Sorting is defined as the separation of the raw material into categories of different physical
characteristics such as size, shape and colour. Grading is defined as the separation of the
raw material into categories of different quality.
Sorting plays an important role in controlling the effectiveness of many food processes.
They are better suited to mechanised operations such as peeling, blanching, pitting and
coring. They are necessary in processes in which uniformity of heat transfer is critical
(sterilization, pasteurisation) and they are advantageous in processes in which uniformity
of heat transfer is desirable.
Flatbed screens, drum screens, roller sorters, belt sorters, screw sorters are used for size
sorting.