walnut

Walnut refers to the edible seed of trees in the genus Juglans, especially Juglans regia, the English or Persian walnut, and Juglans nigra, the black walnut. The tree is a deciduous hardwood that can reach 20–30 meters, with a broad crown and pinnate leaves. The fruit consists of a green husk that encases a hard, woody shell; inside is the wrinkled kernel.

English walnuts are lighter in color with a mild, buttery flavor; black walnuts have a stronger, earthy flavor and require a longer cracking effort.

Cultivation: temperate climates, chill hours, well-drained soils; harvest after the husk splits; major producers: China, United States (California), Iran, Turkey.

Uses: eaten raw or roasted, used in baking and salads; oil is pressed for culinary use.

Nutritional profile: high in fat (mostly unsaturated), protein, fiber; notable for alpha-linolenic acid (ALA) omega-3; minerals such as magnesium, phosphorus; contain antioxidants.

Allergies and ecology: tree and nutshell can cause allergies; juglone in black walnut husks and roots can inhibit other plants.

Storage: whole walnuts keep longer at cool, dry conditions; shelled kernels are prone to rancidity and should be refrigerated or frozen.