
USE OF ETHYLENE ABSORBERS IN EXTENDING SHELF LIFE John A. Ayoub, Dr. Margaret G. Driver, Dr. Irwin A. Taub Nature of the Problem: Ethylene is a natural plant hormone produced by metabolism in most fruit. It initiates and accelerates the ripening of fruit and causes vegetables to deteriorate. This unavoidable process is a major problem, since in almost all applications noncompatible fruits and vegetables (i.e., ethylene emitters and ethylene sensitive items) are stored and/or shipped in the same container. If we could keep the level of ethylene as low as possible, we would be able to slow the maturation of the fruits, protect the vegetables, and reduce spoilage to a minimum. Technical Strategy: One of the simplest ways to remove ethylene from the atmosphere is to absorb it. Field Test II(Korea by Surface Vessel) This test was the most controlled of all the field tests to date. In cooperation with DSR-PAC in Alameda, CA, we set up a three-week shipping test to South Korea. Large lots of FF&V were split and placed into two identical 40 ft. sea vans, one with and one without absorber filters placed near the air inlet to the cooling system operation at 36°F. The produce was inspected by a Quality Assurance Specialist from DSR-PAC and a Natick Project Officer before loading in Alameda and after unloading from the container ship in Pusan, South Korea. The atmosphere in each van was also sampled for the concentration of ethylene. Upon arrival in Pusan, the atmosphere in the test van with the absorber filters had an ethylene concentration of 1.8ppm, while the atmosphere in the control van had 29ppm (more than 16x the concentration). The fruits and vegetables in the absorber-protected van were in excellent condition. In the control van, many of the green leaf vegetables were completely spoiled and most of the fruits were ripe enough for immediate use. | TABLE II – SOUTH KOREA RESULTS – FIELD TEST II | | Product | Test VAN | Control VAN | Cabbage Celery Peas Escarole Pears Nectarines Kiwi fruit | Fresh, crisp, good green color Fresh, crisp, 3% decay-tops Fresh, green, <1% rot Some decay at tips Mostly Firm Mostly Hard Mostly firm, 1% decay | Yellowish green, 11% decay 100% rot surveyed Fresh, green, 14% rot, mold 100% decay surveyed Firm to ripe, many ripe Mostly hard to firm, 13% decay Mostly ripe, 2% decay | Comparative Economic Aspects: In order to know the overall economic benefits of using ethylene absorbers, you have to determine the savings due to reduced spoilage and compare it to the cost of absorbers required. Using the example of the shipment to South Korea, the estimated savings due to a reduction in spoilage at destination was $928 while the cost of the absorbers was $160, thus a net benefit of $768 (A 480% Return On Investment) |