Make room for mushrooms in antioxidant rankings
shown to have a high antioxidant content, like tomatoes and
broccoli. Now new research suggests that mushrooms deserve a place
in the antioxidant hall of fame, with an ORAC value almost on a par
with red pepper.
After almonds, chocolate, 'super fruits' and grapes, mushrooms are the latest food to have the antioxidant spotlight turned on them, as researchers from Penn State University measure the activity of two of the most useful antioxidants in different varieties of edible fungus.
The term antioxidants have entered the consumer consciousness as factors that can help reduce the risk of certain diseases and slow the ageing process by mopping up harmful reactive oxygen species known as free radicals.
Although little attention has been paid to mushrooms to date, according to Dr N Joy Dubost of Penn State, eating a variety of mushrooms alongside other veg can help ensure consumption of a variety of different antioxidants.
For her PhD thesis, Dr Dubost measured the content of two antioxidants - polyphenols and erthiotheneine - in mushrooms using the ORAC assay, the most common antioxidant test, and HPLC instrumentation.
She found that portabella mushrooms had an ORAC value of 9.7 micromoles of trolox equivalents per gram, and crimini mushrooms 9.5.
These scores were just shy of that of red pepper, which has an ORAC value of 10, and streets ahead of carrots and green beans, with a value of 5. Broccoli has an ORAC value of 12.
The results of the study showed that the anti-oxidant effect of mushrooms is primarily down to the polyphenols - but Dubost had previously shown that the fungi also have a high ergothionene content.
"Evidence suggests that ergothionene is biologically very important and, even though the assay does not show it contributes to total antioxidant activity in the mushroom, it may significantly contribute to antioxidant activity in the body," she said.
Dr Dubost stressed that the ORAC assay, which focuses on the prolific peroxl radical, does not show what actually happens in the human body. But further investigations are underway to see how it could predict physiological activity.
The research was presented at the IFT meeting in Orlando, Florida, this week.
