Gita Anggia Putri's Blog: Mei 2013

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UNIVERSITAS KOMPUTER INDONESIA

The History Of Microwave Oven

The microwave oven first came to consumers as by-product of an experimental technology. In 1946, Dr. Percy Spencer, an engineer for Raytheon Corporation, was testing a device called a magnetron. By serendipitous accident, he realized the candy bar in his lab coat pocket had warmed. Curious about this phenomenon, he placed some popcorn kernels near the tube they popped

The next day, Spencer and a colleague observed the magnetron's effect on an egg. The magnetron's effect on the egg caused it to explode onto the faces of the observers. Dr. Spencer refined his device by building an enclosure to create a higher density field of electromagnetic waves. Food placed in this box achieved high temperature very quickly. A multi million dollar business was then born.

Raytheon quickly began developing a consumer unit, and applied for a patent before the end of 1946. In 1947, the first commercial unit to hit the market was tested in the kitchen of a Boston restaurant. The first units produced were just under six foot tall, weighed hundreds of pounds, and cost thousands of dollars.

Initial reactions to the microwave oven were cautious. The unit was cumbersome, and was water cooled. The refinements that took place in the following years, especially the air-cooled magnetron, ensured the microwave's acceptance in the modern kitchen.

Businesses were now able to heat products more quickly than in the past, resulting in fresher products delivered to consumers. The microwave also gained popularity in unexpected ways, as manufacturers of leather, coffee, cork, and other products used the microwave to quickly heat and dry products.

Over the next 20 years, the microwave slowly evolved from a product the size of a refrigerator to the smaller, range top models more common today. The acquisition of the Amana company by Raytheon brought about introduction of the first counter top oven, a 100 watt unit that was safer and more effective than ever.

The 1970s saw an unbelievable success for the microwave oven, and a bevy of myths about the dangers of the oven became popular. Customers feared that the oven might cause radiation sickness, impotence, or blindness. As the oven became more popular, fears of the oven were eased. No one had acquired any of the supposed maladies that could be caused by the microwave oven's electromagnetic waves.

In 1975, sales of microwave ovens reached a landmark as they exceeded the sales of gas ranges. In 1975, Japanese homes were much more likely than American homes to have a microwave. By 1976, microwave ovens became more popular than the dishwasher in American kitchens. In 1976 the microwave had reached the kitchens of nearly 60% of American houses.

Today, the microwave has revolutionized the way Americans eat. The oven has evolved into a variety of forms to suit the diverse needs of the American home and business. Today's consumer can choose from options like convection cooking, probe cooking, and sensor cooking. The savings of energy and time have brought great convenience to American kitchen.

What Is A Microwave Oven

Cooking Concepts

A microwave oven utilizes a magnetron inside the unit to convert ordinary electricity into short radio waves as a 2450 megahertz frequency. Vibrations are caused in the food by the electromagnetic waves to heat the food. Some food molecules heat faster than others; fats and sugars heat the fastest in a microwave oven. Microwaves are distributed throughout the oven by fans.

Heating

Foods are heated with microwave energy through friction as opposed to convection, conduction or radiative heat transfer. Moisture molecules in the food orient themselves to the microwave field by rotating. Working with negatively charged oxygen atoms and positively charged hydrogen atom, the water molecules continue to re-orient themselves to the negative and positive ends of the microwave field. The field polarity changes at a rate of 2450 megahertz, which is approximately 2.45 billion times per second. This causes the friction which in turn heats the food.

Power Levels

Microwave ovens offer different cooking power levels. For cooking foods completely, 100 percent power is usually chosen. Thawing frozen foods when cooking completely is not the intent is generally done as 30 percent power. The magnetron in a microwave oven produces the highest amount of energy at 100 percent power. To achieve the lower power levels, the magnetron cycles off for a percentage of time. For example, when set at 30 percent power, the magnetron operates at full power for 30 percent of the time and cycles off for 70 percent of the time.

Resting Time

Due to the way that microwave ovens heat and cook, food needs to "rest" for a period of time after removing it from the oven. The vibrations of the water molecules that cause the friction which heats the food are still active for a period of time until they settle. The food is actually still heating through during this period of time. Most microwaving directions will indicate the length of this period of time.

How to Use a Convection Microwave Oven

Instructions

1. Reheat leftovers, beverages and cook frozen dinners by following the same methods used in traditional microwave ovens. Cooking time may vary due to higher wattages.

2. Steam items in the microwave convection oven by putting them in a microwave-safe container. Add a few tablespoons of water and cover the food with plastic wrap (puncture a few holes in the wrap to allow steam to escape). Start by cooking for a few minutes and adjust by adding more time if needed. To add more flavor to the dish, replace water with wine or lemon juice.

3. Convert any favorite recipes used in a basic oven by decreasing the cooking temperature by 25 degrees. Cooking time may also vary, and should typically take 1/3 less total time. Always watch the foods, initially, until you are familiar with your microwave convection oven.

4. Cut fish such as flounder, bass and sole (salmon and tuna are better broiled), into thin pieces. Place it in a heat-safe dish. Add wine or beer, garlic and herbs to taste. Lemon slices may also give fish a nice flavor. Cover it with plastic wrap and vent the container for steam cooking. Heat for a minimum of 6 minutes, adjusting cooking times as needed.

5. Bake items such as cookies, casseroles and meals in shallow pans in the microwave convection oven. For best results stray from dishes with high sides, and containers with lids, as these items may not heat well in the microwave convection oven. Note, heat must circulate well inside the oven for efficient cooking.

Advantages and Disadvantages of Microwave Oven

Advantages of Microwave Oven

1. Safety

Microwave ovens are a very safe means of cooking food. They don't produce any flames or areas of intense heat during cooking, which removes the risk of burns until you actually take the cooked food out of the microwave. The lack of an open flame means there's little chance of accidental fires, and a microwave won't leave any hot surfaces after you're finished using it.

Microwaves can also make food safer to eat when users follow the proper procedure. According to the U.S. Department of Agriculture, covering meats and other animal products with a lid while cooking will create moist heat that kills food-borne germs and will help prevent illness.

2. Speed

Microwave ovens heat food from the inside out and cook very quickly. Tasks that would take hours in a conventional oven can be accomplished in a matter of minutes in a microwave, which makes it easier to prepare meals and gives cooks more control over the timing of their food. Microwaves can also thaw frozen food quickly to ready it for cooking in a conventional oven.

3. Energy Use

Because of the short amount of time they need to run to cook food, microwaves use less energy than other types of ovens. They don;t require a natural gas hookup like a gas stove, and they use less power than an electric oven for performing the same tasks, which reduces household utility bills and also lowers demand for electrical production.

4. Cost

Microwaves are generally inexpensive, with even the most full-featured and large models costing less than conventional ovens, which makes microwaves suitable for hotel rooms, offices and other situations where an oven would be too expensive to install and operate.

5. Size

Microwaves come in a range of sizes, but most units are small enough to install in even a cramped kitchen. Some microwaves mount below cabinets or above a conventional oven, meaning they take up no additional counter space, which is another reason that microwaves appear in places where conventional ovens don't.

6. Convenience

If speed is the most important advantage of the microwave oven, then convenience must be second. People who wish to prepare foods quickly can go to the microwave and have a frozen dinner ready in minutes. Hot dogs can be thoroughly heated in 30 seconds and a bag of popcorn can be ready to munch before the commercial break is over during your favorite television show

Disadvantages Of Mivrowave Oven

1. Rubbery Texture

One disadvantage of using a microwave oven is how it affects the quality of the food. When a piece of meat gets put into the microwave for too long it can come out with a rubbery texture that is tough to chew. The taste of food often changes when it is overcooked in the microwave, turning your favorite snack into something less appetizing.

2. Unpredictable Heating Times

Microwaves have trouble heating food consistently when the number of items in the oven changes. In other words, the time it would take to warm up one piece of leftover pizza in the microwave is much different than the time needed to heat up three slices on a plate. This unpredictability can lead to cold spots in the food or food that is too hot to eat.

3. No Browning

Microwaves lack the ability to brown meat surfaces. This disadvantage drastically limits what a cook can do with a microwave. This limitation is one of the major downsides to using a microwave because it often means that the stovetop must also be used.

4. Chemical Dangers

According to the University of Texas Health Science Center at Tyler, heating foods in a microwave inside plastic containers not specifically designed for use with a microwave can lead to the transfer of potentially dangerous chemicals from the container into the food.

Resume

A microwave oven, often colloquially shortened to microwave, is a kitchen appliance that heats food by bombarding it with electromagnetic radiation in the microwave spectrum causing polarized molecules in the food to rotate and build up thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm of a dense (high water content) food item; food is more evenly heated throughout (except in thick, dense objects) than generally occurs in other cooking techniques.

Percy Spencer invented the first microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1947. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. The countertop microwave oven was first introduced in 1967 by the Amana Corporation, which was acquired in 1965 by Raytheon.

Microwave ovens are popular for reheating previously cooked foods and cooking vegetables. They are also useful for rapid heating of otherwise slowly prepared cooking items, such as hot butter, fats, and chocolate. Unlike conventional ovens, microwave ovens usually do not directly brown or caramelize food, since they rarely attain the necessary temperatures to produce Maillard reactions. Exceptions occur in rare cases where the oven is used to heat frying-oil and other very oily items (such as bacon), which attain far higher temperatures than that of boiling water. The boiling-range temperatures produced in high-water-content foods give microwave ovens a limited role in professional cooking,[1] since it usually makes them unsuitable for achievement of culinary effects where the flavors produced by the higher temperatures of frying, browning, or baking are needed. However, additional kinds of heat sources can be added to microwave packaging, or into combination microwave ovens, to produce these other heating effects, and microwave heating may cut the overall time needed to prepare such dishes. Some modern microwave ovens may be part of an over-the-range unit with built-in extractor hoods.

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