Commercially bottled, vitamin C-fortified, cranberry juice cocktail and cranberry-apple (cranapple) juice drinks were stored at 5°C under simulated home-use conditions. Ascorbic acid (AA) and dehydroascorbic acid (DHA) levels were evaluated over a period of seven days by high performance liquid chromatography (HPLC). Total vitamin C content was also determined by a classical spectrophotometric method. The HPLC data revealed a significant decrease of AA during the storage of both juice drinks resulting in losses of 35% and 27% in the cranberry and cranapple drinks, respectively. The loss of ascorbic acid was offset by the simultaneous increase of DHA (a biologically active vitamin) so that the sum of AA+DHA decreased 13% and 0% in the cranberry and cranapple drinks, respectively. Thus ascorbic acid retention was apparently influenced by the nature of the juice system. The spectrophotometric results indicated no significant loss of total vitamin C activity during the storage of either juice drinks. The observed differences between the spectrophotometric and HPLC results were attributed to interference problems associated with the spectrophotometric method. / Graduation date: 1988