(NaturalNews) As pears and apples ripen, the chlorophyll in the peel is replaced by an antioxidant known as nonfluorescing chlorophyll catabolytes (NCCs), according to a new study conducted by researchers from the University of Innsbruck, Austria, and published in the journal "Angewandte Chemie International Edition."
Chlorophyll is the chemical that makes plants' leaves green and enables them to convert sunlight into energy. When a leaf dies, the chlorophyll begins to decay and the leaf loses its green color. This may happen because of age or injury.
Researchers examined the chemicals produced as chlorophyll breaks down, and claim to be the first to identify the transparent NCCs as one of these products.
The decay of chlorophyll in fruits appears to be linked not to death, but to ripening. In apples and pears, chlorophyll in and just below the peel breaks down into NCCs as the fruit ripens. The researchers found that these NCCs are chemically identical to those found in the leaves of pear and apple trees, which are in turn identical to each other.
"When chlorophyll is released from its protein complexes in the decomposition process, it has a phototoxic effect: when irradiated with light, it absorbs energy and can transfer it to other substances. For example, it can transform oxygen into a highly reactive, destructive form," the researchers said.
NCCs, in contrast, have an antioxidant effect.
According to the researchers, the presence of NCCs in ripe fruit suggests that they may have an important nutritional effect in animals that regularly eat fruit, including humans.
NCCs are only the most recent antioxidant to be identified in fruits, and have not yet been well-studied. More well-studied are the flavonoids, a large family that includes flavones, flavonols, isoflavones and flavanols and anthocyanidins.
Flavonoids are found in high concentrations in citrus fruits, onions, berries, green and black tea, grapes and red wine.