Ethylene from `Bartlett' Pears Promotes Early Ripening of `d'Anjou' Pears when Packed Together in Modified Atmosphere Bags

Abstract

`D'Anjou' pears (Pyrus communis L.) harvested at commercial maturity and stored in air at 30 °F (-1 °C) for up to 7 weeks were still incapable of ripening normally at 68 °F (20 °C) for 7 days. `D'Anjou' fruit at this stage were termed as under-chilled fruit. Ziploc bags [1-gal (3.8-L)] perforated with a number of small holes [1/8 inches (0.32 cm) in diameter] were used to pack five `d'Anjou' pears and five `Bartlett' pears [a total net weight of 5 ± 0.2 lb (2.3 ± 0.1 kg)]. The mixed fruit packed in the same bags were placed into a room at 68 °F. When under-chilled `d'Anjou' fruit packed with `Bartlett' fruit in the bags perforated with 6, 8, or 10 holes, `Bartlett' fruit became fully ripe after 5 days while `d'Anjou' fruit were capable of ripening normally after 7 days at 68 °F. Ripened fruit of both pear cultivars developed high dessert quality. The concentration of ethylene in these bags accumulated to ≈50 ppm (mg·L-1) on day 4 while CO2 concentration did not increase to above 3% and O2 concentration maintained at 18%. Ethylene generated naturally by `Bartlett' pears during ripening at 68 °F and accumulated in the bag perforated with 6 to 10 holes was sufficient to induce the normal ripening activities of under-chilled `d'Anjou' pears. This packaging technology may be used to promote early marketing for both pear cultivars.