Elucidating ethylene-mediated physiology and biochemistry in selected climactic and non-climacteric fruits using e+® ethylene remover

摘要

The presence of ethylene in a storage environment can undermine both quality andpostharvest life of many fruits, often generating significant waste and associatedeconomic losses. A demand for discovering alternative technologies capable ofscavenging ethylene has led to the development of a new material, e+® EthyleneRemover, which has significant ethylene adsorption capacity. The material has beenshown to remove ethylene to below physiologically active levels during fruit storage at0-20oC and consequently extend postharvest life for a variety of fresh produce types.Different formats incorporating e+® Ethylene Remover have been developed. Successfulapplication of e+® Ethylene Remover in laboratory settings has created opportunities totest new formats of the product. To this end, work was conducted herein to attestwhether e+® Ethylene Remover, which has been shown to maintain avocado (Perseaamericana cv. Hass) firmness in recent laboratory trials, could result in a meaningfulextension of storage life in a commercial setting. It was shown that e+® EthyleneRemover coated sheets were a highly efficacious format for suppressing ethylene andextending storage life of imported avocado and pluot plums in a series of commercialtrials. Moreover, the potency of the e+® Ethylene Remover treatment in retardingethylene induced ripening was significantly enhanced when avocados were treatedduring the early stages of ripening. After a storage period of up to 31 days (5-6oC),avocado fruits which had received an early treatment at source and then treated again inthe laboratory were significantly more firm and greener compared to fruits treatedfollowing 5 weeks of transit alone .Strawberry is regarded as non-climacteric fruit; nevertheless, exogenous ethylene cannegatively influence postharvest life. The low ethylene produced by non-climactericfruits has been generally ignored and research reporting on the involvement of ethylenein these fruits is typically devoid in the literature. To this end, application of a highlysensitive laser based photoacoustic ethylene detector has revealed a possible role ofethylene in determining the postharvest life of strawberries. Moreover, fruit qualityparameters including disease incidence, sugars, organic acids, phenolic compounds andplant phytohormones/metabolites were found to be profoundly affected by ethylene and likewise the removal of ethylene. Storage of strawberries in the presence of e+®Ethylene Remover was associated with lower disease incidence, significantly less redfruits and higher ascorbic acid content. In contrast, ethylene and 1-methylcyclopropene(1-MCP) treatments resulted in the higher postharvest disease. Ethylene-treated fruitswere associated with lower level of sucrose and higher simple sugars (fructose andglucose) suggesting a role of ethylene in promoting the rate of senescence andconcomitant reduced postharvest quality of strawberries. Changes in ABA, ABAmetabolites and auxins within different tissues of ripe strawberry during storage wereinvestigated. ABA was more abundant in the flesh than in the achenes, while auxinswere undetectable in the flesh tissue. Auxins indole-3-acetic acid (IAA) and theconjugated form indole-3-acetylaspartic acid (IAAsp) were detected in highconcentrations in the achenes and were affected by ethylene and storage length.