ABSTRACT
Vitamins are well-known group of organic, low-molecular-weight substances that are essential in very small amounts for the normal function of human body. Vitamins have generally different chemical and physiological functions and are broadly distributed in natural food sources. Thirteen vitamins have been recognized in human nutrition and have been conveniently classied into two main groups: fat-soluble vitamins mainly include vitamin A (retinol), D (calciferol), E (tocopherol), and K (phylloquinone, menaquinone); and water-soluble vitamins include vitamin C (ascorbic acid) and members of the vitamin B group; B1 (thiamine), B2 (riboavin), B3 (niacin, nicotinic acid), B5 (pantothenic acid), B6 (pyridoxine, pyridoxal hydrochloride), B7 (biotin), B9 (folic acid), and B12 (cobalamin, cyanocobalamin) (Ball, 2006).
