. 2015 Nov 3;4(4):682–698. doi: 10.3390/antiox4040682

Table 1.

Drying process for olive leaf dehydration.

Objectives of the Research	Drying Process and Conditions	Reference
Study the effect of blanching and/or infrared drying on the color, total phenols content and the moisture removal rate of four olive leaf varieties	Infrared dryer Infrared drying temperatures: 40, 50, 60 and 70 °C	[29]
Investigate the main effects of process variables on the product quality during heat pump drying of olive leaves Determine an optimum process conditions for drying of olive leaves in a pilot scale heat pump conveyor dryer	Pilot scale heat pump conveyor dryer Drying air temperature range: 45–55 °C Drying air velocity range: 0.5–1.5 m/s Time range: 270–390 min	[30]
Investigate the main effects of process variables on the product quality during hot air drying of olive leaves Determine an optimum process conditions for drying of olive leaves in a tray drier	Laboratory-type tray dryer Drying compartment dimensions: 0.3 × 0.3 × 0.4 m Drying air temperatures: 40–60 °C Drying air velocities: 0.5–1.5 m/s Process time: 240–480 min	[31]
Study the influence of the ultrasound power application during the drying of olive leaves in the kinetics of process	Pilot scale convective dryer modified to apply power ultrasound Drying temperature: 40 °C Air velocity: 1 m/s Levels of electrical power applied to the ultrasound transducer: 0, 20, 40, 60 and 80 W Ultrasonic power density in drying chamber: 0, 8, 16, 25 and 33 kW/m³	[27]
Determine and test the most appropriate thin-layer drying model. Reveal the effects of drying air temperature and velocity on the effective diffusion coefficient and activation energy for understanding the drying behavior of olive leaves	Thin-layer dryer Drying air temperatures: 50, 60 or 70 °C Drying air velocities: 0.5, 1.0 or 1.5 m/s	[28]
Investigate the effect of solar drying conditions on the drying time and some quality parameters of olive leaves particularly the color, total phenol content and radical scavenging activity	Laboratory convective Solar Dryer Drying air temperatures: 40, 50 and 60 °C Drying air velocities: 1.6 and 3.3 m³/min	[26]
Develop a direct and rapid tool to discriminate five Tunisian cultivars according to their olive leaves by using FT-MIR spectroscopy associated to chemometric treatment	Microwave Two times for 2 min Maximum power 800 W (2450 MHz)	[32]
Study the effect of freezing and drying of olive leaves on the antioxidant potential of extracts Choose an appropriate drying process to obtain extracts rich in bioactive compounds	- Hot air drying by forced air laboratory dryer 70 °C for 50 min and at 120 °C for 12 min Air flow: 0.094 m³/s Air velocity: 0.683 m/s -Freeze air drying by freeze dryer chamber Initial temperature: −48 ± 2 °C, shelf temperature set at 22 ± 2 °C. Time: 48 h and Pressure: 1.4 × 10⁻¹ mbar	[33]