Preheat oven to 350℉ and place pork tenderloin in a 9 x 13-inch pan.
Mix brown sugar, salt, cinnamon, cayenne, chili powder, garlic powder, and onion powder in a separate bowl and rub into the pork tenderloin and then pour pear juice over the top.
Cover with foil and bake for about 1 hour, 15 minutes. Remove foil, add chunked pear and return to the oven for another 15-20 minutes, until the pork is tender, and cooked through.