SUGAR: DIGESTION OF SUGAR
ENERGY; FUEL.—An automobile is a machine. The use of gasoline in this machine gives it energy or the power to move.
The human body is also a machine. Certain foods are taken into the human machine. The utilization of these foods gives the body energy or the power to move (i.e. to do work). The body is capable of both voluntary and involuntary work. Walking and running are examples of the former kind of work, while the beating of the heart and the circulating of the blood are examples of the latter kind.
At the same time that the body works, heat is generated. Hence foods not only give the body the power to do work, but incidentally they heat the body. Foods which enable the body to work are termed energy-giving or fuel foods.
There are a number of energy-giving or fuel foods: sugar is the first one to be considered.
EXPERIMENT 10: THE SOLUBILITY OF GRANULATED SUGAR IN COLD WATER—Place half a teaspoonful of granulated sugar in a test tube, add a little cold water, shake. Is the mixture clear? Set it aside for a few minutes. Does the sugar separate from the water?
EXPERIMENT 11: THE SOLUBILITY OF GRANULATED SUGAR IN HOT WATER.—Dissolve half a teaspoonful of granulated sugar in hot water. Compare with Experiment 10. Which dissolves sugar more readily,—cold or hot water? If you desired to dissolve some sugar quickly, at what temperature would you have the water?
EXPERIMENT 12: THE SOLUBILITY OF POWDERED SUGAR.—Dissolve half a teaspoonful of powdered sugar in the same quantity of hot water used in Experiment 11. Does it dissolve more readily than granulated sugar? Explain this difference. If you desired to dissolve some lumpy sugar quickly, how would you prepare it?
THE DIGESTION OF SUGAR.—Since sugar is so readily dissolved, and since dissolving is an important step in the process of digestion (see Solution and Digestion), it would seem that the digestion of sugar would be easy. Some sugars, such as glucose, need no digestion in a chemical sense, and are wholesome provided their solution is not too concentrated. The digestion of other sugar, such as granulated sugar, is slightly more complex.
Because the digesting of some sugar is simple, one should not conclude that this food should be used in large quantities or in preference to other fuel foods. If sugar is eaten in large quantities there is so much dissolved sugar for the organs of digestion to take care of that the stomach and small intestines become irritated. This is especially true when candy is eaten between meals,—at a time when the stomach is empty. Then, too, it may ferment in the stomach or intestines and produce digestive disturbances. All sweets should be eaten only in moderation and either during a meal or at its close. When sugar is mixed with other foods, it is diluted, and is not so apt to cause distress.
SUGARS AND SIRUPS.—In various plants and in milk, the chemist finds a number of different kinds of sugar. These may be classified into two groups:—(1) single sugars and (2) double sugars. Dextrose or glucose is one of the single sugars, while sucrose or cane sugar is an example of a double sugar.
The solid sugars and sirups found at market and having different trade names consist of one or more of the different kinds of sugars. A discussion of these follows:
(a) Granulated sugar is made either from the sugar cane or sugar beet. The juice is pressed or soaked out of these plants, then purified, refined, and crystallized. Powdered sugar is prepared by crushing granulated sugar. Confectioners' sugar is a very finely ground form of cane or beet sugar. Granulated sugar is 100 per cent sugar. Crushed sugars sometimes contain flour or other materials.
Brown sugar is made from the cane or beet, but is not refined as much as is granulated sugar. It contains some ash and moisture.
(b) Corn sirup is made by boiling corn-starch with an acid and then refining the product. This sirup contains no cane sugar. Its sweet flavor and sirupy consistency are due to the presence of 38.5 per cent glucose and 42 per cent dextrin. Glucose is not as sweet as granulated sugar. Hence, in depending upon corn sirup alone, the tendency is to use more sugar than is advisable so as to satisfy our taste for sweets. At least 1 1/2 times as much corn sirup as granulated sugar is needed to produce the sweetness of the solid sugar. A mixture of corn sirup and granulated sugar is often used for sweetening foods.
(c) Molasses and Sorghum.—Molasses is a by-product of cane sugar. In addition to sugar, it contains certain mineral materials such as lime. Since it is especially necessary that foods given children contain lime, the use of molasses in place of sugar may be recommended for children.
One should remember, however, that much sugar of any kind is not good for children. Molasses contains some acid. Because of modern methods of sugar refining, however, molasses is less acid than the sirup of former days. It also differs in flavor.
Sorghum is a sirup prepared from the sorghum plant. It contains ash and has a characteristic flavor. If the flavor of molasses or sorghum is too strong to be pleasant, a mixture of equal parts of corn sirup and molasses or sorghum may be found desirable. Mixtures of different sirups sold under various trade names may be purchased.
(d) Honey is sugar extracted from flowers. Its limited supply and cost prevent its general use. It is not so rich in mineral matter as is molasses.
(e) Maple Sirup and Sugar.—Maple sirup and sugar are prepared from sap extracted from the maple tree. They both have a distinctive flavor in addition to their sweet taste. Maple sugar contains approximately 83 per cent of sugar, while maple sirup contains about 71 per cent.
PEANUT CANDY
2 cupfuls granulated sugar or 1 cupful granulated sugar and 1 cupful corn sirup (dark) 3/4 cupful chopped peanuts 1/4 teaspoonful salt
Mix the peanuts and salt and place in the warming oven to heat. If sugar is used alone, put it in an iron pan. Place the pan over a low flame and stir constantly until the sugar is changed to a light brown sirup.
If a combination of sugar and sirup is used, put them in a pan, stir, and cook until the mixture is very brittle when tried in cold water.
Add the chopped peanuts and salt to either kind of sirup, stirring them in as quickly as possible. Pour immediately into a hot, unbuttered pan. When slightly cool divide into squares with a chopping knife.
Puffed cereals or shredded coconut may be used instead of peanuts. Commercial salted peanuts may be used also. When the latter are used, the salt in the recipe above should be omitted.
CARAMELIZED SUGAR.—It should be noted that when heat is applied to granulated sugar, the latter liquefies and becomes brown in color. This brown liquid is called caramel The process of making it is called caramelization.
When sugar is caramelizing, it reaches a high temperature. The melting point of tin is near the temperature of caramelized sugar. The enamel of granite ware is apt to chip off if subjected to great changes of temperature. Iron is not affected by the highest cooking temperature, hence it is desirable to use an iron utensil for caramelizing sugar.
NOTE.—When cane or granulated sugar is caramelized, a small quantity of an injurious substance called furfural is formed. (See Journal of Home Economics, Vol. IX (April, 1917), p. 167.) The more sugar is heated, the more of the injurious substance is produced. Also, cane sugar yields more furfural than glucose,—the kind of sugar that is present in corn sirup. When caramelized sugar is boiled with water, however, the furfural is expelled.
In making Peanut Candy, the caramelized sugar cannot be boiled with water, hence it is desirable to use a combination of granulated sugar and corn sirup and heat the mixture until it is only light brown in color.
EXPERIMENT 13: THE SOLUBILITY OF CARAMEL.—Immediately after removing the candy from the iron pan, pour hot water into the pan. Allow it to stand for several minutes, then examine. Is caramel soluble in water? Does it dissolve more or less readily than granulated sugar? What practical application can be drawn from this experiment with regard to washing a pan in which sugar has been caramelized?