Effects of 1-MCP applied postharvest on epicuticular wax of apples (Malus domestica Borkh.) during storage

BACKGROUND: Certain apple cultivars develop a greasy feel when overripe. Treating fruits with the ripening inhibitor 1-methylcyclopropene (1-MCP, SmartFresh (TM)) reduces fruit greasiness. This study examines the nature of this phenomenon. 'Royal Gala' apples were treated with 1-MCP at 1.0 mu 1 L-1 following harvest. Periodically, during storage at -1 degrees C for up to 6months, fruits were evaluated for internal ethylene concentration, fruit epicuticular wax morphology (using scanning electron microscopy) and non-polar organic solvent-extractable (NPOSE) wax constituents of the cuticle (using gas chromatography/mass spectrometry). RESULTS: In 2004, 1-MCP strongly inhibited internal ethylene production; however, total weight of NPOSE wax during storage was unaffected by treatment. In 2005, several wax constituents present in both 'Autumn Gold' and 'Royal Gala' showed differences during storage. In 2006, cuticular wax constituents comprising 80% of the total from 'Royal Gala' showed no treatment differences. Although several minor constituents did exhibit differences within treatment and sampling date, these did not appear sufficient to cause the subtle differences in surface wax morphology. CONCLUSION: 1-MCP strongly inhibited ethylene production and delayed development of certain wax constituents thought responsible for fruit greasiness during cold storage. Subtle differences in surface wax morphology appeared unrelated to wax production. Published in 2008 by John Wiley & Sons, Ltd.