Precondition of 'D' Anjou' Pears for Early Marketing by Ethylene Treatment

Abstract

D 'Anjou 'pears (Pyrus communis, L.) harvested at an optimum maturity with the Jeshjrmness (FF) of 66.7N required 8 weeks of chilling at-IC in order to initiate normal ripening in an ethylene-free environment at room temperature. If harvestedfiuit were not exposed to chilling or chilled at-1 C for less than 8 weeks, they could be preconditioned with I00 ppm ethylene for 3 days at 20C to initiate normal ripening. Fruit preconditioned with ethylene were capable of softening normally, reducing extractable juice, decreasing titratable acidity, and showing the climacteric rise of ethylene production during ripening at 20C when treatedfiuit had been further held at -1C in air for 14 days. The properly ripened fiuit developed an acceptable dessert quality. When 'd 'Anjou ' fiuits had been stored at -I C in air for 8 weeks or longer, they could also be preconditioned without ethylene for 3 days at 20C to enhance ripening capacity. The nonethylene preconditioned fiuit were capable of ripening normally following 14 days in simulated transit at -IC and upon arrival in retail markets at room temperature.

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“…3B). Our previous study had shown that a three-day preconditioning treatment with 100 ppm ethylene was sufficient to trigger the normal ripening of under-chilled 'd'Anjou' pears (Chen et al 1996). In this study, ethylene released from the ethylene capsule could be maintained at a sufficient level (i.e., above 100 ppm) in the perforated bag to trigger the normal ripening of packed 'd'Anjou' fruit ( Fig.…”

“…Winter pear fruit without sufficient chilling are termed "under-chilled" fruit (Chen and Varga 1999). A previous report demonstrated ripening of under-chilled 'd' Anjou' pears could be induced by either external ethylene treatment (Chen et al 1996) or ethylene generated from 'Bartlett' pears when packed in the same perforated bag (Chen and Varga 1999). The disadvantage of preconditioning 'd'Anjou' pears by external ethylene treatment is the potential risk to precondition 'd' Anjou' fruit to a point at which they become vulnerable to bruising damage in transit.…”

ETHYLENE CAPSULE PROMOTES EARLY RIPENING OF ‘d'ANJOU’ PEARS PACKED IN MODIFIED ATMOSPHERE BAGS

“…Winter pear fruit without sufficient chilling are termed "under-chilled" fruit (Chen and Varga 1999). A previous report demonstrated ripening of under-chilled 'd' Anjou' pears could be induced by either external ethylene treatment (Chen et al 1996) or ethylene generated from 'Bartlett' pears when packed in the same perforated bag (Chen and Varga 1999). The disadvantage of preconditioning 'd'Anjou' pears by external ethylene treatment is the potential risk to precondition 'd' Anjou' fruit to a point at which they become vulnerable to bruising damage in transit.…”

Cell Wall Β‐galactosidase in Ripening ‘D'anjou’ Pears

“…Little is known about the biochemistry of ripening in pears (Pym communis L.). Winter pears such as the 'd'Anjou', 'Bosc', 'Eldorado' and 'Conference' cultivars harvested at optimum maturity require 60 days of cold storage before they become capable of ripening (Chen and Mellenthin 1981) but will ripen without cold exposure when exposed to ethylene (Chen et al 1996). During storage at -1C, winter pears do not show appreciable softening (Chen et al 1983), although they produce significant amounts of ethylene and accumulate both 1-aminocyclopropane 1-carboxylic acid (ACC) and ACC synthase mRNA (Wang et al 1985;Knee 1987).…”