Noix du Perigord

Noix du Perigord — the Perigord walnut — is a protected agricultural product of the Perigord region in the Dordogne department of southwestern France. Walnuts have been cultivated in the Dordogne valley since at least the seventeenth century, when the walnut oil trade flourished and was transported down the river by traditional gabarres, the flat-bottomed trade boats of the Dordogne. The walnut received its Appellation d'Origine Controlee in 2002 — the first fresh nut in France to earn原产地命名 status — covering four varieties: Franquette, Grandjean, Marbot, and Corne. The designation also protects walnut oil pressed within the zone, traditionally extracted by stone mills.

A fresh Perigord walnut cracks to a plump, ivory-gold kernel, faintly sweet with a buttery, almost resinous richness that intensifies as it dries. The walnut oil pressed from them is deep amber, with a roasted, toasty aroma that transforms a green salad or a slice of goat cheese; used raw, never cooked, the oil is volatile and goes rancid quickly. The fresh walnut harvest in autumn is a regional event in itself.

The Perigord walnut's character rests on its high oil content and the specific composition of that oil. Walnuts contain upward of sixty percent oil by weight, far more than most nuts; this oil is rich in polyunsaturated fatty acids, particularly linoleic and alpha-linolenic acid, which give the distinctive flavor and the nutritional value — and also explain why walnut oil goes rancid far more quickly than olive oil, since the double bonds in polyunsaturated fats are highly reactive with oxygen. Traditional extraction by stone mill presses the oil cold, preserving the volatile aromatic compounds that give the roasted, toasty aroma. The four protected varieties each carry subtly different flavor profiles, but all share the high-oil, polyunsaturated-rich composition that defines the Perigord walnut.