23 Microwave Cooking

R. Radha

epgp books

 

 

 

 

 

1. OBJECTIVES

 

After learning this session, the readers should able to

 

1.     Describe the functioning and principles of microwaves

2.     Describe how to use the microwave oven for cooking and its safety measures

 

2.  INTRODUCTION

 

Microwaves are high frequency, non-ionizing electromagnetic waves which are similar to radio and television waves but are shorter. Hence they are known as microwaves. They are not, however, as powerful as infrared rays and do not resemble x-rays, gamma rays and ultra violet rays in any way.

 

Inside the microwave oven is a magnetron vacuum tube. This converts ordinary electrical energy into high frequency microwaves. These waves are channelized into oven cavity through a wave guide. A stirrer fan distributes the microwaves evenly.

 

Heat Transfer: The radiated energy, in the form of microwaves, affects only some of the molecules in the food. These are the electrically charged molecules of which the most important in food is water.

 

1. Microwaves penetrate the food to a depth of 2 to 5 cm.

2.Microwave passes on the energy to water molecules. The water molecules then vibrate (move) 2000 million times per second. This movement produces a band of HEAT inside the food.

3. The heat produced in this area is CONDUCTED (solids) or CONVECTED (liquids) throughout the food.

4. Food is heated from all directions producing very fast cooking.

 

Traditional cooking involves loss of heat to the oven, to the equipment and to the kitchen itself. Microwave cookery in comparison with conventional cooking, offers a quick and efficient method of cookery.

  1. EQUIPMENTS: THE MICROWAVE

 

Microwaves are produced from electricity by a magnetron. They are then directed into an oven and distributed evenly by a fan. A shiny oven surface allows the waves to be reflected in all directions to promote fast and even cooking.

 

2.1. Structure of microwave oven

 

Microwave oven generally consists of the basic components listed below:

  i) Power Supply and Control – to control the power to be fed to the magnetron

 ii) Magnetron – it is the vacuum tube where electrical energy is converted to an electromagnetic field.

iii) Waveguide– it is rectangular metal tube to direct the microwave generated from the magnetron to the cooking cavity. It also helps to prevent the direct exposure of the magnetron to any food particles

iv) Stirrer – commonly used to distribute microwaves from the waveguide to allow more uniform heating of food

v) Turntable– it rotates the food products through the fixed hot and cold spots inside the cooking cavity and allows the food products to be evenly exposed to microwaves.

vi) Cooking cavity – space inside where the food is heated when exposed to microwaves

vii) Door and choke – it allows the entry of food to cooking cavity. They are engineered in such a way that they prevent microwaves from leaking between the door and cooking cavity.

 

2.2. Adaption’s of basic equipment

  1. Turntable: Convection currents are slow to develop and therefore many microwaves are fitted with a turntable to stimulate stirring.
  2. Browning attachments: Microwave cooking produces no browning of the surface as temperatures inside the oven are not high enough to produce the surface changes.
  3. Browning dishes: These are ceramic dishes coated with a layer of material which absorbs microwaves and gets heated. Food placed on the hot surface will seal as if in a hot frying pan
  4. Infrared heaters: These are positioned in the oven so that at the end of cooking browning can be achieved quickly.
  5. Microwave cookers: These are conventional ovens with the facility to produce microwaves. They combine both systems to produce a high level of versatility speed and cost effectiveness.

Temperature probes: Because the food may be cooked inside whilst the surface remains cool, traditional eye judgement to determine if food is cooked or not is impossible. Thermometers which will pierce the surface of the food and measure internal temperatures are therefore useful. These are called temperature probes and are available ready-installed in some ovens usually referred to a computerized microwave ovens. They are especially useful in cooking meat and poultry to avoid under cooking and dangers of food poisoning. Example of temperature probe is shown in Figure

 

2.3. Cooking dishes

 

2.3.1. Size and Shape

  • Capacity and depth of the container are very important. Food gets cooked in shallow dishes well than narrow dishes.
  • Round and ring shapes are excellent for foods which cannot be stirred.

 

2.3.2. Types of utensils

 

The range of utensils that can be used for microwaving is much wider than that used for conventional cooking. Remember that dishes should not act as the barrier to microwave energy. Metal dishes are unsuitable

 

2.3.3. Paper containers

 

Paper plates, absorbent kitchen paper, paper napkins, paper cups and cartons all have their uses. Recycled paper should not be used e.g., newspaper. Paper is suitable only for heating and not for cooking.

 

2.3.4. China glass and pottery

 

Oven proof china glass (borosilware) and pottery dishes are perfectly suitable. Ceramic dishes should be non-porous. To check if a dish is non-porous, heat it in the microwave for 15-20 seconds. The dish should not feel warm.

 

2.3.5. Plastics

 

Plastics like Styrofoam are safe for heating but it gets melted or distorts at cooking temperatures.

Melamine, however is not recommended as it may char the food.

 

2.3.6. Cotton and Linen

 

Pure cotton or linen napkins can be used for short reheating purposes and warming of bread rolls.

 

2.3.7. Straw and Wood

 

Use these only for short reheating times. Wooden spoons may be left in the microwave for short cooking period.

 

2.4. Care of Equipment

  1. The oven should be cleaned after every use with warm soapy water
  2. The oven should be serviced and maintained according to manufacturer’s instructions.

    2.5. Suitable Foods

  1. Prime cooking:

Most foods contain a large proportion of water and can therefore be cooked raw in a microwave oven. Baked flour products are not particularly successful as crispness, colour and aeration are difficult to achieve. Cheaper cuts of meats do not have the time to dissolve out the collagen and tempt to remain chunky.

  1. Reheating and deforesting:

Microwave oven is ideally suited for reheating cooked foods and also for defrosting frozen foods.

  1. TIME AND TEMPERATURE

Foods cook well at similar temperatures in microwave oven as compared to traditional methods. The surface of the food will not be the hottest parts as described and if the food overcooks it will be the inside part that begins to char first. Cooking times using microwave oven are determined by specialist’s recipe books and experimentation. The latter may be costly and time consuming, but reaps positive benefits in the long time. In general, cooking times are reduced approximately by 75% compared with the traditional way of cooking.

  1. Type of food:

Using microwaves, porous foods like minced meat or mashed potatoes can be cooked faster compared to dense foods like whole potatoes.

  1. Size and shape of food
  • Foods of uniform shape and size cook more consistently as in traditional cooking.
  • Food substance in round shapes cook more evenly than squares or rectangles, which absorb more energy at the corners.
  • Food placed in a shallow dish will cook faster than the same quantity in a deeper dish.
  • Ring shapes are ideal for microwaving as energy penetrates the food from top, bottom, sides and center, producing minimum cooking times.
  1. Amount of food

Cooking time is directly related to quantity of food. This is because the microwave energy remains constant, but has to be shared among the increased volume of food, therefore requiring a longer period to cook the food.

  1. Power rating

The power output of microwave oven varies between 500 to 700 watts. The lower the output, the longer the cooking time. The amount of microwave energy released in to the oven over time period is controlled by the various cooking control setting. The energy is periodically burnt off and on to produce slower cooking, heating and defrosting.

  1. MICOWAVE COOKING TECHNIQUES

      4.1. Covering food

 

Lids or cling films (specially formulated) are used to trap steam and moisture to tenderize and speed up the cooking. Paper towels can be used to prevent spattering of food. Papers can also be used under the breads, baked potatoes etc to absorb moisture and keep the surface crisp and dry.

 

4.2. Releasing pressure from foods

 

To avoid bursting of food due to excess steam build up, skinned foods should to pierced before cooking. For example foods like potatoes with skin, egg-yolk etc should be loosened before microwaving.

you can view video on Microwave Cooking

Bibliography

 

  1. Eunice Taylor and Jersy Taylor (1990). “Mastering catering Theory”. Macmillian Master Services, Macmillian Press Ltd. ISBN 0-333-47190-3. Page 183-192. 193-195.
  2. Norman N.Pottes and Joseph H.Hotchkiss (2007). ”Food science”. Fifth edition, CBS Publishers and distributors, New Delhi, Page 256-261
  3. Sanjeev kapoor (2005). “Microwave cooking made easy”, Third Edition, Popular Prakashan Pvt Ltd, Tardeo, Mumbai.
  4. Nita Mehta (1999). “Microwave cooking for the Indian Kitchen”, Reprint, Snab Publishers. ISBN 8186004939
  5. Annette Yates (2010). “Microwave cooking properly explained”. Edition (Illustrated). Right Way Publisher. Pages 123.

Weblink

  • www.indianfoodforever.com
  • www.cookinglight.com/food/recipe-finder/microwave-recipes
  • www.food.com/topic/microwave