## 2 Materials and Methods
### Drying Experiments  
Drying experiments were performed using a robust and automated system (HPD-TF1) designed at Institute of Agricultural Engineering, University of Hohenheim in Stuttgart, Germany. The CAD schematic design of the system is illustrated in Figure 1.  
The HPD-TF1 consisted of a climatic test chamber, a column drying unit and a weighing system. The drying air was conditioned through a climatic test chamber (CTS C-20/1000, CTS Clima Temperatur Systeme GmbH, Hechingen, Germany) with precise control of temperature (\(\pm\)0.1 \({}^{\circ}\)C) and relative humidity (\(\pm\)1.0%). Afterwards, the con  
Figure 1: (**a**) Cutaway view of the automated drying system and (**b**) magnified view of the system interior; (1) vibration damping support, (2) mechanical door closer, (3) laboratory computer, (4) climatic test chamber, (5) drying column unit, (6) nylon string, (7) spindle drive, (8) load cell, (9) cooler, (10) air circulation fan, (11) axial fan, (12) vane anemometer, (13) airflow straightener, (14) thin-layer of wheat kernels, (15) acrylic sample holder. ditioned air was sucked by an axial fan (ebm-papst 821J/2H4P, EBM-Papst Mulfingen GmbH & Co. KG, Mulfingen, Germany) through a column drying unit in a downwards direction. The corresponding air velocity was measured by means of a vane anemometer (Lambrecht 1468, Lambrecht meteo GmbH, Gottingen, Germany). In order to straighten the airflow and allow stable readings from the anemometer, an airflow straightener with a honeycomb configuration was employed. An automated and high-precision weighing system consisting of a load cell (AR 0.6 kg, Lorenz Messtechnik GmbH, Alford, Germany) with a precision of \(\pm\)0.02%, was mounted at the chamber ceiling. It allowed the sample holder (\(d\) = 70 mm, \(h\) =100 mm) to be suspended and weighed periodically during the drying experiments. At the bottom of the sample holder, a perforated floor (2 \(\times\) 2 mm apertures) was used to allow the seamless flowing of drying air within the pore volume of kernels and hold them from falling. To prevent the buoyancy of air flow on the sample holder, the fan was stopped during the periodic weighing. The operating conditions and mass data were recorded in real-time and saved on a laboratory computer. A detailed portrayal of the system, its components, operating conditions, as well as measurement consistency, are described in-depth by [PERSON] et al. (2017). For the drying experiments, the conditions of the climatic chamber were set at temperatures \(T\) of 10, 20, 30, 40 and 50 \({}^{\circ}\)C, relative humidity \(RH\) of 20, 40 and 60% and airflow velocity \(v\) of 0.15, 0.50 and 1.00 ms\({}^{-1}\). The drying conditions are represented by codes such as _T30/RH40/V05_, which are ordered by \(T\), \(RH\) and \(v\), respectively. Prior to drying tests, the dryer was operated until the stability of set-conditions was reached. Afterwards, an aggregate mass of 85.41 \(\pm\) 4.35 g of randomly selected wheat kernels was evenly loaded in the sample holder in a layer thickness of 0.04 m. The drying data were recorded at intervals of 720 s for a total of 1194.22 \(\pm\) 239.63 min. At the end of each drying experiment, the final moisture content was re-analyzed using the thermogravimetric analysis. Each drying test was carried out in triplicates and for the drying characteristics, the mean values of the experimental moisture content were used. The equilibrium moisture content of wheat was assessed experimentally using the gravimetric salt method as described by [PERSON] et al. (2018). Temperatures of 10, 30 and 50 \({}^{\circ}\)C and 8 sets of relative humidity produced from the saturated salt solutions ranging from 12.3 to 86.8% were used for the determination of the equilibrium moisture content \(X_{eq}\). A laboratory balance (Sartorius BP22 IS, Sartorius AG, Gottingen, Germany) was employed to measure the changes in the weight with an accuracy of \(\pm\)0.0001 g. The equilibrium state was deemed once these changes were less than 0.1% in the last three consecutive measurements.