Q. Moisture removal in foods by different drying techniques?

To carry out the moisture removal in foods by different drying techniques.

• make yourselves familiarized with different drying techniques, namely sun-drying, tray drying and microwave drying, and

• select the best method of dehydration on the basis of various parameters such as drying time and sensory characteristics of foods.

Principle

The principle of removal of moisture from food includes the process of heat and mass transfer. Factors increasing heat and mass transfer are larger surface area, greater temperature difference between the heating medium and the food, higher velocity of air, dry air, low pressure drying process that employ high temperature for short time do less damage to food than drying process employing lower temperature for longer time.

Commercially, various drying processes are in use as air convection driers, cabinet driers, tray driers, fluidized bed driers, spray driers, drum driers, vacuum drier, freeze drier etc. However, due to limitation of equipment we will be using three processes of drying. These are:

• Sun drying

• Tray drying

• Microwave

Materials Required

Sample material

Sieves

Filter paper

Tray dehydrator

Microwave

Muslin cloth

Procedure

Carry out the activity following the steps enumerated herewith:

1) Wash the vegetable thoroughly.

2) Dice vegetable into small pieces.

3) Divide the vegetable into six parts.