Browning and decomposed products of model orange juice

A model solution of orange juice containing sugars, ascorbic acid, and citric acid was prepared and its browning during storage was examined. The solution gradually turned brown. Ascorbic acid (AsA) most contributed to the browning. Citric acid and such amino acids as Arg and Pro promoted the browning. DTPA, a strong chelator, inhibited the browning. 3-Hydroxy-2-pyrone (3OH2P), 5-hydroxymethylfurfural (HMF), furfural, 5-hydroxymaltol, and 2-furoic acid were identified as decomposed products in the stored solution. When 3OH2P was stored, the solution turned slightly brown. Furfural solution added with amino acids turned yellow. 3OH2P showed a positive relation with the browning of retail orange juice during storage.