Effects of repeated 1-methylcyclopropene (1-MCP) treatments on ripening and superficial scald of ‘Cortland’ and ‘Delicious’ apples

• Published in: Postharvest biology and technology 2013-04, Vol.78, p.48-54
• Main Authors: Lu, Xingang, Nock, Jacqueline F., Ma, Yanping, Liu, Xinghua, Watkins, Christopher B.
• Format: Article
• Language: English
• Subjects: 1-methylcyclopropene; air; antioxidants; apples; Biological and medical sciences; cultivars; diphenylamine; Ethylene; Firmness; Food industries; Fruit and vegetable industries; fruit quality; fruits; Fundamental and applied biological sciences. Psychology; Malus×domestica Borkh; Physiological disorders; ripening; Storage; storage time
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2012.12.007

► Apple cultivars vary in persistence of 1-MCP control of ripening and superficial scald. ► Delicious showed total control of scald for 36 weeks air storage. ► For Cortland, 1-MCP needed to be applied within 4 days for best control. ► Repeated 1-MCP treatments were effective but only if applied soon after harvest. Postharvest 1-MCP can maintain fruit quality and inhibit development of superficial scald, a physiological storage disorder found in apple fruit, but the extent of the inhibition can vary by cultivar. In this study, we investigated whether multiple applications of 1-MCP, which are now permitted by a label modification of the commercial 1-MCP product, SmartFresh™, might improve scald control. ‘Cortland’ and ‘Delicious’ apples were untreated, treated on the day of harvest with the antioxidant inhibitor of scald, diphenylamine (DPA), or with 1μLL−1 1-MCP at different intervals after harvest. Treatment times (days) were 1, 4, 7, 1+4, 4+7, 1+4+7, 7+14, 7+28, 7+42, and 7+84. Internal ethylene concentrations (IECs), flesh firmness, and accumulations of α-farnesene and conjugated trienols (CTols) were measured at harvest, at the time of treatment, and at intervals during air storage at 0.5°C for up to 36 weeks. Scald was completely inhibited by DPA and all 1-MCP treatments in ‘Delicious’. However, effective control of scald in ‘Cortland’ was obtained with 1-MCP treatments within the first 4 days of harvest, either alone or in combination. Scald control with delayed 1-MCP treatments resulted in poorer scald control that was comparable to that obtained with DPA. IECs and α-farnesene accumulation were similar in untreated and DPA treated fruit, but inhibited by 1-MCP. However, differences among 1-MCP treatments became more evident with increasing storage periods. Inhibition of IECs and α-farnesene accumulation was greater in fruit treated on days 1, 4, 1+4, 4+7, 1+4+7, than on day 7 alone. A second application of 1-MCP on day 14 to fruit treated on day 7 increased inhibition of IECs, α-farnesene and CTol accumulations, but increasing delays before the second 1-MCP treatment resulted in progressively less inhibition of these factors. Similar effects of treatment on IECs, α-farnesene and CTol accumulations were found for both cultivars, even though no scald was detected in treated ‘Delicious’ apples. The results indicate that initial 1-MCP treatments should be applied to faster ripening cultivars such as ‘Cortland’ within a few days of harvest.