Submitted to: International Society of Horticultural Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 28, 2004
Publication Date: June 1, 2004
Citation: Rudell Jr, D.R., Mattheis, J.P. 2004. Reactions of diphenylamine and diphenylamine derivatives in 'Granny smith' apples and relationsips to control of superficial scald. 5th International Society of Horticultural Science Proceedings. Abstracts. p. 105. Technical Abstract: Control of apple superficial scald (scald) using diphenylamine (DPA) is a common practice in many of the worlds apple producing regions. While scald control conferred by DPA is thought to be related to its antioxidant capabilities, the specific mechanism has not been characterized. In this study, apple fruit were treated with aqueous emulsions containing DPA or DPA derivatives including 4-hydroxydiphenylamine (4OHDPA), 3-hydroxydiphenylamine (3OHDPA), n-nitrosodiphenylamine (NODPA), and 2-nitrodiphenylamine (2NO2DPA). Scald incidence and severity were evaluated and peel diphenylamine and diphenylamine derivative content characterized and quantified using LC/MS. 4OHDPA, 30HDPA, NODPA, and 2NO2DPA (listed in decreasing quantity) were among the derivatives found in peel of apples previously treated with DPA. Treatment with DPA or 4OHDPA provided the best scald control with slight scald control conveyed by NODPA. Derivatives formed from these compounds during storage will be reported and their relevance to scald control discussed.