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xtrusion, Extruders types,Changes during extrusion, difference b|w Extrusion and pelleting
This document discusses extrusion, including its history, types of extruders, components of extruders, and applications. It covers key topics like: - Extrusion gained popularity due to its versatility, cost-effectiveness, and high productivity. - The main types of extruders are single-screw and twin-screw extruders. Twin-screw extruders can be co-rotating or counter-rotating. - Extruders consist of major components like the pre-conditioning system, feeding system, screw, barrel, and die. - During extrusion, physicochemical changes occur like starch gelatinization, protein denaturation, and
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xtrusion, Extruders types,Changes during extrusion, difference b|w Extrusion and pelleting
- 1. Doctor M.Waseem RiazSabri I.U.B, Islamia Bahawalpur
- 2. Line of learningcontents • Extrusion • Why gain popularity • Extruders types • Extruders components • Principle of operation • Physicochemical changes during extrusion • Extrusion products • Extrusion vs pelleting
- 5.
- 6. Extrusion Developed in 1870for sausages Single screw extruder was evolved in1930 Twin screw extruder in 1940s
- 7. Based on Method of operation Cold extruders Hot extruders Typeof construction Single screw extruders Twin screw extruders Types of extruders
- 9. Twin screw types 1)Co-rotating a) Intermeshing b) Non-intermeshing 2) Counter rotating a) Intermeshing b) Non- intermeshing
- 13. Cylindrical Rotates in groovedbarred made of alloy or stainless steel Length to diameter ratio 2:1 and 25:1 Typical screw speeds are 150–600 rpm Compression is achieved by back pressure Die pressures vary from 2000_103 Pa for low viscosity products 17 000_103 Pa for expanded snack foods Features of single screw extruder
- 14. i. Rotate withina ‘figure of 8’ shaped bore ii. Has segments for different actions iii. Designed in 10:1 length to width ratio Twin screw features
- 17. Extruders part Pre-conditioning system Feeding system Screw or worm Barrel Die andthe cutting mechanism
- 20. When preconditioning isrequired?? Uniform particle hydration Reduces retention times within the extruder Increases throughput Increase the life of the equipment. When feed material contains moisture content of 20-30% Preconditioning favors
- 21. Feeding system Guarantee a constant feed material Non-interrupted feedingof the raw materialsFor an efficient Uniform functioning of the extrusion process
- 22. Determine cooking degree Gelatinization Starch and protein denaturation Finalproduct quality Importance of screw
- 23. Barrel Its surrounded by sleeve Sleeves can besolid But often permits the circulation of steam and heat
- 24. Die Give shape tothe final product Increase internal pressure of extruder
- 25. Physico-chemical changes duringextrusion Major changes occur during extrusion process are: 1) Changes in starch 2) Changes in proteins 3) Changes in lipid 4) Changes in fibers
- 26. General changes duringextrusion Bubbles rapidly expand as the superheated water is released very quickly at atmospheric pressure Recombination Thermal degradation Fragmentation loss of native conformation Cleavage Binding
- 27. • Changes instarches • Gelatinization its define as ‘the irreversible destruction of crystalline order in starch granules so that the surface of each molecule is accessible to solvents or reactants
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- 29. Gelatinization occurs in 3 phases Phase1 Phase 2 Phase 3 slow absorption of water immense absorption Step by step changes
- 31. Changes in protein Disulfidebonds are broken and may re-form. Electrostatic and hydrophobic interactions favor the formation of insoluble aggregates. The creation of new peptide bonds during extrusion is controversial High molecular weight proteins can dissociate into smaller subunits. Enzymes losses their activity due to high temperature and shear
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- 33. Redistribution of insoluble fiberto soluble Rupture of covalent and noncovalent bonds between carbohydrates and proteins associated to the fiber Resulting in smaller molecular fragments, that would be more soluble
- 34. Positive effects ofextrusion
- 37. Effects of extrusion on vitaminsactivity
- 39. Cereals Snacks foods Pet foodAquafeedBaby food Extrusion products
- 40. cereals • Cooked wheat,barley or oats in the form of porridge ready-to-eat cereal Flakes Co-extruded products Directly expanded products
- 41. Snacks Light meals ora partial replacement for a regular meal. Often eaten while travelling or watching sports and other entertainment Directly expanded snacks Indirectly expanded Snacks Shape diversity
- 43. Pet food Filled products Multicolored product Kibbles,for cat & dog
- 44.
- 47. Single-screw extruders includes: •Direct expanded corn snacks • Texturized vegetable protein • Ready-to-eat breakfast cereal • Production of full fat soy • Pet foods • Floating and sinking aquatic feed • Production of baby foods • Rice bran stabilization • Precooked or thermally modified starches, flours and grain • Breading
- 48. Twin-screw extruders products •Co-extruded snacks • • food gums • reformed fruit bits and sheets • topping and bakery analogs • precooked pasta • noodles, spaghetti and macaroni • imitation nuts • third generation snacks • • Semi-moist food • soup and gravy mixes • sugar crust liqueurs • pet treats • three-dimensional snacks • three-dimensional confections and toffees • bread-like products (crisp bread) • pastry Doug • texturized vegetable protein (soy) • wheat gluten textured products • cheese and casein products • meat analog • texturized vegetable protein from partially defatted soy flour • stabilization of rice bran • multicolor food and snacks • meat and power bars • special energy bars with resin filling • marshmallow products • cereals and corn flakes
- 49. Extrusion Pelleting An extruderwill expand the pellet by gelatinization of the starch, expansion and increased porosity thus the reduction of the density. A pellet mill shapes the pellets by compression through long land dies thus the pellet is dense. No need for the addition of a pellet binder in most cases. In most cases, a pellet binder is need in the formula to facilitate the cohesion of the pellet. Extrusion allows you to control the buoyancy of the pellet by the degree of starch gelatinization. Do not control the buoyancy of the pellet Extrusion allows you to use higher level of oil or fat without creating much fines Does not allows to use high levels of oil or fat Shaping is only one part of extrusion pellet mill is mainly utilized to shape or produce a pellet of different shapes.