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
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.
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 components."
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 cooked form.
"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 out."
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.