By Rebecca Searles, published on November 1, 2011 - last reviewed on January 2, 2012
Meet the newest superfood. It's not a meat, not a vegetable, although it can successfully pass as either. Technically, it's a fruit, although you'd probably never guess it; it is, after all, the fruit of a fungus and looks nothing like any fruit seen on American shores. Still, its earthy, musky flavors delight palates the world over. Remarkably versatile, the mushroom ranges from humble to haute, can hold its own at the table or donate all its taste and texture to plate mates such as pasta and risotto. To its list of virtues, now add another: The mushroom, even that pale white cellophane-clad staple of the supermarket, is a powerhouse of nutrition and extranutritional goodies.
Over 2,500 species of mushroom grow naturally around the world, but the popularity prize belongs to Agaricus bisporus, the species that yields the most widely consumed varieties: button mushrooms; their more darkly shaded sibling, the cremini; and their fully developed version, the expansive portobello. While A. bisporus lends itself to commercial cultivation, many mushroom types, including morels, porcini, and chanterelles, do not. They must be harvested in the wild, and connoisseurs around the world make a point of knowing—but rarely telling—just where and when to search for them.
Although the exotic species of mushroom attract top culinary billing (and dollars), the common button mushroom turns out to be severely underrated. Ongoing research shows that it is rich in antioxidants and loaded with agents, including beta-glucans, that keep arteries clear and cholesterol-free, help repair damage to body cells, and inhibit tumors.
Most mushroom eaters are not in pursuit of medicinal benefits—at least not yet. What they do savor is a saucepan of sautéed morsels releasing their own juices and earthy aroma. Mushrooms make mouths water—literally. They are exemplars of umami, the so-called fifth taste. And umami is what confers on mushrooms their great versatility in the kitchen—it softens sour, masks bitter, extends finish, triggers salivation, improves palatability all around—and may even be an aphrodisiac. Umami owes its unique taste to a cocktail of chemical compounds—including glutamate and free amino acids—found naturally in some foods. The more a mushroom ages, the higher its free amino acid content, and the greater its umami flavor.
Perhaps the most valued quality of the mushroom for the home cook is its ability to function as the "meat of the vegetable world." Savory, delicate, and hearty all at once, mushrooms can replace meat in nearly any dish while providing even more vitamins and nutrients, including some protein. Mushrooms are an excellent source of minerals selenium, potassium, manganese, and copper. They host a slew of brain-healthy B vitamins. They're mostly made of fiber. And they're also notable for what they don't have—cholesterol, fat, calories, and sodium.
The near-indistinguishable taste and texture of meat and mushrooms can be credited to a strange fact. In some ways, mushrooms are more like animals than plants. They do not employ photosynthesis; they "breathe" oxygen and "exhale" carbon dioxide. As a result, fungal proteins resemble nothing so much as animal proteins. In some Amazon tribes, there is only one word for both meat and mushrooms. And in the rest of the world there's a single word for both, too—delicious.
White button mushrooms are native to the grasslands of Europe and North America and cultivated commercially. The babies of the A. bisporus family, they are firm in texture and mild in flavor, making them an easy-to-blend ingredient. Cooked or raw, they, like creminis, contain high levels of vitamins B12, B6, riboflavin, and niacin, but unlike creminis, they have loads of vitamin C. And should they catch a ray of sun or UV light, they're rich in vitamin D; growers are now experimenting with production of vitamin-D-enriched button mushrooms.
Creminis are the middle child of the A. bisporus clan—more mature than white buttons but less mature than portobellos, hence often nicknamed "baby bellos." Though widely cultivated, they can be found wild throughout the world. They have a deeper, heartier flavor and firmer texture than buttons and hold up better in soups, stews, gravies, and stir-fries. Vitamin and mineral powerhouses, they also uniquely contain conjugated linolenic acid, thought to reduce the risk of estrogen-dependent breast cancer.
Portobello mushrooms are the creminis in full flower, their caps grown and flattened to 4 to 6 inches. Rich and meaty even after cooking, portobellos do well on a grill and welcome stuffings.
Shiitakes are native to Korea, China, and Japan and enjoy both culinary and medicinal standing. Their rich mineral as well as vitamin content, and their array of phytonutrient antioxidants conferring immune and cardiovascular protection, yield a rich, smoky flavor in firm meaty flesh. Shiitakes are a traditional addition to miso soup and add tasty character to stuffings and stir-fries. Like button mushrooms, they develop high levels of vitamin D after brief exposure to light.
Porcini mushrooms—the fat-stemmed, woods-growing, nutty flavored Boletus edulis—enjoy star status in Italian cuisine, where they are typically eaten fresh or marinated in herb-seasoned olive oil, which turns these dense treasures into silk-textured morsels. Porcini arrive in the U.S. in dried form; the concentrated flavor inclines them for sauces and risottos that also incorporate their steeping liquids.
Oyster mushrooms are easy to cultivate and exude an anise-like scent. They are a good source of B vitamins thiamin, B6, folate, riboflavin, and niacin; and minerals including iron, magnesium, zinc, potassium, copper, and manganese.
Hen of the woods (maitake) are large ruffled delicacies with a crisp texture and a robust woodsy taste that combine well with pasta and salad dishes. Favored in Eastern medicine as an immune booster, they contain an array of cancer-fighting antioxidants as well as minerals, B vitamins, and vitamin D.
Morels are honeycomb-shaped and almost as elusive as truffles. They grow best in freshly burned forests, and butter-sautéeing brings out their delicate flavor. Chefs often pair morels with oysters and light meats. A glass of pinot noir adds morel support, highlighting the mushroom's earthiness.
Chanterelles are trumpet-shaped and, like morels, wild-growing with a fruity or peppery taste. They take well to sautéeing. High in vitamin C, carotene, and potassium, they are unique in being among the richest sources of vitamin D.
Black trumpet mushrooms are dark-hued cousins of the chanterelle. Among the tastiest fungi, they grow only in the wild and give off a rich, smoky but fruity aroma. They are an excellent source of vitamin C as well as of iron and calcium.
Mushroom farming, especially cultivation of the white button, is typically a dirty art, employing dark environments and, well, lots of manure. But in San Marcos, California, the Hokto Kinoko Company, a Japanese import, has turned mushroom growing inside out. Visitors to the brightly lit, super-hygienic growing rooms—where 6 million pounds of king trumpets, maitakes, and other varieties are produced each year—are required to undergo disinfection and a change of footwear before entering the facility. The company believes that in addition to their culinary value, mushrooms are just emerging as a food useful for managing blood sugar levels, blood pressure, and immune health.