ICE CREAM H. A. SCHUETTE AND FRANCIS J. ROBINSON Laboratory of Foods and Sanitation, The University of Wisconsin, Madison, Wisconsin
The evolution of ice cream from the iced bmerages and the rich, cloying, frozen desserts of a bygone period to the scientifically compounded, highly nutritious, modern product is described, with reference to typkal recipes of a later date and to the current commercial manufacturing practice. Factual evidence of its introduction into America, the land of its adoption where i t eventually outstripped the countries of its origin in the degree to which it has been developed and in the popularity accorded it, i s presented i n the form of nmspzper advertisements of the days of the Revolution.
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containing milk and cream and that this occurred wherever the quality of milk and cream as beverages or foods was highly regarded. Then, too, it seems that the literary men of earlier times had not as much concern for milk as for wine. ICED BEVERAGES OF EARLY DAYS
The Pharaohs of ancient Egypt are said to have had their wines cooled by the rapid evaporation of water contained in shallow basins well insulated by a packing of straw. In regions not far removed from mountains a rather common practice was the storing of snow that had been gathered by slave runners from the higher peaks. During the siege of Petra, Alexander the Great is reported to have had thirty trenches dug, filled with snow, and covered with oak branches in order that his coquettes might not languish for want of cool refreshments. Solomon (Proverbs, 25:13), too, appears to have appreciated cool drinks during the warm harvest season, but that was before Hippocrates, the father of medicine, cautioned:
EW food-manufacturing processes are so completely surrounded from ingredient to end-product by the applications and implications of chemistry as is the large-scale production of ice cream. Here testing and research properly belong to the sphere of the food chemist who has, however, allied himself with the dairy chemist, the colloid chemist, the physical chemist, and the bacteriologist to learn of the microscopic and It is dangerous to heat, cool, or make a commotion all of a ultramicroscopic structure of ice cream which manufacturers declare so vitally affects the palate-appeal of sudden in the body, let it be done which way it may, because everything that is excessive is an enemy to nature. Why should the product. Because ice cream is probably the most anyone run the hazard in the heat of summer of drinking iced complex dairy product on the market, one presenting a waters, which are excessively cold, and suddenly throwing the wide field for investigative attack, i t is not strange to body into a different state than it was before, producing thereby find the growth of our knowledge of this food closely many ill effects? But, for all this, people will not take warning, and most men would rather run the hazard of their lives or associated with the development of the several branches health than be deprived of the pleasure of drinking out of ice. of pure chemistry. Thus the dominant interest has The Romans, also, seem to have been fond of nivatae shifted successively from problems of empirical composition to those of qualitative and quantitative meth- potiones (cooled drinks) which were a rather common ods of analysis, then to the organic chemistry of its luxury of the wealthy, yet i t is probable that the pracconstituents and, more recently, to the physical chem- tice of cooling liquors a t the table of the great was not istry and the nutritional aspects of this food. Ice cream usual in any country outside of Italy and the neighborhas been called America's national dessert; yet its ori- ing states before the end of the sixteenth century. gin is as conspicuously foreign as that of the other foods At that time the use of snow and ice was well known a t which have already been discussed in this series (1). the French court although indulgence in this practice What is the meaning of the name "ice cream"? Is was apparently considered by the people themselves as i t a corrupted form of "iced cream"? Does the word a mark of excessive and effeminate luxury. And in "cream" have the force of an adjective in the sense that this connection it may be timely to recall a satirical this food is a cream ice, a product evolved from the ices comment on the voluptuous life of Henry I11 that by of a bygone period? Inasmuch as ice cream is not a royal order, but contrary to the prevalent notion that spontaneous invention, but rather the result of an their use would cause extraordinary maladies, this evolution of a confection, the conclusion that the latter sovereign had decreed that large quantities of ice and hypothesis is probably correct does not appear to be an snow should everywhere be preserved that the people might cool their liquors. a priori one. It is also during this century that other datum points Little is known of the exact origins of ice cream. Its beginnings are almost legendary. Although our knowl- pertinent to this account may be found. For example, edge of the refrigerated articles of food and drink of the the use of saltpeter in conjunction with ice or snow for ancients is limited to frozen or chilled fruit juices and the artificial production of low temperatures first bechilled wines, i t seems not illogical to assume that there came known during the middle of this period, but the was a gradual progression from water ices to mixtures fact that other salts, particularly sodium chloride, might 4ii9
chapter on this subject of how this sovereign was so pleased with the "frozen milk" which his new French chef had prepared for a regal banquet that he pensioned him with twenty pounds sterling a year, provided he would keep the recipe a secret and make the dish for no one else. It seems reasonable to assume that during the eighteenth century ices and ice cream became well known, for in a number of cookbooks of that period recipes for making these dishes may be found. One such, "to make ice cream," is here reproduced verbatim for it illustrates the practice followed in England a t that time (2).
FIGURE ~.-FRONTISPIECE AND TITLE PAGEOF EMY'S" THEART OF MAKING FROZEN DESSERTS'' be similarly employed appears not to have been discovered until later. Like many other important discoveries--gunpowder was once declared to be a trifling find-artificial ice was a t first used merely for amusement, its preparation an interesting experiment, for apparently none suspected that it would ever become first an important item of luxury and then one of necessity. FROZEN DESSERTS APPEAR
This period saw the appearance of frozen desserts in France, introduced in Paris, as has been often claimed for her, by Catherine de Medici herself. Perhaps this is true and if so it was indeed an accomplishment for one whose life, up to the time of her marriage to the Duke of Orleans a t the age of fourteen, had been spent in an Italian convent school. It seems plausible, however, that the Italian cooks following in her retinue gave France these new desserts which eventually became an article of commerce in the year 1660 or thereabouts when Procopio Cultelli, an Italian, established a caf6 in Paris where "iced creams,'' sherbets, and frozen lemonades were served. Its proprietor, it may be added, had begun his career as a limomdier, being one of some two hundred fifty master limonadiers who were organized as a trade guild which officially supplied Parisians with lemonades. England, during the reign of Charles I, was also to make the acquaintance of this new dessert but, if the reported conditions surrounding its introduction are indeed factual, royalty alone was to know of it. The story has several times been quoted by those who have prefaced their treatises on ice cream with an historical
Take two Pewter Basons, one larger than the other; the inward one must have a close Cover, into which you are to put your Cream, and mix it with Raspberries or whatever you like best, to give it a Flavour and a Colour. Sweeten it to your Palate: then cover it close, and set it into the larger Bason. Fill it with Ice, and a Handful of Salt; let it stand in this Ice three Quarters of an Hour, then uncover it, and stir the Cream well together; cover it close again and let it stand Half an Hour longer, after that turn it into your Plate. These Things are made at the Pewterers.
The most pretentious contribution of that day to the subject of ices and ice creams was that of the Frenchman Emy whose efforts in this field, "L'art de b i a faire les glaces d'ofice" (The Art of Making Frozen Desserts), took the form of a treatise of some two hundred forty pages (Figure 1). Its raison d'&tre,so the reader is told in substance, was the absence a t that time (1768) of authoritative information on ways and means of making frozen desserts good and agreeable. This end might be attained, it was stated, by giving attention not only to the proper preparation of the ingredients but also to the manner of congealing them. The author does not merely give directions for producing a "food fit for the gods" but even expounds on the origin of ices as well as on the philosophical explanations of the causes for the freezing of liquids. His "explanations" of freezing, however, do not indicate an intimate acquaintance with the scientific opinions current in his time. ICE CREAM ARRIVES IN AMERICA
Ice cream had definitely arrived in America during Revolutionary days, if not before this time, for what is deemed to be the first newspaper advertisement announcing the sale of ice cream on this side of the Atlantic appeared during this period. It was printed in the Neu, York Gazette of May 19, 1777 (Figure 2). Herein Philip Lenzi, a "confectioner from London," announced that ice cream was obtainable a t his shop almost every day. This advertisement was followed by one three years later in which Joseph Come proclaimed that he was still serving the "Ladies and Gentlemen of this garrison, upon the most reasonable terms,
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with ice cream " (Figure 2). Inasmuch as the words "ice cream" were given a conspicuous position in this advertisement the thought suggests itself that this confection had become fairly well known in a relatively short time. But quite apart from the antiquarian interest which attaches to these advertisements is the fact that they were in a sense prophetic of the day when the adopted home of ice cream was to outstrip the countries of its origin in the degree to which it was to be developed and in the popularity accorded it by Americans who apparently never took seriously the Hippocratic advice against the use of iced foods. What recipe did this "confectioner from London" and his competitor follow in making their ice cream? The answer is, of course, a matter of conjecture, yet it seems not improbable that in the cookbooks of their day may be found some which, if not actually adopted by them, were at least typical of the time. Such a one from "The Experienced English Housekeeper'' (1784). a popular book in its day, might very well serve as an example (3). Pare, stone and scald twelve ripe apricots, heat them fine in a marble mortar, put to them six ounces of double refined sugar. a pint of scalding cream, work i t through a hair sieve, put it into a tin that has a dose cover, set it in a tub of ice broken small. and a large quantity of salt put amongst it, when you see your cream go thick around the edges of your tin, stir it, and set it up. take it out of your tin, and put it into the mould you intend i t t o he turned out of, then put on the lid, and have ready another tub with ice and salt in i t as before, put your mould in the middle and lay your ice under and aver it, let it stand four or five hours, dip your tin in warm water when you turn i t out; if it be summer you must not turn it out till the moment you want it; you may use any sort of fruit if you have not apricots, only observe to work it fine.
Already a trend toward development of the formula is apparent, likewise the probability that ice cream was not then necessarily a seasonal dish. New York, the garrison socially brilliant during British occupancy, gave way to New York the young na.tion's 6rst capital in which another phase of social life began with its balls, its banquets, and its entertainments. To these functions ice cream was a contributive refreshment. It found a place also on the dessert list of banquets honoring officialdomwhen the nation's capital was to find its permanent home in Washington, D. C. The credit for having introduced it there is claimed by some for Mrs. Alexander Hamilton; others aver that this honor should go to Mrs. James ("Dolly") Madison. I t seems certain that ice cream did not appear only at the tables of the socially elect for we find that many of the American cookbooks of the early part of last century contained at least one recipe for making this dish. Even the strenuously titled "Cook not Mad; or Rational Cook'mg" (1831) includes among its "good Republican dishes" a recipe for making ice cream and in a cookbook of somewhat later date (1851) there may be found complete directions for making no less than thirty-four diereut ice creams and eighteen different water ices (4).
May 19. 1777
J O S E P H CORRE,
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ICE CREAM,
New York Gazette,
In marked contrast to the simplicity which characterized the early recipes are those of a later date. These, when analyzed in terms of the present-day practice appear to be frozen custards, since eggs and milk form part of their composition. Their appearance marks another distinct development in this dessert. Data on the first appearance of these custards are, at the moment, obscure, yet an example quoted from amidnineteenth century "simplified and entirely new system of cookery" bearing the bizarre title of "The Gastronomic Regenerator" (5) is illuminating. Vmillo Cream Ice Put the yolks of twelve eggs in a stewpan, with half a pound of sugar, beat well together with a wooden spoon, in another stewpan have a quart of milk and when boiling throw in two sticks of vanilla, draw i t from the fie, place on the lid and Let remain until partly cold, pour it over the eggs and sugar in the other stewpan, mix well, and place i t aver the fire (keeping it stirred) until it thickens and adheres t o the back of the spoon, when pass it through a tammie into a basin, let remain until cold, then have ready a pewter freezing-pot in an ice-p?iI well surrounded with ice and salt; put the above preparation into it, place on the lid, which must fit rather tightly, and commence twisting the pot around sharply, keeping i t turned for about ten minutes. when take off the lid and with your spatula clear the sides of the interior of the pot, place the lid on again, turn the pot ten minutes longer, when again clear the sides and heat the whole well together until smooth, i t being then ahout half frozen, then sdd four glasses of noyean or maresquino and a pint and a half of cream well whipped, beat the whole well together, place the lid upon the top, keep twisting i t round a quarter of an hour, clear well from the sides, beat again well together, proceeding thus until the whole is frozen into a stiff hut smooth and mellow substance. . .
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I t is indeed an interesting reflection of the public taste of those days that the addition of a liquor to a "cream
icev-four out of the eight recipes are involved-was apparently deemed necessary but the use of artificial coloring matter, such as cochineal, was a matter of personal preference, "if approved of." The "pewter basons" (Z),the tightly covered tin (3), or the freezing pot (5) set in a tube of ice were in time superseded by more efficient appliances designed not only to reduce the labors of the pastry cook's assistant but also to improve the quality of the product, for ice cream, in the early days of its preparation, was not agitated as is the current practice. I t was "still frozen" and merely stirred enough to remove the congealed portions from the sides of the vessel so that the unfrozen cream might be brought into contact with the refrigerant.
apparatus as was also the Austin freezer. The latter was a device for congealing the cream in the annular space between two concentric cylinders, the smaller of which was filled with ice and salt whereas the larger was surrounded by this freezing mixture. The cream was agitated with a plunger which served also to scrape the frozen product from the walls. The Masser freezer suggests the modern domestic contrivance with its dasher and revolving container but imitates its predecessor in having also a central freezing core. One other freezer (8)merits mention, not because of any really practical features embodied in its operation but because of the fact that the inventor was probably ahead of his time by actually working for an "over-run" in the ice cream which his freezer would produce. The nature of this invention consisted in causing "a blast of THE ICE-CREAM FREEZER chilled air to permeate, be diffused through and disturb The story of the development of the ice-cream freezer the liquids and materials of which ice cream is made." (6), from the crude beginnings alluded to above to the The chilled blast was obtained by drawing air into a very efficient modern commercial units, constitutes receptacle which was made to surround the sides and quite another field of interest. Of this only that phase bottom of the vessel containing the refrigerant. By which is pertinent to the' domestic appliance need be being led through horizontal branch tubes, it was made reviewed here. France, already rich in ice-cream lore, to bubble up "throughout the whole body of the liquids began to issue freezer patents in 1829; Great Britain and materials intended for ice cream and besides exgranted letters patent to Thomas Masters in 1843 (7) tracting caloric from them by its own immensely exfor a device which consisted essentially of a pewter tended contact therewith," it thoroughly "disturbed can containing a three-bladed revolving "spatula" and them and brought "every portion of the same into consurrounded by a "frigorific material"; whereas on this tinually repeated contact with the refrigerating surside of the Atlantic such patents were first granted in faces." Much was expected, it seems, of an air current the year 1848 (Figure 3). The first of this group of of the force and volume that one could inveigle out patentees makes mention in his application of a freezer of an ordinary manually operated bellows and drive then in use known as "Johnson's," of which the novel into a slowly congealing mass! With the evolution of the freezer in the years that followed came improvements in refrigeration processes, the result of which was that ice cream began to leave the shop of the confectioner for the factory of the wholesaler. That movement was initiated in the United States by Jacob Fussel in 1851. Similar establishments, stimulated at first by Fussel's pioneering and then by the application of electrical power and improvements in manufacturing equipment and transportation facilities, sprang up during the latter part of the past century. The advantages of large-scale production had become apparent. FIGURE 3.-PIONEERS OP THC ICE-CREAM FREEZER INDUS~Y
IN A ~ R I C A ICE-CREAM STANDARDS FORMULATED Freezers patented in the United States, reading from left to Soon after the turn of the century all the food indusright: by W. G. YOUNG,No. 5601, May 30. 1848; by A. H. AUSTIN,NO.5775, September 19, 1848; and by H.B. MAsseR, tries were to feel the newly invoked police power of the No. 5960. December 12. 1848. federal government in the form of the Food and Drugs
feature was a revolving shaft or beater on which there were affixedtwo curved wings for agitating the cream. Although it was known as "Johnsou's Patent Ice-Cream Freezer," there is no record to show that this device was in fact protected by letters patent as the name suggests. To W. G. Young, who "greatly facilitated [the operation of freezing] by causing the freezer itself to move rapidly as well as the cream inside" apparently goes the distinction of receiving the first freezer patent in the United States. I t was a cumbersome piece of
Act of 1906. That its authors sponsored it as an iustrument of regulation but that it exceeded this end by becoming also an unconscious incentive to research in improvement of product, is for the moment beside the point. Relevant to this account, however, is the fact that, following the passage of this law, there came the formulation of a legal standard for ice cream entering interstate commerce. Such of the several states as had not already done so established their own standards for the purpose of intrastate commerce. In so far as they pertain to butter-fat content, these standards
vary throughout the nation from eight to fourteen per cent., the increment being, with one exception, two per cent. I t is difficult to account for this variation. Obviously it reflects the varied preferences of the consumers, some demanding a rich product, others one less so. The distribution of these butter-fat standards defies any exact analysis on a geographical basis. It appears, however, that in the states on the Atlantic seaboard and in the contiguous group the choice is almost equally divided between the eight and ten per cent. products, but in the Pacific coast and mountain states region the ten per cent. ice cream-no lower standard is here recognized-far outstrips in popularity its nearest competitor, one of fourteen per cent. butter-fat content. When the Mississippi river is made the point of departure in a classification scheme it appears that east of it the eight and ten per cent. standards share an equal popularity, whereas west of this line ice creams of ten and twelve per cent. butter-fat content find the greatest favor, the former being in the lead. And so it is throughout the country at large. The ten per cent. fat standard has more proponents than any other; next in favor is that which is also the minimum, or eight per cent. Approximately three-fourths of the states have established two butter-fat standards. One affects plain ice cream whereas the other, which is always lower, pertains to those varieties which contain either fruit or nuts. Wherever such a double standard exists the difference is, with one exception, two per cent. THE INGREDIENTS OF ICE CREAM
The ingredients of an ice-cream mix of an earlier day were cream, milk, sugar, a flavoringmaterial-the latter when a fruit serving also as coloring agent-and eggs. I t is still the household practice to make it from some or all of these materials. When, however, science became interested in ice cream, cookbook methods and recipes were scrapped, the mix was accurately standardized for butter fat, milk serum solids, sugar, and lesser ingredients with the result that a product of better quality and texture, of greater stability and with less tendency to become icy in shipment or in storage under soda fountain conditions was obtained. Most of the raw materials of the modern commercial ice cream are, fundamentally, still the same as those of old although it is probably true, in a sense, that the icecream maker now reconstitutes a cream of such physical and chemical characteristics as will yield a finished product of the desired qualities. Seven diierent kinds of substances are now utilized in compounding an ice-cream mix, the number of each actually entering any one formula being, of course, determined by the type of finished product desired. These substances are dairy and poultry-yard products, sweetening agents, protective colloids or "stabilizers," farinaceous materials, flavoring agents, and coloring matter. An eighth group of ingredients, so-called ".improvers," should perhaps be mentioned for his-
torical reasons if none other. They have lost the vogue which they enjoyed some time ago for it has since been experimentally demonstrated that they possess doubtful merit. These substances are for the most part of biological origin. The majority of them are either rennet or pepsin preparations and, therefore, they depend upon the action of a coagulating enzyme. Among the dairy products upon which the ice-cream maker draws are cream, sweet unsalted butter, butter oil, and milk, or certain of its manufactured products. Besides malted milk, casein, and albumin, the latter are those which are obtained by concentrating it, whole or skimmed, with or without the addition of sugar, or by dehydrating the skimmed product to a powder. The use of unsweetened evaporated milk is limited to those mixes in which its presence will not be noticeable. Malted milk finds also a narrow field of application since it can be used only for making a special ice cream. The same is true of milk albumin although the situation here is not analogous. Some hold that an ice-cream mix to a large extent owes its whipping ability to this ingredient. Sucrose is still the popular sweetening agent. It is, however, finding competition in commercial invert sugar and in those misnamed-scientifically speakingmaize products, corn sugar and corn sirup. Maple sugar, honey, and malt sirup also do service in this capacity but theirs is a dual r81e in that they are added to an ice-cream mix for the flavor which they also contribute. Eggs fresh from the shell, frozen or desiccated, or sometimes only the powdered yolk itself, constitute the contribution of the poultry yard to the ice-cream industry. The custard type of product requires the use of any one of these except the last-named. Since this substance functions as a protective colloid, it finds a more general application because of the ability of materials of this nature to inhibit the growth of ice crystals for it is a well-established fact that an ice cream, having been whipped while it was being frozen, contains a very large number of such crystals and that they tend to coalesce on standing. For this reason, and also because materials of this nature retard the development of "sandiness," a condition ascribed to the separation of lactose crystals, the latter is called a "stabilizer." There are still other stabilizers available for use. Another-very widely used-is gelatin. Once outlawed as an ice-cream ingredient, since its presence in the mix was interpreted as an attempt a t questionable gains, it now has a recognized place there, thanks to our newer knowledge of nutrition. Its stabilizing action does not cease when ice cream enters the alimentary tract and is ingested for it has been shown that it is an ideal adjuvant in the digestion of milk protein in that it retards the formation of coagulated masses of casein. Such a curdy mass offers a much smaller surface and hence is more resistant to gastric digestion than is an emulsion. It acts also as a demulcent in that, because of its presence, the intensity of cold in ice cream is not felt as much as in ice (9).
Besides stabilizers of animal origin, of which gelatin is the outstanding representative, there are some, as for example gum tragacantb, Indian gum, agar-agar, and preparations made from the carob bean, which are obtained from vegetable sources. Regardless of the type of material used, the quantity necessary to effect the desired results is relatively very small with respect to the total quantity of the ingredients of an ice-cream mix. In the group of farinaceous materials utilized by the ice-cream industry are tapioca, rice, corn and arrow root starch, and rice or wheat flour. It is only the frozen custard formula which requires such an ingredient. The substances which are used to flavor an ice-cream mix may be either the natural article or a synthetic imitation thereof. They are too obvious to require enumeration. The trend in choice of coloring matters has been away from those of natural origin, except burnt sugar or caramel, to synthetic dyes. The use of the latter is, however, restricted to such as are of approved character and of certified quality.
ally caused the ice cream to take on a curdled appearance when melted. The next step, freezing and the simultaneous incorporation of air, or whipping, is that stage in which the mix actually assumes those external characteristics which make it in fact ice cream. It is frozen and wbipped a t a temperature somewhere between 21°F. and 25'F., and, when the desired increase in volume or "over run" has been reached, the semifrozen mass is drawn off into cans which are then placed in the hardening room a t 0°F. Here the freezing is completed. The product is now ready for the retailer. Leigbton (12) points out that ice cream is not stable unless there is ice formation and that this stabilization of the wbipped mass may be attributed to one of two possible factors: either the small ice particles go into the interfaces of the air bubbles or the foam is stabilized by the inaease of the protein-fat concentration due to the separation of the ice. He adds also that these relationships will bear investigation. FOOD VALUE OF ICE CREAM
STEPS IN MANUFACTURE
Eight distinct operations are involved in the manufacture of a commercial ice cream. A thorough mixing of the ingredients is followed by the application of heat in order to dissolve them. Close attention to the first step helps to increase the capacity of the mix to whip over that which would result if this precaution is disregarded, a better body and a smoother texture in the finished product are in part obtained as a result of the second operation. Pasteurization of the mix is the next step. Aside from the fact that this is a health measure which makes ice cream a safe food, i t enhances also its keeping qualities. A very important operation now follows. While still hot the mix is homogenized, or "viscolized," the results of which are manifold, to wit: a multiplication of the number of fat globules and with i t enlarged surface areas, an increase in the viscosity of the mixture, a reduction in the quantity of gelatin required to form a gel in the ice cream ( l o ) , and a reduction, by about one-half ( l o ) , of the size of the air cells in the finished product. The sum total of all of these effects is a smooth ice cream of an improved quality. The usual practice, after homogenization, is to cool the mix to a temperature slightly above freezing and to hold it a t this point for a t least a day. This operation is known as the aging or ripening stage. Since it is apparently closely connected with the surface phenomena and equilibria of the proteins and fat particles (11) i t would seem that during this period of rest these ingredients come to equilibrium with the surrounding medium (12). It was for the purpose of effectingeconomies in time here that recourse was once made to the use df so-called "improvers." These economies, however, were often nullified by the fact that the coagulation of the proteins proceeded too far with a resulting loss of the entire batch or that the enzymic action of the ".Improver," although temporarily controlled, eventu-
Ice cream is a concentrated food. It is a milk product, a sufficientreason in itself why its dietary virtues need no praise. A brief re-statement of these virtues should, therefore, suffice. An easy digestibility, qualitatively and quantitatively abundant mineral constituents and proteins wbich are complete and better assimilated than most others, make ice aeam a food of an unusual nutritional value. It has a high energy content and is well supplied with vitamins. It is an outstanding source of vitamin A. As for G , i t has been estimated (13) that, weight for weight, it should contain about two-thirds to threefourths as much of this vitamin as fresh milk, itself our most important source of this factor. It is a good source of B but not an outstandmg one for either C or D. Pasteurization, if i t does not destroy, a t least probably depletes the vitamin C stores of the mix, a loss which could be partially compensated by the incorporation of fresh fruit. The vitamin D content of milk fat is less than that of some other fats, notably that of the egg, yet, as Sherman points out (Id), the amount of this vitamin obtained by the individual is considerable in view of the consumption of the former not only as milk itself but also in the form of its products, as cheese, butter, cream, and ice cream. Besides those properties of its components wbich have been enumerated above, ice cream has nutritional virtues of its own. The stabilizing action of gelatin and its prevention of the formation of large curds in the stomach, a condition insuring a better and more rapid digestion of the casein, has already been mentioned. Ease of digestion is further facilitated by the finely dispersed condition of the milk fat globules, the result of homogenization. Ice cream, as now made, is no longer the rich, sweet, cloying product of the days of its infancy. Rather it is a highly palatable food, an attractive way of getting milk into the diet. Pediatricians do not hesitate to
feed it to infants when they have reached the age when they may have other foods besides milk, and physicians prescribe it for convalescents. The popularity of this f w d is reflected statistically by the fact that in the year 1910, when the first data were made available, the per capita annual consumption was 1.04 gallons. Nineteen years later it had almost trebled (3.0 gallons)! Ice cream is not the product of any facile magic. It apparently took its origins in the water ices and chilled
beverages of ancient times and eventually, by a gradual process of evolution, became the grand dessert of sixteenth century Italy and France. During modern times i t acquired a more democratic flavor. I n America, especially, has it left the small shop of the confectioner and the kitchen of the housewife for the factory of commerce to become a standard commodity within the reach of any one having a five-cent piece. I t is our national dessert.
LITERATURE CITED
(1) S C ~ E T T EH., A,, "Know your foods. I. Oleomargarine,'' J. CBEM.EDUC..5, 1621-6 (Dec., 1928); 11. "Graham bread," ibid., 6, 59-64 (Jan., 1929); 111. "Canned foods." ibid... 6. 314-8 (Feb... 19291. GLASSE.MRS. HANNA,"The a r t of cookery made plain and easy. Which far exceeds any thing of the kind ever yet published by a lady," 5th ed.. London, 1755, p. 332. (The first edition of this book appeared in
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1747) -. -.-, RAFRALD,ELIZABETH,"The experienced English housekeeuer." minted for R. Baldwin. London. 1784.. D. - 249. PARKINSON, "The complete confectioner, pastry-cook and baker," Leary and Getz, Philadelphia, 1854, pp. 69-77. SOYLER, ALEXIS,"The gastronomic regenerator," 3rd ed., Simpkin, Marshall, and Co., London, 1847, pp. 597-600. (6) SCH~JETTEAND ROBINSON, "The development of the ice
. -. .
cream freezer." Trans. Wisconsin Aced. Sci., 27, 71-83 (1932). (7) MASTERS, THOMAS, British Patent 9825, July 6, 1843. ( 8 ) COPFEEN,GOLDSMITH, In., U. S. Patent 6865, Nov. 13, 1849. (9) CUSIINY,"A textbook of pharmacology and therapeutics." 9th pd., revised, Lea and Febiger. Philadelphia. 1928, p. 45. (10) DAmBERc, "The texture of ice cream," New York Agr. Expt. Sta., Tech. Bull. 111 (Mar., 1925). "Why age the icecream mix?" Ice Cream Trade (11) SOMMER, 1..25.41-3 (Tulv. 1929). (12) L E I G ~ O N' ',~ b p & t i o n ' of physical chemistry t o ice
(14) S ~ E W A N ibid., , p. 45%
