Postharvest evaluation of stored Dudaim melon fruits (Cucumis melo var. dudaim) harvested at different stages of maturity

Authors: HATAMI, MOHSEN - University Of Tehran; KALANTARI, SLAMAK - University Of Tehran; SOLTANI, FOROUZANDEH - University Of Tehran; Beaulieu, John

Submitted to: Annual Meeting Horticultural Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Melons are a very important horticultural crop worldwide and one of the most important in Iran. Worldwide, there are hundreds of edible commercial melons and several types have been well characterized over the years. However, some local and regional land races, accessions and cultivars lack detailed postharvest characterization. For example, Dudaim or Queen Anne’s Pocket melon is a unique member of the edible melon (Cucumis melo L.) family and its postharvest physiology is poorly described. Investigating the relationship between optimum harvest window and storage temperature with postharvest physiology related to sugar, ethylene (the ripening “climacteric”) and quality changes would provide useful information to the commercial industry. Two dudaim melon cultivars (‘Zangi-Abad’ and ‘Kermanshah’) were planted at the University of Tehran, and harvested at two maturity stages (21 and 28 days after anthesis, DAA) and stored at two storage temperatures (5 and 13 °C) and analyzed weekly through 21 days. Quality parameters assessed included color, firmness, TA, pH, TSS, weight loss, protein content, glucose, fructose, sucrose, maltose and ethylene production. The experiment was performed according to a factorial design and data subjected to a statistical analysis. The a* color increased (from green toward orange/red) in both cultivars throughout storage in fruit harvested 21 DAA. After three weeks of storage at 13 °C, fruit harvested at 21 DAA had relatively similar color values (L*, a*, b*), TA and firmness compared to late harvested fruits (28 DAA) but some quality traits such as TSS were not similar. Glucose and fructose generally decreased, while sucrose and maltose increased with advancing maturity. Storage at 5 °C seemed to create some maturity-related “delays” regarding typical and normal ripening. For example, ‘Zangi-Abad’ held at 5°C did not ripen fully (possibly an incomplete ethylene climacteric). Yet, this finding could have been confused if there were not enough harvest dates assessed (for example if 35 DAA was also required). The cultivar ‘Kermanshah’ demonstrated a climacteric-like ripening behavior in both 21 and 28 DAA harvests but, not when stored at 5 °C. Increased ethylene production during storage at 13 °C, in concert with color development, reaching similar qualities to ripe fruits, and the changing balance of mono and disaccharide sugars, likely indicates that ‘Zangi-Abad’ and ‘Kermanshah’ are climacteric. Further study could determine the per cultivar-dependent optimum harvest windows regarding days after anthesis. Generally, it can be concluded that dudaim fruits can be harvested at an optimum stage of maturity, similar to known climacteric melons, and allowed be ripen at proper storage temperatures (e.g. 13 °C) before consumption. Herein, the co-authors have combined their expertise to deliver one of the first investigations for 2 commonly grown Iranian cultivars of the dudaim melon type.

Technical Abstract: Dudaim or Queen Anne’s Pocket melon is a unique member of the edible melon (Cucumis melo L.) family and less attention has been paid to its postharvest physiology. They are characterized by small reddish yellow fruits with ochre stripes, a unique fragrant and musky aroma, ornamental beauty, medicinal properties and a whitish and insipid pulp that is oftentimes barely edible. Volatile information exists for these fruit but, only one previous paper outlining the horticultural and cultural attributes was found. In order to investigate postharvest behavior of the fruit, two dudaim melon cultivars (‘Zangi-Abad’ and ‘Kermanshah’) were planted at the research station of the University of Tehran, and harvested at two maturity stages (21 and 28 days after anthesis, DAA). Fruits were stored at two storage temperatures (5 and 13 °C) and analyzed weekly through 21 days. Quality parameters assessed included color, firmness, TA, pH, TSS, weight loss, protein content, glucose, fructose, sucrose, maltose and ethylene production. The experiment was performed according to a factorial design and data subjected to an ANOVA. The a* color increased (from green toward orange/red) in both cultivars throughout storage in fruit harvested 21 DAA. After three weeks of storage at 13 °C, fruit harvested at 21 DAA had relatively similar color values (L*, a*, b*), TA and firmness compared to late harvested fruits (28 DAA) but some quality traits such as TSS were not similar. Glucose and fructose generally decreased, while sucrose and maltose increased with advancing maturity. Storage at 5 °C seemed to create some maturity-related “delays” regarding typical and normal ripening. For example, ‘Zangi-Abad’ held at 5°C did not ripen fully (incomplete ethylene climacteric). Yet, this could be confounded if insufficient DAA were assessed (i. e. if 35 DAA was required). The cultivar ‘Kermanshah’ demonstrated a climacteric-like behavior in both 21 and 28 DAA harvests but, not when stored at 5 °C. Increased ethylene production during storage at 13 °C, in concert with color development, reaching similar qualities to ripe fruits, and the changing balance of mono and disaccharide sugars, likely indicates that ‘Zangi-Abad’ and ‘Kermanshah’ are climacteric. Further study could determine the per cultivar-dependent optimum harvest window regarding days after anthesis. Generally, it can be concluded that dudaim fruits can be harvested at an optimum stage of maturity, similar to known climacteric melons, and allowed be ripen at proper storage temperatures (e.g. 13 °C) before consumption.