Effect of Changing the Fat and Nonfat Solids of Milk

Milk containing 2 and 3% fat was more acceptable in flavor than milk containing 4% fat, when each was standardized to 12, 13, 14, and 15% total solids.No statistically significant differences in flavor were observed for milk containing 2 or 3% fat together with 11 or 12% nonfat milk solids, but these were more acceptable in flavor than regular unfortified University plant milk containing 3.7% fat and 9.2% nonfat milk solids.By comparison, the regular plant milk tasted watery and flat.The total amount of fat and nonfat solids (NFS), as well as the ratio of fat to NFS, is quite variable in market milk.In 1958, when this study was initiated, there was a very large surplus of nonfat milk solids.The study to determine the acceptability of milk and/or milk beverages in which both the fat and NFS were standardized to definite levels had the following objectives: (a) To find a method for placing into food channels the surplus NFS, (b) to' find a method of placing before the public a unit volume of milk of definite nutritional value.Industry has had fine success in marketing nonfat milk when NFS are increased to approximately 10%.Another milk beverage, "2-10" (2% fat and 10% NFS), is popular with the housewife.The increase in the NFS eliminates to a considerable degree the flatness and watery flavor inherent in nonfat milk.After this study was under way, Stull and Hillman (4) reported, "Many people can differentiate between milk beverages with variations of 0.5 and 1.0% in fat and NPS, respectively."They found, by paired preference test, that beverages with 0.5 and 1.0% added NFS were preferred.However, they found no significant difference in preference for a regular whole milk (3.5% fat and 8.5% NFS) when compared with a low-fat beverage (2.0% fat and 10% NFS). EXPERI~IENTAL PROCEDURESource and treatment of milk.The milk used in the experiment was a mixture of evening and morning milk from the University herd of Holstein, Guernsey, and Jersey eaftle.The milk was standardized before pasteurizing to 3.7% fat and the NFS content ranged from 9.2 to 9.3%.The milk was vat-pasteurized at 143-145 ° F. for 30 rain.as a part of the regular University dairy plant operation.After the milk was cooled in the Yat