Rheology Solid and Liquids ·Rheology TXUT& [Greek rheos-“to flow"】is the study of deformation and Solids-Elastic:Materials that can flow of matter support a applied stress ·Name was coined by Dr. Liquids-Viscous:Materials that can Marcus Reiner instead of the more obscure not support an applied stress “continuum mechanics” (that is they flow under stress) Motto of the Society of Rheology:"Panta Rhei"or “everything flows'” after Heraclitus Pie Units of Measure ·Force (Newton) Distance (meter) ·Time(second) Liquid or derived measures Semi-Solid Stress(N/m2 or Pascals) olid ·Velocity(ml/s) Forces and Stresses Table 2.6 Forces Exerted Between Teeth (in Pounds)" Male Female Compression Tensile Subject Mean Maximum Mean Maximum 348 200 200 85 mencan (dentures) 60 "Data taken from Waugh (1937)and Klatsky (1942). Shear 1 pound=0.45 Kg 1
1 Rheology • Rheology [Greek rheos - “to flow”] is the study of deformation and flow of matter • Name was coined by Dr. Marcus Reiner instead of the more obscure “continuum mechanics” • Motto of the Society of Rheology:“Panta Rhei” or “everything flows” - after Heraclitus Solid and Liquids • Solids - Elastic: Materials that can support a applied stress • Liquids - Viscous: Materials that can not support an applied stress (that is they flow under stress) Pie Liquid Semi-Solid Solid Units of Measure • Force (Newton) • Distance (meter) • Time (second) or derived measures • Stress (N/m2 or Pascals) • Velocity (m/s) Forces and Stresses Compression Tensile Shear
Secondary parameters Table 2.3 Size Threshold Between Smooth and Grainy Texture Hardness Softfirm-hard wy-Ou Food Particle size(m) Chocolate 13 56cy+ac南→gooy Chocolate Chocolate Class Fondant(sugar crystals) 20-25 Ice cream (ice crystals) 55 Margarine(fat crystals) 22 Sweetened condensed milk(lactose crystals) 10-12 Secondary parameters Popular terms Tofu (soy particles) Dy→moi+w+wat Fat content 8 Stress Deformation-Strain Compression Compression Stress=Force/Area Ay Strain=△yy Deformation-Strain Ax Shear 门7 Shea Bcompression Shear Stress=△r/y 2
2 Stress Compression Stress = Force / Area Deformation - Strain Compression y Δy Strain = Δy/y Deformation - Strain Shear y Δx Shear Stress = Δx / y
Elastic Solids Force Measures of Texture Compression Shear Fundamental Tests-Rheology F- ·Imitative Tests ·Empirical Tests Stress=F/A=o Stress=F/A=o Strain=△y/y=8 Strain=△rIy=Y G=E8 0=GY E=Compressive Modulus G=Shear Modulus Texture Imitative Hands-on Gel Ridgelmeter Cone App山 Penetrometer Force apply force (gravit中 and (weight of cone) Measure Deformation and measure (sag of gel) deformation (distance of penetration) 3
3 Elastic Solids Δy Compression y Force Stress = F / A = σ Strain = Δ y/ y = ε σ= E ε E = Compressive Modulus Δx F Shear y Stress = F / A = σ Strain = Δx / y = γ σ= G γ G = Shear Modulus Measures of Texture • Fundamental Tests - Rheology • Imitative Tests • Empirical Tests Imitative Texture Hands-on Cone Penetrometer apply force (weight of cone) and measure deformation (distance of penetration) Gel Ridgelmeter Apply Force (gravity) and Measure Deformation (sag of gel)
Christel Warner Bratzeler Texturometer Applies Cutting Deformation and Measures Apply Forces Deformation And measure Force Armour Tenderometer Warner Bratzeler for meat tenderness General Foods Texturometer First attempt at a Imitative, General Empirical, Foods and Fundamental Texturo Test for Texture meter Evaluation ￥
4 Christel Texturometer Apply Deformation And measure Force Warner Bratzeler Applies Cutting Deformation and Measures Forces Warner Bratzeler Armour Tenderometer for meat tenderness General Foods Texturometer First attempt at a Imitative, Empirical, and Fundamental Test for Texture Evaluation General Foods Texturo meter
Use different Texturometer fixtures for either Imitative, Empirical, and Fundamental Tests Texture Profile Analysis Instron (TPA) Universal combination of Testing Imitative, Machine Empirical, and Fundamental Types of Rice Grains 6 Long Medium Short Waxy (N) 4 000 3 L-204 M-202 Koshihikari Calmochi-101 Increasing Amylose Content 2 DESPLAZAMIENTO (mm) 5
5 Texturometer Use different fixtures for either Imitative, Empirical, and Fundamental Tests Instron Universal Testing Machine Texture Profile Analysis (TPA) combination of Imitative, Empirical, and Fundamental L-204 M-202 Koshihikari Calmochi-101 Long Medium Short Waxy
Preparation of Cooked Preparation of cooked rice Rice Weigh 10g rice in a 50 ml beaker 50 ml beaker Rinse rice 3 times with 3 volume tap water x1.0.12.4.1.6w Soak rice with 1.0 to 1.6 weight to rice at room temperature(22~24C) Cook rice with a rice cooker for 10 min Steam rice in the rice cooker for 20 min 8 10 g sample rice Cool rice for 40 min at room temperature Cook 10 min Steam 20 min Cool 40 min Uniaxial Compression Test Volume of cooked rice At 0.5 mm/sec distance/0.75 X compression→stop→extension πd2 75% Time(s) Long grain rice (10g) Short grain rice(10g) Cooked with Cooked with 10gH20 10gH20 12gH0 12gH,0 14gH20 14gH20 16gH0 16gH20 6
6 Preparation of cooked rice • Weigh 10g rice in a 50 ml beaker • Rinse rice 3 times with 3 volume tap water • Soak rice with 1.0 to 1.6 weight to rice at room temperature (22 ~ 24 °C) • Cook rice with a rice cooker for 10 min • Steam rice in the rice cooker for 20 min • Cool rice for 40 min at room temperature Preparation of Cooked Rice 10 g sample rice 50 ml beaker water x1.0, 1.2, 1.4 , 1.6w Cook 10 min Steam 20 min Cool 40 min start extension end compression stop Time (s) 75% Uniaxial Compression Test 0 10 20 30 40 50 60 8000 7000 6000 5000 4000 3000 2000 1000 0 -1000 Fuerza (g) Tiempo (sec.) 75% compression At 0.5 mm/sec Volume of cooked rice = distance/0.75 X π d2 0 10 20 30 40 50 60 70 12000 10000 8000 6000 4000 2000 0 -2000 Fuerza (g) Tiempo (sec.) Long grain rice (10g) Cooked with 10g H2O 12g H2O 14g H20 16g H2O 0 10 20 30 40 50 60 70 7000 6000 5000 4000 3000 2000 1000 0 -1000 Fuerza (g) Tiempo (sec.) Short grain rice (10g) Cooked with 10g H2O 12g H2O 14g H20 16g H2O
Waxy grain rice(10g) Cooked rice(10g) Cooked with with H2O(10g) 10gH20 Waxy 12gH20 Long 14gH20 Short 16gH20 Comparison of Delta Ebro Japanese short grain Valencia 10g一16g and 10g rice Spanish short grain 12 g Water 10g-16g 3 Abstract TPA Definitions n several com tries,Cali Australia.and Rice Experi 夏夏1g旦 Hardness Stringiness Time Adhesiveness Balance=Stickiness/Hardness Modified Balance =Adhesiveness /Toughness 7
7 0 10 20 30 40 50 60 70 80 10000 8000 6000 4000 2000 0 -2000 Fuerza (g) Tiempo (sec.) Waxy grain rice (10g) Cooked with 10g H2O 12g H2O 14g H20 16g H2O 10 15 20 25 30 35 40 45 50 12000 10000 8000 6000 4000 2000 0 -2000 Fuerza (g) Tiempo (sec.) Cooked rice (10g) with H2O (10g) Waxy Long Short 0 20 40 60 80 100 5000 4000 3000 2000 1000 0 -1000 Fuerza (g) Tiempo (sec.) Delta Ebro Valencia 10g rice 12 g Water 0 10 20 30 40 50 60 70 80 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 -1000 Fuerza (g) Tiempo (sec.) Comparison of Japanese short grain 10g 16g and Spanish short grain 10g 16g Abstract Koshihikari was obtained from several countries, California-USA, Australia, and Uruguay. California Koshihikari was supplied from the California Rice Experiment Station. Australia and Uruguay Koshihikari were obtained at the Foodex Japan '98. California medium grains, M-202 and M-401, were also supplied from the California Rice Experiment Station as references. Ten single rice kernels from each cooking water ratio were tested by uni-axial compression test using a Tensipresser. Hardness, stickiness, toughness, and adhesiveness were obtained from the test. Hardness and toughness were defined as maximum force and work done to compress a cooked rice kernel. Stickiness and adhesiveness were defined as maximum force and work done to separate compressed rice kernel from a sample probe. Balance*, the ratio of stickiness to hardness, has been commonly used as the index of cooked rice texture in Japan. A modified balance is defined as the ratio of adhesiveness and toughness and was used to differentiate the texture of cooked Koshihikari samples. * Okabe, M.: Texture measurement of cooked rice and its relationship to the eating quality. Journal of Texture Studies 10 (1979) 131-152. TPA Definitions start compress stop extend stop Hardness Stickiness Force Time Stringiness Toughness Adhesiveness Work done = Force X Time Balance = Stickiness / Hardness Modified Balance = Adhesiveness / Toughness
Textural differences among Materials cooked Koshihikari harvested Koshihikari (Japanese premium short grain) from different countries .California:Califomia Rice Experiment Station97 .Australia:the Foodex Japan98(harvested97) Uruguay:the Foodex Japan98(harvested97) M-202 (California medium grain,Calrose) .California:Califomia Rice Experiment Station97 .M-401(California premium medium grain) California:California Rice Experiment Station'97 Rice Grain Starch Granules +Granules of Glucose Polymers amylopectin and amylose .Size-5um to 50um Crystalline and Amorphous regions 6mm Amylopectin .Highly Branched Amylose Glucose Polymer .Linear Glucose Polymer .Main Component of Starch .Smaller Component of Starch -MW-107to109 .MW -105 to 106 8
8 Textural differences among cooked Koshihikari harvested from different countries Materials • California: California Rice Experiment Station ‘97 • Australia: the Foodex Japan ‘98 (harvested ‘97) • Uruguay: the Foodex Japan ‘98 (harvested ‘97) X Koshihikari (Japanese premium short grain) X M-202 (California medium grain, Calrose) X M-401 (California premium medium grain) • California: California Rice Experiment Station ‘97 • California: California Rice Experiment Station ‘97 6 mm •Granules of Glucose Polymers amylopectin and amylose •Size - 5µm to 50µm •Crystalline and Amorphous regions R ci e 10µm •Highly Branched Glucose Polymer •Main Component of Starch •MW - 107 to 109 •Linear Glucose Polymer •Smaller Component of Starch •MW - 105 to 106
Amylose content(%) dW/d logM Differential M.W.Distribution 4.0 (Concanavalin A method) Koshihikari 14.8 3.0 光 M202 M-202 16.8 2.0 Koshihikari 84 M-401 17.5 1.0 1.0e+7 1.0e+8 1.0a+9 M(g/mol) dw/d logM Differential M.W.Distribution 20 Instrument Rice Mw l M40172 15 Tensipresser(Model:My Boy) M202 61 Koshihikari 84 10 Calmochi 174 5 010e7 1.0e+8 1.0e+9 M(g/mol) Balance of Koshihikari and Definitions Medium Grains 夏11夏且 4h after cooking 24h after cooking Work dane Feree X Time Hardness Toughnes8一 20 Stringiness Time Stickiness Adhesiveness Balance=Stickiness/Hardness Modified Balance Adhesiveness/Toughness California Australia Uruguay M-202CAM-401,CA Koshihikari Medium grains一 9
9 Amylose content (%) (Concanavalin A method) Koshihikari M-202 M-401 14.8 16.8 17.5 1.0e+7 1.0e+8 1.0e+9 M (g/mol) 1.0 2.0 3.0 4.0 dW/d logM Differential M.W. Distribution Rice Mw M401 72 M202 61 Koshihikari 84 1.0e+7 1.0e+8 1.0e+9 M (g/mol) 0 5 10 15 20 dW/d logM Differential M.W. Distribution Rice Mw 106 M401 72 M202 61 Koshihikari 84 Calmochi 174 Instrument X Tensipresser (Model: My Boy) Definitions start compress stop extend stop Hardness Stickiness Force Time Stringiness Toughness Adhesiveness Work done = Force X Time Balance = Stickiness / Hardness Modified Balance = Adhesiveness / Toughness Balance of Koshihikari and Medium Grains Balance 0.00 0.05 0.10 0.15 0.20 0.25 0.30 California Australia Uruguay M-202, CA M-401, CA 4h after cooking 24h after cooking Koshihikari Medium grains
Modified Balance of Koshihikari and Medium Grains Conclusions ☐4 h after cooking ☐24 h after cooking 0.30 Modified balance,which is defined as the ratio of 0.25 adhesiveness and toughness,could differentiate the 0.20 texture of cooked Koshihikari samples from different countries. 0.05 Modified balance could express the texture changes due to the storage after cooking California Australia Uruguay M-202,CA M-401.CA appropriately. Koshihikari Medium grains' Evaluating Methods Goals ·Sensory test -Subjective To clarify differences of cooked rice texture -Time-consuming among California rice varieties. -Fluctuating Instrumental test To determine factors influencing cooked -Objective rice texture -Easy operation -Reproducible To establish methods to control quality of cooked rice texture. Materials Maximum Stress Medium grains (size 5.51~6.60 mm) 1.0 - M-202 Extension Volume of Work Done Cooked Rice -M-401 Short grains (size up to 5.50 mm) -Koshihikari Stringiness Compression -Akitakomachi Ratio Work Done -S-102 Minimum Stress All varieties were harvested in 2001 and 2002 at the California Rice Experiment Station in Biggs. Koshihikari01vs.‘02 California. 01==02 10
10 Modified Balance of Koshihikari and Medium Grains 0.00 0.05 0.10 0.15 0.20 0.25 0.30 California Australia Uruguay M-202, CA M-401, CA Modified Balance 4h after cooking 24h after cooking Koshihikari Medium grains Conclusions Õ Modified balance, which is defined as the ratio of adhesiveness and toughness, could differentiate the texture of cooked Koshihikari samples from different countries. Õ Modified balance could express the texture changes due to the storage after cooking appropriately. Evaluating Methods • Sensory test – Subjective – Time-consuming – Fluctuating • Instrumental test – Objective – Easy operation – Reproducible Goals • To clarify differences of cooked rice texture among California rice varieties. • To determine factors influencing cooked rice texture. • To establish methods to control quality of cooked rice texture. • Medium grains (size 5.51~6.60 mm) – M-202 – M-401 • Short grains (size up to 5.50 mm) – Koshihikari – Akitakomachi – S-102 All varieties were harvested in 2001 and 2002 at the California Rice Experiment Station in Biggs, California. Materials Koshihikari ‘01 vs. ‘02 Extension Work Done 0.0 0.5 1.0 1.5 Maximum Stress Volume of Cooked Rice Compression Work Done Minimum Stress Stringiness Ratio ’01 ’02
