ABSTRACT
Expeller pressing is a mechanical method for extracting liquids like oil; water entrapped in the matrix of solid material, such as oil-bearing seeds, fish, food waste, and cattle waste. The extraction can be done by a solvent, supercritical fluid, and mechanical expelling. Mechanical expression with a suitable design is a good alternative in view of the growing demand of natural essential oils with food-grade quality. The principle of operation of hydraulic and screw expellers, design, and applications are discussed in this chapter. The design considerations optimization of the expeller for a particular application is narrated. Pretreatments, machine variables, yield performance, must satisfy the final product quality requirements.
