Vegetable Acids

The Chemistry Of Food and Nutrition
by A. W. Duncan, F.C.S.

(Page 2 of 11)

The most esteemed and dearest oil is Almond. What is called Peach-kernel oil, but which in commerce includes the oil obtained from plum and apricot stones, is almost as tasteless and useful, whilst it is considerably cheaper. It is a very agreeable and useful food. It is often added to, as an adulterant, or substituted for the true Almond oil. The best qualities of Olive oil are much esteemed, though they are not as agreeable to English taste as the oil previously mentioned. The best qualities are termed Virgin, Extra Sublime and Sublime. Any that has been exposed for more than a short time to the light and heat of a shop window should be rejected, as the flavor is affected. It should be kept in a cool place.

Not only does it vary much in freedom from acid and rancidity, but is frequently adulterated. Two other cheaper oils deserve mention. The "cold-drawn" Peanut oil has a pleasant flavor, resembling that of kidney beans. The "cold-drawn" Sesame oil has an agreeable taste, and is considered equal to Olive oil for edible purposes. The best qualities are rather difficult to obtain; those usually sold being much inferior to Peach-kernel and Olive oils. Cotton-seed oil is the cheapest of the edible ones. Salad oil, not sold under any descriptive name, is usually refined Cotton-seed oil, with perhaps a little Olive oil to impart a richer flavor.

The solid fats sold as butter and lard substitutes, consist of deodorized cocoanut oil, and they are excellent for cooking purposes. It is claimed that biscuits, made from them may be kept for a much longer period, without showing any trace of rancidity, than if butter or lard had been used. They are also to be had agreeably flavored by admixture with almond, walnut.

The better quality oils are quite as wholesome as the best fresh butter, and better than most butter as sold. Bread can be dipped into the oil, or a little solid vegetable fat spread on it. The author prefers to pour a little Peach-kernel oil upon some ground walnut kernels (or other ground nuts in themselves rich in oil), mix with a knife to a suitable consistency and spread upon the bread. Pine-kernels are very oily, and can be used in pastry in the place of butter or lard.

Whenever oils are mentioned, without a prefix, the fixed or fatty oils are always understood. The volatile or essential oils are a distinct class. Occasionally, the fixed oils are called hydrocarbons, but hydrocarbon oils are quite different and consist of carbon and hydrogen alone. Of these, petroleum is incapable of digestion, whilst others are poisonous.

Vegetable Acids are composed of the same three elements and undergo combustion into the same compounds as the carbohydrates. They rouse the appetite, stimulate digestion, and finally form carbonates in combination with the alkalis, thus increasing the alkalinity of the blood. The chief vegetable acids are: malice acid, in the apple, pear, cherry; citric acid, in the lemon, lime, orange, gooseberry, cranberry, strawberry, raspberry; tartaric acid, in the grape, pineapple.

Some place these under Class III or food adjuncts. Oxalic acid (except when in the insoluble state of calcium oxalate), and several other acids are poisonous.

Proteins are frequently termed flesh-formers. They are composed of nitrogen, carbon, hydrogen, oxygen, and a small quantity of sulfur, and are extremely complex bodies. Their chief function is to form flesh in the body; but without previously forming it, they may be transformed into fat or merely give rise to heat. They form the essential part of every living cell.

Proteins are excreted from the body as water, carbon dioxide, urea, uric acid, sulfates.

The principal Proteins of animal origin have their corresponding Proteins in the vegetable kingdom. Some kinds, whether of animal or vegetable origin, are more easily digested than others. They have the same physiological value from whichever kingdom they are derived.

Jellies are of little use as food; not only is this because of the low nutritive value of gelatin, but also on account of the small quantity which is mixed with a large proportion of water.

The Vegetable Kingdom is the prime source of all organic food; water, and to a slight extent salts, form the only food that animals can derive directly from the inorganic kingdom. When man consumes animal food - a sheep for example - he is only consuming a portion of the food which that sheep obtained from grass, clover, turnips. All the Proteins of the flesh once existed as Proteins in the vegetables; some in exactly the same chemical form.

Flesh contains no starch or sugar, but a small quantity of glycogen. The fat in an animal is derived from the carbohydrates, the fats and the Proteins of the vegetables consumed. The soil that produced the herbage, grain and roots consumed by cattle, in most cases could have produced food capable of direct utilization by man. By passing the product of the soil through animals there is an enormous economic loss, as the greater part of that food is dissipated in maintaining the life and growth; little remains as flesh when the animal is delivered into the hands of the butcher.

Some imagine that flesh food is more easily converted into flesh and blood in our bodies and is consequently more valuable than similar constituents in vegetables, but such is not the case. Fat, whether from flesh or from vegetables is digested in the same manner. The Proteins of flesh, like those of vegetables, are converted into peptone by the digestive juices - taking the form of a perfectly diffusible liquid - otherwise they could not be absorbed and utilized by the body. Thus the products of digestion of both animal and vegetable Proteins and fats are the same. Formerly, Protein matter was looked upon as the most valuable part of the food, and a large proportion was thought necessary for hard work. It was thought to be required, not only for the construction of the muscle substance, but to be utilized in proportion to muscular exertion.

Manchester the Vegetarian Society, 1905.