Conventional macro- & micro-molecules separation

The second step for the recovery of valuable compounds from food wastes is macro- and micro-molecules separation. The objective of the current chapter is to present different technologies (i.e. alcohol precipitation, ultrafiltration, isoelectric solubilization/precipitation and extrusion) that have been implemented for this purpose. For instance, solutes are precipitated in the presence of an antisolvent agent, even they exist in very low concentration within the feedstock. Besides, the solubility of proteins or lipids could be reduced when pH value turns to their isoelectric point, causing their precipitation. On the other hand, ultrafiltration is a pressure driven membrane separation technology, which is basically used to separate macro- and micro-molecules based on their size. Extrusion is a process using shear energy and heating in order to modify (physically or chemically) the physicochemical properties of macromolecules (polysaccharides, dietary fibers, or proteins) and micromolecules (sugars, polyphenols, vitamins or minerals). This ability has also been used in particular applications of compounds' recovery from food wastes.