Mushrooms beat wheatgerm to top antioxidant slot
functional foods might wish to promote the use of mushrooms, with
fresh research from food scientists suggesting button mushrooms are
the number one source for the antioxidant ergothioneine.
Researchers at Penn State university in the US claim that white button mushrooms, the most commonly consumed kind in the US, have about 12 times more of the antioxidant than wheat germ and four times more than chicken liver, the previous top-rated ergothioneine sources based on available data.
"Ergothioneine, a unique metabolite produced by fungi, has been shown to have strong antioxidant properties and to provide cellular protection within the human body," says Joy Dubost, doctoral candidate in food science, who conducted the study.
Antioxidants - scavengers of free radicals - found in a host of fruit and vegetables are believed to help the body fight a raft of chronic diseases.
Benefiting from accumulating research into this area, the food industry has leapt on the opportunity to develop food formulations that absorb health-fighting compounds.
The €819.9 million European and US fruit and vegetable extracts and powders market, for example, is on course to grow 4.5 per cent annually, to reach €1.07 billion by 2009.
The food scientists claim that until the creation of their new assay for examining fungi, there was no testing method sensitive enough to quantify the amount of ergothioneine in fungi.
And there could be more discoveries in the wings, as the researchers claim their new assay can be used for other plants, not just mushrooms.
The Penn State food scientists report that among the most commonly consumed mushrooms, portabellas and criminis have the most ergothioneine, followed closely by the white buttons.
They found that that a standard 3-ounce serving (a handful) of these mushrooms, supplies up to 5 milligrams.
The exotic mushrooms have even more ergothioneine. The same standard serving size of shiitake, oyster, king oyster or maitake (hen of the woods) can contain up to 13mg in a three ounce serving , or about 40 times as much as wheat germ.
Dubost notes that the levels of ergothioneine do not decrease when the mushrooms are cooked.
In developing their new assay, the researchers adapted an assay used to quantify the amount of ergothioneine in bovine ocular tissue. They used high performance liquid chromatography (HPLC), a UV-VIS detector and mass spectroscopy, instruments normally used in analytical chemistry.
Dubost presented the paper on the new assay and the amounts of ergothioneine in the most common and exotic mushrooms available on the US supermarket shelves last week at the American Chemical Society meeting in Washington, D. C.