Decreased ascorbic acid levels and brown core development in pears (Pyrus communis L. cv. Conference)

Abstract

Changes in ascorbic acid content are measured in the cortex tissue of Conference pears stored at various compositions of carbon dioxide and oxygen. Enhanced carbon dioxide levels cause ascorbic acid concentrations to decline. Soon after ascorbic acid has declined below a certain value, browning of the core tissue can be observed. Reducing carbon dioxide levels before this value is reached causes ascorbic acid levels to increase again and prevents browning to a great extent. In preliminary experiments with a photoacoustic laser-based detection system, it was shown that pears that show browning produce ethane, which is most likely a result of membrane peroxidation. Storage conditions, ascorbic acid levels and browning in pears are discussed in relation to diffusion characteristics, energy metabolism and energy maintenance levels of the fruit.