A Rotten Apple Spoils The Whole Barrel. Really.

rotten apple

You’ve heard the expression that a rotten apple spoils the whole barrel. Wonder why? The ripening and subsequent rotting of an apple can be linked to its internal production of a gas called ethylene. As in other fruits, ethylene stimulates a large number of enzymatic processes which are in general responsible for ripening. An increase in concentration of this gas enhances tissue respiration (oxygen uptake) which leads to a slightly increased internal temperature. This then leads to a breakdown of chlorophyll and the synthesis of other pigments. The starch in the fruit is converted to simple sugars and at the same time the compound pectin, a component of fiber which cements cell walls together, begins to disintegrate, softening the tissue. A rotting apple can stimulate this process in other apples. Usually undesired, unless you want to ripen bananas.  Put a green banana in a bag with a ripe, cut-up apple and watch it turn yellow. This ripening process can be carried out “commercially” as well; easily perishable produce such as bananas and tomatoes which must travel a long distance are often picked before they are ripe and are treated with ethylene gas on the way to their destination.

Joe Schwarcz


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