I think you shouldn't say anything at all. It is presumptuous to imply that the other person should be grateful for your commitment or contribution. And maybe they aren't thankful and you asking them about it will put them in an awkward position of having to come up with a reason for not thanking you.
Just take care and pleasure in whatever it is you are going to help with and who cares if anyone thanks you. Are you doing this activity because you want to be thanked or admired for it?
You should only say things like, "It helps me to feel encouraged when you thank and praise me for something I did" to a person you are in a very close, interdependent relationship with, like a spouse or significant other.