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Journal of Dairy Science Vol. 28 No. 6 473-494
© 1945 by American Dairy Science Association ®
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The Vitamin A Potency of Creamery Butter Produced in Minnesota1

Robert Jenness and L. S. Palmer2

Division of Agricultural Biochemistry, University of Minnesota, St. Paul, Minnesota

ABSTRACT

A survey of the vitamin A and carotene contents of creamery butter produced in Minnesota in 1943 and 1944 led to the following conclusions:

  1. In 1,019 samples analyzed in 1943 the unweighted mean vitamin A and carotene contents were respectively 6.21 ± 0.03 and 3.68 ± 0.04 µg. per gm. The means weighted by regional and seasonal butter production were respectively 6.14 and 3.71 µg. per gm.; these values correspond to a total potency of 13,958 I.U. per pound if vitamin A itself is considered to have a potency of 4.00 I.U. per µg.
  2. With a few exceptions, and for all practical purposes, the butters of the state were rather uniform in vitamin A potency in any given season of the year.
  3. Marked seasonal fluctuations in potency, similar to those reported else where, and undoubtedly attributable to variations in feeding conditions were found to occur. From January 1 to April 22, 1943, the samples averaged 9,000–10,000 I.U. per pound. With the beginning of pasturing, a rapid rise occurred until the summer level of 16,500–18,500 I.U. per pound was attained in the period May 21 to June 17. This level persisted until early October whereupon the potency gradually declined nearly to the winter level during the remainder of the year. The picture for the first half of the year was corroborated by analyses of samples secured from January 1 to June 15, 1944.
  4. The distribution of total potency between vitamin A and carotene varied with season. In winter butter carotene furnished only 11 to 15 percent of the potency while in summer butter it furnished 21 to 25 per cent of it.
    In general changes in carotene content lagged behind those in vitamin A content.
  5. It was calculated that about 90 per cent of the butter produced in 1943 had vitamin A potencies of more than 9,000 I.U. per pound; about 45 per cent of it had potencies greater than 15,000 I.U. per pound.
  6. It was estimated that 1,800 pounds of vitamin A and 1,100 pounds of carotene were produced in Minnesota butter in 1943.
  7. No evidence was found for loss of vitamin A potency by butter during storage.

FOOTNOTES

1 Paper No. 2203, Scientific Journal Series, Minn. Agr. Expt. Sta., St. Paul, Minnesota.

2 Deceased March 8, 1944.






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Copyright © 1945 by the American Dairy Science Association ®.