Radiolysis of Ascorbic Acid in Aqueous Solution by Gamma Radiation

Abstract

Interest in the application of high-energy ionizing radiation for food sterilization has led a number workers to investigate the radiation sensitivity of vitamins (1-7). Ascorbic acid, which is known to be very sensitive to oxidation, has received special attention (3-7). Anderson and Harrison (3) studied the effect of X-rays on ascorbic acid in simple solution and in mixtures of naturally occurring compounds. Later, Proctor and co-workers (5, 6) reported in a series of papers the effect of X-rays on the destruction of ascorbic acid, riboflavin, and niacin in aqueous solutions. In the above studies, ascorbic acid was found to be highly sensitive to X-irradiation. Since the main interest in these investigations was to determine vitamin losses on irradiation, little attention was paid to evaluating quantitatively the interaction of radiation with ascorbic acid per se. Further, these workers used ascorbic acid solutions containing either oxalic acid (4-7) or metaphosphoric acid (3) in order to minimize the natural destruction of ascorbic acid. Since the interaction of radiation with ascorbic acid is likely to be modified by the presence of these other solutes, the reported results may not describe its true radiolysis. Moreover, no reports are available which describe in detail the sequence of chemical changes that take place in ascorbic acid solutions on irradiation.