The Dutch club were visitors to Anfield on Thursday night for their Europa Cup tie. Utrecht fans baited Babel with chants about his mother being a whore.
Babel said: "It was not nice for me. I know why they did it. It has everything to do with the fact that I have an Ajax background.
Utrecht chairman Jan Willem van Dop said: "I contacted Dirk Kuyt, who used to be a Utrecht player, for Ryan's details. Once I got them I wrote to Ryan and offered him our apologies. Stuff like that should not be said by our fans."