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Copy of Copy of HY-white 0.1.1
Transcript of Copy of Copy of HY-white 0.1.1
M.Sc. Food Science
Cereal Technology Group
and Zhongqing Jiang
Oat protein fraction used in experiment
UNIVERSITY OF HELSINKI
Faculty of Agriculture and Forestry/Weijing Wu/Gelling properties of oat protein deamidated by by protein glutaminase
Design and Methods
Gelling properties of oat protein deamidated by protein glutaminase (PG)
Oat (Avena Sativa)
Food products of oat
Oat grain bar
Quick oat porridge
Characteristics of oat products
(1) Based on starch and beta-glucan
(2) Low protein concentration
Nutritional value of oat protein
* High content (15-20%)
*Balanced amino acid content
*Digestibility ≈ 90%
*Biological value ≈75%
Protein glutaminase (PG)
>A novel enzyme
>Safe for food application.
PG on oat protein functionalities
Yogurt protein gel
Cow or soy Milk+Lactic acid bacteria(LAB)
Acid-induced protein gel
Cow milk yogurt
Fig. Process flow chart of oat dry fractionation
of beta-glucan concentration
Native oat protein
Evaluation of gel
Gel structure properties
Rheology describes the
of a body under
Cone-and-plate sensor system
Upward curve : thinning under increasing shear rate
Orientation of flow > Brownian movement of molecules
Processing of yogurt
Protein Gel in food
pH ≈ pI
Fermentation until pH 4.3-4.8
Addition of starter
Change of protein
Fig. Deformation of solid body
Weak bonds: hydrogen bond and ionic bond
Thixotropic liquid is defined
of gel structure.
Protein gel structure in common in food.
Egg protein gel
a certain degree of order
and whey protein
solid-like gel characteristic
>Physical and chemical properties
Good for human health
Composition of oat protein
Analysis of dynamic oscillation
No damage to gel structure
(1)If G’ >G’’ in different frequency sweep, it represents the solid-like properties.
(2) The higher value of G', the stronger gel is.
Continuous shear flow test (Rotation)
Scanning electron microscope (SEM)
Example: microscopy picture of yogurt
Microstructure of yogurt
Protein gel network
Thanks for your attention.
Oat globulin 110 C
Oat albumin 87 C
Rice : 73-82 C
Soybean: 78-90 C
Red bean: 82-92 C
Other grain protein
Wheat: 70 C
pI = pH 4-6
Protein solubility at neutral condition (pH 7)
Bad Foaming properties!
(1) to study
of PG deamidated oat protein;
(2) to study
made of PG deamidated oat protein
Thermal coagulated of oat globulin (Ma and Harwalkar, 1987)
Gelling properties of oat protein
Master Thesis Schedule
Alfonso Totosaus, Jose G. Montejano, Juan A. Salazar and Isabel Guerreo. (2002). A review of physical and chemical protein-gel induction. International Journal of Food Science and Technology(37): 589-601.
Anne Saint-Eve, Alexandre Juteau, Samuel Atlan, Nathalie Martin, and Isabelle Souchon. 2006. Complex viscosity induced by protein compostion variation influences the aroma release of flavored stirred yogurt. J. Agric. Food Chem.(54):3997-4004.
C, -Y. MA. 1983.Chemical characterization and functionality assessment of protein concentrates from oats. Cereal Chem. 60 (1): 36-42.
Ching-Yung Ma, Ghanikhan Khanzada, and Ventesh R. Harwalkar. 1988. Thermal Gelation of Oat Globulin. J. Agric. Food. Chem. (36): 275-280
Franzen KL, Kinsella JE. 1976. Functional properties of succinylated and acetylated soy protein. Journal of agricultural and food chemistry. (4):788-95.
Gebhard Schramm. 1998.A Practical Approach to Rheology and Rheometry. Gebrueder HAAKE GmbH, Karlsruhe, Federal Republic of Germany.
Mirmoghtadaie L, Kadivar M, Shahedi M. 2009. Effects of succinylation and deamidation on functional properties of oat protein isolate. Food Chem. 114(1):127-31.
O. Sandoval-Castilla, C. Lobato-Calleros, E. Aguirre-Mandujano, E.J. Vernon-Carter. 2004. Microstructure and texture of yogurt as influenced by fat replacers. International Dairy Journal (14): 151-159.
Peterson M. David. 1978. Subunit structure and composition of Oat Seed Globulin. Plant Physiol(62): 506-509.
Y.H. Cho, J.A. Lucey, H. Singh.1999- Rheological properties of acid milk gels as affected by the nature of the fat globule surface material and heat treatment of milk. 9(8):537-545.
(Mirmoghtadaie et al. 2009)
(Franzen and Kinsella, 1976)
(Zhongqing Jiang Master Thesis, 2012)
(Saint-Eve et al. 2006)
(Totosaus et al., 2002)
(Adjusted from Lee and Lucey, 2010)
(Adjust from Cho, 1999)
Fig. Shear stress changes as a function of shear rate
(From Mavern Instruments Limited)
Oscillate back and forward
Soy protein has also good gelling capacity.
> Good for health
per 100 g
Example: oat milk
per 100 ml
(Hoseney, 1994&Ma, 1983)
High temperature. Hard gel. Difficult to compare.
Lack of knowledge!
Protein glutaminase (PG)
Useful to reveal the gel structure