ABSTRACT
Popcorn is one of the eldest documented snacks and it is extensively consumed all over the globe with a market of approximately 10 billion USD in 2020. The popability of popcorn and other related cereals like sorghum and millets is strongly associated with the physical properties of kernels especially in terms of pericarp thickness and structure of the vitreous endosperm cells. Popcorn is merchandized in three kernel types: white, small-yellow, and large-yellow. Besides the genetic traits, the popping expansion is affected by harvesting practices, drying, and final moisture content of kernels. Popping occurs at about 177oC equivalent to a steam pressure of 2.5 t/cm2 inside the kernel. Burst kernels with a spherical shape are called ball or mushroom and are preferred in the confection industry whereas the most popular butterfly type, with a higher expansion rate, is desired for most other applications. There are fundamentally two popping methods: wet and dry. Wet-popping is more applied because the use of cooking oil yields products with better flavor. However, dry-popping which only employs heated air is also gaining relevance for the production of low-fat products. Microwaveable popcorn has increased in popularity for in-home popping. The quality of raw kernels, the blend of oil-flavorings, and the complex packaging system play an important role in the quality of microwavable popped corn. Similarly in other parts of the world, popping of other cereals like sorghum and millets have been traditionally performed. Puffing of other grains like white rice, wheat, and amaranth are normally assisted with gun-puffing or high-convection baking. These puffed cereals, pseudocereals, and legume seeds are utilized as RTE breakfast cereals and for the formulation of snack bars. Oven-puffing conducted at atmospheric pressure normally yields fewer expansion rates compared to high-pressure gun-puffing.
