What does 'zest' refer to in cooking?

In cooking, 'zest' specifically refers to the outer colorful skin of citrus fruits like lemons, limes, oranges, and grapefruits. This part is rich in aromatic oils that contribute vibrant flavor and fragrance to dishes, both sweet and savory. Zesting is a common technique used to enhance the overall taste profile of a recipe, as it adds a fresh and tangy element without the acidity that the juice from the fruit would provide.

The other options describe different aspects of citrus or cooking methods that do not pertain to zest. For example, the inner fruit is not what is meant when discussing zest, as zest focuses solely on the skin. Similarly, cooking methods involving spices or the use of citrus juice in cocktails do not accurately capture the definition or application of zest in culinary arts.