You probably will have to experiment with this one. DR. Pepper claims to use 23 different flavors and will not tell any of them to the public. Thats why generics are generally a failure to replicate the flavors. I know that you can buy the flavoring, made by them, for making candies and such, but I dont know if you can use it for your
juice. It's worth a try though, as Dr. Pepper is one of my favorite soft drink.