Black Pepper can be tough to digest so it wouldn't surprise me. I have poor digestion so I have seen lots of things come through unaltered. Bloating can be bacterial imbalance (more bad bacteria than good) or it can be from certain foods that are difficult for the bacteria to breakdown. So aside from black pepper particals you may be having other things pass through you with some difficulty (i.e. whole grain, fiber, sugar).
I have improved my situation (under guidance) with hydrochloric acid pills, pancreatic enzymes, and probiotics, and by avoiding foods that obviously give me challenges. My bloating is down about 98%.
One interesting note however, is that black pepper can actually aid digestion. I avoid it because after a few meals with it I start to get heartburn (I have a hiatal hernia). I would suggest a finely ground pepper as opposed to using one of those table grinders which leave it pretty coarse.