Nevertheless, loss of quality during drying is a major problem that limits the market demand for dry food products. One of the main reasons for that loss in quality is the structural changes
caused by the product shrinkage during drying. Consequently, among the drying techniques available there has been an increasing interest in the freeze-drying which provides dried products of porous structure with advantageous quality properties, which are weighted against its high treatment cost. The solid state of water during freeze-drying protects the primary structure and minimizes changes in the shape of the product, with minimal shrinkage. In addition,the low temperatures employed in the process contribute to preserve constituents like minerals and vitamins, as well as to retain original flavor and aroma.