Food preservation is a process in which various food items are
kept for long time without spoilage. If you want to deliver quality products to
your customers, you must know how to preserve your products. There are
different methods of food preservation. Food preservation techniques improve
quality of food products.Spray drying is one of them. It converts liquid into
powder/ dried form.
Nowadays,
Micro capsulation is being used in food and pharmaceutical industry for food
preservation.Micro capsulation is used to preserve various foods. It is a
process in which food ingredients are incorporated in small capsules. Food
Industry uses spray drying for microencapsulation. Modern spray drying method
preserves valuable nutrients during processing. Spray drying is used to
preserve baby food, milk, beverages.
Principle:
Spray drying is considered a dehydration method. The basic principle of spray
drying method is atomizing the food, preferably preheated and concentrated to
form very minute droplets which are directed to drying chamber, where they are
mixed with a current of hot air. Here food particles lose moisture and dried to
fine power. Spray drying is widely used for heat-sensitive
foods. It is most economical drying process where large quantities can be
handled smoothly. Dairy Industry uses this technique for making milk power and
dairy whitener.
Mechanisms:Water
is the main cause of deterioration. It supports microbial growth. In Spray Drier, condensed product is atomized and
dispersed in hot air stream. As the product changes from liquid at the entrance
to a moist solid to a dried solid, the rate of drying also changes. The rate of
drying may be constant rate and falling rate.
During constant rate, there is uniform loss of moisture from the
product which is controlled by speed and temperature of air over the droplets
and continuous until free water on the surface. After this period, a crust or
solid phase is formed over the droplets which resist the flow of moisture from
the droplets. The resistance increases as the water vapour phase proceeds to
the center of droplets. This happens at falling rate.
Spray drying method yields superior milk powder. It is most appropriate
method for making baby food products as it preserves nutrition. Spray Drying
improves flavor and solubility of milk powder. Foam Spray Drying is a popular
spray drying method for food preservation. This is an improved version of
conventional spray drying method.Another effective method for food preservation is foam spray drying.Foam Spray Drying is
a process of forcing gas into liquid products after the pump but before the
atomizer in order to produce foam. This method is mainly used for skim milk,
butter milk, cream and whey. After obtaining the final product, moisture proof
packaging is done. It prevents microbial growth and water activity. Thus it preserves
the quality and nutritive value of the product. In recent days,Nitrogen
packaging and vacuum packaging are widely used in dairy and food industry to
improve durability of food products.
