WALNUT

Chemical properties

Majestic tree up to 30 m (98 ft) in height, branched, with large, alternate pinnatifid leaves and staminiferous and pistilliferous flowers (April to June). The fruits have a fibrous mesocarp, woody endocarp and fleshy, oily seeds edible when ripe (September). The parts used are the leaves, husks and edible seeds. Walnut has a bitter-tonic flavor and a warm, sweet odor.

Composition

The total oil content of walnut ranged from 62.6 to 70.3%, while the crude protein ranged from 13.6 to 18.1%. Dietary fiber ranged from 4.2 to 5.2%, while the starch content made up no more than 2.8% of the remaining portion of the kernel. The amino acid content of the walnuts was similar between cultivars and the patterns of essential amino acids were characteristic of a high quality protein.* The immature fruit is one of the richest sources of ascorbic acid. The leaves, also rich in ascorbic acid (almost 1% of the weight), are rich in carotene (ca. 0.3% wet weight). Juglone is the active compound in the leaves; also quercetin, cyanadin, kaempferol, caffeic acid and traces of p-coumaric acid, hyperin (0.2%), quercitrin, kaempferol-3-arabinoside, quercetin-3-arabinoside. The seed oil contains 3 to 7% palmitic, 0.5 to 3% stearic, 9 to 30% oleic, 57 to 76% linoleic and 2 to 16% linolenic acids.