ANNUAL REPORT, 1930 253 



Use of Gelatin in Ice Cream. (W. S. Mueller). Investigation for new 

 uses of gelatin in ice cream has resulted in developing (1) gelatin fruit 

 cubes, (2) modified Aufait ice cream, (3) filling for ice cream pies and 

 cubes. The same principle is employed in all these uses; namely, the addi- 

 tion of edible gelatin to fruit juice or to a water solution containing fruit 

 acid. Crushed fruits may also be added. The fruit cubes are cut to ^/^ 

 inch size and scattered into the ice cream at time of drawing. Modified 

 Aufait ice cream is made by placing layers of jellied fruit juice, with or 

 without crushed fruit, into brick ice cream. The filling for the ice cream 

 pies is similar to the material used in making the modified Aufait ice cream. 

 Some difficulty has been experienced in keeping tiie jellied fruit juice clear, 

 due to the low temperatures to which it must necessarily be subjected when 

 used in ice cream. This troublesome ice crystallization has been largely 

 overcome by using the correct amount and kind of sugar and also main- 

 taining the correct amount of acidity. A variety of sugars; namely, cane, 

 corn, invert and corn syrup, has been used in various combinations. 

 Freezing point determinations are being made for various sugar-gelatin- 

 H2O solutions. The addition of jellied fruit juice to ice cream seems de- 

 sirable from the standpoint of attractiveness which the clear, bright-colored 

 jellied fruit juice gives to the ice cream. 



A study of the eflTect of time and temperature in cooling an ice cream 

 mix upon the behavior of gelatin has been made. Initial cooling tempera- 

 tures ranging from 0°C. to 60°C. were used. An initial cooling tempera- 

 ture of 20° C. for 4 hours gave the maximum basic viscosity, increased 

 the gel strength, increased melting resistance and improved the texture for 

 the particular mix used. A study is now under way to determine what fac- 

 tors influence the degree of results obtained when using a high initial cool- 

 ing temperature. The following factors are being studied: 



1. Strength of gelatin 



2. Amoimt of gelatin 



3. Amount of butterfat 



4. Amount of serum solids 



5. Amount of sugar 



6. Source of butterfat and serum solids 



A new type of colloid mill is being used experimentally in place of a 

 homogenizer for processing ice cream mixes. The effect upon the physical 

 properties of the mix and the desirability of the finished product are being 

 studied. 



Preliminary experimental work on the value of gelatin in retarding 

 "sandiness" in ice cream has shown that gelatin has a greater value in 

 this respect than is generally conceded. 



A number of commercial stabilizers are being used with gelatin in ice 

 cream. Preliminary experiments have shown a mutual precijiitation of 

 gelatin with some of the stabilizers and no mutual precipitation with others. 

 Experiments are now being planned to determine the cause for this mutual 

 precipitation. 



The Comparative Efficiency of Electrically-operated Tanks Versus Ice 

 in the Cooling of Milk. (J. H. Frandsen). Whether the tank is of home 

 construction or specially manufactured, it is essential that it be of ample 

 capacity; roughly speaking, when filled with cans to full capacity there 

 should still be room for twice as much water and ice as milk. If the tank 



