Which substance is frequently used for dusting chocolates to prevent sticking?

Cocoa powder is frequently used for dusting chocolates to prevent sticking because it not only helps to absorb excess moisture but also complements the chocolate’s flavor. When chocolates are formed, especially truffles, they can be sticky due to the fats and moisture involved. Cocoa powder provides a dry barrier that allows for easier handling and serving, while enhancing the overall chocolate experience with its rich and familiar taste.

Other options, while they might have some application in different contexts, do not serve the same dual purpose effectively. Flour could integrate poorly with the chocolate’s flavor, leading to an unappealing taste. Confectioners' sugar, while it creates a sweet coating, can also melt if exposed to moisture, potentially leading to a sticky surface. Cornstarch may prevent sticking but lacks the complementary flavor profile that cocoa powder provides, making it a less desirable choice for chocolate dusting.