Heat is transferred to the food during cooking by conduction, convection, radiation or microwave energy. Cooking takes place by moist and dry heat. Moist heat involves water and steam. Air or fat are used in dry heat.
Cooking methods -
1.Moist Heat :
MOIST HEAT COOKING METHODS
Boiling is a method of cooking foods by just immersing them in water at 100 o C and maintaining the water at that temperature till the food is tender. Rice, egg, dhal, meat, roots and tubers are cooked by boiling.
1. Simple method - It does not require special skill and equipment.
2. Uniform cooking can be achieved.
1. Continuous excessive boiling leads to damage in the structure and texture of food.
2. Loss of heat labile nutrients such as B and C vitamins if the water is discarded.
3. Time consuming - Boiling takes more time to cook food and fuel may be wasted.
4. Loss of colour - water soluble pigments may be lost.
It refers to the simmering of food in a pan with a tight fitting lid using small quantities of liquid to cover only half the food. This is a slow method of cooking. The liquid is brought to boiling point and the heat is reduced to maintain simmering temperatures (82 o C - 90 o C). The food above the liquid is cooked by the steam generated within the pan. Apple, meat along with roots, vegetables and legumes are usually stewed.
1. Loss of nutrients is avoided as water used for cooking is not discarded.
2. Flavour is retained.
1. The process is time consuming and there is wastage of fuel.
It is a method of cooking food in steam generated from vigorously boiling water in a pan.
The food to be steamed is placed in a container and is not in direct contact with the water or liquid. Idli, custard and idiappam are made by steaming. Vegetables can also be steamed.
2. Less chance of burning and scorching.
3. Texture of food is better as it becomes light and fluffy. Eg. Idli.
4. Cooking time is less and fuel wastage is less.
5. Steamed foods like idli and idiappam contain less fat and are easily digested and are good for children, aged and for therapeutic diets.
6. Nutrient loss is minimised.
1. Steaming equipment is required.
This method is limited to the preparation of selected foods.
When steam under pressure is used the method is known as pressure cooking and the equipment used is the pressure cooker. In this method the temperature of boiling water can be raised above 100 o C. Rice, dhal, meat, roots and tubers are usually pressure cooked.
2. Cooking time is less compared to other methods.
3. Nutrient and flavour loss is minimised.
4. Conserves fuel and time as different items can be cooked at the same time.
5. Less chance for burning and scorching.
6. Constant attention is not necessary.
1. The initial investment may not be affordable to everybody.
2. Knowledge of the usage, care and maintenance of cooker is required to prevent accidents.
3. Careful watch on the cooking time is required to prevent over cooking.
This involves cooking in the minimum amount of liquid at temperatures of 80 o C - 85 o C that is below the boiling point. Egg and fish can be poached.
1. No special equipment is needed.
2. Quick method of cooking and therefore saves fuel
3. Poached foods are easily digested since no fat is added.
1. Poached foods may not appeal to everybody as they are bland in taste.
2. Food can be scorched if water evaporates due to careless monitoring.
3. Water soluble nutrients may be leached into the water.
In meal preparation, it is often necessary only to peel off
the skin of fruits and vegetables without making them tender. This can be achieved by blanching. In this method, food is dipped in boiling water for 5 seconds to 2 minutes depending on the texture of the food. This helps to remove the skin or peel without softening food.
Blanching can also be done by pouring enough boiling water on the food to immerse it for some time or subjecting foods to boiling temperatures for short periods and then immediately immersing in cold water. The process causes the skin to become loose and can be peeled off easily.
1. Peels can easily be removed to improve digestibility.
2. Destroys enzymes that bring about spoilage.
3. Texture can be maintained while improving the colour and flavour of food.
1. Loss of nutrients if cooking water is discarded.