S.F.
Ask your OT about oral tactile therapy and brushing therapy. My 5 yo has many sensory issues, textures is also one of his problems. Until we started brushing and oral tactile therapies with him, he only had about 4 or 5 things he would eat period. He still struggles with new foods at times, but we can at least get him to try them now.
Just keep trying. One doctor told us it takes on average 10 tries of a new food before kids decide to like it or not.
If you haven't already, check out sensory processing disorder (also know as sensory integration dysfunction), specifically the oral defensiveness. If your OT isn't specialized in this, seek out a therapist who is. The therapies I mentioned above have literally made my little guy a totally different person (and for the good too).
Good luck and hope you find the right therapies for you little one!