`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.
We have established that `d'Anjou' pears (Pyrus communis) are properly ripened for fresh-cut use when flesh firmness (FF) is between 5 lb (2.3 kg) and 7 lb (3.2 kg). In this study, the fruit was ripened in air enriched with 100 ppm (mL·L-1) ethylene at 68 °F (20.0 °C). Afterward, we investigated three slicing methods, each employing a fruit sectionizer for dividing individual pears into eight wedges. The easiest and most convenient cutting procedure involved pouring an antibrowning agent onto the incision, but without allowing the fruit to directly contact the air. We evaluated various combinations of L-ascorbic acid (vitamin C) and potassium chloride (KCl) for their ability to prevent any discoloration while also not affecting taste or injuring the cut surface. The most suitable antibrowning solution contained 10% L-ascorbic acid and 2% KCl (pH 2.3). A dipping time of 30 s was sufficient for maintaining the wedges with little discoloration over a 14-d period, at either 30 or 35 °F (-1.1 or 1.7 °C). Here, we also present a prototype design for a 1.6-pt (0.76-L) transparent plastic container with eight compartments for holding wedges sliced with a commercially available sectionizer.
`Bartlett' pears (Pyrus communis L.) were harvested at commercial maturity (average flesh firmness of 18 lb), stored at 30F for 0, 2, or 4 weeks, and then placed into a ripening room at 68F with or without ethylene to evaluate ripening activities. Pears that were stored in air at 30F for <4 weeks did not ripen after 7 days at 68F in an ethylene-free (no-ethylene) room. These pears ripened normally and uniformly after 7 days at 68F in a room enriched with 100 ppm ethylene (yes-ethylene). `Bartlett' pears that were stored in air at 30F for 4 weeks ripened normally after 5 days at 68F in the yes-ethylene room or 6 days at 68F in the no-ethylene room. The amount of cans produced per ton of fresh processed pears can be maximized most economically by exposing freshly harvested `Bartlett' pears to 100 ppm ethylene at 68F for 7 days before canning.