walnuts

Walnuts are edible seeds from trees in the genus Juglans. The most widely cultivated species is Juglans regia, commonly known as the English or Persian walnut, native to parts of Central Asia and the Caucasus but grown in many temperate regions. Another commercially important species is Juglans nigra, the black walnut, native to eastern North America. Walnuts grow on large deciduous trees that produce a green, leathery husk surrounding a hard shell, which in turn contains the wrinkled kernel eaten as a nut.

The kernel is pale and creamy inside, with a brown, thin skin that can be removed. The shell is relatively thick and requires cracking to access the kernel. Walnuts have a high oil content and a distinctive, mildly bitter skin. They are rich in polyunsaturated fats, including alpha-linolenic acid (an omega-3 fatty acid), and provide protein, dietary fiber, and minerals such as manganese, copper, magnesium, and phosphorus.

Uses and cultivation: Walnuts are grown in temperate climates with adequate winter chilling. Harvest typically occurs in autumn when the husks split and the nuts are collected for drying. Kernels are consumed raw, roasted, or used in baked goods and confections. Walnut oil is produced for culinary uses, including dressings and dips.

Ecology and safety: Walnuts produce juglone, a natural compound that can inhibit growth of some nearby plants. Walnuts are also a common tree-nut allergen, and exposure can trigger reactions in sensitive individuals. Proper storage in a cool, dry place helps maintain quality and shelf life.