2019 ASHS Annual Conference

The plant hormone ethylene plays a key role in various ripening-related irreversible changes in the fruit. The fruit ripening process involves changes in rates of respiration and ethylene production, fruit softening, metabolism of sugars and acids, physiological loss of weight and depletion of bioactive compounds. The efficacy of two potential ethylene antagonists namely 1H-cyclopropabenzene (BC) and 1H-cyclopropa[b]naphthalene (NC) as well as 1-methylcyclopropene (1-MCP) in retarding the rates and delaying the onset of respiration and ethylene climacteric peaks as well as in maintaining the quality in 150 and 200 days controlled atmosphere (CA) - stored Gold Rush pear fruit were investigated. The Gold Rush pear fruit were fumigated with the ethylene antagonists for 18 h using 60 L hermetically sealable plastic drums and the untreated fruit were considered as control. The experiments were laid in one or two-factor factorial completely randomised design with four replicates and fifteen fruit per replication. The fumigation treatment with ethylene antagonists (BC, NC and 1-MCP) significantly (P ≤ 0.05) reduced respiration and ethylene climacteric peak rates when compared to control, in 150 and 200 days CA-stored fruit. The pear fruit fumigated with ethylene antagonists maintained significantly higher fruit firmness and reduced physiological loss of weight (PLW) in comparison with the control fruit. The mean soluble solid concentration (SSC), glucose, and sorbitol values were maintained low in the CA-stored fruit fumigated with BC and NC. Levels of organic acids, total phenols, ascorbic acid, and total antioxidant capacity were not significantly affected by any of the ethylene antagonistic treatments. In conclusion, fumigation treatment with 1-MCP followed by BC and NC effectively reduced rates of ethylene and respiration but new ethylene antagonists were equally effective in maintaining postharvest fruit quality parameters studied in the long term CA-stored Gold Rush pear.