 Started during World War II  Large, heavy and very expensive  $1,300  Modern microwaves  Convenient, and available in different sizes

3 different places of use 1. Home  Used to boil water, heat frozen foods, defrost foods, or to make popcorn  Consumers use it because of convenience

2. Foodservice  Have high-output capabilities  Used to reheat foods  Not frequently used, unless for individual portions  Not a time saver with large quantities

3. Food Industry a. Meat tempering Largest use of microwaves in food industry As food is tempered, it is brought to temperature below freezing Not frozen, but still firm Conventional thawing would take several days Microwave tempering takes a few minutes Less drip loss and microbial growth

b. Microwave Drying  Saved time and energy  Can be used for pasta, fruit juice concentrates, herbs, breadcrumbs, chips, and snack foods c. Pasteurization  Fresh pasta, bread, granola, yogurt, meat products, and prepared meals

d. Sterilization --Using overpressure conditions --Produces temperatures 230 to 266 degrees F. e. Proofing -- Used for baking bread, pizza, cake, and pastry products. --Usually used with conventional baking

High-frequency electromagnetic waves of radiant energy. a. How do they heat food?  i. Interact with electrically polarized molecules (dipolar molecules) Include water, protein, and CHO.  ii. Dipolar molecules act like tiny magnets and align in the microwave electromagnetic field.  iii. Field alternates rapidly  iv. Causing polarized molecules in the food to rotate rapidly  v. Heat is produced by the friction that is created.

 Speed of Cooking and Reheating of Food  Reduction of Nutrient Loss  Energy Conservation

 a. Surface Browning of Foods  b. Overcooking  c. Unevenness of Heating  d. Food Safety  May not destroy all of the Salmonella or Trichinella spiralis

a. Browning  Large pieces of food are able to brown in the microwave  Small pieces of food need another way b. Stirring and Turning  Power is unevenly distributed  Needs to be turned around, turned over, and stirred

c. Standing Time  i. Foods still cook after a few minutes after being removed  ii. Take this into consideration to avoid overcooking d. Defrosting e. Combine Microwaves and Conventional Cooking  Food can be prepared more efficiently f. Heating Meals