Strategies for drying tomatoes in a tunnel dehydrator

A tunnel dehydrator can be operated using batch or semi-batch modes and while a batch mode is the simplest, it has the inherent characteristic of producing non-uniform moisture content. Although semi-batch mode does not have this problem, because all product experiences the same drying conditions, it is not used when drying tomatoes in Australia. The operation of most dehydrators is based on operator experience and rules of thumb, methods that are not likely to give optimum performance. A model that is suitable for simulating the operation of a tunnel dehydrator with any fruit has been developed. This model has been applied to the development of strategies for drying tomatoes with the objective of achieving optimum throughput, colour and drying efficiency. The results of these simulations are presented in this paper.