Wild about walnuts

DAVIS, Calif. — Pop quiz: What nut was beloved by the Romans, has fascinated artists through the centuries, and is produced predominantly by one state of these United States?

Answer: Walnuts. The Romans willingly paid dearly for this flavorful nut and threw them at weddings, for fertility. The convoluted shape of the walnut kernel, resembling the human brain, in its tan wrinkled shell has captivated artists. And the state of California supplies 99 percent of U.S. walnuts and the majority of the world supply.

Walnuts have a history that's even more ancient than the Romans, dating back to prehistoric times. Today they are used in cuisines around the world, particularly for baked goods and confections.

These days, with the focus on good fats and bad fats in our diet, the walnut has come into fashion with those who see it as an easy way to stock up on those good fats. This year the Walnut Marketing Board dubbed the walnut the "Mega Nut" to highlight its polyunsaturated fats, a source of heart-healthy omega-3 fatty acids.

(One ounce of walnuts, about 14 walnuts halves, contains 190 calories, 4 grams of protein, 2 grams of fiber, 0 cholesterol, 1.5 grams saturated fat, 2.5 grams monounsaturated and 13 grams polyunsaturated fat, according to the USDA.)

The marketing board recently sponsored a two-day gathering with industry experts, growers and researchers to give visitors a behind-the-scenes look at walnuts.

The two major species of walnuts in the United States are the English or Persian walnut, which originated in Persia and was brought here from Europe, and the black walnut, native to the United States.

English walnuts were first planted in Southern California about 1770 by the Spanish Mission fathers," explained Gail McGranahan, a pomologist at the University of California at Davis. (The "English" refers to the English merchant marines who transported the nuts for world trade.)

The temperate climate and nutrient-rich soil in California's Central Valley attracted growers and helped the industry thrive. Walnut trees are now cultivated in a 370-mile region, primarily in the San Joaquin and Sacramento valleys. Now there are more than 5,000 growers and 50 processors in the state, producing a yearly average of 300,000 tons of walnuts.

The black walnut, though edible and historically a staple of American Indians, is not used commercially for food because of its hard shell and small nutmeat yield. The Eastern American black walnut, found east of the Rocky Mountains, is grown for its wood. Walnut wood is prized for furniture — in particular burled walnut, used as a veneer and for dashboards in luxury cars.