The scientists working at the Raytheon Company during World War II were undoubtedly highly stressed.聽 Britain was being attacked by Nazi warplanes and their task was to develop an electronic system capable of tracking the invading aircraft.聽 Rising to the challenge, the researchers came up with 鈥渞adar,鈥� which helped change the course of the war and made possible the extensive air travel we enjoy today.聽 Lots of coffee must have been consumed during those pressure-packed days at Raytheon, with cups sometimes getting cold as they were left sitting on a bench as the research heated up.聽 But not all the coffee cooled down!聽 Coffee in cups that had been left near the electronic tubes used to produce the microwaves needed for the operation of radar actually heated up.聽 The concept of a microwave oven was born!
Microwaves are a form of low energy electromagnetic radiation.聽 Unlike x-rays or ultraviolet light, they don鈥檛 have enough energy to break chemical bonds.聽 They do, however, have the ability to interact with molecules that have positive and negative regions.聽 Water is an excellent example of such a 鈥減olar鈥� substance since the oxygen in H2O has a partial negative charge while the hydrogens have a positive character.聽 Just like waves in water, microwaves have crests and troughs.聽 The charged regions of a water molecule align differently with the crests and troughs, which means that as a wave passes through a molecule, it begins to spin.聽 These spinning molecules are jammed so close together that friction is created and it is this friction that generates heat.聽 Microwave ovens therefore work by heating up water.聽 Since most foods have a significant water content, they can readily be cooked by microwaves.
By the 1980s cheap microwave ovens had been developed and began to alter the kitchen landscape.聽Heating left overs became a snap and fresh popcorn was only a couple of minutes away.聽But it didn鈥檛 take long for the critics to target the novel technology.聽Microwaves cause cancer, they said.聽You might as well have a nuclear reactor in your kitchen, one health food advocate declared.聽That is just plain silly!聽 Microwaves do not break chemical bonds and therefore cannot disrupt DNA, a process essential to carcinogenesis.聽Furthermore, microwaves are confined to the oven and there are no 鈥渞esidual鈥� waves attacking unsuspecting consumers as the door is opened.聽Then there was the allegation that microwaves change the chemistry of the food, making it unhealthy.聽One anti-microwave advocate declared that the force that causes water molecules to spin also rips apart and deforms the molecular structure of the food so 鈥渢hat it is no longer food, it just looks as though it is.鈥澛燯tter nonsense.
Yes, microwaving does change the chemical makeup of food.聽Any form of cooking does that.聽Heat initiates a number of chemical reactions, most of which are desirable.Proteins become more digestible and various flavored compounds are produced.聽True, microwaved cooking may lead to a less tasty meal since compounds such as thiazole, furan and pyrazine, all very flavorful are not as extensively produced by the lower temperatures and shorter cooking times in a microwave.聽On the other hand, heterocyclic aromatic amines (HAAs), which have been linked to cancer, are far more likely to form in fried, grilled or broiled meats than in those that have been microwaved.聽
Spanish researchers recently caused quite a stir when they compared nutritional losses in steamed, boiled and microwaved broccoli.聽They were interested in levels of flavonoids, compounds which have decided anti-cancer effects.聽 Microwaving broccoli resulted in a 97% loss of flavonoids, while there were minimal losses associated with steaming.聽Reports in the lay press inferred that this research demonstrated that nutrients are destroyed by microwave cooking.聽 It did no such thing.聽What it did show was that the researchers have no idea about how broccoli should be cooked in a microwave oven.聽They immersed the florets in water and cooked on 鈥渉igh鈥� for five minutes!聽Perhaps they like the texture of disintegrated broccoli.聽I don鈥檛.聽The way to cook broccoli is to put just a couple of spoonfuls of water in the bottom of a glass bowl, add the florets, cover, and cook for two minutes.聽Had they done this, I鈥檇 bet that losses would be comparable to steaming.聽But that doesn鈥檛 make for as good a story as 鈥渕icrowaving destroys nutrients,鈥� does it?聽聽
Is there any real risk with microwave ovens?聽 You bet!聽They have a long history of causing terrible eye injuries.聽The problem, considering the extensive use of such ovens is not huge, but there are at least thirteen cases in the medical literature of people being viciously attacked by microwaved eggs.聽One of the first such reports appeared in the New England Journal of Medicine back in 1991.聽A 19 year old man, for reasons known only to him, heated seven eggs in their shells in a microwave oven at full power for five minutes.聽He managed to remove them from the oven uneventfully, but when he sat down at a table, six of the eggs spontaneously exploded causing severe burning about the face.聽 The problem of course is pressure buildup due to steam inside the egg.聽Even eggs cracked into a bowl can be dangerous.聽Several people have been injured when they pierced the yolk of a microwaved egg with a fork.聽The cooked membrane around the yolk can sustain a great deal of pressure, at least until it is pierced.聽 Then it retalliates by releasing a jet of steam.聽聽
Be careful with microwaving coffee as well. Sometimes the liquid can become superheated without boiling.聽 Then when the cup is picked up, the coffee can virtually explode out of the cup.聽So wait until you see the liquid clearly boiling in the oven before handling the cup.聽Those researchers at Raytheon may have noted this effect, but probably saw no need to comment on it.聽After all, they would have never guessed how their work on radar would eventually make waves in virtually every kitchen.
