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This paper presents investigations on thin layer convective solar drying of four olive leaves varieties (Chemlali, Chemchali, Chetoui and Zarrazi). Olive leaves were dried at three drying air temperatures (40, 50 and 60C) and at two drying air velocities (0.566 and 1.133 m/s). The drying air temperature is the main factor in controlling the drying rate. The experimental drying curves show the presence of only a falling rate period. Mathematical models, namely, Newton, Page, Henderson and Pabis, Logarithmic, Wang and Singh, Two-term and Two-term exponential models were fitted to the experimental data. Among these models, the Logarithmic model showed the best agreement with the experimental data. The effective moisture diffusivity was estimated by applying the Fickian law to the drying kinetics. The effective moisture diffusivity values varied from 3.437 10−10(Chemlali variety) to 2.427 10−9 m2/s (Chemchali variety). The values of activation energy were calculated assuming an Arrhenius-type temperature reliance. The activation energy ranged from 24.704 (Chetoui variety) to 53.743 (Chemlali variety) kJ/mol. The quality attributes of the dehydrated olive leaves samples were investigated in term of color. The effect of solar drying on L*, a*and b*parameters was significant (P

This paper aims to promote the artificial ripening of Algeria's dry Deglet-Nour dates commonly named Frezza, by successive treatments using hot water soaking and hot vapor steaming. The main objective of the study was to optimize the gain in mass during the proposed hydrothermal process using an experimental design method. Water uptake during rehydration has been optimized according to two complete factorial designs; the first 23 based on eight experiments and the second 22 of four experiments. The conducted experimental investigations showed a maximum of water gain by water soaking and a little part by steaming operation. Obtained and analyzed results led to optimal conditions defined by soaking in water at 30 °C during 8 h followed by hot vapor treatment in a confined chamber at 60 °C under 90% RH. Practical Applications Artificial ripening of Deglet-Nour dates, with different hydration techniques, is an industry practice known in Algeria since the 1950s, but under nonoptimized operating conditions. This paper presents a contribution to the optimization of the rehydration process of dates by water soaking and hot vapor steaming. The results of the study will be useful in the sense of ensuring an added value by enhancing the product quality. The obtained results also permit to minimize the necessary energetic consumption for steam production.