The browning reactions between ascorbic acid and the 20 amino acids except tyrosine were studied as 44℃ and 72℃ in model svstems and the colour formation was followed by measurement if the absorbance at 400 mm. The progress and the extent of the colour development in unbuffered systems were dependent other assitives. All amino acids except cysteineinteracted with ascorbic acid, uesulting in more pronounced colour formation than when ascorbic acid was present alone. Cysteine protected ascorbic acid against the formation of the brown pigment Tryptophan exceeded all the other amino acids in enhancing the browning of ascorbic acid. At 72℃ colout development caused by ascoibic acid, citric acid, FeSO4, CuSO4, and Na2HPO4, but colour formation was reduced by fumaric acid , tartaric acis, succinic acid, CaCl2, NaHSO3, tetrasodium pyrophosphate, sodium tripolyhosphate, sodium tetraphosphate, sodium metaphosphate, and sodium polyphosphate.