... Physico-chemical properties:Light Yellow PowderPicture:Vitamin A is the name of a group of fat-soluble retinoids, including ... retinol, retinal, retinoic acid, and retinyl esters. Vitamin A is involved in immune function, vision, reproduction, and cellular communication ... esterified form, retinyl ester) and provitamin A carotenoids. Preformed vitamin A is found in foods from animal sources, including ...