WWI “M WWII ‘ W H!“ J O J) r .11 __ H .32 H L’ 7 31 ’i'.’ 3 \ll Lined; ID i THE RELATION OF SUGAR CONTENT OF THE ICE CREAM WX T0 OVERRUN AND QUAUTY 0F ICE CREAM Thesis for Degree of M. 5. 'Tcshihide Matsui i 9 2 r3. :1“ v: 'i ‘5 I've. ‘ "‘13?" I. k .' ‘.h ‘ " ,ka 4% w) 1H. clr|;a . ... u l! (flimfl «u—m- mm RELATION or swam comma: or THE ICE CREAM MIX TO manna AND QUALITY or ICE cam THE RELATION OF SUGAR 008131!!! 01' THE ICE CREAM IIIX T0 OVERBUI LED QUALITY 03' ICE CHEM! 1110613 for Dost“ of lbs. Momma. 1943111 1926 ACKNOWLEDGEMENTS Tho author desires to soknowlsdgs his indobtodnoss to O.E. Rood, Professor of Dairying, and 2.8. Lucas, Assooisto Professor of Dairy'nsnufsoturos, for helpful suggestions and kindly criticisms. 1.053870 CON TEN TS Page 'INTBODUCTION 5 REVIEW OF LITERATURE lo Relation of sugar to the freezing point 11 Relation of sugar to overrun 12 Relation of sugar to quality 15 Sugar substitutes 18 EXPERIMENTAL WORK 20 A. Plan of experiment 20 Object 20 General plan 21 Methods of testing 27 B. Experimental data 29 Specific gravity 29 Freezing point 30 Overrun 31 Determination of the time required for ice cream.with different percentages of sugar to melt under'summer conditions 40 The effect of different percentages of sugar on the body and texture of ice cream 43 0. Summary 45 COHCLUSIONS 47 BIBLIOGRKPHY 48 INTRODUCTION Ice cream has been defined as a frozen dairy product containing sugar, with or without natural flavoring, and containing a specified amount of butterfat as required by the laws or regulations of the various states and the Federal government. It is unknown when, or by whom, ice cream was first made. Its origin is lost in antiquity. From the informa- tion available, however, it seems probable that recipes for water and milk ices were brought from Asia by Marco Polo, who visited Japan in the thirteenth century. They were introduced into France about 1550 by Catherine de Medici, and Frenchmen in turn brought them into England. In the United States the industry has been deveIOped commercially to a much greater extent than in any other country. English “cream.ice" was made by a French cook, Clement, and made from cream and milk, sugar, eggs, arrowroot or flour, and flavoring. In this country ice cream was first sold in New York by a Mr. Hall, but was first made commercially in 1851 by Jacob Fussel, a milk dealer of Washington and Baltimore, who began its manu- facture as a side-line to his regular business. From an humble beginning, the industry grew rather slowly until about 1900, when the production in the United States was about 25,000,000 gallons. Since then, due to mechanical refrigeration, improved machinery, and -i5-- a greater technical knowledge of the processes of manu- facture, the business has increased tremendously until now there is an annual output of nearly 300,000,000 gallons. It is one of the youngest of the world‘s manu- factured dairy products. In less than a century, it has sprung from a rare delicacy to a nation-wide ne- cessity, and enjoyed by practically everyone regardless of season. From a national industry in America, ice cream making has developed into an international one. Echrting of ice cream mix to the Orient has been car- ried on by manufacturers of the Pacific Coast for years. American machinery, flavors, etc., are going into Germany, Japan, and other countries each year. "Japan has taken quickly to frozen cream products. Commercial Attache E.G. Babbitt says (1) there are several concerns manufacturing ice cream for wholesale distribution. As there is much milk produced around the district of Tokyo, the manufacturers find ' it more profitable to make and ship the ice cream into the city than to send in the milk.‘ There is a widely known drug store operated by a Japanese who learned his trade in Los Angeles. He is catering to the popular demand in making both ice cream and ices. 'Fresh milk and cream,‘ he states, 'form the basis of most of the ice cream manufactured, but there is much adultera- --7-. tion. Cornstarch, gelatin, and ice creamchwders are used to some extent; also eggs. The best is made with imported flavors. According to unofficial estimates there are 4,000 retail establishments with a total yearly consumption of 6,570,000 gallons." According to the statistics of the Chiba Live Stock Experiment Station in 1924, the value of ice cream is estimated at nearly 3,500,000 yen. The history of milk in Japan is very short, dating back to not more than fifty years ago. It is told, however, that cow‘s milk and dairy products were introduced about 1,500 years ago through Korea, but they were used merely as medicine and not as foodstuffs. After the Meiji restoration cow's milk and dairy products were turned to account as foodstuffs. Ice cream is said to have been introduced by an.American to Japan. In 1920. the first manufacturing plant was built in Tokyo by the Oriental condensed Milk Co, and in 1921 the Kyokutc Condensed Milk Co.(Ltd.) started in this business on a large scale, using the American system, an example which was followed by entrepreneurs. The larger res- taurante use electric power in the manufacture of ice cream, some hotels use the ammonia process, but the smaller employ hand turned freezers. The Japanese people are becoming educated to the use of ice cream as a staple food, and, as this process goes on, the “BUOfl construction of large plants capable of producing ice cream in large amounts the year around, will be a natural development. The ice cream industry offers an exceptionally good market for sugar. This material performs useful functions in ice cream. In this experiment, sugar in ice cream was studied in its relation to the overrun, freezing point of the mixture, body and texture, and palatability of the final product. Although sugar contributes to the food value of ice cream, its chief function is to properly sweeten the product and make it palatable. The sweetening value can be supplied by other food products than sugar. The amount of sugar is important because of its bulk; and its effect on rate of freezing and overrun. Sugar also acts as a slight preservative of the cream. Cane and best sugar are identical in chemical composition and are the chief sources of sweetening in ice cream. These sugars are ordinarily used in the granulated form and should be clean and free from mold. Sometimes invert sugar syrups prepared by treating cane or beet sugar with tartaric or other acids, are used in the mix. Glucose and corn sugar were considered sugar substia tutes by the Food Administration during the war, but invert sugar is not so considered because it is --9-- manufactured from the same sources as sugar. Honey together with malt, maple and other syrups, are sometimes used as sweeteners. -.1o-- REVIEW OF LITERATURE. The ice cream.industry has been developed so recently that research on its manufacture is very brief and practical in nature. Early methods in this industry were kept secret and scientific workers in educational institutions and private corporations that published their findings began their research work after the rudimentary methods of making ice cream were fairy well established. Iashburn (2) in 1910 published a very extensive article giving the results of investigations on ice cream which even today are of outstanding importance. He states in his bulletin entitled, “Principles and Practice of Ice Cream Making“ that {being an American product, the literature on this subiect is doubtless almost entirely in the English language. It is quite safe to say that there is no other American dairy industry representing so large an investment which has received so scant attention at the hands of investigators.“ -Until 1910, there were almost no articles treat- ing ice creaa.making, save from the standpoint of the caterer. There were a few books, giving recipes of ice cream.making in.c1umsily stated style and makeup, but they contain nothing regarding the principles of freez- ing, and, but little of methods. --11-- Relation of Sgggg to the Freezing Point. Sugar goes into true solution and has a low molec- ular weight as compared with eggs or gelatin. Washburn (2) states the effect of increased sugar content is to depress the freezing point very materially and uniformly in proportion to its presence. Ice cream sweetened to average taste contains approximately fourteen per cent added sugar, and has a freezing point of about 28.5 F. He obtained the following data: Table I:- Relation of Sugar to the Freezing Point of Ice Cream Mixes. Material Observed freezing point Plain SkiMilkOOOOI.OIOOOOOOOOOOOOOOOO0031.03 F. 5% Solution in skimmilk.................30.40 F. ‘O% " " W .................29.70 F. 14% N N H .................28.60 Fe 25% " " " .................27.07 F. The more sugar there is in any ice cream, the lower the freezing point and the more difficult it is to hold-it frozen hard. In 1921 Reid (3) found that increase of sugar content from ten to twelve per cent changed the freezing time from fifteen to sixteen minutes; while raising the sugar content from fourteen to sixteen per cent resulted in an increase in time of freezing from eighteen to twenty three minutes. That is, an increase of sugar in- creased the time required to freeze, and this proved to be greater with the higher percentages than with the lower percentages of sugar. Relation.g£,§gggg,gg Overrun. Yield or overrun applied to ice cream has been defined as "the volume of ice cream obtained over the volume of mix before freezing." It is the result of ex- pansion, due chiefly to the air which is incorporated by the violent agitation during the freezing process. Factors affecting overrun may be divided into two general classes according to Fiskld): I. Kind and preparation of‘materials used, 11. Manner or method of freezing. Gregory and:lanhart(5) divide these factors into three general classes: 1. Composition of the mix., II. Preparation and treatment of the mix. III. Freezing conditions. Pisk(4) illustrated these factors as follows: (A). Age, Viscosity, acidity, and fat-content of milk and cream; (B), Size of fat globules in cream; (C), Aging of mix; (D), Pasteurization of milk and cream; (3), Use of homogenizer and emulsor; (1), Method of mixing; (0), Use of condensed mix; (H), Amount of duels-ea sugar; (1), Different kinds of flavoring; (J), Fillers and binders; (E). Total solids in mix. Thomas (6) thinks that the sugar is a much more important factor in controlling overrun than is milk solids. Sugar being the cheapest solid used in the ice cream mix, the manufacturer naturally endeavors to use the largest amount possible, yet not an excessive amount so that quality of the product will be impaired. There is an optimum amount or combination of sugar to use with the other constituents of the mix for the best results. Davis(7) in 1916 reports that decreasing the amount of sugar in the ice cream.mix below normal increased the per cent of swell; while increasing the amount of sugar in the ice cream mix above normal decreased the per cent of swell. Uilliams(8) classifies sugar as one of the major deterrents of overrun. He states that," sugar increases the density of the mix. This increase in density is one of the principal means of retarding the abnormal ever- run that otherwise would be obtained. In mixes contain- ing thirteen and sixteen per cent sugar, high overruns can be obtained and the final overruns are about the same for both.mixes.' Reid(5) conducted an experiment to determine the direct relation of sugar content to the ultimate swell or overrun of the finished ice cream. Five different mixtures were used, the percentage of sugar varying from eight to sixteen per cent. There was an increase of four and three tenths per cent in overrun of the mixture containing but eight per cent sugar. A loss of four and three tenths per cent overrun was noted in comparing mixtures containing twelve to sixteen per cent sugar, due to the use of the larger amount. Haximum swell was obtained when twelve per cent of sugar was added to the mixture. He further states that the difference in temperature of brine did not effect the relative curve of the maximum.swell, and that sugar was the principal factor influencing the swell of the mixture. According to Manhart and Gregory's (5) investiga- tion into ice cream commercial practices, the data collected from forty seven ice cream plants, do not show a lower overrun in those mixes containing the higher percentage of sugar. The mixes were divided into three groups according to sugar content, as 1, containing twelve and two tenths per cent of sugar; 11, thirteen and one tenth per cent; and III, four- teen and two tenths per cent. The average per cents overrun for groups I. II. III. were ninety four, ninety and five tenths, and ninety and seven tenths, which would indicate that as high as fifteen per cent sugar when in proper proportion with other constituents of the mix will not necessarily cause a low overrun. Reid (12) ran a second experiment to determine the relation of sugar to overrun. He found that over- run increased up to twelve per cent with each additiOn of sugar. When more sugar was added, the overrun de- creased with the same rapidity as it had increased, until the maximum decrease was reached. This shows that the amount of sugar that can be added to a mixture and assure an increase in overrun is limited. This result is the same as the one he published in 1921(3). Relation 2: Sugar 32 Quality. The quality of sugar in ice cream is varied in commercial practice according to the sweetness desired, but such variations effect the quality of ice cream in different ways. In discussing the factors which improve the smoothness of ice cream, washburn (2) enumerated several, but no mention is made especially of sugar. That sugar is essential to a smooth texture is known in the indus- try and has been demonstrated by Davis (7). In 1916, he reports that decreasing the amount of sugar in the ice _-15-- cream mix below normal increased the per cent of swell, but produced a favorable effect upon the finished product from the standpoint of flavor and texture, while increas- ing the amount of sugar in the ice cream mix above normal decreased the per cent of swell, and, while it produced a better texture, resulted in ice cream which was too sweet. According to an eXperiment of Reid (3), to deter- mine the effect of an increased percentage of sugar on the hardness of ice cream, he found that there was a gradual reduction in hardness with each additional two per cent of sugar. The depth of penetration of a standard needle when sixteen per cent sugar was added to the mixture was nearly double that secured when eight per cent sugar was used. The greatest resistance was offered when eight per cent sugar was added to the mixture; the least when sixteen per cent was added. He also found that ten per cent of sugar gave an ice cream that offered the maximum resistance to a standard summer temperature. Each additional per cent of sugar added to the mixture lessened its resistance. It is the opinion of Zoller (10) that "Whereas the proteins and fat in the ice cream mix readily gave up their water in the form of ice, the sugar tended to hold a portion of water with great resistance, --17-- because of their molecular structure. " He (9) also found that sugar increased the extent of super-cooling during the freezing process. In summing up his work, Dahlberg (11) states that sugar improved the texture of ice cream by reducing the amount of ice that was formed. The water partially froze out leaving a very concentrated or super-saturated sugar solution which did not freeze due to its low congealing point. Reid (12) tried scoring the mixtures made up of eight to sixteen per cent of sugar. The score after a one-day and a seven-day period would indicate that the product containing twelve per cent sugar was superior in body, texture, and flavor, the eight per cent present- ing an open texture and the sixteen per cent a rather close texture and firm body. An ice cream containing twelve per cent sugar is the more desirable, the eight per cent lacking in sweetness, and the sixteen per cent proving somewhat excessive. To show the public's preference for ice cream of varying richness in butterfat, sweetness, and fineness, Williams and Campbell (13) of the United States Depart- ment of Agriculture, made ice cream of different com- positions and sold them on a market where about fifty daily purchasers had an opportunity to choose from three different kinds without knowing anything of the ingredi- ents contained. More than sixty per cent chose ice cream containing nineteen per cent sugar; nearly thirty per cent preferred a sugar content of sixteen per cent, and ten per cent selected the product with thirteen per cent sugar. In other words, about ninety per cent of the consumers indicated a preference for ice cream containing sixteen per cent or more of sugar. It has been stated often that sucrose, glucose, and corn syrup in the mix would tend to inhibit sandiness. Dahle (14) showed that where different sugars were used as inhibiting factors, there was no pronounced effect. It has been stated by practical investigators that high sugar content caused the precipitation of lactose to become less and in some instances prevented it entirely. This view was not borne out in his experiment. m Substitutes. Cane sugar or beet sugar is the most satisfactory sweetening agent for ice cream. None of its substitutes will satisfactorily replace more than about fifty per cent of the cane sugar in the mix. When the supply of'cane sugar is low and the price high, such products as malt sugar, corn sugar, corn syrup, invert sugar, and honey may profitably be used. As compared‘with cane sugar, the .’. k. l —- L e» . . , .. L L _ , , —e' I. ‘1: "a ’ I . . t b ' O . u . ‘ ‘ . Y’ 0 . I s . 1 1 ' S e . t. ‘ 0...”. a.» .e - -A-- 'we v 4‘ CL. -e; 1 P '1 1 i. ' ‘ . ii:- . 17):) ' a 4 ~ ‘ e '. i v . ,- 1 e L . e . ‘ U 1 1 he ‘J J .5 a- d a. a e . e . " ) ' d — ‘ ' J 55. a ‘ , e or I y . L - --19-- sweetening power of invert sugar seems to vary from eighty five to a hundred twenty per cent, corn sugar seventy per cent, and corn syrup from fifty to sixty per cent. Frandsen, Rovner, and Luithly (15) investigated substitutes used for conservation of sugar in ice cream making, and found that none of the substitutes tested would satisfactorily replace all the cane sugar in the ice cream mix. They worked out four formulas which save from.thirty to fifty per cent of cane sugar in the mix, lower the cost of sweetening per gallon of ice cream, and produce ice cream of satisfactory flavor and tex- ture. Corn sugar can replace fifty per cent of cane sugar in the mix. Corn syrup dissolves with difficulty in cold cream, but when added to cream before pasteuriz- ing, it dissolves readily. It is thought that hydrolyz- ing corn syrup in the presence of an acid will enhance its sweetening properties. These experiments were per- formed during the war, when prices were abnormal and at variance with their usual relation. They have but little value under present conditions. EXPERIMENTAL WORK P g; Eeriment. Obi. to The object of this investigation was, mainly, to determine the effect of the different percentages of sugar on the physical properties of ice cream. The observations were as follows: (1) The effect of the sugar content of the mix upon the maximum.swell obtained, (2) The effect of the sugar content of the mix upon the quality of the ice cream, (5) The effect of the sugar content of the mix upon its freezing point, (4) The effect of the sugar content of the mix upon the specific gravity, and, (5) The effect of the sugar content of the mix upon the resisting power to a standard summer tempera- tuICe --21-- General Plgg. inmate. Before beginning the actual experimental work, it was deemed advisable to adopt standard mixes. Five different mixtures were used in conducting the experi- ments. In these, all ingredients remained constant except sugar, the latter being used in the following amounts: eleven, thirteen, fifteen, seventeen, and nineteen per cents. The calculated composition of the mixes is given in the following table: Table II:- Calculated Composition of the Experimental Mixes. Calculated Composition. Per Cent Per Cent Per Cent Per Cent Fat M.S.N.F. Sugar. Total Solids. Mix No. . I. 12 10 11 55.7 Mix No. II. 12 10 13 35.4 Mix.No. III. 12 10 15 57.2 Mix No. IV. 12 10 17 58.9 M1! N0. Y. 12 10 19 40.5 fl...“— _—., -—_.—. a-..— --22-- Table III:-Ana1ysis of Materials Used in Experimental Mixes. Percentage Composition Materials £33 M.S.N.F. M M Sweetcream 20 5.50 26.50 Milk 5. 8.75 11.75 Skimmilk powder - 95.00 95.00 Sugar - - 95.00 Gelatin - - 90.00 Table 1?;- Composition of Iixes. Forty-five pounds of these were used in each mix. Mix 1. Materials nggdg Cream 55.79 Milk 28.14 Sugar 11.00 Skimmilk Powder 4.47 Gelatin .60 Tbtal 100.00 on... Table IV:a Continued, Composition of Mixes. Materials Cream Milk Sugar Skimmilk powder Gelatin Total Materials Cream Milk Sugar Skimmilk powder Gelatin Total Mix II. Pounds. 55.91 26.02 15.00 4.47 .60 100.00 Mix III. mums 56.42 25.51 15.00 4.47 .60 100.00 Table IV:- Continued, Composition of’Mixes. Mix IV. Materials Pounds Cream 56.84 Milk 21.09 Sugar 17.00 Skimmilk powder 4.47 Gelatin .60 Total 100.00 Mix V. Materials Pounds Cream 57.18 Milk 18.75 Sugar ' 19.00 Skimmilk powder I 4.47 Gelatin .60 Total 100.00 Preparing the Mixes. The mixtures were carefully standardized as follows. First, the cream was standardized to twelve per cent fat with milk, and weighed into five gallon cans numbered to correspond to the number of the mix. Then sugar, gelatin, and skimmilk powder, which had been carefully weighed and well mixed together, was slowly added to each can. After these materials had been added to each can, they were well mixed by agitating with a stirring rod. These cans were placed in a hot water tank where they were pasteurized at a temperature of one hundred forty five degrees Fahrenheit and held for twenty five minutes. The mixes were constantly agitated with stirring rods. At the end of twenty five minutes the mixes were immediately cooled down to one hundred ten degrees Fahrenheit and then viscolized at a pressure of a thousand five hundred pounds. From the viscolizer the mixes flowed over a surface coil cooler, the top section of which was cooled with water and the bottom section cooled with brine. In each case, the mixes were entirely emptied from the supply tank and the pipes. They were then held in a cold room at about thirty two to thirty five degrees Fahrenheit and aged forty eight hours. --25-- Method 9: Freezing. The same freezer was used for each experiment. The type of freezing machine used was a United States fifty- quartabatch horizontal brine freezer. Freezing was done by circulating brine cooled by an ammonia refrigerating machine. First the brine pump was run and after the brine temperature became constant, by closing the freezing valve, and opening the freezing valve long enough to chill the freezer, the dasher was started. The temperature of the brine varied somewhat from day to day, but the five batches in the experiment were frozen at nearly the same temperature. The temperature of all mixes before freezing was about thirty five degrees Fahrenheit. The brine was shut off at the same time on each series, and two ounces of vanilla flavor was added as soon as brine was shut off. Records of the overrun were taken at two minutes intervals. --27-- Methods _o_f_ Testing. 9.2.2.92. is silk agar The samples were tested by the Babcock:Method. Pasteurization. This was done in a tank where each mix was heated to one hundred forty five degrees Fahrenheit for twenty five minutes and cooled immediately to one hundred ten degrees Fahrenheit, and then viscolized. Viscolization. Temperature of the mixes at viscolization was one hundred ten degrees Fahrenheit and a pressure of one thousand five hundred pounds used. same. The mixes placed in the cold room were kept at between thirty two to thirty five degrees Fahrenheit and aged forty eight hours. Specific gravity. A picnometer was used. All mixes were weighed at the temperature of 15.55 degrees Centigrade. Freezinglpgggp. The freezing point was taken by a Hortvet CryoscOpe and determined to the third decimal point. Overrunigggg. The records of overrun were taken at two minutes intervals and continued until the maximum overrun was --2g-- obtained. A.Mojonnier overrun tester was used. The over- run cup was adjusted each time before using. Resistancs'gggg‘ggg standard summer temperature. Five one quart samples were drawn into cartons for brick ice cream, when seventy five per cent overrun had been obtained. For the melting test a cheese making vat was used to maintain a constant temperature of eighty six degrees Fahrenheit, which is considered average sum- mer temperature. Rectangular pieces of wood, the size of brick ice cream, having a nail driven up through the cen- ter, were used to hold the ice cream. Pictures of the melting bricks were taken at the end of five hours ex- posure and six and seven hours eXposure. Scoring _t_1_1_e. 1553 £292. One pint samples were drawn when the overrun reach- ed to seventy five per cent. These samples were scored by Professor P.S. Lucas and the writer. Body and texture only were judged. Twenty five points were allowed as a perfect score. --29-- Experimental Data. Table V:- Relation of Sugar Content of Mixes to Specific Gravity at 15.55 Degrees 0. Per Cent Specific Sugar Gravity Mix I. 11% 1.0550 13% 1.0560 15% 1.0626 17% 1.0668 19% 1.0723 Mix III. 11% 1.0520 13% 1.0574 15% 1.0622 17% 1.0655 19% 1.0724 Mix V. 11% 1.0543 13% 1.0582 15% 1.0622 17% 1.0672 19% 1.0727 Per Cent Specific Sugar Gravity Mix II. 11% 1.0532 13% 1.0585 15% 1.0609 17% 1.0674 19% 1.0715 Mix IV. 11% 1.0555 13% 1.0607 15% 1.0634 17% 1.0674 19% 1.0720 Average Specific Gravity 11% 1.0540 13% 1.0590 15% 1.0623 17% 1.0669 19% 1.0721 Table VI:- Relation of Sugar to Freezing Point. Temperature is given in Degrees Centigrade. Per Cent Freezing [Per Cent .Freezing 22522 22121. 122822. 22121 Mix 1. Mix II. lr% -2.l75° 1r% -2.17o° 15% -2.504° 15% -2.512° 15% -2.s72° 15% -2.865° 17% ~5.082° 17% -5.oeo° 19% -5.225° 19% -5.210° Mix III. Mix IV. 1r% ~2.1oo° 1r% ~2.175° 15% -2.515° 15% -2.522° 15% ~2.s75° 15%. -2.882° 17% -5.oeo° 17% ~s.0900 19% -5.220° 19% -s.215° ‘Average Mix V. Freezing 32133 1r% ~2.172° 1r% -2.170° 15% ~2.515° 15% -2.514° 15% -2.87o° 15% -2.e75° 17% -5.095° 17% -5.os7° 19% -5.252° 19% -5.220° --31-- Overrun. Although the freezing process was conducted for each series under almost identical conditions, the time required to reach the maximum overrun was different in each. Consequently there were slight differences in the amount of maximum overruns tabulated in Table XII, giving the mean per cent overrun at every other minute, and in Table XIII, giving the average maximum overruns of the different per cents sugar batches. Figure I, shows very clearly the results of maximum overruns taken on by the different batches. Table VII:- Per Cents Overrun by Two Minute Intervals for M1: Ia Maximum Swell is underlined. Time (Minutes) (110165100 10 12 14 16 18 11% 9 O 21 56 79 81 85 89 87 13% 9 o 52 71 7e 81 87 so 93.5 87 15% 11 o 51 50 as 75 78 80.5 so 84 1w% 11 o 21 55 55 60 55 59 74 7s 76 No.I. No.11. No.III. No.1V. Eo.V. 19% 11 0 54 50 62 66 68 71 Per Cent Sugar Brine Tempt. F . Table VIII:- Per Cents Overrun by Two Minute Intervals for Mix 11. Time No.I. No.11. No.III. No.IV. No.V. (Minutes) Per Cent 11% 15% 15% 17% 19% Sugar Brine 6 4 4 4 5 Tempt. F. 0 O O 0 0 O 2 55 40 28 25 18 4 78 59 59 59 46 6 81 68 71 59 55 8 85 74 79 65 64 10 88 79 82 71 75 12 2g _9_2_ 84 76 78 14 89 89 87 81 2.9. 16 85 75 78 Table IX:- Per Cents Overrun by Two Minute Intervals for Mix III 0 Time No.1. No.11. No.111. No.1V. No.7. (Hinutes) Per Cent 11% 15% 15% 1773 1993 Sugar Brine 12 15 12 12 15 Tempt. F. - O O 0 O O O 2 15 17 14 15 17 4 5O 22 22 25 25 6 57 52 52 52 27 8 75 72 62 4O 56 10 84 82 7O 69 41 12 86 90 78 75 58 14 29 25 85 78 66 16 89 9O 81 79 75 18 77 7O ‘--35~- ‘stle X:- Per Cents Overrun by Two Minute Intervals for Mix IV. Time No.1. No.11. No.111. No.17. No.7. (Minutes) Per Cent 11% 1576 1536 17% 193’. Sugar Brine 7 10 9 8 < 8 Tempt. F. O O O O O O 2 25 24 21 17 16 4 4O 55 42 59 24 6 68 69 66 65 46 8 74 77 79 75 64 10 85 85 86 79 76 12 231 91 39 81 81 14 92 26 88 84 82 16 93 82 80 -L35-- Table X1:- Per Cents Overrun by Two Minute Intervals for Hi: 7. Time N001. NOeIIo NOOIIIO NOOIV. NOOVO (Minutes) Per Cent 11% 13% 16% 17% 19% Sugar Brine 5 5 4 5 5 Tempt. F. O O O 0 O O 2 54 45 45 58 41 4 84 75 64 59 61 6 88 79 77 54 7O 8 89 88 80 69 74 10 _9_9_ 92 82 72 77 12 es 2;; §_:_5_ 76 7e 14 95 81 79 79 16 77 77 --37-- Table XII:- Mean Per Cent Overrun of Five Mixes. Time No.1. No.11. No.111. No.17. No.7. (Minutes) Per Cent 11% 13% 15% 17% 19% Sugar 0 O 0 O O O 2 54 52 28 25 25 4 58 52 47 59 41 6 75 65 65 55 52 8 81 78 75 61 61 10 86 87 80 71 67 12 89 91 85 75 75 14 22 2.3; 9.2 2.2. 76 16 89 91 85 78 17 18 77 72 _ Table XIII:- Average Maximum Obtained from Each Series. Per Cent Sugar Per Cent Overrun 11% 90 13% 94 15% ee 17% so 19% 7e roan M1 u-a’... {MINT or nmuuncl --4o-- Determination of the Time Reguired for Ice Cream with Different Percentages of Sugar £2_Melt Under Summer Conditions. Brick ice cream containing sugar ranging from eleven to nineteen per cent were hardened and then exposed to a constant melting temperature of eighty six degrees Fahren- heit. After an exposure of two hours, they assumed a honey- comb appearace, and the bricks containing fifteen, seven- teen and nineteen per cent sugar began to spread out. After three hours exposure, large cracks appeared on all surfaces, all bricks were flattened, and the corners had melted and fallen off. At the end of four hours of melting, the bricks con- taining eleven and thirteen per cent of sugar had offered the greatest resistance to the heat as shown in the pic- tures on pages 41 and 42. These bricks containing the high- er percentages of sugar had sloughed greatly. 1n the pictures which were taken at the end of six and seven hours, the bricks which contained eleven and thirteen per cent sugar retained better form, especially in the picture.taken at the end of seven hours. The bricks containing eleven per cent sugar showed best standing-up qualities. The remainder of the bricks had almost melted away. This standing-up property decreased as the content of sugar increased. -1141..- Figure 11. Showing the five bricks of ice cream after melting four, six, and seven hours at a temperature of 86 F. Bricks were arranged corresponding to their per cent of sugar, left to right, beginning with the smallest per- oentage. . Mix No.7: After four hours Iii: No.1: After four exposure. hours exposure. L1 Mix No.11: After six hours exposure. --42—~ Figure 11. Continued. Showing the five bricks of ice cream after melting four, six, and seven hours at a temperature [0: 86 Fe ,Mix No.111: After seven hours exposure. --43-- The Effect of Different Percentages of Sugar 23 the Body and Texture gg_gggIQgg§m. The hardened ice cream was judged and scored by Pro- fessor P.S.Lucas and the writer. Only body and texture of the ice creams of different per cent of sugar, were scored. The following score-card, used in the New York State College of Agriculture at Cornell University, was adopted in Judging body and texture. In this score-card twenty five points were allowed as a perfect score for body and texture. Flavor 40 Body and texture 25 Bacterial count 15 Riohness 10 Appearance 5 Package 5 Total 100 The results were as follows: The mix containing eleven per cent sugar was open, porous and coarse in texture, giving a rough feeling to the tongue, and was icy. It was not sweet enough for the average taste. The mix containing thirteen per cent sugar had a closer texture as compared with the one containing eleven per cent sugar, but was a trifle coarse. Sweetness was about to the average taste. --44-- The samples of ice cream having fifteen and seven- teen per cent sugar showed the best qualities. There was a noticeable improvement in both body and texture over the former mixtures. The texture was smooth, desirable, and medium close, mellow and firm body, free from iciness, but a little too sweet, especially the latter. The mix containing nineteen per cent sugar had the firmer body and closer texture, but was rather sticky and a trifle too sweet. The following table shows by scores the body and texture of the ice creams containing different per cents of sugar. Table X173- Scores of the Body and Texture of Ice Cream. Per Cent Sugar Mix 1. “ix 11. Mix 111. Mix 17. Mix 7. 11% 20 21 21 20 21 15% 22 22 21.5 20.5 21.5 15% 24 25 25 25.5 25 17% 24 25 24 25 24 19% 22.5 25.5 25.5 25 22.5 --4:-_ J Summary. The study of the effect of sugar upon the quality of ice cream is an important problem from the economical standpoint to the manufacturer of commercial ice cream, since it affects the quality of his finished product. The results show that the addition of sugar to the mix decreases the per cent of swell. Table XIII showed that maximum swell was obtained when thirteen per cent of sugar was added to the mixture. A less per cent of swell was obtained from the mixture containing eleven per cent sugar. The per cent swell of those mixtures containing more than thirteen per cent sugar gradually decreased. There was a decrease of sixteen per cent in overrun in those mixtures, containing nineteen per cent sugar over those mixtures containing but thirteen per cent sugar. Table 17 showed that the freezing point of the finished ice cream lowered as the percentage of sugar was increased. The specific gravity of different mixes increased uniformly by the addition of sugar to the mixes. The determination of the rapidity with which the bricks of ice cream containing different percentages of sugar melted when exposed to summer temperatures demon» strated that increase in sugar lowers standing-up properties. --45-- Ice creams containing eleven per cent sugar showed the highest resisting power to a standard summer tem- peratures. Ice creams, containing eleven and thirteen per cent of sugar had rather coarse and open textures, were icy, and were not sweet enough; while the mixtures containing fifteen and seventeen per cent sugar showed much smooth- er texture and were medium close. Ice cream containing nineteen per cent of sugar were rather sticky in texture and firm in body. Sweetness was excessive. Judging from these data a mixture containing thir- teen to fifteen per cent sugar seems to be the most desir- able ice cream to manufacture. Such ice creams had the most desirable body and texture, resistance, overrun, and freeze more quickly. 1. 2. 5. 4e 5. CONCLUSIONS An addition of sugar above thirteen per cent decreases the per cent of overrun. Maximum overrun can be obtain- ed when thirteen per cent of Sugar is added to the mixture. Increased sugar tends to depress the freezing point of the mix; that is, the more sugar there is in the ice cream the lower the freezing point. Creams containing eleven per cent sugar have the great- est resistance to standard summer temperatures. The resistance of ice cream to summer temperatures decreas- es with further addition of sugar to the mixture above eleven per cent. Ice creams containing eleven and thirteen per cent of sugar usually have a coarse, open texture and are not sweet enough. An ice cream containing fifteen and seventeen per cent sugar has a smoother and closer texture, and firm body. An ice cream containing nine- teen per cent sugar has a firmer body and closer tex- ture, but is sticky and too sweet. The addition of sugar to the mix, uniformly increases the specific gravity of the mix. (1) (2) (5) (4) (5) (6) (7) (8) BIBRIOGBAPHY Babbitt,E.G: The Ice Cream Review. 701.8, No. 10. (1925). 74. Washburn,R.M: Principles and Practice of Ice Cream Making. Vermont Agr. Exp. Sta. Bull. 155. (1910). 9, 65. Reid,Wm.H.E: The Effect of Each Ingredient in the Manufacture of’Ice Cream. Hissouri Agr. Exp. Sta. Bull. 179. (1921). 24, 25. Fisk, Walter W: The Book of Ice Cream. (1925). 140. Gregory,H.l: and.Manhart,7.C: Factors Affecting the Yield of Ice Cream. Indiana Agr. Exp. Sta. Bull. 287. 15, 29. Thomas,N.M2 Overrun Control. The Ice Cream Review, 701.7. No.10. (1922). 142. Davie,1..l: Relation of Consistency and Percentage of Swell of an Ice Cream Mixture. Calif. Agr. Exp. Sta. Report. (1916). 48. Williams,O.E: Effect of Composition on Overrun. Creamery and Milk Plant Monthly. 11, 100. (1922). (9) (10) (11) (12) (15) (14) (15) Zoller, Harper F: Separation of Ice in Freezing Ice Cream Mixes. Ice Cream Trade Jour. 701. 17. No.8. 40-42. No.9. 45-47. No.10. 50-52. (1921). Zoller, Harper F: Measuring the Refrigeration Used in.Making Ice Cream. Ice Cream Trade Jour. 701. 20. No.6. 55-56. (1924). Dahlberg, A.C: The Texture of Ice Cream. New York Agr. Exp. Sta. Tech. Bull. No.111. (1925). Reid, Wm. H.E: The Effect of the Sugar Content in the Manufacture of Commercial Ice Cream. Missouri Agr. Exp. Sta. Research Bull. 69. (1924). Williams, 0.E: and Campbell G.R: Effect of Composition on the Palatability of Ice Cream. U.S. Dept. Agr. Bill. No. 1161. (1925). Dahle, C.D: Proceeding of World's Dairy Congress. 701. 1. 500. (1925). Brandsen, J.H: Rovner, J.W. and Luithly, J: Sugar-saving Substitutes in Ice Cream. Nebraska Agr. Exp. Sta. Bull.168. (1918). L"! 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