BREAD. 443 BREAD. The average percentage eoniposition of a num- V)er of common kinds of bread is shown in the following table: AVEBAOE Composition- of a Ntmbee of Differext Kinds of Bread KIND OF BREAD Corn bread (johnnycake).. Rye bread Rye and wheat bread Wheat bread "gluten".... Wheat bread, "graham".. Wheat bread, "roll" Wheat bread from high grade patent flour M neat bread from regular patent flour Wheat bread from bakers flour Wheat bread from low- grade flour Wheat bread, average of a large number of analyses Whole-wheat bread Crackers % 38.9 35.7 35.3 38.2 35.7 29.2 32.9 34.1 39.1 40.7 35.3 38.4 % 7.9 9.0 11.9 9.3 8.9 8.9 8.7 9.0 10.6 12.6 9.2 9.7 10.7 % 4.7 0.6 0.3 1.4 1.8 4.1 1.3 1.2 1.1 1.3 0.9 8.8 -I % 46.3 63.2 51.5 49.8 52.1 56.7 56.5 54.9 48.3 44.3 53.1 49.7 71.9 2.2 l.S 1.0 1.3 1.5 l.I 0.5 0.7 0.9 1.3 1.1 1.3 1.8 It will be seen that wheat bread from low- grade flour, wheat bread from bakers' flour, and rye-and-wheat bread contain the largest amount of protein ; corn bread and wheat rolls, the most fat ; and wheat rolls, wheat bread from high- grade patent flour, and wheat bread from regular patent flour, the most carbohydrates. The amount of fat would, of course, vary greatly with the amount of shortening added in making the bread, and the examination of a large number of anal3"ses of the same kind of bread has shown that the amount of each of the several nutrients varies in the same sort of bread within rather wide limits. Judged by their composition, all breads are nutritious foods, and too great stress should not be laid on the variations in composi- tion between the different kinds. The chemical composition of the finished loaf differs somewhat from that of the original ma- terial, as is shown by the following table, which compares flour and the breads made from it: Atebaoe CoMPOsrrios of White Bread and of the Flour from Which it was Made a S o ■eg .a < B. % % % % % Bread 35.3 12.0 9.2 11.4 1.3 1.0 63.1 75.1 1.1 Flour 0.6 The increase of water in the bread hardly needs explanation, since it is evidently due to the water added in making the dough. The use of butter or lard and salt probably accounts for the excess of fat and ash. The protein and carbohydrates lost doubtless went to nourish tiie yeast. Most of the carbon dioxide ihto which they were con- verted passed out of the bread, .ccording to Birnbaum the baked bread contains an average of 0..314 per cent, of alcohol, by no means all of that generated by the yeast (about 1 per cent.. Vol. III.— 29." according to Snyder) ; part is evaporated and part is 2'robably changed into acetic acid. The bacteria and other microscopic plants which ac- companied the yeast doubtless took their share of the protein and carbohydrates, returning a part in the form of the characteristic acids and otlicr bodies which they produce. Part of the starch in the crust has been changed into de.trin, and that in tlie crumb has l)eeonie gelatinous or partly soluble. The gluten has taken definite sliape; in other words, it has coagulated very much as the white of an egg does in boiling. Effect of Bakixg-Powders. 'arious mix- tures of acid and soda called baking-powders (q.v. ) are prepared by which carbonic acid may be introduced directly into the dough, instead of awaiting the slower i)rocess of fermentation. By this means there is no loss of nutritive qualities in the bread by decomposition, while in ferment- ed bread this amounts to 1 per cent. One of the disadvantages of this method is that in the case of most of the acids used to liberate carbonic acid from soda, the reaction is instantaneous, and much of the gas is dissipated before the bread reaches the oven. Cream of tartar is the only acid substance which does not liberate the gas by simple contact in the cold ; it is therefore best adapted to cooking. Another objection to this method of raising bread is that a residue of harmful salts may be left in the bread. Hence it is that the various baking-powders on the mar- ket should be used with caution. When cream of tartar and soda are put in separately by the cook instead of a baking-powder, care should be taken not to use an excess of the former, as the flavor may be injured and the product be un- wholesome. Self-Raising Floubs are simply flours into which acid and soda preparations have been mixed in such proportions that the addition of water, by liberating the carbon dioxide, produces a spongy dough. Lightness is produced in bread or cake by the simple addition of well-beaten eggs, because the air is caught by the sticky albu- men of the eggs and remains imprisoned in the dough. Air at "0° F. expands to three times its bulk when the temperature is raised to 500° F., and the whole mass of dough is expanded with it. If the heat of the oven is too intense when dough thus prepared is placed in it, the bubbles of air will swell so rapidly that they will burst, and the dough will fall. Besides the ordinary white wheat bread, there are innumerable fancy white breads, breads made from Hours other than wheat, and unleavened breads, on the market. So few analyses of them have been made, however, that they can hardly be more than enumerated here. Most like the ordi- nary bread are the fancy leaven white breads, such as Vienna and French rolls, milk breads, etc. These usually difl'er chiefly in the use of milk, sugar, butter, lard, etc., in the dough. En- tire wheat, graham, rye, bailey, or oatmeal flours are made into bread in essentially the same way as ordinary wheat flour, and vary in texture and nutritive value according to their original com- position. The original graham bread, made without yeast from graham flour according to the receipt of its inventor, and not to be confounded with raised graham bread, is made by kneading the flour and water thoroughh-, and allowing the dough to stand several hours before baking. It is heavier
