FROM THE DRYING OF WALNUTS TO THE MANAGEMENT OF A DRYER
The quality of dried walnuts depends on mastering the drying operations which will ensure the conservation if their original properties. The drying process therefore constitutes a key element in the production of quality nuts. The process is one involving a transition from the ripe nut, with a high water content and prone to rapid degradation, to a stable product. In large part, the end product is a conditioned by the circumstances in which this transition takes place. To model the behavior of a heap of walnuts in the dryer one has to analyze this behavior at the level of the constituents of the nuts, in a situation of convective exchanges, on the basis of drying kinetics obtained experimentally using a single layer of nuts. Parameters relevant to the length of time the quality of the nut is maintained are thereby revealed and assessed. From these results, one can develop a model of a heap of nuts; the heap is, in effect, a pile made up of many single layers. In passing through each layer, the drying stream of air will be modified, becoming charged with water and giving up energy. These new characteristics acquired by the fluid will be used in simulating the drying of the next layer. This code then serves to provide the elements needed to optimize the performance of dryers and to define the routes for designing new types of dryer, or for improving existing types.
PRUNET CTIFL, J.P. (1997). FROM THE DRYING OF WALNUTS TO THE MANAGEMENT OF A DRYER. Acta Hortic. 442, 345-350