Title: EFFECTS OF POSTHARVEST CALCIUM INFILTRATION ALONE AND IN COMBINATION WITH SURFACE COATING TREATMENTS ON VOLATILE LEVELS, RESPIRATION, ETHYLENE PRODUCTION, AND INTERNAL ATMOSPHERE OF 'GOLDEN DELICIOUS' APPLES
Submitted to: American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 13, 1998
Publication Date: N/A
Interpretive Summary: Two major thrusts of postharvest research are to extend postharvest life of fresh produce and to reduce postharvest use of synthetic fungicides for controlling decay and losses of fresh produce during storage. We found that postharvest calcium chloride treatments that increase fruit calcium to levels that are known to control the growth of postharvest, decay-causing pathogens transiently inhibited flavor-associated volatile levels. Surface coating the fruit after calcium treatment to protect the fruit from surface injury and decay during storage further inhibited flavor-associated volatile levels. The results indicated that postharvest calcium treatments to maintain firmness and other quality characteristics and to control postharvest pathogens would not adversely affect apple flavor when used in conjunction with commercial storage conditions of 4 months or more and simulated ripening periods of several weeks or more. This information provides apple growers and packinghouse operators with a natural strategy to maintain the postharvest quality of apple fruit in storage and the preferred withdrawal times of calcium- treated fruit from storage for optimal flavor.
The effects of postharvest pressure infiltration of distilled water, 0.14 or 0.27 mol per liter calcium chloride solutions without and with subsequent fruit coating treatments of preclimacteric apples (Malus xdomestica Borkh. 'Golden Delicious') on volatile levels, respiration, ethylene production and internal atmospheres after storage at 0 C for 1 to 6 months, and during subsequent ripening at 20 C were investigated. Pressure infiltration of increasing concentrations of calcium chloride resulted progressively in reduced total volatile levels, respiration, ethylene production and internal oxygen levels and increased carbon dioxide levels in 'Golden Delicious' apples following 2 to 4 months of storage in air at 0 C. Total volatile levels, respiration, ethylene production and internal atmospheres of 0.14 mol per liter calcium chloride treated apples gradually recovered to untreated control levels following two weeks of ripening at 20 C and/or storage at 0 C in air for more than 4 months. Following the calcium treatments with a shellac- or wax-based coating had similar but stronger and more persistent effects on volatile levels, respiration, ethylene production and internal atmospheres than those found in fruit treated with calcium chloride alone. Calcium infiltration did not change the composition of volatile compounds found in 'Golden Delicious' apples. The results suggest that pressure infiltration of 'Golden Delicious' apples with calcium chloride solutions transiently inhibited volatile levels, respiration and ethylene production, at least in part, by forming a more-or-less transient barrier to carbon dioxide and oxygen exchange between the fruit tissue and the surrounding atmosphere.