Question has been raised concerning the vitamin A potency of stored
yellow corn. Samples of 1954 corn and 1948-49 stored corn were
analyzed for provitamin A content by a separation and chemical determination
of the carotene and crude cryptoxanthin contents. The 1948-49 sample was found to have a vitamin A activity of about 800 units
per pound, slightly less than one-third of that of 1964 corn. In this
work 1 mg. of carotene was given a vitamin A value of 1.6 unit-s and
cryptoxanthin one-half that value, which are the vitamin A activities
previously determined by bioassay with rats. Although much vitamin
A activity apparently had been lost during storage of yellow corn, there
was still the problem of the availability of the remaining vitamin A for
animals. This was studied, using weanling pigs as the experimental
animal.
