny blood-vessels. Toward the ends of the muscles the fibres dwindle down till only a firm mass of connective tissue, called tendon, is left. 146 THEORY AND PRACTICE OF COOKERY The contents of the tubes and blood-vessels may be scraped out, leavmg these, with the connective tissue, in a pale-colored, stringy mass. 258. Two facts important to bear in mind in cooking meat. — 1. Heat, by causing the collagen in the con- nective tissue to swell, tends to force the juices out of the muscle-fibres.^ 2. Dry heat hardens connective tissue. 259. The pulp of meat consists chiefly of myosin, a jelly- like proteid similar to the fibrin of blood. Both myosin and fibrin are liquid during life, but clot after death.^ Directions for making Raw Beef Sandwiches (for Invalids) Cut juicy, lean beef into thin strips. Scrape the pulp from them, season it highly with salt and pepper, and spread between thin slices of bread. 260. Microscopical examination of meat fibre. — Soak in salted water a few fibres of beef from leg or round. Examine them under a microscope, using a one-inch objective. Look at the ends of the fibres. Can you see that they are hollow tubes ? Observe the fine stripes (strice) on the fibres. The muscles of the stomach and some other organs are not striped. 261. Tests for mineral salts in meat. — A. Heat a bit of meat in a crucible or evaporating dish over a Bunsen burner for several 1 See § 244. Though collagen swells, a mass of connective tissue, as a whole, shrinks when heated. This shrinkage is caused by loss of water. 2 The liquid forms, myosinogen ?iXi6. fibrinogen^ differ chemically from the clotted substances, bearing the same relation to them that caseinogen does to casein. (§ 169, note 1.) ) THE FLESH OF ANIMALS 147