Extrusion expanded products

Allen, K. E., Carpenter, C. E., and Walsh, M. K. (2007). Influence of protein level and starch type on an extrusion-expanded whey product. Int. ]. Food Sci. Technol. 42, 953-960. 

Walsh, M. K. and Wood, A. M. (2010). Properties of extrusion-expanded whey protein products containing fiber. Int. J. Food Prop. 13,702-712. 

Soy, and Other Legume Proteins Two quite different product types have been constructed by extrusion, high-density flaked structures for meat analogues, and lower density and crispy products for high-protein snacks. The latter uses conditions similar to that of starch-based cereal extrusion to obtain low bulk density in the expanded product the former uses a higher water content in the extruder barrel and lower exit temperatures to obtain a dense material with open pores or even flaked structmes. For these two types of processes, molecular changes in the extruder barrel are not dissimilar. Post-die structuring of the extrudates determines final product properties. 

Nonetheless, the correlations they obtained with product structure are very informative. The melt penetration was defined as the temperature above the 7) /moisture curve at the point of extrusion. (Note that from the arguments presented above, this parameter will correlate positively with both the steam-driving pressure for expansion and inversely with melt elasticity and viscosity, that is, conditions for rapid bubble expansion.) The second parameter measured was the moisture and temperature of the expanded product immediately after the die, and its value was compared to the midpoint of the measured Tg of the ingredient mix at the same water content. 

Stojceska et ah (2008) studied the incorporation of cauliflower trimmings into ready-to-eat expanded products (snacks) and their effect on the textural and functional properties of extrudates. It was found that addition of cauliflower significantly increased the dietary fiber and levels of proteins. Extrusion cooking significantly (P < 0.0001) increased the level of phenolic compounds and antioxidants but significantly (P < 0.001) decreased protein in vitro digestibility and fiber content in... 

Bread and related products, or expanded products formed by extrusion, reasonably fit the theory. This is not so for plant tissues. Here the modulus depends on three main factors the rigidity of the cell walls, the turgor of the cells, and the strength of the material cementing the cells. All of these parameters greatly decrease upon cooking. 

Irradiation of (132) leads to products arising from cyclization of the diene unit as well as from extrusion of nitrogen. Thermolysis of (133) gives the cyclopropane (134) and the ring-expanded product (135). ... 

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. 

The higher protein content whey products are used in many products, and have been mainly promoted for their health benefits. Our contribution is creating extrusion texturized whey products that expands the range of products that can contain whey proteins (Onwulata, 2009 Onwulata et al., 2010). 

Onwulata, C. I., Konstance, R. P., Smith, P. W., and Holsinger, V. H. (2001a). Co-extrusion of dietary fiber and milk proteins in expanded corn products. LWT Food Sci. Technol. 34, 424-429. 

We use variants of profile extrusion to produce tubing -with diameters of less then 1 mm and pipes with diameters exceeding 1 m, Wall thicknesses can vary from a few tens of micrometers up to several centimeters. Extruded window and door frames are more complex than pipes. Such profiles are largely hollow with internal ribs and fins that reinforce and divide the interior into two or more channels. We use solid rubber profiles in applications such as door seals and windshield wipers. We can produce foamed extrudates by incorporating a blowing agent, such as butane or carbon dioxide, into the polymer in the molten state. As the polymer exits the die, its internal pressure drops and the dissolved gas expands to form bubbles within the product. Examples of foamed extrudates include pipe insulation and automobile door gaskets. 

Foamed polystyrene - which is also known as expanded polystyrene - is used extensively in a variety of applications, ranging from packaging peanuts to insulation board and single-use cups and plates. We produce it by two processes foam extrusion and bead expansion. Both types of expanded polystyrene consist of closed cells, i.e., bubbles with continuous walls. We can visually distinguish the two types of foam by the fact that products made by the expanded bead process consist of discrete beads that are welded together... 

Expanded Rubber This class of product has an essentially closed cell structure. These products are most usually formed by moulding or extrusion processes and have a solid outer skin around the cell structure. Organic blowing agents are used for this type of process. 

Unicellular foams are used for insulation, buoyancy, and flotation applications, while multicellular foams are used for upholstery, carpet backing, and laminated textiles. Expanded PS (Styrofoam), which is produced by the extrusion of PS beads containing a volatile liquid, is used to produce low-density moldings such as foamed drinking cups and insulation boards. Foamed products are also produced from PVC, LDPE, urea resins, ABS, and PU. PU foams are versatile materials, which range from hard (rigid) to soft (flexible). These are produced by the reaction of a polyol and a diisocyanate. 

In extrusion, when the hot melt exits from the die, the compressed gas expands and foams the extrudate. In injection molding, the hot melt is injected into the mold, but the quantity is reduced ( short shot ) so that there is not enough melt to fill the mold the compressed gas expands, and the melt foams and fills the mold. Either way, the foamed melt cools and solidifies, producing a product with a solid skin and a somewhat expanded internal foam structure. It looks like a solid product, but it is lighter in weight and offers a number of advantages. 

Wet heating is more effective for bran stabilization for oil extraction than is dry heating. Lipase is inactivated in 3 minutes at 100°C (37). The equipment that can be used include steam cookers, blanchers, autoclaves, and screw extruders with injected steam and water (30). Extrusion with steam injection and up to 10% added water reduces the temperature required for lipase inactivation. Temperatures are reduced to 100-120°C. Product may be held at 100°C for 1.5-3.0 minutes before drying to a stable moisture content. Bran expands as it exits the extruder, and water flashes to steam (8). Porous pellets assist in solvent percolation during oil extraction. Fines are agglomerated as well. 

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