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purple orange

Purple orange
“We conducted numerous tests to find out why this orange turned purple overnight,” Carswell said in a public statement reporting his findings.
It turns out Moffitt’s husband had recently sharpened the blade she used, and the naturally occurring anthocyanin pigments in the orange reacted with iron particles on the knife to produce the purplish-blue color on the fruit’s flesh.
By the very definition of their name, oranges are not supposed to turn purple.
A little internet sleuthing unearthed a similar incident of an orange-to-purple fruit transformation that occurred in Queensland three years earlier, but by the time that family had shipped the orange to government scientists for testing, the pigment had already faded, which meant the mystery had yet to be solved.
“Anthocyanins are antioxidants and are found in many different fruits and vegetables including red cabbage and blueberries,” he continued. “It is not recommended to eat any food that has an unusual colour without knowing why. In this instance, there’s nothing indicating the presence of toxic compounds.”
That chain of events began earlier this month on Sept. 4 when Annette Moffitt started slicing up a normal-looking orange as a snack for her young son, Charlie. He snacked on half of the fruit’s slices, then left the remains and the rinds in the trash, while his mom put the other half of the uneaten fruit in a bowl.
“The orange sat in a bowl overnight with some homegrown lemons, and fast forward to the next morning, while I was making a cup of coffee, I noticed that the orange had turned purple,” Moffitt told TODAY Food by phone from her home in Brisbane, Queensland.
“I shared some pictures with my friends and connections on [Facebook], everybody came up with their own theories,” said Moffitt. “There were no nerves, because my son was fine, it was more of a case of curiosity. I’m the kind of person who likes to know why things work.”
The verdict? The knife Moffitt was using proved to be the culprit in this whodunit.
An Australian woman and government scientists from Queensland Health uncovered the chemical reason that an orange turned purple after being sliced with a knife.
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Stewart Carswell, Queensland Health’s chief chemist, said “numerous tests” were conducted to determine the cause of the colour change.
On Wednesday, Mr Carswell described the investigation as unusual.
Scientists have now revealed it was due to a natural reaction between the fruit and a sharpened knife. The orange did not pose a health risk, they added.
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Ms Moffitt told the BBC that it was “brilliant” to have the mystery solved.
An Australian woman asked for an investigation after her son ate fruit that later changed colour.