The Relation of Certain Factors to the Drying of Whey Mixtures on the Atmospheric Drum Drier

Abstract

Summary 1.Some material which will form a sheet when scraped from the drum must be mixed with whey to dry it satisfactorily on the atmospheric drum drier. 2.Sweet skim milk was found to be such a material. A satisfactory drying combination was obtained by mixing sweet whey and sweet skim milk together in equal amounts. 3.As the titratable acidity of the whey increased, the amount of sweet skim milk required to produce a satisfactory drying combination also increased. 4.Reducing the acidity of sour whey in varying degrees with sodium hydroxide enables one to dry it by using only slightly more skim milk than was required with whey which had developed lactic acid to a corresponding degree of acidity. 5.Sweet whey acidified to various degrees of acidity with hydrochloric or sulphuric acid gave practically the same results as whey which had developed lactic acid to a corresponding acidity. 6.Precondensing the skim milk to be used as the drying agent, enables one to satisfactorily dry a mixture of skim milk solids and whey of a higher lactose/nitrogen ratio at any given whey acidity than was possible when non-condensed skim milk was used. 7.Sour whey neutralized to various degrees of acidity and dried with condensed skim milk, would dry with about as high lactose/nitrogen ratio as whey which had developed lactic acid to a corresponding degree of acidity. 8.Precondensing the whey seemed to have no beneficial effect insofar as the drying properties of mixtures were concerned. 9.It was not possible to dry a mixture of as high a lactose/nitrogen ratio when casein was used for mixing with whey for drying as when other sources of milk solids were used. 10.Spray process powdered skim milk proved satisfactory for mixing with whey for drying when used at the rate of 8 pounds to 100 pounds of sweet whey. 11.Powdered skim milk prepared by the atmospheric drum process did not prove satisfactory, even when used at the rate of 20 pounds per 100 pounds of sweet whey. 12.Ground and sifted cereals, such as corn starch, wheat flour, oats, and barley proved satisfactory as a material to be added to whey when used at the rate of 3–3 3 4 pounds per 100 pounds of liquid whey. An increase in the titratable acidity of the whey increased slightly the amount of wheat flour or corn starch necessary to produce a satisfactory film, but did not increase the amount of either ground oats or barley required. 13.Similar results have been obtained in all cases with cheddar cheese whey and with acid-type cottage cheese whey.