Lemon zest

Zest is a food ingredient that is prepared by scraping or cutting from the outer, colorful skin of unwaxed citrus fruits such as lemon, orange, citron, and lime. Zest is used to add flavor ("zest") to foods.

In terms of fruit anatomy, zest is obtained from the flavedo (exocarp) which is also referred to as zest. The flavedo and white pith (albedo) of a citrus fruit together makes up its peel. The amounts of both flavedo and pith are variable among citrus fruits, and may be adjusted by the manner in which they are prepared. Citrus peel may be used fresh, dried, candied, or pickled in salt.

For culinary use, a zester, grater, vegetable peeler, paring knife, or even a surform tool is used to scrape or cut zest from the fruit. Alternatively, the peel is sliced, then excess pith (if any) cut away.

The white portion of the peel under the zest (pith, albedo or mesocarp) may be unpleasantly bitter and is generally avoided by limiting the peeling depth. Some citrus fruits have so little white mesocarp that their peel can be used whole.

The zest and mesocarp vary with the genetics of the fruit. Fruit with peels that are almost all flavedo are generally mandarines; relatives of pummelos and citrons tend to have thicker mesocarp. The mesocarp of pummelo relatives (grapefruit, orange, etc.) is generally more bitter; the mesocarp of citron relatives (Mexican and Persian limes, alemows etc.) is milder. The lemon is a hybrid of pummelo, citron, and mandarin. The mesocarp is also edible, and is used to make succade.

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