Most ingredients and animal feeds undergo a processing step, which can damage the nutritional quality of the proteins that they contain. Physical and chemical changes in the proteins due to processing can restrict enzyme accessibility for protein digestion. Increasing the processing (toasting) time of rapeseed meal, one of the most important protein sources for pigs, induces physical and chemical damage to the proteins and reduces the speed at which the proteins are hydrolysed and digested. The ingredients are then mixed into diets and re-processed for the production of feeds, using agglomeration techniques such as pelleting and extrusion. Pelleting and extrusion can diminish the negative effects of toasting on protein digestibility in growing pigs. These effects were more clear for the rapeseed meals that contained the most damaged proteins. This is important, as it allows to include damaged protein sources in animal feeds.