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Thermoplasticization of zein and kafirin

Thermoplasticization of zein and kafirin. IMCB-CNR November 2004. IV. III. I. II. Processing condition for extrusion. zein-25%PEG400, 50rpm Heating rate: 10°C/5min. Increase of viscosity due to plasticization Decrease of viscosity due to the increase of T

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Thermoplasticization of zein and kafirin

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  1. Thermoplasticization of zein and kafirin IMCB-CNR November 2004

  2. IV III I II Processing condition for extrusion zein-25%PEG400, 50rpm Heating rate: 10°C/5min • Increase of viscosity due to plasticization • Decrease of viscosity due to the increase of T • Increase of viscosity dueto further plasticization and/or chemical reactions • Decrease of viscosity due to the increase of T and degradation The second peak does not depend on rpm

  3. Profile T1 T2 T3 T4 Extrusion of zein • Materials and procedures • Zein/PEG 400 or zein/stearic acid were mixed before feeding • The following T profiles were utilized • T1=30°C, T2=60°C, T3=T4=65°C, 70°C, 75°C, 80°C, 85°C. • For each profile the rotational speed of the screws were: 20, 40, 80 e 120 rpm.

  4. Extrusion process Zein, 25%PEG400

  5. Extrusion process Zein vs stearic acid

  6. Mixing process of Kafirin Kafirin from batch 4 does not thermoplasticize like batch 2 Different plasticizers and experimental conditions were used

  7. Tensile properties of extruded zein films

  8. Tensile properties of extruded zein films

  9. Tensile properties of extruded zein films

  10. Water permeability of extruded zein films

  11. Oxigen permeability of extruded zein films

  12. Kafirin-mechanical properties

  13. Kafirin-mechanical properties

  14. Film blowing process

  15. Film blowing process

  16. Film blowing process

  17. The protepack…edible??

  18. Fiber spinning

  19. Foams with CO2

  20. Conclusions on zein • Zein (from Aldrich) can be thermoplasticized directly in the extruder • Extrusion parameters are correlated to mixing process parameters • The mechanical properties of extruded zein varied with the extrusion conditions. The variation in oxigen and water permeability was not relevant. • Residence time and T must be optimized to get melt with good rheological properties • Preliminary results showed that, in certain conditions, the elongational properties of zein are suitable for film blowing and fiber spinning.

  21. Conclusions on kafirin • From FTIR (Peter) analysis batch 2 and batch 4 contained different amount and alfa-helix and beta-sheets. • When compated to batch 2, the termoplasticization of batch 4 required a higher amount of plasticizer (30% instead of 25%) and lower T (45°C instead of 60°C) • The higher amount of plasticizer required leaded to melt with poor rheological properties, not suitable for film blowing. However, the amount of kafirin available was not enough to optimize process parameters. • We believe kafirin films can be obtained but need a lot….sorry!!!

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