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

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

3. 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. T1T2T3T4Profile

4. Zein, 25%PEG400 Extrusion process

5. Zein vs stearic acid Extrusion process

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

7. Tensile properties of extruded zein films

9. Plasticizer  R (MPa)  R (mm/mm) E (MPa) PEG 400 8.06  0.480.11  0.0015516.84  45.16 Stearic acid 17.91  6.330.023  0.0161302  62.285

10. Water permeability of extruded zein films

11. Oxigen permeability of extruded zein films

12. Kafirin-mechanical properties T  R (MPa)  R (mm/mm) E (MPa) 30°C 3.31  0.430.69  0.12157.74  40.14 38°C 4.77  0.440.68  0.13172.33  13.11 45°C 2.97  0.560.72  0.12107.96  12.02

13. Kafirin-mechanical properties Plasticizer type  R (MPa)  R (mm/mm) E (MPa) PEG 400 2.97  0.560.72  0.12107.96  12.02 Lactic acid 1.48  0.111.17  0.2538.54  6.37

14. 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!!!