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In the production of glucose by the hydrolysis of starch, a considerable quantity of fat occurs in the glucose liquor. From the previous treatment of the raw starch this fat appears to be an inherent part of the starch itself. This investigation was undertaken to determine whether fat is really combined with the carbohydrate in the starch molecule.

It was shown that:

(a) Fat is liberated upon the hydrolysis of starch.

(b) Although no definite compound of carbohydrate and fat was isolated in pure condition, still a residue relatively high in fat content was obtained.

(c) The fatty acid of the fat was chiefly palmitic.

(d) The palmitic acid was combined with an unsaturated material, of unknown composition, as an ester.

(e) The unsaturated material served as a link between the palmitic acid and the carbohydrate part of the starch.

It has been shown that maize starch cannot be regarded as simply made up of glucose, but contains a minor constituent, a fatty substance made up of palmitic acid and an unsaturated material whose composition is still unknown.

Fat associated with starch: It is well known that the starches as they are obtained ordinarily from the plants have a certain amount of fat associated with them. It has been assumed generally that this fat can be removed by solvents, and that its presence is a contamination of the starch with other constituents which occur intimately associated with the starch in the plant.

In the manufacture of glucose commercially from corn starch an insoluble product known as “refinery mud” occurs in the sugar liquor after the hydrolysis, and is separated by filtration. This refinery mud as recovered contains about 50% of fat, chiefly the higher fatty acids, and after washing and other treatment is sold as soap stock.

Considering the process employed in the commercial hydrolysis of starch it is improbable that the source of this fatty material can be attributed to extraneous matter accompanying the starch from the kernel, since its presence is observed only during or after the destruction of the starch by hydrolysis. The occurrence of free fatty acids during the hydrolysis and disruption of the complex starch molecule leads to the
interesting question of whether the fatty material constitutes an inherent part of the starch itself.

The present article is an account of an attempt to answer this question, and the results obtained lead to the following conclusions :

I. The major part of the fatty material present in starch cannot be removed by solvents before hydrolysis.

II. Hydrolysis of corn starch freed of extraneous fat liberates fatty acids.

III. The liberated fat is principally palmitic acid, but an unsaturated substance of unknown structure also occurs with it.

IV. The fat is liberated when hydrolysis has reached the erythrodextrin stage.

V. It is possible to obtain from starch residues containing relatively large amounts of fat combined with carbohydrate.

VI. The palmitic acid apparently is attached indirectly to the carbohydrate, but directly to the unsaturated component.

VII. Starches from other sources than corn also contain combined fat.

VIII. Extraneous Fat Accompanying the Starch.

The corn starch used was the best alkali-washed product available in the open market. A 82.26 g. sample of this material was extracted, first with ether, then with petroleum ether and finally with carbon tetrachloride. The duration of the extraction in each case was 36 hours.

The amount of soluble matter, chiefly fat, obtained by means of each successive solvent was Solvent. Ether (dry) 0.057, Petroleum ether 0.012, Carbon tetrachloride 0.046, total 0.115. Further extraction gave no weighable residues upon evaporation of the solvent. The residues, obtained by evaporation of the solutions from the first extractions and the weights of which are given in the table above, were yellow and gummy.

Upon solution in alcohol and titration with alkali, the combined residues gave an acid value 1 of 95.1. A comparison of this acid number with 186.0, that of the fat described under II, indicates the presence of considerable foreign matter, probably nitrogeneous in character

Food is the matter that is taken into the body to supply nourishment or to replace tissue-waste. Every physical act consumes a part of the force that has been derived from food. The maintenance of the body-heat consumes another part, and in growing individuals a certain amount is utilized in building up the new tissues.

Food as it is taken into the body differs very much in composition from the material that can be utilized in cell-growth and in replacing the tissue-waste. The function of digestion is so to alter the food that it may be absorbed by the blood, and prepare it for assimilation and utilization by the various tissues. The food of mankind is most varied in nature, differing with the seasons, and with climates, races and countries.

The study of foods is a most complex one, and until recently few scientific investigations along this line had been made. Fortunately, however, experiments are now being carried on the world over, and it is to be hoped that the subject of diet in health and in disease will soon be lifted out of the vale of empiricism where it has so long rested.

Water enters into the composition of every tissue in the body and forms more than 60 per cent, of the entire body weight of a full-grown man. As it is not burned up in the metabolic processes, it does not furnish any energy.

The earthy salts, which form about 6 per cent, of the body weight of an adult man, furnish little if any energy. They are most abundant in the bones and teeth, but they also enter into the composition of other tissues and fluids of the body. The principal salts of the body are calcium phosphate and the various compounds of potassium, sodium, magnesium, and iron. The mineral salts are very necessary to life and health.

Proteins are substances which contain nitrogen, are essential to life, and are regarded as combinations of the various amino-acids. In addition to carbon, hydrogen, oxygen, and nitrogen protein generally contains sulphur and some of them phosphorus, iron, copper, iodine, manganese and zinc.

The proteins are variously classified and two elassfications, based on the solubility, have been suggested, one by the English Society of Physiologists and one by the American Society of Biochemists.

Proteins are essential to life and the body is constantly metabolizing it, whether any is being taken in or not. In ordinary life the body is in protein (or nitrogen) equilibrium and as much protein as is ingested is metabolized. It is difficult to get a positive nitrogen balance, except after prolonged fasting or after recovery from wasting diseases or during the period of body growth.

A negative nitrogen balance is seen in starvation where more is used up than is taken in and in all wasting diseases, such as tuberculosis, in fevers, and hyperthyroidism. In pathological states such as nephritis there may be retention of nitrogen compounds in the body due to the failure of the kidney to excrete them, and if the amount exceeds a certain amount a condition of poisoning and uremia is brought about.

Some food proteins are better suited for human food than others, because when broken up into their elementary parts or amino-acids more of these can be utilized in forming the various body tissues than those derived from other foods. For this reason the proteins of milk, meat, eggs and fish are most valuable, those of rice and potatoes next in value, while those of wheat, maize and beans are distinctly inferior.