Sphingolipids associated with flesh browning onset and development in ‘Cripps Pink’ apples (Malus domestica Borkh.)

Authors: SANCHEZ-CONTRERAS, JAVIER - University Of Talca; Rudell, David; Mattheis, James; TORRES, CAROLINA - Washington State University

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2021
Publication Date: 6/16/2021
Citation: Sanchez-Contreras, J., Rudell Jr, D.R., Mattheis, J.P., Torres, C.A. 2021. Sphingolipids associated with flesh browning onset and development in ‘Cripps Pink’ apples (Malus domestica Borkh.). Postharvest Biology and Technology. 180. Article 111623. https://doi.org/10.1016/j.postharvbio.2021.111623.
DOI: https://doi.org/10.1016/j.postharvbio.2021.111623

Interpretive Summary: Many apple varieties ripen slowly after harvest if they are stored at a low temperature. While low temperature can slow softening and other characteristics related to edibility, there is a risk of peel or flesh browning development as storage duration lengthens. Flesh browning is a natural process but is undesirable as most consumers are not thrilled find brown flesh when apples are cut. The biology of browning development is poorly understood, a lack of knowledge that limits development of storage protocols that could limit browning development. ARS scientists in Wenatchee, WA in collaboration with university scientists from Chile and Washington State University examined how the browning process proceeds at a metabolic level, an approach similar to how medical practitioners monitor patient health with laboratory analyses. The research identified several plant compounds that change in advance of and during browning development. This information may be useful to identify fruit that will develop browning in advance of symptom development and provide a means to sell fruit before it has browning. The information also may be useful to diagnose the causes of browning, a difficult process as there are many factors that can result in browning development that has similar symptoms but differs in chemical makeup.

Technical Abstract: Flesh browning (FB) of ‘Cripps Pink’ apples can cause significant economic losses to apple producers worldwide. Although FB symptoms appear during cold storage, there are several pre-harvest factors involved in susceptibility that are poorly understood. Flesh tissue from fruit collected starting 150 days after full bloom (DAFB), through harvest, then, until 200 d into cold storage were sampled for non-targeted metabolic analyses using gas and liquid chromatography coupled with mass spectrometry. FB symptom development was positively associated with sphingolipids metabolism. Elevated levels of multiple glucocerebrosides and ceramides were found in apples at risk for developing the disorder, while the concentrations of a few others increased in healthy tissue during storage. Based on previous reports in other plant and animal species, elevated sphingolipid concentrations could be associated with membrane lipid catabolism, cell apoptosis, and fruit senescence involved in FB symptom development.