Table 3. Specific mechanical energy (SME) of each shear stress condition.

Shear stress	SME (Wh/kg)
Low	41.52 ± 3.18
Middle	65.80 ± 3.59
High	79.15 ± 9.57

SME was calculated based on slight modified formula presented in the reference [23].

$$\text{SME}=\frac{\text{Mechanical energy input}}{\text{Mass flow rate}}=\frac{N_{act}}{N_{max}}\times \frac{{\tau }_{act}}{{\tau }_{max}}\times \frac{K_w}{\text{Q}}$$

N_act: actual screw speed (rpm)

N_max: maximum screw speed (408.74 rpm in this study)

τ_act: actual torque value (N∙m)

τ_max: maximum torque value (175.16 N∙m in this study)

K_w: power of direct current motor (7.5 kW)

Q: the amount of product per time (kg/h)