Researchers at the University of Innsbruck in Austria have discovered that the breakdown of chlorophyll in ripening apples and pears produces the same decomposition products as those in brightly colored leaves.
And, they say, these decomposition products -- nonfluorescing chlorophyll catabolytes (NCC) -- are highly active antioxidants.
The findings of the research team, led by Bernhard Kräutler, have been reported in the latest issue of the journal Angewandte Chemie.
Leaves change colour in autumn under a process called senescence, which causes the disappearance of chlorophyll, the substance that makes leaves green.
So what happens to the chlorophyll? Kräutler and his team have found that it decomposes into colorless NCCs.
They also found a similar process occurs when raw fruit - often green in colour - ripens.
"There is clearly one biochemical pathway for chlorophyll decomposition in leaf senescence and fruit ripening," notes Kräutler.
Thus, says Kräutler, given the high NCC content in ripe fruit, there is something to the saying, "An apple a day keeps the doctor away."