In order to develop the most excellent stabilizer for ascorbic acid, various phosphoric acids and phosphates were examined and the effects of concentrations, temperatures and metal ions on the stability of ascorbic acid were also investigated. 1) Among various phosphoric acids and phosphates, sodium trimetaphosphate (P3m) was found to be most effective for the stability of ascorbic acid. A considerable effect was also observed in sodium dihydrogen pyrophosphate (P2) and metaphosphoric acid (Pm). 2) The rate of the oxidation of ascorbic acid increased with a decrease in concentration of phosphoric acids or phosphates used. 3) Ascorbic acid tended to be oxidized with increasing temperature and at 70°no difference in the kinds of phosphates could be detected for the stability of ascorbic acid. At a temperature as low as 10°, ascorbic acid was highly stable irrespective of the kinds of phosphates. 4) In the presence of various metal ions, P3m, P2 and Pm were also effective for the stability of ascorbic acid.
