Puffed foods
The puffing of food refers to a method of treating with heat and pressure , which a the food foamy imparts internal structure. The best-known representatives are popcorn ( puffed corn) and puffed rice , in which starchy plant seeds are puffed. Puffed foods have a very low specific weight and are easy to chew.
Manufacturing
When puffing seeds, the water contained in the seeds evaporates explosively due to a sudden reduction in pressure. The hot, swollen starch of the grains expands to a multiple of its original volume and solidifies in this state.
Certain types of grain (e.g. special popcorn for making popcorn) can be puffed by heating the whole grains alone, as the seed coat is able to withstand high internal pressure before it ruptures and allows the starch it contains to expand suddenly . Popcorn made in this way was already known to the indigenous peoples of Central America .
For grain types whose seed coat does not have the necessary strength (e.g. rice and wheat), a pressure vessel is used in which the raw material is heated dry or with the addition of water. The resulting overpressure is then suddenly released to trigger the popping up.
Another manufacturing process based on the foaming of swollen starch while reducing the pressure is the extrusion of snacks, such as. B. peanut flips . This is a continuous process in which the pressure is reduced when a hot starch paste emerges from a nozzle. Soy meat is made from defatted soybean meal in the same way . However, this starting material consists mainly of proteins with only comparatively small amounts of starch.
In principle, food can experience an increase in volume without a sudden reduction in pressure, for example when preparing puff pastry or crab chips . The water vapor that is created when it is heated continuously expands the food. However, such preparations are not referred to as “puffed”.
use
Today, puffed foods are mainly used for nibble snacks or confectionery ingredients. In contrast to popcorn , puffed quinoa grain, amaranth , puffed rice or wheat can be found as an ingredient in muesli mixes or as the main component of breakfast cereals , as well as a component of confectionery, such as chocolate or muesli bars .
Rice in particular is sometimes colored by adding food coloring. A specialty is puffed rice as part of the Japanese green tea preparation Genmaicha .
