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Cursul predat. C. Mateescu, Reologia alimentului,
Ed. Eurostampa, Timişoara, 2008 J.F.Steffe, Rheological Methods in
Food Process Engineering, Freeman Press, USA, 1996 – format pdf Internet (http://www.egr.msu.edu/~steffe/freebook/STEFFE.pdf)
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Dictionar: The study of the deformation and flow of matter. Sci-Tech Encyclopedia: that part of mechanics which deals with the relation
between force and deformation in material bodies. Food and Nutrition: Study of deformation and flow of materials; in food
technology it involves plasticity of fats, doughs, milk curd, etc. It provides a scientific basis for subjective measurements such as mouth feel, spreadability, pourability.
Medical Dictionary: The study of blood flow, pressure, and velocity through the vascular system.
Architecture: The science dealing with flow of materials, including studies of deformation of hardened concrete, the handling and placing of freshly mixed concrete, and the behavior of slurries, pastes, and the like.
Columbia Encyclopedia: branch of physics dealing with the deformation and flow of matter.
Veterinary Dictionary: The science of the deformation and flow of matter, such as the flow of blood through the heart and blood vessels.
Wikipedia: Rheology is the study of the flow of matter: mainly liquids but also soft solids or solids under conditions in which they flow rather than deform elastically
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Termenul “reologie” a fost utilizat primadata în 1929 de către Eugene Bingham, profesor la Universitatea Lehigh, la sugestia colegului său Markus Reiner. Termenul a fost inspirat din grecescul “panta rei” – totul curge, atribuit în prezent lui Simplicius.
Există păreri autorizate ce consideră că primele noţiuni de reologie au fost utlizate de către Arhimede, cu 250 ani înainte de Cristos.
Intr-un eseu publicat de dr. Deepak Doraiswamy, de la DuPont Technologies, istoricul reologiei cuprinde două perioade distincte, anul 1929 fiind cel ce desparte cele două perioade.
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Solid - deformare - elasticitate (proprietate)
La solide, deformarea se recuperează, total sau parţial
Lichid - deformare - curgere - vâscozitate (proprietate)
La lichide deformarea NU se recuperează
Fluide complexe – vâscoelastice – vâscoelasticitate (proprietate)Smântână, ketchup, sosuri, aluat, brânza moale, geluri, suspensii alimentare
Plasticitate
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Reologia studiază comportarea corpurilor care posedă cel puţin una din următoarele proprietăţi: elasticitate, vâscozitate, sau plasticitate. Preocuparea de bază a reologiei o constituie răspunsul corpurilor la solicitări mecanice, reologia putând fi definită ca ştiinţa legată de curgerea fluidelor şi deformarea materialelor (solidelor)
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Proprietăţile reologice ale materiilor prime pot fi utilizate la:- elucidarea structurii şi compoziţiei alimentelor, precum şi la
analiza modificărilor structurale care se produc în timpul procesării.
- proiectarea şi dimensionarea pompelor, conductelor, valvelor, reactoarelor, rezervoarelor
- calculul transferului termic şi masic din timpul procesării
Reologia produselor alimentare permite asigurarea controlului calitativ înainte, în timpul şi după procesul de fabricare.
Măsurătorile reologice se utilizează şi pentru a urmări modificările survenite în aliment în cursul depozitării.
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Z. Liu et al. / Acta Materialia 51 (2003) 365–371
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E.L. Sliwinski et al. / Journal of Cereal Science 39 (2004) 231–245
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Journal of Cereal Science 29 (1999) 33–42
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Fig. 1. Compression curve for dough with 0.15% a-amylase after 70 minutes of fermentation
INFLUENCE OF -AMYLASE ON RHEOLOGICAL PROPERTIES OF DOUGH
Rodica Chereji, Diana Dogaru, Despina Bordei, C. Mateescu R. Chereji, et al. Journal of Agroalimentary Processes and
Technologies, 11(1), (2005), 101-108
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Journal of Food Engineering 81 (2007) 42–53
transglutaminase (TG), alpha-amylase (AMYL), xylanase (XYL),protease (PROT)
Transglutaminases are a family of enzymes that catalyze the formation of a covalent bond between a free amine group and the gamma-carboxamid group of protein- or peptide-bound
glutamine.
α-Amylase is an enzyme that hydrolyses alpha-bonds of large alpha-linked polysaccharides such as starch
Xylanase is the name given to a class of enzymes which degrade the linear polysaccharide into xylose, thus breaking down hemicellulose.
A protease breaks down proteins. A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming
the protein.
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Effects of temperature on viscosity of dodol (concoction)Dodol is one of the very popular snack food prepared from glutinous rice flour, coconut milk and sugar, sometimes with the addition of permitted food additives.
Journal of Food Engineering 80 (2007) 423–430
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S. Shin, D.-Y. Keum / Journal of Food Engineering 58 (2003) 5–10
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0 10 20 30 40 50 60 700
5
10
15
20
25
30
35
40
She
ar s
tres
s (P
a)
Shear rate (s-1)
0 10 20 30 40 50 60 70
0.1
1
10
Sh
ear
str
ess
(Pa
)
Shear rate (s-1)
0.1 1 10
5
10
15
20
25
30
35
40
She
ar s
tres
s (P
a)
Shear rate (s-1)
0.1 1 10
0.1
1
10
Sh
ea
r st
ress
(P
a)
Shear rate (s-1)
Sunflower oil, 20°C (unpublished data)
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Density, viscosity and coefficient of thermal expansion of clear grape juice at different soluble solid concentrations and temperatures
Journal of Food Engineering 71 (2005) 143–149
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0 20 40 60 80 100 120 140 160 1800
10
20
30
40
She
ar s
tres
s (m
Pa)
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Ulei dovleac - ■ - 5°C; ● - 10°C; ▲ - 15°C; ▼- 20°C; ◄ - 25°C; ► - 30°C; □ - 40°C; ○- 50°C; Δ - 60°C; - 70°C;
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S. Yanniotis et al. / Journal of Food Engineering 72 (2006) 372–377
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Temp.(°C)
Newtonian
(Pa . s) R2
50 0.475(1) 0.99996
47.5 0.596(1) 0.99960
45 0.742(2) 0.99939
42.5 0.937(3) 0.99938
40 1.189(5) 0.99884
37.5 1.526(5) 0.99926
35 1.985(6) 0.99924
32.5 2.584(9) 0.99906
30 3.411(9) 0.99950
27.5 4.526(6) 0.99984
25 6.060(7) 0.99991
22.5 8.116(15) 0.99973
20 11.132(27) 0.99957
Miere salcam – Continut apa 18.5%
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0 500 1000 1500 2000 2500 3000 35000
20
40
60
80
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120
140
She
ar s
tres
s (P
a)
Shear rate (s-1)0 500 1000 1500 2000 2500 3000 3500
0
20
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Sh
ea
r st
ress
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a)
Shear rate (s-1)
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Journal of Food Engineering 57 (2003) 97–102
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Food Research International 32 (1999) 29-33
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Food Research International 32 (1999) 319-325
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Food Research International 34 (2001) 695–703
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Influence of salt content on viscous flow curves. (A) Emulsions stabilized by 1% egg yolk and 7% pea protein blends (starch 1%). (B) Emulsionsstabilized by 7% egg yolk and 1% pea protein blends (starch 1%).
I. Martı´nez et al. / Journal of Food Engineering 80 (2007) 1272–1281
saladdressing-type emulsions stabilized by emulsifier blends
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Typical viscosity profiles of the thickeners in the milk at 20 C.
food thickeners from guar gum, modified starch and xanthan gum in homogenised and pasteurised full cream (HPFC), skim milk (SKIM) and ultra-high temperature or ultra-heat treated full cream (UHT)
Journal of Food Engineering 84 (2008) 553–562
Rheological characterisation of food thickeners marketed in Australia in various media for the management of dysphagia.
