Oh, so you are going to get the troll all nice and diseased while you eat his flesh? What a wonderful idea.
If you are going to be keeping the troll chained up, and eating him, get him a ring of Sustenence or something, then put locked gauntlets on both his hands while he is helpless, then chain him out spread-eagle with masterwork adamantium so he can't move at all (and such that he can't take 20 to break/escape from those bonds). The ring sustains him, he sustains you.
Of course, such torture is evil, so you'd better not have a paladin around...