Constituents of the Crude Carotene of Some Forages 1

T carotene content of Texas range forages has been discussed in a previous paper (4)3 Recently, i~ has been found ~ha~ carotene extracts are more complex mixtures than they were considered to be at thaC ~ime (~, 2, 3). The c~de carotene solutions may contain betacarotene, impurity A, neo-be~a-carotene B, neo-be~a-caroCene U, and sometimes alph~ carotene (3). The neo-be~a-caro~enes are s~ereoisomers of beta-carotene and can be formed from, and converted into, beta-carotene (3, 5)Neo-be~a-carotene B and alpha-carotene have one-half the vitamin A potency of beta-carotene, while impurity A and neo-beta-carotene U do not appear to possess vitamin A potency