Some Properties of Freeze-Dried Milk

Summary The effect of freeze-drying milk on the physical state of certain milk constituents and on the keeping qualities of the resulting powder has been studied. The fat emulsion of freeze-dried powder is partially destabilized. The presence of free fat in the powder makes reconstitution difficult. No crystallization of the lactose is evident in the spray- and freeze-dried powders. The data show that the ratio of β to a lactose in these powders is dependent upon the temperature of drying. The ratio in spray-dried powder closely approaches the equilibrium ratio in a lactose solution at 212° F., while the ratio in freeze-dried powder closely approaches that at 32° F. Flavor and keeping quality characteristics of freeze-dried milk are essentially the same as for spray-dried whole milk powder. Both dry milks have essentially the same flavor characteristics when fresh and both become tallowy in storage. They also may exhibit deterioration of the type associated with the Maillard reaction. The freeze-dried powder, however, frequently acquires a fruity flavor which is not apparent in spray-dried milk. Freeze-drying by the methods used in this study does not produce a more satisfactory product than spray-dried milk.

[1]  C. Tatter,et al.  A Solubility Method for the Determination of Alpha and Beta Lactose in Dry Products of Milk , 1949 .

[2]  S. T. Coulter,et al.  Some Factors Influencing the Reducing Systems in Dry Whole Milk , 1949 .

[3]  E. W. Flosdorf,et al.  Freeze-drying. Drying by sublimation. , 1949 .

[4]  S. T. Coulter,et al.  The Reducing Capacity of Milk and Milk Products as Measured by a Modified Ferricyanide Method , 1948 .

[5]  S. T. Coulter The Keeping Quality of Dry Whole Milk Spray Dried in an Atmosphere of an Inert Gas , 1947 .

[6]  J. Findlay,et al.  341. The effect of the pre-heating temperature on the bacterial count and storage life of whole milk powder spray-dried by the Krause process , 1946, Journal of Dairy Research.

[7]  C. C. Thiel,et al.  338. The ferric thiocyanate method of estimating peroxide in the fat of butter, milk and dried milk , 1946, Journal of Dairy Research.

[8]  S. T. Coulter,et al.  Packing dry whole milk in inert gas , 1945 .

[9]  R. Chapman,et al.  A COLORIMETRIC METHOD FOR THE ESTIMATION OF REDUCING GROUPS IN MILK POWDERS , 1945 .

[10]  A. Mattick,et al.  326. The effect of temperature of pre-heating, of clarification and of bacteriological quality of the raw milk on the keeping properties of whole-milk powder dried by the Kestner Spray Process , 1945, Journal of Dairy Research.

[11]  C. H. Lea,et al.  328. Experiments on the use of antioxidants in spray-dried whole-milk powder , 1945, Journal of Dairy Research.

[12]  U. S. Ashworth,et al.  The use of thiamin disulfide for the estimation of reducing substances in processed milk. , 1945 .

[13]  P. H. Tracy,et al.  The Relation of the Use of Certain Antioxidants and Methods of Processing to the Keeping Quality of Powdered Whole Milk , 1942 .

[14]  P. F. Sharp,et al.  Quantitative Determination of Alpha and Beta Lactose in dried Milk and Dried Whey , 1941 .

[15]  P. F. Sharp Seeding Test for Crystalline Beta Lactose , 1938 .

[16]  P. F. Sharp,et al.  α and β Lactose in Some Milk Products , 1930 .

[17]  G. R. Greenbank,et al.  Results of Preliminary Experiments Upon the Effect of Separating, or Clarifying, and Pasteurizing of a Milk Upon the Keeping Quality of Its Milk Powder , 1926 .

[18]  H. Hering,et al.  Réactions thermodynamiques chez les poudres de lait. Leur emploi pour le dosage rapide de leur teneur en eau (1er Mémoire). , 1924 .