Effects of Frozen and Other Storage Conditions on -Tocopherol Content of Cow Milk

¹ Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
² Departamento Nutrición y Bromatología, Universidad Alcala de Henares, Alcala de Henares, Madrid 28871, Spain

The effect of temperature and length of storage on the stability of -tocopherol in UHT milk was studied by HPLC. The effect of water activity conditions during storage of milk powder on the stability of the same vitamin was also studied. Losses of -tocopherol occurred in UHT milk after 1 mo of storage at 30°C; losses increased as storage time increased. In general, when the storage temperature changed from 30 to 40°C, decrease in -tocopherol content was greater. Short periods of frozen storage of the UHT milk (up to 60 d) had no effect on -tocopherol content. However, frozen storage from 4 to 8 mo produced losses in -tocopherol. When water activity was increased, the -tocopherol content in milk powder decreased significantly after 2 mo of storage at 20°C.

Key Words: -tocopherol • milk • freezing • storage

Submitted on January 2, 1992
Accepted on August 20, 1992