On food and cooking the science and lore of the kitchen ( PDFDrive ) 1480

employing enough oil to immerse the food altogether As a technique, it resembles boiling more than pan frying, with the essential difference that the oil is heated far above the boiling point of water, and so will dehydrate the food surface and brown it Microwaving: Microwave Radiation Microwave ovens transfer heat via electromagnetic radiation, but with waves that carry only a ten-thousandth the energy of infrared radiation from glowing coals This shift makes for a unique heating effect Whereas infrared waves are energetic enough to increase the vibratory movement of nearly all molecules, microwaves tend to affect only polar molecules (p 793), whose electrical imbalance gives the radiation a kind of handle with which to move them So foods that contain water are heated directly and rapidly by microwaves But the oven air, composed of nonpolar nitrogen, oxygen, and hydrogen molecules, and nonpolar container materials like glass, stoneware, and plastic (made of hydrocarbon chains), are unaffected by the microwaves; the food heats them as it heats up Here’s how a microwave oven works A transmitter, very much like a radio transmitter, sets up an electromagnetic field in the oven which reverses its polarity some 2 or 5 billion times every second (It operates at a frequency of either 915 or 2,450 million cycles per second, compared to wall socket currents at 60 cycles, and FM radio signals at some 100 million cycles per second.) Polar water molecules in the food are pulled by the field to orient themselves with it, but because the field is constantly changing, the molecules oscillate back and forth with it The water transmits this motion to neighboring molecules by knocking into them, and the ...by microwaves But the oven air, composed of nonpolar nitrogen, oxygen, and hydrogen molecules, and nonpolar container materials like glass, stoneware, and plastic (made of hydrocarbon chains), are unaffected by the. .. some 100 million cycles per second.) Polar water molecules in the food are pulled by the field to orient themselves with it, but because the field is constantly changing, the molecules oscillate back and forth with it The water... or 5 billion times every second (It operates at a frequency of either 915 or 2,450 million cycles per second, compared to wall socket currents at 60 cycles, and FM radio signals at some 100 million cycles per second.) Polar