Is Ethylene the Ripening Hormone

Abstract

The fruits constitute a commercially important and nutritionally indispensable food commodity since they play a vital role in human nutrition by supplying the necessary growth factors essential for maintaining normal health.  One of the limiting factors that influence their economic value is the relatively short ripening period and reduced post-harvest life.  The fruit ripening involves a wide spectrum of coordinated biochemical and physiological processes that eventually leads to development of soft edible fruit with desirable qualities such as carotenoids, anthocyanin, color, sweetness, texture, firmness, flavor and aroma.  The ripening is the phase of fruit development just before senescence, therefore the excessive tissues softening due to the high ethylene exposure leads to the spoilage upon the storage.  Ethylene, a fruit ripening hormone can trigger many events of cell metabolism including ripening particularly in climacteric fruits even in minute amounts.  As fruit mature, the rate of ACC and ethylene biosynthesis increases as well as the enzyme activities for ACC oxidase and ACC synthase enhance.  However, the application of ethylene inhibitors such as 1-MCP, AVG and the ethylene remover proved to reduce the ripening where some quality attributes of ripening were reduced due to suppressed expression of the ripening hormone.