Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 5, 2006
Publication Date: April 1, 2007
Citation: Saftner, R.A., Luo, Y., Mcevoy, J.L., Abbott, J.A., Vinyard, B.T. 2007. Analytical quality characteristics of fresh-cut watermelon slices from non-treated and 1-methylcyclopropene- and/or ethylene-treated whole fruit. Postharvest Biology and Technology. 4(1):71-79. Interpretive Summary: Whole and fresh-cut watermelon sales have increased steadily in the last few years. Major losses occur when watermelons are exposed to ethylene, a gas that causes tissue breakdown, during transport and storage of the fruit. In this paper, we report that treatment of whole watermelons with a gaseous inhibitor of ethylene, 1-methylcyclopropene (1-MCP), prior to ethylene exposure completely prevented ethylene-mediated quality loss in fresh-cut slices. This information will be of use to the fresh and fresh-cut fruit industry in assuring the quality and in reducing the postharvest losses of watermelon products during transport and storage.
Technical Abstract: Maintaining the postharvest quality of fresh-cut fruit after processing and throughout distribution and marketing is a major challenge facing the fresh-cut fruit industry. Analytical quality characteristics of packaged fresh-cut watermelon slices from non-treated and 1-methylcyclopropene (1-MCP)- and/or ethylene-treated whole fruit were investigated. Freshly harvested seedless watermelon (‘Sugar Heart’) were stored 1 to 7 d in air before exposure to 0, 0.5 or 1.0 µL L-1 1-MCP for 18 h followed by 5 d exposure to 0 or 10 µL L-1 ethylene, all at 20 °C. Following treatment, fruit were processed into wedge-shaped slices, packaged into rigid trays sealed with a high oxygen transmission rate film overlap and stored 1, 6 or 12 d at 5 °C. During storage, fresh-cut watermelon slices from non-treated and 1-MCP- and 1-MCP + ethylene-treated whole fruit maintained similar respiration rates and internal atmospheres of CO2 and O2 and were of similar quality with total aromatic volatile concentrations decreasing and puncture firmness, soluble solids content (SSC), cut surface pH and color remaining relatively stable. In contrast, fresh-cut slices from fruit treated with ethylene alone had higher respiration rates and modified package atmospheres containing more CO2 and O2; lower firmness, SSC and chromaticity values; higher pH and an altered volatile profile compared to those of slices from non-treated and 1-MCP- and 1-MCP + ethylene-treated fruit. Most of the more abundant volatiles were aldehydes and alcohols; others were ketones. During storage, many individual volatiles decreased in concentration but some increased including (Z)-6-nonen-1-ol, a volatile having a pumpkin-like aroma. Extending the time from harvest to 1-MCP treatment had no appreciable effects on respiration rates or quality characteristics of the fresh-cut slices, irrespective of treatment. The results indicated that low dosage 1-MCP treatments prior to ethylene exposure of whole watermelons prevented ethylene-mediated quality deterioration in fresh-cut slices stored under modified atmosphere conditions at 5 °C.