Title: Diphenylamine Metabolism in 'Braeburn' Apples Stored under Conditions Conducive to Development of Internal Browning Authors
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2008
Publication Date: April 2, 2008
Citation: Mattheis, J.P., Rudell Jr, D.R. 2008. Diphenylamine Metabolism in 'Braeburn' Apples Stored under Conditions Conducive to Development of Internal Browning. Journal of Agricultural and Food Chemistry. 56:3381-3385. Interpretive Summary: Continuous availability of apples at retail depends on successful fruit storage over an extended period. Many factors influence fruit marketability including edible quality and appearance but development of physiological disorders during storage can seriously reduce grower returns and fruit availability. Internal browning of apple can arise from a number of factors including excessive carbon dioxide present in the storage environment. While control of carbon dioxide can limit or prevent the disorder, development of new or improved cultivars that are tolerant of carbon dioxide would increase warehouse efficiencies by removing the need to manage carbon dioxide during storage. The research conducted using ‘Braeburn’ apples, highly sensitive to carbon dioxide, shows a number of ways fruit respond to the presence of high carbon dioxide that have not been recognized previously. Fruit without symptoms due to prestorage treatment with antioxidant or antiripening materials respond differently compared to non-treated fruit. The information shows changes in fruit metabolism occurs in the presence of high carbon dioxide concentrations, and that genetic improvement may be a means to enhance fruit tolerance to carbon dioxide.
Technical Abstract: Oxidative metabolism and ethylene action were evaluated as factors influencing development of ‘Braeburn’ apple internal browning and cavitation during cold storage. Apples treated with the antioxidant diphenylamine (DPA) and/or the ethylene action inhibitor 1-methylcyclopropene were held at 1 oC for up to 6 months in air or a controlled atmosphere (CA) containing 1 kPa O2 and 3 kPa CO2. Cortex tissue from fruit without disorders as well as from symptomatic and asymptomatic areas of fruit with disorders were analyzed for DPA, DPA derivatives, E,E-a-farnesene, and conjugated trienol content. Internal browning and cavities developed in control and 1-MCP-treated fruit stored in CA, while air-stored and CA fruit treated with DPA or DPA and 1-MCP prior to storage did not develop disorders. Significant treatment interactions between storage duration, storage environment, pre-storage treatment, and DPA metabolites were identified. Depending on the storage regime and duration, less DPA was detected in 1-MCP-treated fruit. 4OHDPA content of control fruit decreased during air storage duration but increased between 2 and 4 months in CA storage. 4OHDPA content in 1-MCP-treated fruit increased with storage duration in CA but not air. NODPA was detected after 2 months in control fruit stored in air or CA and in 1-MCP-treated fruit stored in CA, and NODPA content in control fruit was higher compared to content 1-MCP-treated fruit. Accumulation of 4MEODPA in control fruit stored in air increased with storage duration, but amounts did not change in 1-MCP-treated fruit stored in air or CA. 2-nitrodiphenylamine content was reduced by pre-storage treatment with 1-MCP but storage environment and duration had no significant effects on its accumulation. Cortex E,E-a-farnesene content in control fruit that did not develop disorders increased between 4 and 6 months storage in air. Treatment with 1-MCP, DPA, 1-MCP and DPA, or storage in CA prevented the E,E-a-farnesene increase with storage duration. An inverse relationship between E,E-a-farnesene content and browning incidence was evident at 2 but not 4 or 6 months. Conjugated trieneols were not detected in any of the samples. The results indicate that CA storage increases risk of disorder development in ‘Braeburn’ apples, that DPA can prevent disorder development, that content of DPA and DPA derivatives is influenced by storage environment and ethylene action, and E,E-a-farnesene content was in many cases lower in tissues obtained from fruit with internal disorders compared to symptomless fruit.