This section is from the book "Health", by W. H. Coefield.
I will now mention the important preparations we make from milk. Butter, which you know is made from the cream of milk, consists almost entirely of the fat. Fresh butter contains from 10 to 15 per cent of water, and the remainder is fat, with the exception of a small quantity of caseine-viz., 3 to 5 per cent, and salt is sometimes added, when, of course, we have salt butter. Butter keeps better the less curd there is in it, as the greater the quantity of curd the quicker decomposition sets in. Salt butter may be kept much longer than fresh, but fresh butter may be kept for a long time if placed under water, which is frequently changed, and if a small quantity of tartaric acid be added the preservation is much more complete.
Cheese varies very much according to the amount of cream that is left in the milk from which it is made. For the richest cheeses cream is even added to the milk; for second-class cheeses new milk is used; and cheeses like double Gloucester contain all the fat and curd of the milk. For the poorer cheeses, which are not so digestible, as they offer greater resistance to the gastric juice, and some of them have to be grated to be eaten at all, skim milk is used; these keep much more readily than the richer cheeses, which more easily decompose.
Cheese is an exceedingly nutritious article of food, and it forms a very important addition to the food of large classes of the community.
It is not a good plan to eat much of a cheese that has been allowed to reach an advanced stage of decomposition, as poisonous effects have resulted from eating cheese in that state.
Let us now turn to vegetable foods. The most important of these I have to speak about are the cereals, the grains of which contain substances of great nutritive value; they contain, in the first place, several nitrogenous substances, one of which goes by the name of gluten ; they also contain a large proportion of starch, some fat, and some very important mineral salts, especially phosphates.
The first and most important cereal is wheat, which stands in an average position among grains as regards the amount of starch it contains ; it contains less than some, but more than others, and a considerable quantity of gluten. Barley is frequently used for making bread, and is especially used for making malt for brewing, and also for making the preparation known as pearl barley.
Oats are still more hardy than barley, and are an exceedingly nutritious food; they contain much fat and a quantity of nitrogenous matter, but no gluten, and so cannot be used for making bread, but their highly nutritious nature makes them a very important food for the inhabitants of certain countries.
Bye thrives on dry, poor, sandy soils in the north of Germany, and is also a very nutritious form of food ; but from eating diseased rye certain diseases have been known to arise and spread among human beings, especially the disease which goes by the name of ergotism.
Maize, a cereal especially cultivated in the New World, but now grown in most parts of southern Europe, in Africa, and southern Asia, contains more fatty matter than any other cereal, and is exceedingly valuable because of the enormous yield that it gives. But this and rice have, unfortunately, to be cultivated in very wet ground, and rice is usually grown in positive swamps.
Bice is the poorest of all cereals ; it contains less nitrogenous substance, and but little of the mineral salts ; it is commonly stated to be the staple food of millions of people, but, being so poor, it requires to be mixed with other things, as milk, cheese, etc.
Several of these grains, notably wheat, are subjected to certain processes for the preparation of bread ; such of them as contain gluten, are capable, when ground up into flour and mixed with water, of forming a mass that will stick together, and can then be made into bread.
For this, either the whole grain may be used or part. . The outer part of the grain contains much nitrogenous matter, and a large proportion of salts ; the inner part contains almost all the starch and some nitrogenous matter, more especially gluten ; so you can see if the grain alone is ground up we lose the nitrogenous matter and the salts of the outer part, and for that reason Baron Liebig said that bread should be made from the whole grain, not from the white part alone, which consists for the most part of starch. He, however, did not take the whole matter into consideration, because, in the first place, if we do not live on bread alone we may certainly choose whether we will eat white bread, or whether we will have brown bread; and, in the second place, it is perfectly certain that bread made out of the inner part of the grain is far more digestible than that made from the whole grain. Brown bread, which formerly was eaten by poor people, was found in the end to be more expensive, because it is not so digestible, and therefore is now usually eaten by the rich rather as a luxury. Brown bread is taken on account of the mechanical action it exerts on the lining membrane of the stomach and intestines; it slightly irritates the mucous membranes, and causes them to secrete their juices more freely,
New bread is much less digestible than that which has been kept a short time, because, when new, it forms a sticky mass in the mouth, with which the saliva is not readily mixed, and so the action of the saliva upon the starch takes place only to a comparatively small extent, and the starch does not get properly digested.
Toast and rusks are very easily digested; as they are brittle* and easily broken up in the mouth, they readily mix up with the saliva and get aerated, forming a mass easily digested.
Muffins, crumpets, pastry, and bread insufficiently baked, are very indigestible, from their doughy nature, so much so that some of them go by the name of " sudden deaths."
Bread is aerated by one of three methods, either by yeast added to the dongh to set up fermentation, or by carbonate of soda and some acid, such as tartaric or citric acid. It is advisable not to use hydrochloric acid, because it generally contains arsenic, and in some instances bread prepared in this way has actually caused symptoms of poisoning. The third method is that of forcing carbonic acid gas into it, and this forms a very light kind of bread, known as aerated bread, which, however, compared with that lightened by fermentation, is generally considered to be somewhat tasteless.