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Many processes in the food industry involve sorting and
separating food. Some types of separation processes are as simple as
sorting fruit by size. Others are more involved, such as the process
of isolating gluten from wheat fl our.
Technology has resulted in many new methods for separating
foods. There are two basic types of separation processes: mechanical
and chemical. Mechanical methods rely on physical traits of the food.
Separation may be based on such qualities as color, size, or density.
For example, cranberries are mechanically separated based on their
ability to bounce. They are dropped next to a barrier. Berries that
meet standards for quality bounce over the barrier. Cranberries that
do not meet these standards remain behind the divider. Chemical
separations depend on how food components will react on a
molecular level.
In this chapter, you will read about the basic methods used to
separate foods. You will also study how the separation process of
osmosis is related to the way the human body metabolizes food.
Mechanical Separation
Mechanical methods do not rely on chemical changes to separate
foods or food components. Some of these methods use machines
to physically isolate foods or parts of foods. Other methods rely on
nonchemical changes in a food product or the addition of force.
Separation by Physical Properties
A standard separation technique used in many food plants is
sorting. Sorting separates by physical characteristics, such as size,
shape, or color. One example of sorting is separating eggs by sizes
such as small, large, and jumbo. Another example is separating
ground wheat into bran, germ, and endosperm. This type of sorting
Objectives
After studying this chapter, you will be able to
• classify mechanical methods of sorting or separating foods
and food components.
• list chemical methods of separating food components.
• explain how the principle of osmosis is used to separate food
components at the macromolecular level.
• compare osmosis in food products with digestion and
metabolism of food components in the human body.
Reading Prep. Look up this
chapter in the table of contents.
Use the detailed contents as
an outline for taking notes as
you read the chapter.