Fig. 16.—Nutrients of a Ration With Sugar.
The hacket parts represent the proportion of nutrients not digested.
75. Sugar in the Dietary.—Sugar has an important place in the dietary. It not only serves for the production of heat and energy in the body, but is also valuable in enabling the proteids to be used more economically. In reasonable amounts, it is particularly valuable in the dietary of growing children, as the proteids of the food are then utilized to better advantage for growth. The unique value of sugar depends upon its intelligent use and its proper combination with other foods, particularly with those rich in the nitrogenous compounds or proteids. Sugar alone is incapable of sustaining life, but combined with other foods is a valuable nutrient. The amount which can be advantageously used depends largely upon the individual. Ordinarily three to five ounces per day is sufficient, although some persons cannot safely consume as much as this. In the case of diabetes mellitus, the amount of sugar in the ration must be materially reduced. Persons in normal health and engaged in outdoor work can use sugar to advantage.[[29]] Many of the "harvest drinks," made largely from molasses with a little ginger, and used extensively in some localities, are not without merit, as they contain an appreciable amount of nutrients. Milk contains more sugar as lactose or milk sugar than any other nutrient.
Fig. 17.—Nutrients of a Ration Without Sugar.
The hacket parts represent the proportion of nutrients not digested.
The craving for sugar by growing children and athletes is natural. Sugar, however, is often injudiciously used, and a perverted taste may be established which can be satisfied only by excessive amounts. This results in impaired digestion and malnutrition.
76. Maple Sugar.—Sugar obtained by evaporation from the sap of the maple tree (Acer saccharinum) is identical, except for the foreign substances which it contains, with that from the beet and sugar cane. The mottled appearance and characteristic color and taste of maple sugar are due to the various organic acids and other compounds present in the maple sap and recovered in the sugar. Maple sugar, as ordinarily prepared, has 0.4 of a per cent or more of ash or mineral matter, while refined cane sugar contains less than one tenth as much.[[30]] Hence, when maple sugar is adulterated with cane and beet sugars, the ash content is noticeably lowered, as is also the content of organic acids. It is difficult, however, to determine with absolute certainty pure high grade maple sugar from the impure low grade to which a small amount of granulated sugar has been added.
77. Adulteration of Sugar.—Sugar at the present time is not materially adulterated. Other than the substances mentioned which are used for clarification and color, none are added during refining which remain in the sugar in appreciable amounts. Sugar does not readily lend itself to adulteration, as it has a definite crystalline structure, and materials that would be suitable for its adulteration are of entirely different physical character.[[31]] Cane sugar is not easily blended with glucose, or starch sugar, because of the physical differences between the two. The question of the kind of sugar to use in the household, as granulated, loaf, or pulverized, is largely one of personal choice, as there is no appreciable difference in the nutritive value or purity of the different kinds.
78. Dextrose Sugars.—Products known as glucose and dextrose sugars are made from corn and other starches; they can also be prepared from cane sugar by the use of heat, chemicals, or ferments for carrying on the process known as inversion. The dextrose sugars differ from cane sugar in containing a dissimilar number of carbon, hydrogen, and oxygen atoms in the molecule. The formula of the dextrose sugars is C6H12O6, while that of cane sugar is C12H22O11. By the addition of one molecule of water, H2O, to a molecule of sucrose, two molecules of invert sugar (dextrose and glucose) are produced:[[1]] C12H22O11 + H2 = C6H12O6 + C6H12O6. In bringing about this change, acids are employed, but the acid in no way enters into the chemical composition of the final product; it is removed as described during the process of sugar manufacture. The action of the acid brings about a catalytic change, the acid being necessary only as a presence reagent to start the chemical reaction. When properly prepared and the acid product thoroughly removed, dextrose and glucose have practically the same food value as sugar. When they are digested, heat and energy are produced, and a given weight has about the same fuel value as an equal weight of sugar. Some of the glucose-yielding products can be made at less expense than sugar, and when they are sold under their right names there is no reason why they should not be used in the dietary, as they serve the same nutritive purpose.
79. Molasses is a by-product obtained in the refining of sugar. It is a mixture of cane sugar and invert sugars, as levulose and dextrose. When in sugar making the sucrose is removed by crystallization, a point is finally reached where the solution, or mother liquid, as it is called, refuses to give up any further crystals;[[31]] then this product, consisting of various sugars and small amounts of organic acids and ash, is partially refined and clarified to form molasses. The term "New Orleans" molasses was formerly applied to the product obtained by the use of open kettles for the manufacture of sugar, but during recent years the vacuum pan process has been introduced, and "New Orleans" molasses is now an entirely different article. The terms first, second, and third molasses are applied to the liquids obtained after the removal of the first, second, and third crops of sugar crystals; first molasses being richer in sucrose, while third molasses is richer in dextrose and invert sugars. The ash in molasses ranges from 4 to 6.5 per cent. Some of the low grades of molasses are used in the preparation of animal foods.
The taste and physical characteristics of molasses are due largely to the organic acids and impurities that are present, as well as to the proportion in which the various sugars occur. When used with soda in cooking and baking operations, the organic acid of the molasses liberates carbon dioxide gas, which acts as a leavening agent. Because of the organic acids, molasses should not be stored in tin or metalware dishes, as the solvent action results in producing poisonous tin and other metallic salts.