ABSTRACT
Mass transport is involved in many, if not most, food processes. In the present book we are concerned with food preservation processes, and mass transfer features significantly in many of them. Mass transfer is a key feature of processes that preserve foods by lowering the availability of water for microbial activity and for deteriorative reactions. The role of mass transfer in lowering water activity is discussed in Chapter 5, and Chapters 8, 9, and 10 are devoted to processes that achieve the lowering of water activity by freezing, concentration, and dehydration. Control of mass transfer is also the dominant feature of protective packaging of foods, which is discussed in Chapter 12. Mass transfer has in common with other transport processes the general dependence of its rate on a driving force and on resistance: Rate of mass transfer is proportional to driving force divided by the resistance.
