Vitamin A in oranges

Abstract

In an earlier paper dealing with citrus fruits 1 we stated that preliminary tests indicated that dried orange juice contains some vitamin A. This conclusion was based on the fact that when the equivalent of 10 c.c. juice was furnished daily to rats on a diet practically devoid of vitamin A, the symptoms which characteristically ensue upon such a dietary régime did not develop within the period of 190 days during which our observations continued. For example, the now well known ophthalmia 2 was either cured or averted.

A reinvestigation of the subject has substantiated our earlier conclusion. In a number of rats maintained on a diet consisting of casein, starch, lard and salt mixture, 3 together with 0.2 gm. of dried brewery yeast as a source of vitamin B, the characteristic ophthalmia associated with a lack of vitamin A was completely cured within a few days after the daily administration of either 10 c.c. of fresh orange juice or the same amount of juice desiccated, admixed with starch, in a current of hot air. Five c.c. of juice sufficed to cure the ophthalmia but a larger quantity appeared to be necessary to secure restoration of growth. Inasmuch as Cooper 4 has reported the presence of vitamin A in orange peel, special precaution was taken in our work to avoid contamination of the juice with the latter.

Owing to the comparative richness of orange juice in carbohjdrates, so that IO C.C. represent a not inconsiderable intake of non-protein calories, it is important that the proportion of protein and essential salts in the rest of the ration be large enough to promote growth at the normal rate. The data now available from animal feeding experiments indicate the presence of vitamins A, B, and C in the orange and the possibility of conserving them, in part at least, undeteriorated by suitable processes of desiccation.