Food study

All the members of the first and second group are sugars, and all are soluble in water and more or less sweet in taste. The two groups are sometimes called single and double sugars. A plant probably manufactures a single sugar out of carbon dioxide and water, and then changes the single sugar into either double sugar or polysaccharides. When polysaccharides or disaccharides are digested, or boiled with water and acid, the plant-manufacturing process is reversed and the substances are finally broken down into single sugars. To prove this, chew a bit of cracker, being careful not to swallow it before the sweet taste of the sugar is evident. The breaking down process also goes on in the plant when stored starch or sugar is used for further growth, as, for example, in a potato when it sprouts. Glucose and fructose occur in many fruits and vegetables and are present in large quantities in honey. Glucose is used so extensively for food that it is also manufactured from cornstarch by boiling the starch with acid. The chief points to be remembered about these two sugars are that they do not need to undergo any process of digestion before being absorbed, that they do not crystallize so readily as cane sugar, and that they give the sugar test. Galactose is a digestive product of milk sugar and is not found as such in foods. Of the disaccharides, sucrose and lactose are the more important in OUT foods. Lactose is found in milk. It ferments in the stomach less readily than sucrose and so is probably much better for babies. Accordingly, modified milk and other baby foods are often prepared by the addition of lactose. It is also used as a basis for sugar pills. It is manufactured commercially by separating it from milk. When sucrose is boiled with an acid in the presence of water it changes into equal parts of glucose and fructose. Glucose is far less sweet than sucrose, but fructose is much sweeter. Consequently the mixture, "invert" sugar as it is called, is not very different in sweetness from the original sucrose, but the latter is probably a little sweeter. Some recipes call for the addition of sugar to acid fruits after boiling, so that this change will not take place as a result of the cooking. The saving is probably so small as not to be appreciable. On the other hand, this change is deliberately sought after in making candies like fondant and fudge which must be smooth and velvety, not granular, and in candies like butter-scotch which must not "sugar." The single sugars crystallize with much more difficulty than sucrose, and the presence of even small amounts of them makes the candy less liable to "grain" or "sugar." Sometimes, instead of bringing about the change by boiling with acid, a little glucose syrup is added to produce the same result. During digestion all the carbohydrates are broken down into single sugars and are then absorbed and carried to the liver. Here and in the muscles any sugar in excess of that needed in the blood is stored as glycogen, or animal starch. At need, the process is reversed, the stored glycogen is again broken down into sugar to keep the supply of it constant in the blood. Saccharin is a chemical substance with a sweet taste and is entirely unlike the carbohydrates. It has no