Antoxidant properties and fruit quality during long-term storage of "Rocha" pear: effects of maturity and storage conditions

Free radical scavenging activity and the content of ascorbic acid and glutathione were investigated during long-term storage of the pear (Pyrus communis L. 'Rocha') fruit harvested at different maturity stages, stored in air or under controlled atmosphere and subjected to postharvest treatments with diphenylamine (DPA) and 1-methylcyclopropene (1-MCP). Harvest maturity had a significant effect on storage disorders, fruit firmness, soluble solids content and acidity. Differences in ascorbate content and free radical scavenging activity at harvest did not persist during storage. Controlled atmosphere and DPA strongly reduced the incidence and severity of browning disorders and superficial scald, whereas 1-MCP provided the most effective control. Neither DPA nor 1-MCP affected the free radical scavenging activity or the levels of ascorbate and glutathione in the pear. These results suggest that the benefits of 1-MCP on internal breakdown are not directly related with its effects on the antioxidant levels and that, under good storage conditions, the antioxidant properties of the "Rocha" pear can be maintained for up to 8 months. The importance of fruit antioxidant metabolites as beneficial phytochemicals has been widely recognized. Interestingly, the same metabolites are also essential for the health of the fruit itself. Thus, maintaining high levels of antioxidants in fruits throughout the supply chain is of utmost importance to maintain fruit quality and to deliver to consumers the health benefits of fruit consumption. Many studies have addressed fruit antioxidants, but these studies either report comparisons among fruit types analyzed at a single (often uncharacterized) stage of development or they study changes during short storage periods. European consumers have pears available all year round and the typical storage duration of European pears extends up to 8 months. Moreover, different storage regimes and several postharvest treatments that may impact fruit antioxidants are used in commercial practice. It is thus relevant to characterize pear antioxidants during long-term storage and the effect of storage conditions and common postharvest treatments on fruit antioxidants. Harvest data are known to have a large effect on post-storage fruit quality, but its effect on antioxidants during storage is unknown. This information is useful to nutritionists and consumers who have to choose fruit and to all involved in the fruit supply chain in order to provide fruit with better quality.