Aqueous foams have been intensively studied in the past, providing a significant understanding of the mechanisms involved in foam properties, such as drainage, ripening, rheology. . . On the other hand, industry widely resorts to foaming processes involving complex raw materials, such as granular suspensions and pastes. For such systems, where complex fluids are mixed to bubbles, much less is known. I will present several experimental results obtained recently for the drainage and the rheology of model foams made with granular suspensions and concentrated emulsions.