OFFICERS AND STAFF. BOARD OF CONTROL. His Excellency, Marcus H. Holcomb, ex-officio, President. James H. Webb, Vice President.. George A. Hopson, Secretary... E. H. Jenkins, Director and Treasurer. Wilson H. Lee. Administration. Chemistry. ...Hamden Wallingford New Haven ...Avon ..Orange E. H. JENKINS, PH.D., Director and Treasurer. Analytical Laboratory. †JOHN PHILLIPS Street, M.S. Protein Research. Botany. Entomology. Forestry. Plant Breeding. Vegetable Growing. WALTER O. FILLEY, Forester; also State Forester and State Forest Fire Warden. A. E. Moss, M.F., Assistant State and Station Forester. DONALD F. JONES, M.S., Plant Breeder. C. D. HUBBELL, Assistant. W. C. PELTON, B.S. † Absent on leave. In U. S. Service. Food Oils and Fats 處 Chemically all fats resemble one another in that they are combinations of fatty acids with glycerin. Physically they differ in that some are liquid while others are solid. The term "fixed" or "fatty oil" is generally applied to those fats which, at the ordinary temperatures, remain in the liquid condition, but chemical industry has eliminated this natural distinction by the introduction of the "hydrogenating" or "hardening" process which converts liquid oils into the solid state. As food stuffs fats belong to the same category as sugars, i. e., they are chiefly energy producers, in contrast with protein foods which are, in addition, tissue builders. When taken with other food in the diet, fats (and sugars) have the property of reducing the protein requirements of the body and this is what is meant by their so-called protein-sparing action. The calorific (energyproducing) value of fat is about 2.25 times as great as that of either protein or sugar, and it is practically the same regardless of the particular source of the fat or oil, or whether it be of animal or vegetable origin. By accurate measurement it has been found that one ounce of fat yields 264 calories to the body. On the basis of calorific values, substitutions among fatty foods in the diet may be made with considerable freedom, but personal tolerance, preference, or prejudice, will influence the choice in this as in other types of foods. Although so nearly alike in energy-producing capacity, the fats show differences in other nutritional aspects. We refer especially to the growth-promoting properties possessed by some fats and lacking in others. It has been shown' that butter possesses this peculiar efficiency to a marked degree and that the efficiency resides in the butter fat itself. This shows us an additional and important reason for the effectiveness of milk as a food for children. Other fats show this property, among them beef fat, and, as 1 Osborne and Mendel Jour. Biol. Chem. 16. 423-37 1913; ibid 20, 379-90, 1915. might be expected from their ingredients, the oleomargarines made of the so-called oleo-oil from beef fat. Lard and olive oil lack this peculiar property, as do those margarines also which are made from the commonly used vegetable fats and hydrogenated oils; as has been shown by Halliburton and Drummond. The particular substances or properties responsible for this phenomenon are obscure, and as yet unidentified components of the fats. They have been detected in other types of food, and for lack of better definition have been called "vitamines" or "accessory diet factors." Fatty foods not possessing the virtue just mentioned should not, however, be discriminated against on this account when used in the ordinary liberal diet, but it would appear to be inadvisable to eliminate butter entirely from the menu, particularly that of children. We have referred already to the process of "hydrogenation," by which the physical and chemical characters of fats are modified, the conspicuous physical change being that liquid fats are hardened and converted into solids. The question of the wholesomeness and digestibility of fats so treated at once presented itself. The considerable amount of work which has been done on this subject has not resulted in anything to prejudice us against the use of products so treated. Upon this point Ellis says: "It seems to be generally accepted by those who have investigated the matter, that the hydrogenated oils have as desirable a degree of digestibility as the oils from which they are derived." The debate as to their suitability for food has centered chiefly upon the presence of certain metals, more particularly nickel, which are used in the process of their manufacture. The amounts of nickel retained in the finished product, in the case of some hardened cottonseed oils, has been determined and quantities ranging from .020 to .075 milligrams per kilo (1,000 grams) found. The significance of such figures is better understood by comparing them with the quantities of nickel acquired by various foods prepared in nickel-lined cooking utensils which have been in common use for some years. Spinach contained from 25 to 27 milligrams per kilo; peas, 12 to 16; plums, 35; fruit cooked in 2% acetic acid (about one half the acid strength of ordinary vinegar), 65 to 67; cabbage, 83; sourkraut, 127; potato, 80. No injurious effects have been attributed 1 Jour. of Physiol., LI., p 250. Hydrogenation of Oils, Van Nostrand & Co., 1914, p. 144. to the use of foods so prepared, yet it is seen that they contain amounts of nickel one thousand or more times greater than has been found in the hardened oils examined. However, it is perfectly obvious that this phase in the production of hydrogenated products should be carefully controlled. The inspection of foodstuffs such as, of necessity, more and more engrosses the attention of this laboratory, involves tests for purity and tests to determine truthfulness of label or guaranty. When such inspections result in the detection of substances positively poisonous or deleterious to digestion and health, their value from the standpoint of public health is obvious to all. But instances of flagrant and vicious adulteration are largely passing out of the experience of the food control chemist of to-day, so that frequently the results of his labors lie within the realm of public health in its broader sense, which includes public economy. The substitution of one edible oil wholly or in part for another, and the sale of such substitute does not constitute a sin against the consumer's digestion, but it does defraud him of the difference in commercial values between the product he actually gets and that which he thinks he is buying. And now more than ever before he is anxious to protect himself in this direction. It is intended that our analyses should guide the consumer to intelligent purchasing; aid him to a better appreciation of comparative food values, and foster alertness to the deceptions of flashy labels and cunning advertising literature. Particularly at this time we desire to help him to co-operate in the program of economy that is being urged upon us. These general considerations seem justified, in view of recent inquiries which have come to us on this subject. In addition we shall indicate briefly the source, preparation and composition of the principal fatty foods and summarize our accumulated experience with them. We shall include also some analyses not heretofore published, and some data, not our own, which may be of interest from a culinary standpoint. Any classification of edible fats on the basis of their domestic uses will necessarily include the same fat in two or more classes, but for convenience we shall group them as follows: (1) Salad Oils. (2) Cooking fats and (3) Butter and its substitutes. |