NONENZYMATIC BROWNING IN MODEL SYSTEMS CONTAINING SUCROSE

Freeze-dried systems containing sucrose and organic acids were found to undergo rapid nonenzymatic browning, even at low relative humidities. Addition of protein reduced the rate of browning, especially at low humidities. It was determined that the browning was due to reducing sugars produced by acid-catalyzed hydrolysis of sucrose. This hydrolysis occurred even when water content was well below 1 and below B.E.T. monolayer coverage Brunauer-Emmett- Teller method of calculating monolayer values. These findings have important implications for storage stability of dehydrated foods since they point to a new mechanism for initiation of browning in such foods as freeze-dried juices.