Snack direct expanded

Most popular category of snack foods, generally obtained after simple shaping of doughs or dry-milled fractions forced through an extruder (direct expanded products). Raw materials include various types of flours and grits. 

There are basically two families of snack items obtained with thermoplastic extruders the direct expanded snacks and the third-generation snacks produced from pellets or half-products obtained after the sequential cooking and forming extrusion steps. The direct extruded types are subdivided into baked puffs and fried puffs (Rooney and Sema-Saldivar 2003, Serna- Saldivar et al. 2008). 

FIGURE 12.6 Flowchart of the manufacturing processes for the production of direct expanded haked or fried snacks. 

Second-generation snacks These are the most important snack category. Second-generation snacks are simple shaped products such as com and tortilla chips, puffed curls, and all directly expanded snacks generally produced via thermoplastic extrusion. 

Thermoplastic extrusion Name of the continuous extrusion process in which raw materials, generally refined milled fractions, are cooked and plasticized due to heat and pressure occurring inside the extruder barrel. The starch is gelatinized, and the exiting extrudate is usually formed into predetermined shapes. This process is widely used to produce direct-expanded-products and pellets or intermediate products used for production of many breakfast cereals and snacks. 

Nowadays, extrusion-cooking is used for the production of different food staff, ranging from the simplest expanded snacks to the highly processed meat analogues. The most popular extmsion-cooked products are direct extrusion snacks, RTE (ready-to-eat) cereal flakes and diverse breakfast foods produced from cereal... 

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