1-MCP effects on ethylene emission and fruit quality traits of peaches and nectarines

1-methylcyclopropene (1-MCP), an ethylene antagonist, is an effective device to improve the shelf-life and quality of fruits, vegetables and ornamentals. It also represents a useful tool in studies aimed at clarifying the ethylene physiology in plants. Peaches and nectarines are climacteric fruit which exibit a sharp rise in ethylene synthesis at the onset of ripening associated with changes in colour, texture, aroma and other biochemical features. Therefore, treatments with ethylene antagonist such as 1-MCP has been performed for extending postharvest storage and shelf life of peach fruit. Fruit developmental stage must be considered when applying 1-MCP, as its effects vary with fruit maturity. In fact, the efficacy of 1-MCP treatment decreases with advanced fruit development. In order to study the effects of 1-MCP on peaches and nectarines at different ripening stages, the fruit was divided into homogeneous classes by using the NIRs (Near InfraRed Spectroscopy) non destructive technology. This technology allowed to correlate the difference of absorbance at the wavelength of 670 and 720 nm (DA index) to ethylene emission levels in peach fruit. Immediately after harvest, three groups of fruit were set, with different DA index intervals: the first one included “pre-climacteric” fruit, characterised by very low or undetectable ethylene emission levels, the second one included “early-climacteric” fruit (low ethylene emission levels) and the third one “late-climacteric” fruit (high ethylene emission levels). The fruit of the three classes was treated with 1-MCP (1 or 5 l l-1) for 12 h at 25°C. Treated and control fruit was then kept at 25° C for about 1 week and the effects on ethylene emission, volatile organic compounds (VOC) and fruit quality traits (flesh firmness, total soluble solids content, titratable acidity) were evaluated.