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A Talk on Food: Sugar

Starch Group Cane Sugar Group Grape Sugar Group C6 H10 O5 C12 H22 O11 C6 H12 O6 Starch Cane Sugar Grape Sugar Dextrin Malt Sugar Fruit Sugar Cellulose Milk Sugar Gums Glycogen STARCH You are already familiar with starch, having washed it away from the gluten in the dough you made of flour and water. Starch is found only in the vegetable kingdom. It is produced by all green plants and stored, in varying proportions, as microscopic grains, throughout the plant structure. In the laboratory, iodine is the test for starch; pour a few drops of iodine, diluted with water, into half a cup of laundry starch, cooked and cooled for use, and the starch will assume a deep blue color. Or you may grind a vegetable substance in a mortar with a little warm water, add a drop of iodine solution, and note the effect. What is true in these cases is true of all starch mixtures and is thus tested. But in your kitchen you will recognize starch by its thickening when cooked. When you come to cook rice, tapioca, the breakfast cereals, etc., in liquid, you will note the thickening of the liquid and come to know that it shows the presence of starch. DEXTRIN, CELLULOSE, GLYCOGEN, ETC.

Starch ultimately becomes sugar. In an intermediate state it is in the form of dextrin. The composition of dextrin and starch is the same, as can be seen by looking at the starch group, but that dextrin is not starch can be determined by the use of iodine. In cookery starch becomes dextrin on being subjected to high heat, as in the crust of bread. This change is also brought about by the digestive ferments.

The framework of plants and vegetables, or the cellular structure that enfolds the starch grains, is cellulose. From a nutritive point of view cellulose cannot be considered valuable; much, however, depends upon the tenderness to which it can be reduced by cooking; but it gives bulk, a necessary item in food. Gums are largely found in the juices of plants. Not all the carbohydrate principle, taken as food, enters at once into the circulation; a part is stored in the liver, as glycogen, and may be drawn upon as needed. Use of Starch. Starch when digested furnishes energy, which is expended as work or as heat, or it is stored between the tissues as fat. As it builds no tissue, it cannot be used alone as food, but needs be combined with proteid. SUGAR The difference between starch and sugar is merely a difference in the proportions of the same elements, these being repeated indefinitely in composition. In the cane and grape sugar groups we refer to five varieties of sugar; these are made up of the same kind of atoms and, in the case of grape and fruit sugar, of the same number of atoms, but the atoms in each case are grouped differently. This difference in the grouping of the atoms results in sugars of different properties, which, when partaken of as food, differ in digestibility.

Sources of Sugar. Sugar is found in a large number of vegetable juices; it is in the stems and roots of all the grasses and in many of the vegetables served on our tables, as the carrot, parsnip, turnip, beet and sweet potato. It is found in the sap of the sugar maple, in most of the sweet fruits, as bananas, dates and figs, in the nectar of flowers, which is stored by bees as honey, and in the milk of certain animals. The sugar of commerce is usually obtained from sugarcane or beets and is a manufactured product. When we consider how much vegetable matter must be taken to obtain half a cup of granulated sugar, we understand that this sugar contains certain elements in a very concentrated form. If it is best to take food compounds as they occur in nature -- diluted with other natural elements -- ought we not to consider rather carefully the quantity of commercial sugar used at our tables? Of course, when we eat milk and sweet fruits, we are eating sugar in its natural condition. The beet properly cooked affords sugar in a wholesome and natural form. In chewing sugar-cane, though the fibres be not swallowed, we get the sweet product in a comparatively dilute form. But these foods are not available to all and the manufacture of sugar, at a price that puts it within the reach of every one, must be considered as one of the blessings of the age. The proper use of sugar will be taken up more fully in lessons where its use is indicated. Fats. Fat comes from both the animal and the vegetable kingdom; like the carbohydrate it is composed of carbon, hydrogen and oxygen. There is, however, in fat, a much larger proportion of carbon and less of oxygen than in starch and sugar, and on this account it burns very freely and gives intense heat. For heating purposes in the body fat is more valuable than carbohydrate and thus its use as food in cold weather is indicated. Olive oil, butter, bacon, cream and the fat of meat are the principal sources from which this compound is obtained.

Water and Mineral Matter. In discussing the value of a food we commonly consider only the proteid, carbohydrate and fat it contains. Water is a necessity, but, as all food contains this compound in generous measure, we need not pay particular attention to it now. As regards mineral matter, except in the case of growing children, enough will be present in our food, unless our diet be extremely restricted.

Nutrient Ratio. When we speak of the food value of any article of food we refer to the quantity of proteid, carbohydrate and fat present in the article, and the ratio that exists between the proteid, on one side, and the carbohydrate and fat, on the other. One part of fat (on account of the heat it liberates) is estimated as equal to two and one-fourth parts of starch. Thus corn meal, having a composition of 9 per cent. protein, 75.4 per cent. carbohydrate and 1;9 per cent. fat would have a nutrient ratio of about 1 to 9. 75.4 starch + 4.3 (fat in equivalent starch) = 79.7; i.e., 9 per cent. protein to 79.7 per cent. starch or about 1 to 9. There are many things to influence a decision as to the nutrient ration desirable in the food to be supplied daily by the young house-keeper, as bodily weight, degree and kind of activity, climate, health, etc., but, in general, the ratio to be sought for in the diet of an adult is about 1 part protein to five and three-tenths parts carbohydrate and fat; while in the diet of a child the proportions are as 1: 4.3.