Once Puff Snacks Processing Line is installed, controlled quantities of raw materials and process liquids are premixed and then dosed to feed the double screw extruder continuously and consistently. The homogeneous mix thus created by the action of two co-rotating screws is subjected to thermo-mechanical processing to gelatinize the starch and cook the product. The paste is then pushed through the die to shape, expand and give the product its light and airy finished texture. The design of the die insert, the moisture content in the extruder and the expansion ratio are key factors in determining the texturing and shaping of expanded snack products.
At the extruder exit, the expanded product is either cut directly at the die head or conveyed on a belt to be cut by a post extrusion cutting system. The product can also be filled (injection of the filling at the level of the die) when the unit is equipped with a co-extrusion module.
Shaped snacks are transported on a multi-layer dryer at a controlled temperature to achieve the target level of moisture content. The dried product is then cooled for storage or directly conveyed to the coating system. Two types of coating are used: an oil/flavors mixture to produce a slurry to be applied directly to the snack or, alternatively, an oil spray and dusting with flavors, spices, salt and other powdered materials. The flavored snacks are then cooled to room temperature before being transported to the packaging units.