Topic from Unit 3 - OBT554 - Principles of Food Preservation - Annas University R2017

1. Application of Infra-Red
Microwaves
OBT554
Unit 3

11. Microwave Cooking
 In ordinary cooking, heat is applied to the outside
of food and it gradually penetrates to the inside.
 In microwave cooking, the heat is generated within
the food.
 In a microwave oven, microwaves penetrate the food
and are converted into heat within the food.
 Thus, the whole food heats up very quickly.
 Microwaves can only penetrate food to a depth of 3–
5 cm; thus, small pieces of food are cooked very
quickly.
 Larger pieces of food are cooked more slowly,
however, because where the microwaves cannot
penetrate, the food is heated by conduction.

15. Advantage & Disadvantage
 The great advantage of microwave cooking is its speed.
 For example, a fish fillet is cooked in only 30 s, a chop in 1
min, a chicken in 2 min, and a baked potato in 4 min.
 Microwave ovens also have some disadvantages.
 For instance, cooking times must be carefully controlled.
 In addition, food does not turn brown or develop crispness
in a microwave.
 Crispy bacon or conventional-looking brown crusty chops
need to be finished off under the broiler.

23. THANK YOU