Fructose

“ Glucose (often called also dextrose, fruit sugar, or grape sugar) occurs widely distributed in plants, most commonly in the juices of ripening fruits, where it is usually associated with fructose and sucrose, the two hexoses being easily derived from sucrose by hydrolysis. Glucose is also produced by the hydrolysis of many of the more complex carbohydrates, by the action either of enzymes or of dilute acids; lactose, maltose, raffinose, starch, and cellulose, as well as many glucosides all yielding glucose as one of the products of their hydrolysis. ”

“ Four sugars having the formula C6H12O6, namely, glucose, fructose, mannose, and galactose, occur very commonly and widely distributed in plants. In addition to these, thirteen others having the same percentage composition have been artificially prepared, while seven additional forms are theoretically possible. In other words, twenty-four different compounds, all having the same empirical formula and similar sugar-like properties are theoretically possible. ”

“ Its universal use as a sweetening agent is due to the combined facts that it crystallizes readily out of concentrated solutions and, hence, can be easily manufactured in solid form, and that it is sweeter than any other of the common sugars except fructose. ”

“ The principal carbohydrates are starch, dextrine, cane-sugar or common table sugar, grape-sugar, the principal sugar in fruits, and milk-sugar, the natural sugar in milk. They are substances made up, as before stated, of carbon, hydrogen, and oxygen, but no nitrogen. They are important food substances, but are of themselves incapable of sustaining life.
The carbohydrates, both starch and sugar, in the process of digestion are converted into glucose. This is stored in the liver in the form of glycogen, which the liver has the power of manufacturing ”

“ Sugar is said to consist of about ninety-five per cent nutritive value.
Glucose is made by converting the starch in corn into sugar. It is pure, wholesome, and cheap, and, for this reason, it is often used to dilute other sugars. It is not as sweet as other sugars, and it ferments more readily. Many of the syrups on the market are made from it.
The common, granulated sugars are made from sugar cane or beets; beet sugar is becoming more generally used. ”

“ In [106] the United States thirty-two factories are engaged in the manufacture of glucose, which consume about 40,000 bushels of corn daily, their annual production having an estimated value of 10 millions of dollars. In commerce, the term grape sugar is applied to the solid product, the syrup or liquid form being known as glucose. The chief uses of starch sugar and glucose are in the manufacture of table syrups, and as a substitute for malt in the brewing of beer and ale. ”

“ Commercial Glucose.—The glucose of commerce, which may be regarded as a mixture of grape sugar, maltose and dextrins, is prepared by hydrolysing starch by boiling with a dilute mineral acid. In Europe, potato starch is generally employed; in America, corn starch. The acid employed may be hydrochloric, which gives the best results, or sulphuric, which is used in Germany; sulphuric acid is more readily separated from the product than hydrochloric, since the addition of powdered chalk precipitates it as calcium sulphate, which may be removed by a filter press. ”

“ Sugar, on the other hand, is a perfectly soluble or "meltable" substance, and can soak or penetrate through any membrane or substance in the body. Therefore all the starches which we eat—bread, biscuit, potato, etc.—have to be acted upon by the ferments of our saliva and our pancreatic juice, and turned into sugar, called glucose, which can be easily poured into the blood and carried wherever it is needed, all over the body. Thus we see what a close relation there is between starch and sugar, and why the group we are studying is sometimes called the starch-sugars. ”

“ Glycogen is readily reconverted into glucose, which is used by the body for the production of energy. It has been estimated that over half the energy manifested in the human body is derived from glucose, and it is in this form that the tissues of the body will ultimately make use of most of the carbohydrates in food. Practically all of the fruits, and many of the vegetables, are rich in this form of carbohydrate, but grapes contain more than any of the other fruits, while sweet corn, onions, and unripe potatoes contain appreciable amounts. ”

“ This, together with the fat found in milk, supplies the child with energy before it is able to digest a variety of foods. The sap of various plants contains such large quantities of sugar that it can be crystalized out and secured in dry form. The liquid that remains is valuable as food, for, by boiling it down, it forms molasses. Sugar is also present in considerable amounts in all fruits, and much of it is in a form that can be assimilated, or taken up by the body, quickly. A sugar very similar to this natural fruit sugar is made from the starch of corn and is called glucose. ”

“ Where glucose is substituted for sugar and used instead of natural sweetening agents, the ruling has been made that its presence should be plainly declared upon the label of the product. The reasons for this action are: (1) where a manufactured substance is substituted for a natural one it is believed that the purchaser is entitled to be informed of the substitution; (2) the cost of glucose is usually somewhat lower than that of sucrose; (3) glucose consists only in part of a sugar, dextrose, and is inferior to sucrose in sweetening power. ”

“ As the fruit begins to ripen, these acids act upon the various substances, namely, starch, gum, dextrine, lignine, cellulose, &c., also contained within it, and grape sugar or glucose is formed in consequence with the advent of ripening, therefore, the fruit becomes richer in sugar and poorer in acids ”

“ The Carbohydrates comprise starch, sugar, gum, mucilage, pectose, glycogen, &c.; cellulose and woody fibre are carbohydrates, but are little capable of digestion. They contain hydrogen and oxygen in the proportion to form water, the carbon alone being available to produce heat by combustion. Starch is the most widely distributed food. It is insoluble in water, but when cooked is readily digested and absorbed by the body. Starch is readily converted into sugar, whether in plants or animals, during digestion. There are many kinds of sugar, such as grape, cane and milk sugars. ”

“ Sugar and butter therefore are not so easily digested, when taken in large quantity, as those things, which contain less nutriment; hence, where the stomach is weak, they must be used in less quantity. But the custom of some people in restraining children entirely from them, is depriving them of a very wholesome, agreeable, and substantial part of their diet. Honey, manna, sap-juice, are different kinds of less pure sugar.
3. All the esculent vegetables contain a bland oil, or mucilage, or starch, or sugar, or acid ”

“ Those who object to flesh, dairy products, cereals, tubers, legumes, refined sugars, fruits or vegetables, should do without the class which they find objectionable, for it is easy to substitute from other classes. Eggs, milk or legumes may be taken in place of flesh foods. The salts contained in fruits may be obtained from vegetables. The starch, which is the chief ingredient of cereals, is easily obtained from tubers and legumes; fats and sugars will take its place. Commercial sugar is not a necessity. ”

“ It is interesting to note that while the cane is growing and in an unripe state, there is no discernible sucrose or pure sugar in it. As the ripening process goes on, the content of the cane juice is changed by the action of the sun’s rays, and the amount of sucrose as determined by polariscopic test shows when the time for harvesting is at hand. Nature’s operation in thus changing glucose or invert sugar into sucrose or pure sugar cannot be accomplished by any human means. ”

“ The vegetable kingdom furnishes numerous compounds, known as glucosides, which are capable of definite and distinctive fermentations, one of the fermentation products in each instance being sugar. A number of these glucosides are found in fruits. One of the most important of these is amygdalin, a glucoside found in the fruits, leaves, etc., of plants of the almond family, especially in the kernels of the bitter-almond, peach, and cherry, the leaves of the cherry-laurel, and the bark of the wild-cherry. ”

“ Glucose, which is abundant in the juice of plants and fruits, and to a more or less degree in the blood of all animals (usually about 0.1%) occurs free in nature. This sugar is likewise obtained from many carbohydrates, either through the action of acids, or as the result of the digestive enzymes, and as such becomes the principal form in which the animal body utilizes the carbohydrates ingested. Under normal conditions the glucose in the blood is constantly being burned and replaced ”

“ Every time we move a muscle, we manufacture soda water. Every time we think, we turn a half dozen different chemicals into the blood. We take a mouthful of cracker, which is mostly starch; and straightway a ferment, or “enzyme,” in the mouth begins to turn the starch into sugar. That is why a cracker or a potato tastes sweeter and sweeter the longer one chews it. When the sugar gets into the blood, another enzyme (the “y” is like “i,” and the word sounds like en-zime) in the liver turns it back to starch again, so that it stays there in the liver, and can’t get out. ”

“ Of the common cereals rice contains more starch than any other and oats the least. Sugars are intimately related to starch and are included under the term starchy food or carbohydrate food. The carbohydrate matter in the flesh mentioned above, namely glycogen, is of the nature of a sugar. Among the typical sugar foods are beets, melons, and fruits, some of which contain large percentages of sugar. All fruits contain greater or less quantities of sugar, and that is true, also, of all vegetables. ”

“ Some unripe fruits contain starch and various other carbohydrate substances, many of which are distasteful and unwholesome. On the other hand, when fruits become over-ripe, and decay sets in, the sugar is changed into carbon dioxid, alcohol, and acetic acid, and the fruit rapidly deteriorates in nutritive value and unwholesomeness. ”

“ Certain forms of carbohydrates are more susceptible to bacterial fermentation than others. Herter claims that sucrose and glucose are much more so than lactose, maltose, or starch. The substances thus formed through bacterial activity are not believed to be toxic in character, but merely irritating. However, the irritation arising from excessive fermentation in the stomach may lead to gastric disturbances of a more or less serious nature; hence the amount of carbohydrate taken under certain conditions must be adjusted carefully. ”

“ In other words, milk-sugar and cane-sugar are disaccharides, and if they are to be absorbed in forms capable of being made use of by the body they must be split apart into simpler sugars, viz., monosaccharides, such as dextrose, levulose, etc. The great bulk of the carbohydrate food consumed by man is in the form of starch, and this, as we have seen, is converted into maltose by the action of saliva and pancreatic juice. ”

“ Acid and subacid fruit juices do not contain sufficient carbohydrate or protein materials to unduly excite the digestive processes, while on the other hand they are very rich in Nature's best medicines, the mineral salts in organic form. Sweet grapes and sweetened grape juice should not be given to patients suffering from acute, febrile diseases because they contain too much sugar, which would have a tendency to start the processes of digestion and assimilation, to cause morbid fermentation and to raise the temperature and accelerate the other disease symptoms. ”

“ The proportions of sugar and acid best adapted to the production of wine of good quality are at least 20 per cent. of the former to not more than 0·5 per cent. of the latter. As these conditions do not always obtain in grape-juice, artificial methods are employed to supply the necessary constituents. Of these, the most rational consists in diluting the must until the amount of acid is reduced to 0·5 per cent., and increasing the sugar to a proportion of 20 per cent. by the addition of glucose. ”

“ A relish for sugar lessens the inclination for alcohol, and seldom accompanies the love of strong drink.
With young children, cane sugar is apt to form acids in the stomach, chiefly acetic, by a process of fermentation which causes pain, and flatulence, so that milk sugar should be given instead to those of tender years who are delicate, as this produces only lactic acid, which is the main constituent of digestive gastric juice. ”

“ Whether the sugar of fruits is formed within them, or introduced through the stem, and, if formed in the fruits, from what substance formed, are questions which have been investigated, but not wholly settled. It has been pretty generally held that starch in the unripe fruits is converted into sugar in the ripe fruits; the fruit acids inducing the change, as we know they have power to do. But starch is not found in the unripe stage of all fruits, and, in the cases where found, its quantity is sometimes too small to serve as the source of all the sugar of the ripened fruit. ”

“ Of course, there may be excessive fermentation, and then harm rather than good, is done. Ordinarily a certain amount of sugar is demanded by nature and practically all the food materials, even the meats, contain it. All the starches from vegetables have, as the end products of their digestion, various forms of sugary material. These are just the classes of foods that many nervous persons, suffering from constipation and anxious about their digestion, eliminate from their diet under the mistaken notion that they are indigestible, or are productive of undesirable fermentations. ”