These last are not strictly foods, if we keep to the definition already given; but they are consumed with the true foods or nutrients, comprised in the other two classes, and cannot well be excluded from consideration.
Water forms an essential part of all the tissues of the body. It is the solvent and carrier of other substances.
Mineral Matter or Salts, is left as an ash when food is thoroughly burnt. The most important salts are calcium phosphate, carbonate and fluoride, sodium chloride, potassium phosphate and chloride, and compounds of magnesium, iron and silicon.
Mineral matter is quite as necessary for plant as for animal life, and is therefore present in all food, except in the case of some highly-prepared ones, such as sugar, starch and oil. Children require a good proportion of calcium phosphate for the growth of their bones, whilst adults require less. The outer part of the grain of cereals is the richest in mineral constituents, white flour and rice are deficient. Wheatmeal and oatmeal are especially recommended for the quantity of phosphates and other salts contained in them. Mineral matter is necessary not only for the bones but for every tissue of the body.
When haricots are cooked, the liquid is often thrown away, and the beans served nearly dry, or with parsley or other sauce. Not only is the food less tasty but important saline constituents are lost. The author has made the following experiments:—German whole lentils, Egyptian split red lentils and medium haricot beans were soaked all night (16 hours) in just sufficient cold water to keep them covered. The water was poured off and evaporated, the residue heated in the steam-oven to perfect dryness and weighed. After pouring off the water, the haricots were boiled in more water until thoroughly cooked, the liquid being kept as low as possible. The liquid was poured off as clear as possible, from the haricots, evaporated and dried. The ash was taken in each case, and the alkalinity of the water-soluble ash was calculated as potash (K2O). The quantity of water which could be poured off was with the German lentils, half as much more than the original weight of the pulse; not quite as much could be poured off the others.
| G. Lentils. | E. Lentils. | Haricots. | Cooked H. | |
| Proportion of liquid | 1.5 | 1.25 | 1.20 | — |
| Soluble dry matter | 0.97 | 3.38 | 1.43 | 7.66 per cent. |
| Ash | 0.16 | 0.40 | 0.28 | 1.26 " " |
| Alkalinity as K2O | 0.02 | 0.082 | 0.084 | 0.21 " " |
The loss on soaking in cold water, unless the water is preserved, is seen to be considerable. The split lentils, having had the protecting skin removed, lose most. In every case the ash contained a good deal of phosphate and lime. Potatoes are rich in important potash salts; by boiling a large quantity is lost, by steaming less and by baking in the skins, scarcely any. The flavour is also much better after baking.
The usual addition of common salt (sodium-chloride) to boiled potatoes is no proper substitute for the loss of their natural saline constituents. Natural and properly cooked foods are so rich in sodium chloride and other salts that the addition of common salt is unnecessary. An excess of the latter excites thirst and spoils the natural flavour of the food. It is the custom, especially in restaurants, to add a large quantity of salt to pulse, savoury food, potatoes and soups. Bakers' brown bread is usually very salt, and sometimes white is also. In some persons much salt causes irritation of the skin, and the writer has knowledge of the salt food of vegetarian restaurants causing or increasing dandruff. As a rule, fondness for salt is an acquired taste, and after its discontinuance for a time, food thus flavoured becomes unpalatable.
Organic Compounds are formed by living organisms (a few can also be produced by chemical means). They are entirely decomposed by combustion.
The Non-Nitrogenous Organic Compounds are commonly called carbon compounds or heat-producers, but these terms are also descriptive of the nitrogenous compounds. These contain carbon, hydrogen and oxygen only, and furnish by their oxidation or combustion in the body the necessary heat, muscular and nervous energy. The final product of their combustion is water and carbon dioxide (carbonic acid gas).