Responses of ‘Zucchini’ Squash to Storage in Low-O2 Atmospheres at Chilling and Nonchilling Temperatures

Abstract

Zucchini squash ( Cucurbita pepo L.) was stored 2 weeks at 2.5°, 5°, or 10°C and with 1%, 2%, 4%, 8%, or 21% O 2 and then was aerated 2 days at 10°. Low O 2 levels inhibited the rates of CO 2 and ethylene production, particularly at 5° and 10°. Both rates increased during aeration, but much more in samples held previously at 2.5° or 5° than in those from 10°. About 75% and 55%, respectively, of the burst in CO 2 production in samples from 2.5° and 5° was due to exposure to low temperature; the remainder was attributed to the effect of exposure to low O 2 levels. For ethylene production, the corresponding values were about 95% and 70%. Zucchini squash stored at 5° for 2 weeks was virtually free of chilling injury (Cl), surface mold, decay, or off-flavors; almost all of the fruit still was rated good to excellent in appearance. About ¾ of the squash was still in this category after 2 additional days at 10°. At 5°, squash did not benefit from storage in low-O 2 atmospheres. Storage at 2.5° induced severe Cl, which was ameliorated by holding the squash in 4%, 2%, or 1% O 2 instead of in 21% or 8% O 2 . However, amelioration was no longer evident after 2 days of aeration at 10°. Defects not related to Cl—especially off-flavors—developed most noticeably in squash held at 10°; the benefit from low O 2 levels was slight. Storing zucchini squash at 6° ± 2° likely would be optimal if it must be held longer than a few days.