Effects of frozen and other storage conditions on alpha-tocopherol content of cow milk.
The effect of temperature and length of storage on the stability of alpha-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 alpha-tocopherol occurred in UHT milk after 1 mo of storage at 30 degrees C; losses increased as storage time increased. In general, when the storage temperature changed from 30 to 40 degrees C, decrease in alpha-tocopherol content was greater. Short periods of frozen storage of the UHT milk (up to 60 d) had no effect on alpha-tocopherol content. However, frozen storage from 4 to 8 mo produced losses in alpha-tocopherol. When water activity was increased, the alpha-tocopherol content in milk powder decreased significantly after 2 mo of storage at 20 degrees C.
Vidal-Valverde
C
C
Instituto de Fermentaciones Industriales, Madrid, Spain.
Ruiz
R
R
Medrano
A
A
D000818:Animals; D002417:Cattle; D005519:Food Preservation; D005615:Freezing; D008892:Milk / Q000737:chemistry*; D014810:Vitamin E / Q000032:analysis*
D014810:Vitamin E