Popcorn air popped

Air-popped unbuttered popcorn is low in calories and very high in fiber... 

E. Lusas and L.W. Rooney (eds.). First edition. Technomic Pnblishing, Lancaster, PA. Metzger, D.D., Hsu, K.H., Ziegler, K.E., and Bern, C.J. 1989. Effect of moisture content on popcorn popping volume for oil and hot air popping. Cereal Chem. 66 247-248. Meuser, F., and Wiedmann, W. 1989. Extrusion plant design. Chapter 5 in Extrusion Cooking. C. Mercier, P. Linko and J.M. Harper (eds.). American Association of Cereal Chemists, St. Paul, MN. 

Among snacks, popcorn is one of the best snack foods nutritionally because it is rich in starch and dietary fiber, and contains important amounts of vitamins present in the whole kernel. In fact, the American Diabetes Association and the American Dietetic Association allow popcorn as a bread exchange in weight-control diets. Oil-popped popcorn contains more than 25% oil, and provides approximately 500 kcal/100 g serving (Table 17.15). In contrast, air-popped popcorn only contains the intrinsic oil mainly associated with the germ (4%) and 380 kcal. Air-popped popcorn also contains the highest amount of dietary fiber and protein. One 100-g serving supplies about 15 g dietary fiber and 12 g protein. 

A different clay derives from the layered mineral talc, Mg3(Si40io)(01T)2. If iron(II) and aluminum replace magnesium and silicon in varying proportions and water molecules are allowed to take up positions between the layers, the swelling clay vermiculite results. When heated, vermiculite pops like popcorn, as the steam generated by the vaporization of water between the layers puffs the flakes up into a light, fluffy material with air inclusions. Because of its porous structure, vermiculite is used for thermal insulation or as an additive to loosen soils. 

The shell of a popcorn kernel is a hard, moisture-resistant coating protecting an interior filled with starch and some water. As the kernel gets hot, the starch inside first softens and then the water turns into steam, which raises the pressure inside the kernel. At some temperature the pressure inside the corn kernel is high enough to rupture the hard shell, and the kernel pops. The hot starch quickly cools, trapping tiny air bubbles inside and making a (delicious) solid foam. 

Hot air is used to pop popcorn and separate popped com from com kernels, as follows An upward flow of hot air levitates a com kernel the kernel s terminal velocity equals the velocity of the hot air. 

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