Drying or dehydration of foods may be one of the oldest preservation methods known. Research has been performed on it for many years, and, surprisingly, it is still an active topic, according to Martin Okos of Purdue University (phone 765-494-1211). Martin holds appointments in Agricultural Engineering, Food Science, and Chemical Engineering. His research on drying is focused on combining heat and mass transfer, the traditional concerns, with fluid dynamics and rheology of the material being dri…