Factors Responsible for the Development of a Hay-Like Flavor in Vitamin A Fortified Low-Fat Milk

Dcpartme'~tt of Dairy and Foo(1 Industries, University of Wisco~tsin, Madiso~tModified low-fat milk has become an important bottled milk product in many cities (3).It consists of skimmilk, or skimmilk modified by the addition of either or both 0.25-0.75%fat and 0.5-2.0%milk solids-not-fat (6).The vitamin content is usually increased to levels of at least 2,000 I.U.vitamin A and 400 I.U.vitamin D per quart by use of processed vitamin concentrates.Vitamin A in the form of a natural derivative from marine oil, or as a vitamin A palmitate or acetate, and vitamin D as a natural derivative from marine oil, or as D~ or D~, are used (12).A distinct abnormal flavor occasionally develops in such modified low-fat milk and is present invariably only when fortified with vitamin A (11).The