*3.2. Extrusion Process*

The extrusion process was done according to the method reported by Huang et al. [15] with minor modification. In brief, a single-screw laboratory extruder (Tsung Hsing Co. Ltd., Kaohsiung, Taiwan) equipped with screw diameter 74 mm, L/D ratio 3.07:1, and rounded die head with a diameter of 5 mm was used. The algal sample was used as the raw material and was preconditioned to a moisture content of 35%. The feed rate was constant at 10.4 kg/h. Other extrusion parameters were set with barrel temperature at 115 ◦C and screw speed at 360 rpm. The algal extrudate was dried at 55 ◦C for 30 min, cooled to room temperature (RT), ground into particles that could pass through a 20-mesh screen, and stored at 4 ◦C for further extraction experiments.
