Effect of high CO2 and controlled atmosphere (CA) on the ascorbic and dehydroascorbic acid content of some berry fruits

High CO2 concentrations as well as controlled atmosphere storage are widely used to extend the storage and shelf-life of many fruits. To investigate the effect of these storage procedures on several berry fruits, strawberries, raspberries, currants and blackberries were stored at three different elevated CO2 concentrations, with or without a parallel reduction in O-2. Vitamin C content (ascorbic acid plus dehydroascorbic acid) was reduced by high CO2 concentrations (10-30% CO2), particularly in strawberries. This reduction in vitamin C was moderate in black currants and blackberries and almost absent in raspberries and red currants when compared with strawberries. Reducing the O-2 concentration in the storage atmosphere in the presence of high CO2 had little effect on the vitamin C content. Ascorbic acid was more diminished al high CO2 than dehydroascorbic acid. This suggests a stimulating effect of high CO2 concentrations on the oxidation of ascorbic acid and/or an inhibition of mono- or dehydroascorbic acid reduction to ascorbic acid. (C) 1997 Elsevier Science B.V.