High moisture extrusion : optimisation of texturisation through control of rheological and textural parameters

1. High moisture extrusion : optimisation of texturisation through control of rheological and textural parameters D. Bounie, E. Van Hecke USTL (Université des Sciences et Technologies de Lille) IAAL (Institut Agricole et Alimentaire) Bâtiment C6 59655 Villeneuve d’Ascq Cedex - France Tel : +33 (0)3 20.43.49.21, Fax : +33 (0)3 20.43.44.86 E-Mail : Bounie@univ-lille1.fr, vanhecke@univ-lille1.fr Smart Extrusion Workshop, Sydney, 2 december 1997 (p1)

2. PLAN (p2) • High moisture extrusion • Usual extrusion conditions(50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences(reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

3. PLAN • High moisture extrusion • Usual extrusion conditions (50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences (reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

4. HIGH MOISTURE EXTRUSION : APPLICATIONS Wet extrusion vs. dry extrusion (Roussel, 1996) Wet extrusion : usual raw materials (Roussel, 1996) Moisture content % 80 % Fruits and vegetables Cheese analogs Enzyme reactors 60 % TVP Petfood-moist Pasta 40 % Breakfast cereals 20 % Dry petfoods Snacks - Flat breads Confectionery 0 % APPLICATIONS (Cheftel and al., 1992) (p3a) • Animal raw materials • red and white meat minces • meat trimmings • fish meats (surimi) • filleting co-products • minced from shell fish or cephalopoda • egg or milk proteins • Vegetable raw materials • protein-rich meals • protein concentrates or isolates (soya, wheat, peas, brans,...) after adequate rehydratation • Sterilization • preparation of sterile vegetables purées, meat-vegetables mixes • Chemical reaction (enzymic or acid hydrolysis) • starch or proteins modification for preparation of glucose syrups, fermentation substrates, flavor preparations • Texturization • Gelation/fibration • gelation and fiber formation using vegetable proteins (soya, gluten) • restructuration of mince, surimi, mechnically deboned meats (with binders) • texturization and fiber formation with fish muscle proteins • Emulsification/gelation : « microcoagulation » of dairy proteins • processed cheeses • cheese analogs • fat substitutes • casein coagulation

5. MACRO AND MICRO STRUCTURES OF FIBROUS EXTRUDED PRODUCTS A commercial extruded crab analog from Nippon Suisan (Cheftel and al, 1992) Scanning electron micrographs of an extruded surimi/soya concentrate mix (Thiebaud,1995) (p3b)

6. Feeding device TYPICAL EXTRUSION LINE FOR PRODUCT FIBRATION Twin screw extruder with accurate temperature control Gear pump Extra long cooling die (Nippon Suisan patent) (p3c)

7. PLAN • High moisture extrusion • Usual extrusion conditions (50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences (reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

8. TEXTURIZATION : MELTING + FIBRATION Flow in extruder and cooled die Die Metering zone Transition zone Biopolymer phases separate into different domains in extruder Domains orientate as a result of flow through die Products sets to fibrous structure on cooling Structure formation as a result of phase separation in biopolymer mixtures followed by subsequent orientation in flow through die (Tolstoguzov, 1986 ; Mitchell et al., 1994) (p4)

9. PLAN • High moisture extrusion • Usual extrusion conditions (50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences (reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

10. COOLING DIES FOR TEXTURATION Rectangular die Circular die Annular die (p5)

11. FLOW PATTERN IN EXTRUDER AND DIE (Bhattacharya and Padmanabhan, 1992) Intermediary region (relaxation) Metering zone Entrance region Viscometric flow region Exit region Shear flow Extensional flow Shear flow P DPentry DPshear flow DPexit die axis (p6) DPtotal = DPentry + Dpshear flow + DPexit

12. FLOW PROFILES THROUGH DIES Effect of cooling Flow through insulated die Flow through supercooled die Liquid Liquid / solid Solid (p7)

13. EFFECT OF OPERATING CONDITIONS ON FLOW, TROUBLESHOOTING Effect of implementing a non-newtonian fluid Effect of viscosity Increase of viscosity m = 1 m < 1 m << 1 Decrease of viscosity : . increase of water content . increase of temperature Troubleshooting «Shark-skin» : periodic rupture of fluid bed (no slip at die wall) «Two-phases wavy flow» : insufficient cooling rate (die too short or too thick) ; inner layers of flow are still melted at die outlet (p8)

14. PLAN • High moisture extrusion • Usual extrusion conditions (50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences (reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

15. STRESS TENSOR s2,2 s2,1 s1,2 s2,3 s3,2 s1,1 s1,3 2 s3,1 s3,3 1 3 • Shear stress (if no rotation, i.e. no torque) • s3,1 = s1,3 • s3,2 = s2,3 • s2,1 = s1,2 N1 = s1,1 - s2,2 (first normal stress difference) = hee = k (e : elongational strain rate) N2 = s2,2 - s3,3 (second normal stress difference) N2 < 0, N2 << N1 . g 2 • Normal stress • s1,1 • s2,2 • s3,3 (p9)

16. sT SHEAR VISCOSITY x dl F dx S v sT Bingham plastic F sT = shear stress (N.m-2 = Pa) S hs dl v = shear velocity (m.s-1) Newtonian s T,o Yield stress dt Dilatent (shear thickening) . dv g = shear rate (s-1) dx sT Pseudoplastic (shear thinning) . hs = shear viscosity (Pa.s) g . g (p10)

17. VISCOSITY : LAWS OF BEHAVIOUR Newtonian h = constant Power law (Ostwald’s law) (K : index of consistency, m :flow behaviour index . Non Newtonian h = K g m-1 Effect of temperature T (Harper and al., 1971) Effect of thermo- mechanical history W (SME) (Della Valle and Vergnes, 1994) . . h » (K g m-1) e -a T h » (K g m-1 ) e -e W Effect of moisture content MC (Harper and al., 1971) Effect of chemical reaction (DE, R) (Remsen and Clark, 1978) -DE RTa(t) . h » (K g m-1 ) e -b MC dt - k e . h » (K g m-1)e Example : corn starch at low MC (Della Valle and Vergnes, 1994) DE RTa . h = Ko e ( - a MC - b W) g m’-1 with : m’ = c1 T + c2 MC + c3 MC.T (p11)

18. IN-LINE MEASUREMENT OF VISCOSITY Qv DL (Mac Master and al., 1987) P DP L Apparent shear rate at wall gw, a Real shear rate at wall gw, r Shear stress at wall sw Viscosity h . . sw gw, r 4 Qv p R3 4 Qv p R3 3m + 1 4m R DP 2 DL . R W sw gw, r 6 Qv W h2 6 Qv W h2 2m + 1 3m h DP 1 2 DL . h W h 1 + for different Qv Log sw m Log K . Log gw, a (p12)

19. IN-LINE RHEOMETERS WITH CONTROLLED FEEDRATE By pass or side stream rheometers (Goettfoert system for plastics) Gear pump « Rheopac » slit die rheometer (Vergnes et al., 1990 and 1993) Piston keys Rheometer Derivation (p13)

20. DISPLAY OF ELASTICITY : Weissenberg effect, Barus effect sN Weissenberg effect increase with increasing g . sT Barus effect : swelling at die outlet fdie fextrudate sN (sN) sT (p14)

21. IN-LINE MEASUREMENT OF ELASTICITY : EXIT PRESSURE METHOD (Padmanabhan and Bhattacharya, 1991) related to extensional viscosity DPentrance proportional to elasticity P DPexit L (p15)

22. IN-LINE MEASUREMENT OF ELASTICITY HOLE PRESSURE METHOD ( Baird, 1976 ; Padmanabhan and Bhattacharya, 1992 ; Bhattacharya M. and Padmanabhan M., 1992, Malkus and al., 1992 ; Bouvier and Gelus, 1994) sN flush-mounted transducers P1 P2 P3 Qv transducer at the bottom of the hole P4 P P1 DP1,3 (shear viscosity) P2 P3 Dphole (elasticity) P4 L N1 = s1,1 - s2,2 = hee (p16)

23. DYNAMIC DETERMINATION OF VISCOELASTICITY (1) (Ross-Murphy, 1988) Accelerometer Force transducer Imposed oscillatory straing = f(t) Measured stress s = f(t) Viscous fluid Elastic fluid • Stress • s Stress s Strain g Strain g t t p d = 0 d = 2 g(t) = g0 cos (wt) Viscoelastic fluid Stress s Strain g s(t) = s0 cos (wt + d) t p 0 < d < 2 (p17)

24. DYNAMIC DETERMINATION OF VISCOELASTICITY (2) Ideal viscous liquid Viscoelastic fluid Ideal elastic solid Newton’s law Hooke’s law . sT = h g sN = E g Viscosity Viscoelasticity Elasticity Storage modulus Loss modulus s0 s0 G’’ G’ G’ = cos d G’’ = sin d = tg d g0 g0 log scale ortg d G’ G’’ Temperature Transition (p18)

25. ELONGATIONAL VISCOSITY he (Trouton modulus) hs Type of extensional flow Newtonian fluid Non-newtonian fluid Uniaxial extension 3 >> 3 ex : spinning of fibers Planar extension 4 >> 4 ex : foil stretching, central disk injection Biaxial extension 6 >> 6 ex : blowing extrusion, plug extrusion (p19)

26. ELONGATIONAL vs. SHEAR VISCOSITY Non-newtonian fluid Newtonian fluid h h he he hs hs . . g g he he ¹ constante = constante hs hs . [= f(g)] (p20) • In-line determination of extensional viscosity : • Entrance pressure drop method • (White and al., 1987 ; Bhattacharya and al., 1994)

27. PLAN • High moisture extrusion • Usual extrusion conditions (50 - 80 % water, 15 - 30 % proteins, fats <8 %, q > 130 °C) and consequences (reduction of : shear, viscous dissipation of energy and expansion at die outlet, especially with long cooling dies) • Raw materials • Main applications • Typical extrusion line • specific feeding device • special screw profiles (+ break plates) • long cooling-dies • temperature control • Fundamentals of high moisture texturization during extrusion-cooking • Main steps • protein melting (plasticising) : within the extruder • material texturization (fibration) : along the die • Flow in extruder and die during texturization • Control of texturization through control of rheological behaviour • (shear) viscosity • elasticity • visoelasticity • elongational viscosity • Correlation between on-line and off-line assessment of rheological and textural parameters • Perspectives

28. PERSPECTIVES : NEW DIES ? Breaker plates (p21)

29. BIBLIOGRAPHY • Baird D.G., 1976.Fluid elasticity measurements from hole pressure error data. J. Appl. Polym. Sci,20, pp 3155-3173. • Bhattacharya M. and Padmanabhan M., 1992. Extrusion processing : texture and rheology. In : Encyclopedia of Food and Science Technology, Hui Y.H. Ed., Willey Interscience, New York, pp 800-814. • Bhattacharya M., Padmanabhan M. and Seethamraju K., 1994. Uniaxial extensional viscosity during extrusion cooking from entrance pressure drop method. J. Food Sci., 59(1), pp 221-226, 230 • Bouvier J.M. and Gelus M., 1994. Apport des mesures en ligne à l’analyse du procédé de cuisson-extrusion. In: La Cuisson-Extrusion, Colonna P. and Della Valle G. Eds., Tec & Doc Lavoisier, Paris, pp 323-355. • Cheftel J.C., Kitagawa M. and Quéguiner C., 1992. New protein texturization processes by extrusion cooking at high moisture levels. Food Rev. Int., 8(2), pp 235-275. • Cheftel J.C., Kitagawa M. and Quéguiner C., 1994. Nouveaux procédés de texturation protéique par cuisson-extrusion à teneur élevée en eau. In: La Cuisson-Extrusion, Colonna P. and Della Valle G. Eds., Tec & Doc Lavoisier, Paris, pp 45-84. • Cheftel J.C. and Dumay E., 1993. Microcoagulation of proteins for development of "creaminess". Food Rev. Int., 9(4), pp 473-502. • Della Valle G. and Vergnes B., 1994.Propriétés thermophysiques et rhéologiques des substrats utilisés en cuisson-extrusion. In: La Cuisson-Extrusion, Colonna P. and Della Valle G. Eds., Tec & Doc Lavoisier, Paris, pp 439-467. • Harper J.M., Rhodes T.P. and Wanninger L.A., 1971. Viscosity model for cooked cereal doughs.A.I.Ch.E. Symposium Series, 676(108), pp 40-43. • Malkus D.S., Pritchard W.G. and Yao M., 1992. The hole-pressure effect and viscosimetry. Rheol. Acta, 31, pp 521-534. • Mc Master T.J., Senouci A. and Smith A.C., 1987. Measurements of rheological and ultrasonic properties of food and synthetic polymer melts. Rheol. Acta, 26, pp 308-315. • Mitchell J.R., Areas J.A.G. and Rasul S., 1994. Modifications chimiques et texturation des protéines à faible teneur en eau.. In : La Cuisson-Extrusion, Colonna P. and Della Valle G. Eds., Tec & Doc Lavoisier, Paris, pp 85-104. • Padmanabhan M. and Bhattacharya M., 1991. Flow behavior and exit pressures of corn meal under high-shear-high-temperature extrusion conditions using a slit die. J. Rheol., 35(3), pp 315-343. • Padmanabhan M. and Bhattacharya M., 1992. Rheological measurement of fluid elasticity during extrusion-cooking. Trends in Food Science and Technology, 6, 149-151. • Quéguiner C., Dumay E., Cavalier-Salou and Cheftel J.C., 1991. Application of extrusion cooking to dairy products : preparation of fat analogues by microcoagulation of whey proteins. In : Applied Food Extrusion Science, Kokini J. and al. Eds., Dekker, New York, pp 363-376. • Quéguiner C., Dumay E., Cavalier-Salou and Cheftel J.C., 1992. Microcoagulation of a whey protein isolate by extrusion cooking at acid pH. J. Food Sci., 57, pp 610-616. • Remsen C.H. and Clark J.P., 1978. A viscosity model for a cooking dough.J. Food Process Eng.,2, pp 39-64. • Ross-Murphy S.B., 1988. Small deformation measurements. In : Food Structure : its Creation and Evaluation, Blanshard J.M. and Mitchell Eds., Butterworth, London, pp 387-400. • Roussel L., 1996. Making meat products using extrusion technology. Extrusion Communiqué, nov-dec, pp 16-18. • Thiebaud M., 1995. Texturation par cuisson-extrusion de mélanges protéiques hydratés à base de surimi de poisson. Influence des paramètres opératoires et de la formulation sur les caractéristiques biochimiques et physicochimiques des extrudats. PhD. Thesis, University of Montpellier. • Tolstoguzov V.B., 1986. Functional properties of protein-polysaccharides mixtures. In : Functional Properties of Food Macromolecules, Mitchell J.R. and Ledward D.A. Eds., Elesevier Applied Science Pub., London, pp 385-415. • Vergnes B., Della Valle G. and Tayeb J., 1990. Rheopac : a new on-line rheometer with controlled feed rate to determine the viscosity of starchy products. In : Proceedings of ACoFoP2, 13-14 nov. 1990, Bimbenet J.J. and Trystram G. Eds., Paris. • Vergnes B., Della Valle G. and Tayeb J., 1993. Rheopac : a specificin-line rheometer for extruded starchy products. Design, validation and application to maize starch. Rheol. Acta, 32, pp 465-476. • White S.A, Gotsis A.D. and Baird D.G., 1987. Review of the entry flow problem : experimental and numerical. J. Non-Newtonian Fluid Mech., 24, pp 121-160. (p22)