There sure were! Women were raped and their children were raised just the same the children of native concubines. They were raised as Muslims: the girls married off and the boys following whatever career path was approved by their "families".
Islamic countries have long tradition of this sort of thing. There was no real "slave" population because the children of slaves intermarried into the general population. That's why they kept having to take more captives (and still do in some places).
With Semitic Muslims (and others) skin tones vary and some are very light indeed. Although lighter skin is usually preferred in multi-tone populations, color was probably not much of an issue here.