Solar convective drying kinetics and sorption isotherms of Citrus aurantium flowers

[EN] Citrus aurantium flowers are high value aromatic and medicinal plants. The storage conditions and quality of dried Citrus aurantium flowers depends on their hygroscopic stability. The equilibrium moisture content was determined at temperatures (from 30 to 60 °C), and the sorption phenomenon is well described by Peleg model. The optimal water activity for the storage of the product was estimated at awop=0.373. Afterwards, the net isosteric heat was evaluated in the range of 88 kJ.mol−1 for small values of the moisture content (Xeq=0.14kg water/kg d.b), and it decreased along with the increase of Xeq. The experimental drying curves showed only a falling rate period. Finally, Midilli-Kucuk model was found to be the more suitable to describe the drying kinetic of Citrus aurantium flowers.This work was supported by the research institute IRESEN and all of the authors are grateful to the IRESEN for its cooperation.El Ferouali, H.; Zoukit, A.; Doubabi, S.; Abdenouri, N. (2018). Solar convective drying kinetics and sorption isotherms of Citrus aurantium flowers. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 965-972. https://doi.org/10.4995/IDS2018.2018.7656OCS96597

Solar drying, hygroscopic equilibrium and biochemical quality of Punica granatum legrelliae’s flowers

Punica granatum Legrelliae is a valuable medicinal plant that is widely planted in Morocco. The equilibrium moisture content was investigated. Peleg model was found the most suitable to describe the sorption phenomenon. The drying kinetic of Punica granatum Legrelliae’s flowers was investigated by using a convection solar dryer. Midilli-Kucuk model described well the drying curves’ trend. The effective moisture diffusivity values were obtained. The Arrhenius relation, with an activation energy value of 92.91 kJ.mol-1 expressed the temperature effect on the diffusion coefficient. Finally, the effect of drying these flowers at different temperatures on their quality was investigated. To assess the quality of the product after solar drying; the color, polyphenols content, antioxidant activity, and polyphenoloxydase and peroxydase activities were considered. 40 °C was the best drying temperature for the preservation of color and bioactive molecules with antioxidant property