Don't be so hasty to throw away slightly over-ripe apples and pears.
A group of scientists at the University of Innsbruck in Austria claim to be the first to identify the decomposition mechanism and products of apples and pears, and their findings suggest that as these fruits start to go bad their antioxidant levels dramatically increase. Key to the process is the change in color that occurs as fruits ripen.
According to lead researcher Berhard Krautler, fruit undergoes a similar decomposition process as leaves turn from green to red to yellow to brown. This color change is caused by the breakdown and disappearance of chlorophyll, which is what gives leaves and fruits their green color.
Through their research with botanists over the past several years, they claim to have identified the first decomposition products in leaves. These are colorless, polar nonfluorescing chlorophyll catabolytes (NCCs) that contain four pyrrole rings - like chlorophyll and iron.
After examining the peels of apples and pears, they found that in ripe fruits, NCCs replace the chlorophyll, especially in the peel and the flesh immediately below it.
"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," reported the research team.
"However, the NCCs have the opposite effect," they said.
"These are powerful antioxidants and can thereby play an important physiological role for a plant. In the same way, when these are consumed as part of the human diet, they can play the same anti-oxidative role in humans."
Now isn't this great news at the height of autumn apple and pear season?