Studies in the stability of vitamins A and D

Abstract

Irradiation of vit. A-containing oils and concentrates diminishes the values of E1%1cm 328 m[mu] to an extent roughly proportional to its duration and intensity. On standing in the dark or in light of lower intensity the u.-v. absorptions revert towards their original values, the more completely the less the previous loss on irradiation. Vit. A appears to suffer reversible photochemical isomerisa-tion and simultaneous slow photochemical destruction.