Popping and Puffing of Cereal Grains: A Review

Popping is a simultaneous starch gelatinization and expansion process, during which grains are exposed to high te mperatures for short time. During this process, super heated vapour prod uced inside the grains by instantaneous heating, cooks the grain and expan ds the endosperm suddenly, breaking out the outer skin. Puffing is a similar process; differ from popping as a process in which controlled expan sion of kernel is carried out, while the vapour pressure escapes thro ugh the micropores of the grain structure due to high pressure or thermal gradient. Popping and puffing imparts acceptable taste and desirable arom a to the snacks. There are different methods of popping/puffing used viz., conventional method of dry heat, sand and salt treated, hot air popping, g un puffing, popping in hot oil and by microwave heating. Though a wide range of cereals and millets such as rice, wheat, corn, sorghum, ragi, foxtail m illet are used for popping/puffing; only few of them pop well. The reason behind this may be the factors which influence popping qualities of ce reals, such as season, varietal difference, grain characteristics such as moisture content, composition of grain, physical characteristics, typ es of endosperm, and also the method of popping. Therefore, this paper aimed at providing brief review of popping characteristics of different cere al grains and popping methods in response to high popping yield and great er volume expansion ratio.