تثمين بطاطس منطقة الوادي بطريقة التجفيف الشمسي

Résumé: The production of potatoes in El-Oued has increased at a very rapid rate in the last few years. In 2013, El-Oued occupied the first rank nationally in terms of production. Using solar drying is one of the best and economical ways for preserving the vegetables and for reduction in post harvesting losses. The indirect hybrid dryer (solar- electric) with forced convection exists at the Laboratory of Development of new and Renewable Energy in Arid zones (LENREZA), University of Ouargla. Our contribution in the amelioration of the solar collector performance consisted in coating the collector by a thin layer of sand dune. It was noticed that, for a fixed mass of sand (given thickness of layer), the improvement of the collector was inversely proportional to the sand particle diameters. The output temperature in the collector for a fixed particle diameter increases with the increase in the thickness of the sand layer. These results are applied to the flat plate solar collector of hybrid dryer and led to reducing the fraction of electrical energy during the drying operation. Modeling results by Curve Expert show that the Midilli and Kucuk model is most suitable model for the description of the potato drying operation for this range of temperatures (50 -60°C). The curves of the effective diffusion coefficient show that the diffusion in the product of the potato increases with the increase in the temperature. The results of quality indicated that, the drying air temperature of 50°C was the best as it resulted in a dried product having lightest total color change, lesser reducing sugar content, similar value of pH and the best sensory evaluation (taste, color, flavor and overall acceptability) comparably to the original product before drying process.

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