GENETIC, METABOLIC, AND PHYSIOLOGICAL FACTORS REGULATING DECIDUOUS TREE FRUIT QUALITY
Location: Physiology and Pathology of Tree Fruits Research
Title: Cell wall, cell membrane, and volatile metabolism are altered by antioxidant treatment, temperature shifts, and peel necrosis during apple fruit storage
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 10, 2013
Publication Date: January 13, 2013
Citation: Leisso, R.S., Buchanan, D.A., Lee, J., Mattheis, J.P., Rudell Jr, D.R. 2013. Cell wall, cell membrane, and volatile metabolism are altered by antioxidant treatment, temperature shifts, and peel necrosis during apple fruit storage. Journal of Agricultural and Food Chemistry. 61:1373-1387.
Interpretive Summary: Superficial scald is a peel browing disorder of certain apple cultivars that appears several months into cold storage. Symptoms of the disorder may worsen during shelf-life. This study contrasted fruit treated with the antioxidant dipenylamine which prevents the symptoms of this disorder compared to fruit that was left untreated. Peel metabolism was examined from harvest through six months of cold storage and at room temperature following different duration of cold storage. At 4 and 6 months, untreated fruit has symptoms of superficial scald that worsened during warm temperature conditions. This work illuminated changes in metabolism that may be used to better understand and maintain fruit storage quality and find alternatives to conventional storage techniques.
The transition from cold storage to ambient temperature alters apple quality through accelerated softening, flavor and color changes, and symptom development of physiological peel disorders, such as superficial scald, in susceptible cultivars. To reveal global metabolism associated with the transition from cold to ambient temperatures and superficial scald development, the 'Granny Smith' apple peel metabolome was evaluated during storage and shelf-life periods alongside disorder development following cold storage through 6 months. Treatment with the antioxidant diphenylamine (DPA) was used to contrast peel that is developing or has developed superficial scald. Superficial scald symtoms developed on control fruit after 120 d storage and symptoms progressed following transition to ambient temperature shelf-life conditions. The metabolic profile of control and DPA-treated fruit was divergent after 4 weeks of cold storage due to differing levels of a-farnesene oxidation products, methyl esters, phytosterols, and other compounds potentially associated with chloroplast integrity and oxidative stress response. Hierarchical cluster analysis revealed co-regulation within the volatile synthesis pathway including control of the avalability of methyl, propyl, ethyl, acetyl, and butyl alcohol and/or acid moeties for ester biosynthesis. Overall, the application of metabolmics techniques lends new insight into physiological processes leading to cell death and ripening processes that impact fruit flavor, appearance, and overall quality.