Optimized Processing Parameters in Post-Harvest Treatments of Algerian Dry Dates using Hot Water and Hot Vapor Successive Operations.

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. [ABSTRACT FROM AUTHOR]