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Chemical analysis of mushrooms
shows their nutritional benefits
Life Sciences Editor
Ill. — An analysis of previously uncharted chemical contents,
mostly carbohydrates, in U.S.-consumed mushrooms shows that these fruity
edible bodies of fungi could be tailored into dietary plans to help
fill various nutritional needs.
Using modern analytic tools, scientists at the University of Illinois
at Urbana-Champaign found that the six mushroom varieties tested –
in raw and cooked forms and at various harvest times and maturity levels
– are rich in total dietary fibers, including those associated
with cholesterol-lowering (chitin) and healthy hearts (beta-glutan).
The findings appear online in advance of regular publication by the
Journal of Agricultural and Food Chemistry. The same researchers last
year reported in the same journal the carbohydrate profile of selected
plum and prune products. The findings will become part of the U.S. Department
of Agriculture’s National Nutrient Database.
“What we’ve reported in these papers are the complete carbohydrate
profiles of these two lines of popular foods,” said George C.
Fahey Jr., a professor of nutritional
sciences in the department of animal
sciences at Illinois. “These profiles include the digestible
carbohydrates, the starches and the fermentable fibers that reach the
large bowel. This work was important to the two commodity organizations
that funded this research, because they had little information on these
It was already known that mushrooms offer high-quality protein, vitamins,
unsaturated fatty acids and fiber, but a precise carbohydrate breakdown
had been elusive.
The mushrooms studied were white button, crimini and portabella, all
of which represent different maturity levels of Agaricus bisporus, and
maitake (Grifola frondosa), shiitake (Lentinus edodes) and enoki (Flammulina
velutipes). The latter two mushrooms were analyzed only in their consumed
“The maitakes and shiitakes tended to be very similar in their
nutrient concentrations, and quite a bit different than the others,”
said Cheryl L. Dikeman, a doctoral student in Fahey’s lab and
lead author on both papers. “Portabellas were off on their own
in terms of their contents of oligosaccharides, beta-glucans and chitin.”
Chitin concentrations were 8 percent in raw, mature portabellas and
6 percent in raw, immature ones. When cooked, chitin content fell to
2.7 percent in both forms, but their levels of total dietary fibers
went up significantly. Also showing the same pattern were raw enokis,
which had a 7.7 percent chitin content; cooking also lowered it to 2.7
percent but total dietary fibers jumped from 29.3 percent in raw to
41.6 percent in cooked.
Raw, mature white buttons and cooked, mature shiitakes boasted chitin
levels of 3 percent and 3.6 percent, respectively.
Raw, mature portabellas also had the highest level of beta-glucan (0.2
percent), while most of the other mushrooms had 0.1 percent. Enokis
and maitakes had none. Relatively small amounts are required to provide
cardiovascular benefits, Fahey said.
Cooking tended to increase starch, total dietary fibers and fat contents
and to decrease chitin concentrations in all of the mushrooms. “Some
nutrients went up after cooking, while some went down,” Dikeman
said. “Part of that you’d expect to happen as water is cooked
Also measured were oligosaccharide levels. These sugar molecules are
only partially digestible, but the undigested components are considered
prebiotics in that they elicit growth of healthful bacteria in the colon.
Raw, immature portabellas had a total oligosaccharide concentration
of 5,272 micrograms per gram (ug/g). Also found to have more than 1,000
ug/g were raw, mature portabellas and cooked, immature crimini. None
were detected in enokis, maitakes or shiitakes. Most of the total oligosaccharides
were in the form of glucooligosaccharides, but fructooligosaccharides
(FOS) accounted for the total concentrations in cooked, immature white
buttons. FOS did not appear in other samples.
In other findings: White buttons had the highest levels of ash; starch
was highest in maitakes and shiitakes; and crude protein and acid-hydrolyzed
fats were highest in crimini, white buttons and maitakes.
For plums and prunes, which are known to be good sources of dietary
fiber, the researchers analyzed individual carbohydrate components that
are in the various forms used by consumers: powders, juices, purees
and fruits. They also looked at the waste byproducts, including dried
All of the prune/plum products were found to have high total concentrations
of oligosaccharides and free sugars. High in total dietary fibers as
a percentage of total dry-matter were generally the various powder and
The research primarily involved the use of high-performance liquid chromatography,
which was adapted by Laura L. Bauer, a research specialist in animal
sciences and a co-author on both papers, to quantify chitin concentrations
in each mushroom. A spectrophotometer was used to analyze beta-glucan
levels and sort out uronic acids that are associated with total dietary
The information obtained in the two studies, Fahey said, will allow
people to choose the mushrooms and forms of plums and prunes that provide
the dietary punch they may be needing. It also should allow food scientists
to search for optimum preparation strategies for using the various products.
The Mushroom Council of Dublin, Calif., funded the mushroom study and
provided the samples. The plum/prune study was done with samples and
funding provided by the California Dried Plum Board. Elizabeth A. Flickinger,
a former postdoctoral researcher in Fahey’s lab, also was a co-author
on the plum/prune study.