CHICAGO — Wrigley has entered the "energy" arena with Alert Energy Caffeine Gum. Each piece contains 40 mg of caffeine, the equivalent of a half cup of coffee. The company said the gum is targeted to adults who consume caffeine for energy and are looking for a "portable solution." The gum's bitter taste is designed to deter children from using it. The gum is available in eight-piece packs in fruit and mint flavors, and has a suggested retail price of $2.99.