Stability of vitamin C in fruits and fruit blends

The levels of the two biologically active forms of vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA), were determined in individual fruits, in fruit blends and in model systems over a 3‐h incubation period at room temperature. There was essentially no reduction in the AA content in the orange juice sample and in the model solution of analytical l‐ascorbic acid. A rapid decrease in the AA content was observed in the banana, apple and guava samples and in blends consisting of orange juice‐banana‐apple or L‐ascorbic acid‐banana‐apple blends. However, the reduction in AA was concomitant with a quantitative increase in DHAA content.