ISHS Acta Horticulturae 1364: XXXI International Horticultural Congress (IHC2022): International Symposium on Postharvest Technologies to Reduce Food Losses
Superficial scald induction in ‘Granny Smith’ apples subjected to different storage treatments |
| Authors: | M. Gerber, T. Karuppanapandian, D.W. Viljoen, W.J. Botes, I.J. Crouch, E.M. Crouch |
| Keywords: | controlled atmosphere, dynamic controlled atmosphere-chlorophyll fluorescence, 1-methylcyclopropene, diphenylamine |
| DOI: | 10.17660/ActaHortic.2023.1364.33 |
| Abstract:
Superficial scald is a postharvest oxidative stress disorder that develops in susceptible apple cultivars during prolonged low-temperature storage. Scald development consists of an induction period, that initially occurs during regular air (RA) storage and is characterized by irreversible physiological changes, followed by symptom expressed as browning of the peel during or following RA or low-oxygen storage. This negatively impacts the fruits fresh market value and contributes to significant annual losses. Therefore, the South African export industry routinely uses low-oxygen storage practices, such as controlled atmosphere (CA) and dynamic controlled atmosphere monitored by chlorophyll fluorescence (DCA-CF) storage, to delay scald induction and maintain fruit quality. Symptom expression usually occurs during the extended shipment and shelf-life period. This paper assessed the efficacy of different storage practices in combination with diphenylamine (DPA) and 1-methylcyclopropene (1-MCP) to control superficial scald. ‘Granny Smith’ apples were subjected to 12 different storage practices for 4, 8, 16, 24, and 34 weeks (W) cold storage (1°C) followed by a simulated 6W RA shipment period (-0.5°C) and 10 days at 20°C shelf-life (10d SL). The storage practices included RA, DPA (9.6 mL L‑1) + RA, 1-MCP (1 µL L‑1) + RA, CA (1.5% O2 and 1.0% CO2), 1-MCP+CA, DCA-CF (≈0.4% O2; 1% CO2), 1-MCP+DCA-CF, 1-MCP+CA+(1-MCP- after 24 and 34W cold storage), 1-MCP+CA+(DCA-CF for 7d after 24 and 34W storage) and 1-MCP+CA+(DCA-CF+1-MCP). The results for the 2019-2020 season indicated that scald induction was effectively delayed up to 34W under CA and DCA-CF storage. However, symptoms developed following 16W+6W RA+10d SL and 24W+6W RA+10d SL. The inclusion of 1-MCP offered a higher degree of control against superficial scald for fruit stored under RA, CA, and DCA-CF with symptom only evident 34W+6W RA+10d SL. The 1-MCP+DCA-CF and the post storage 1-MCP treatments, 1-MCP+CA+1-MCP and 1-MCP+CA+(1-MCP+DCA) had no superficial scald development at the end of storage. These storage treatments also maintained fruit quality the best (higher firmness, higher titratable acids, greener background colour, less fruit decay) compared to CA and DCA-CF alone (higher internal ethylene and CO2). | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
