Ground pepper becomes bitter when scorched - and the heat of a hot frying or saute pan, broiler compartment, or barbecue unit is sufficient to do the bad deed. If an oven is warmer than 325 degrees F, the same fate probably awaits the pepper. Consequently, if you use dry heat, it is recommended that you sprinkle on the pepper near the end of the cooking period.
Some chefs add the pepper to a side of steak as soon as it has been cooked and turned, but unless you are careful not to scatter the pepper particles beyond the meat, your food or sauce may end up with the distasteful flavor of scorched pepper. Scattered salt is not as much of a problem because it will not scorch.
** Asian Recipes