Bài giảng Chất keo thực phẩm - Mạc Xuân Hòa

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CHẤT KEO THỰC PHẨM
(Food hydrocolloids)
Giảng viên: Mạc Xuân Hòa
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
3. Modification
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
3. Modification
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Hydrocolloids
 Hydrocolloids are a heterogeneous group of long chain
polymers (polysaccharides and proteins) characterised
by their property of forming viscous dispersions and/or
gels when dispersed in water.
 The foremost reason behind the ample use of
hydrocolloids in foods is their ability to modify the
rheology of food system. This includes two basic
properties of food system namely, flow behaviour
(viscosity) and mechanical solid property (texture) 
to modify its sensory properties.
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Kích thước cấu tử hòa tan
Dung dịch 1 pha
(<10-6 mm )
Dung dịch keo
(10-4 - 10-6 mm )
Huyền phù
(1 - 10-2 mm )
pH
Nhiệt độ
Lực ion,
Đông 
tụ
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Nguồn gốc
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Functional properties
• Thickening (basic)
• Gelling (basic)
• Emulsifying 
• Controlling the crystal growth of ice and sugar
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
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 Thickening agent/Thickener
 Gelling agent
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
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 Thickening agent/Thickener
 Gelling agent
Thickening agents
 A thickening agent or thickener is a substance
which can increase the viscosity of a liquid
without substantially changing its other
properties.
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Examples of food products containing hydrocolloids
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Soups GraviesSalad dressings
Sauces Toppings
Process of thickening
In dilute dispersion, the individual molecules of
hydrocolloids can move freely and do not exhibit
thickening. In concentrated system, these
molecules begin to come into contact with one
another; thus, the movement of molecules
becomes restricted. The transition from free
moving molecules to an entangled network is the
process of thickening.
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Factors effecting thickening properties
 Molecular weight
 Concentration
 Shear rate
 Temperature,
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 M: the molecular weight
 K, α: the parameters of Mark-Houwink equation
Mark-Houwink equation
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The critical overlap concentration C*
 The polysaccharide concentration at which the
sharp change in viscosity occurs is referred to as the
critical overlap concentration and is denoted by C*.
 Polysaccharide dispersions below C* will typically
exhibit near Newtonian steady shear flow and the
increase in the viscosity of the dispersion is roughly
proportional to the number of molecules present.
Above C* entanglement dispersion networks will
exhibit shear thinning meaning that apparent
viscosity decreases with increasing shear rate.
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Khi C>C* độ nhớt (viscosity) và tốc độ cắt (shear rate) có
quan hệ như dạng đường cong ở trên.
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Shear thining
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At low shear rates, solutions of xanthan gum have approximately 15 times the
viscosity of guar gum and significantly more viscosity than carboxymethylcellulose
(CMC) or sodium alginate which accounts for its superior performance in stabilising
suspensions.
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Amylose will have a higher intrinsic viscosity
than amylopectin.
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Regulations
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Xanthan Gum
(E415)
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XANTHAN GUM
 Nguồn gốc
 Cấu tạo hóa học
 Tính chất
 Ứng dụng
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XANTHAN GUM
 Nguồn gốc
 Cấu tạo hóa học
 Tính chất
 Ứng dụng
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Nguồn gốcXANTHAN GUM
 An extracellular polysaccharide secreted by the
bacterium Xanthomonas campestris.
 Xanthan gum is produced from a pure culture of
the bacterium by an aerobic, submerged
fermentation process.
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XANTHAN GUM
 Nguồn gốc
 Cấu tạo hóa học
 Tính chất
 Ứng dụng
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Cấu tạo hóa họcXANTHAN GUM
Xanthan gum is a linear (1 
4) linked β – D - glucose
backbone (as in cellulose) with
a trisaccharide side chain on
every other glucose at C-3,
containing a glucuronic acid
residue linked (14) to a
terminal mannose unit and
(12) to a second mannose that
connects to the backbone.
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XANTHAN GUM
 Nguồn gốc
 Cấu tạo hóa học
 Tính chất
 Ứng dụng
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Tính chấtXANTHAN GUM
Xanthan gum is widely used as a rheology control
agent for aqueous systems: Increasing viscosity
(thickening)
 Stabilizing emulsions
 Preventing the settling of solids
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Tính chấtXANTHAN GUM
 The viscosity and yield value of compositions containing the gum will
not change significantly between ambient temperature and 60°C.
 Xanthan gum provides the same thickening, stabilizing and
suspending properties during long-term storage at elevated
temperature as it does at ambient conditions.
 It imparts excellent freeze/thaw stability to most compositions.
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Tính chấtXANTHAN GUM
Complex aggregates, with weak intermolecular forces
 High viscosity at low shear rates (suspension stabilising
properties)
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At low shear rates, solutions of xanthan gum have approximately 15 times the
viscosity of guar gum and significantly more viscosity than carboxymethylcellulose
(CMC) or sodium alginate which accounts for its superior performance in stabilising
suspensions.
Tính chấtXANTHAN GUM
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Tính chấtXANTHAN GUM
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Tính chấtXANTHAN GUM
The viscosity remains nearly constant
between pH 2 and pH 12
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Tính chấtXANTHAN GUM
Synergistic Effect
Xanthan gum có có hiệu ứng “hiệp đồng” với các
chất keo sau:
 Guar gum
 Locust bean gum
 Cassia gum
 Konjac mannan
 Tăng khả năng làm dày
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XANTHAN GUM
 Nguồn gốc
 Cấu tạo hóa học
 Tính chất
 Ứng dụng
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Ứng dụngXANTHAN GUM
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Introduction
• Stabilizer gums are used to improve the
texture, increase the firmness and prevent
syneresis in yogurt. This is important to
help maintain good textural and visual
properties during transportation and
storage.
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Introduction
Xanthan is used widely in the food industry because it has:
 Solubility in hot or cold water,
 High viscosity at low concentrations,
 Little variation in viscosity with changing temperature,
 Excellent solubility and stability in an acid system,
 Unique rheological properties that provide high viscosity
under low shear and low viscosity under high shear,
 Excellent compatibility with a wide range of salts,
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Objectives
• To determine the influence of laboratory-
produced xanthan gum either singly or in
combination with other gums on the
rheological properties of yogurt and soy
yogurt during refrigerated storage.
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Method: Preparation of yogurt
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Cow's 
milk
Treat ment I
0.005% All treatments were heated to 90 °C for 10 min and
rapidly cooled to 42 °C, inoculated with 2% yogurt
starter, and were then distributed into 120 ml plastic
cups and incubated at 42 °C until a uniform
coagulum was reached (3 - 5h depending on the
type of milk). The yogurt and soy yogurt cups were
then transferred to refrigerated storage and
analyzed after 1, 5 and 10 days of storage for their
chemical, microbiological, rheological,
microstructural and sensory properties.
Treat ment II
Treat ment III
Treat ment I
0.01%Treat ment II
Treat ment III
Soy 
milk
Treat ment I
0.005%Treat ment II
Treat ment III
Treat ment I
0.007%Treat ment II
Treat ment III
Treat ment I: Xanthan gum
Treatment II: Xanthan gum + CMC
Treatment III: Xanthan gum + locust bean gum + guar gum
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Method: Rheological properties
• Viscosity:
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Method: Rheological properties
• Curd tension:
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Method: Rheological properties
• Syneresis:
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Syneresis of yogurt and soy yogurt was determined
by measuring the volume of separated whey
(milliliters whey/50 g yogurt). The amount of free
whey collected after 30 min at room temperature
(25±1 °C) was taken as the index of syneresis.
 The viscosity values of cows’ milk yogurt
or soy milk yogurt during the fermentation
period were affected by the type and
concentration of stabilizer used.
 These values increased markedly using
gum either singly or in combination with
other gums.
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Results: 
Viscosity of yogurt and soy yogurt during fermentation
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Results: 
Viscosity of yogurt and soy yogurt during fermentation
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Results: Curd tension
• The use of xanthan gum or its mixtures at mentioned
concentration rates markedly increased the curd tension
of yogurt as compared to the control when fresh and
during storage. This increase may be attributed to the
interaction between the gum and the milk portion.
• Yogurt: treatment (I) with xanthan gum at a
concentration of 0.01% exhibited the highest curd
tension.
• Soy yogurt: the addition of xanthan gum at a
concentration of 0.005% (Treatment I) resulted in the
highest curd tension of soy yogurt
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Results: Syneresis
• No syneresis was found with xanthan gum
at a concentration of 0.005% when fresh
or during storage (in both yogurt and soy
yogurt).
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
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 Thickening agent/Thickener
 Gelling agent
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Gels are
 A three-dimensional network that traps or
immobilizes water within it to form a rigid
structure
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Gels are
 A form of matter intermediate
between solid and liquid and show
mechanical rigidity.
 A viscoelastic system with a ‘storage
modulus’ (G′) larger than the ‘loss
modulus’ (G″).
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Rheology of gels
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What is  ? Phase angle
Solid-like 
Fluid-like 
Deformation tests: Oscillatory rheometer 
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  = 0 tan = 0: G” = 0
 Solid
  = /2 tan = : G’ = 0
 Fluid
 0 <  < /2 0 < tan < 
 Viscoelastic material
 Gel is a viscoelastic material with G’ > G’’
 We can measure G’ and G’’ by using a Oscillatory
rheometer
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Silly putty
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Which one is stronger ?
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Which one is stronger ?
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Process of gelling
• The formation of gel is the phenomenon
involving the association of the polymer
chains to form a three-dimensional
network that traps or immobilizes water
within it to form a rigid structure.
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Process of gelling: physical association 
 Hydrogen bonding
 Hydrophobic association
 Cation mediated cross-linking
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Junction
zones
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Process of gelling: ‘junction zones’
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• Type of hydrocolloids
• Concentration of Gelling Agent
• Conditions at which “junction zones” can
be formed: temperature, ionic strength,
high pressure,
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CONDITIONS OF GEL FORMATION
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Type and Concentration of hydrocolloids
• Not all hydrocolloids can form gel. Gel
formation only occurs above a critical
minimum concentration, C∗.
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Conditions at which “junction zones” can
be formed:
 Temperature (low or high): agar, gelatin,..
 Ionic strength: alginate, LM pectin, or
carrageenan,..
 pH: HM pectin
 High pressure
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Conditions at which “junction zones” can be
formed:
 Temperature: agar, gelatin,..
 Ionic strength: alginate, pectin, or
carrageenan,..
 pH
 Pressure
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Một số loại chất keo tạo gel khi làm lạnh
(agar, gelatin, pectin, tinh bột,)
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Thermoreversible gels: agar, gelatin,
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GELATIN
Cooling
Sol
Heating (35–40ºC): ‘melt in the mouth’
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AGAR
Gelling temperature: around 380C
Melting temperature: around 850C
Gelling concentration: between 0,5 – 2%
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Conditions at which “junction zones” can be
formed:
 Temperature: agar, gelatin,..
 Ionic strength: alginate, pectin, or
carrageenan,..
 pH
 Pressure
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Low Methoxyl Pectin
DUNG DỊCH GEL
Ca2+
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Alginate gel 
formation
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Conditions at which “junction zones” can be
formed:
 Temperature: agar, gelatin,..
 Ionic strength: alginate, pectin, or
carrageenan,..
 pH
 Pressure
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High Methoxyl Pectin
DUNG DỊCH GEL
(hydrogen bonds)
65% chất khô
H+
[Pectin] = 0,5-1%
 Đường có khả năng hút ẩm giảm mức độ
hydrat hóa của phân tử pectin trong dung dịch;
 H+ trung hòa bớt các gốc COO- làm giảm độ
tích điện của các phân tử;
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Making Jam
Cooling
Conditions at which “junction zones” can be
formed:
 Temperature: agar, gelatin,..
 Ionic strength: alginate, pectin, or carrageenan,..
 pH
 High pressure (a single process or in
combination with increased temperature):
usually applied to form protein gels
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Keywords
 Rapeseed
 Protein isolate
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Bodybuilder
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Introduction
• Heat and high pressure can improve
gelation propertie of food protein:
increased exposure of hydrophobic and
sulfhydryl (SH) groups (structure
modification).
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Introduction
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• The effect of high pressure-induced
modification depends on the protein
system, the treatment temperature,
the protein solution conditions, and
the magnitude and duration of the
applied pressure.
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Introduction
• The objectives of this study are to
determine the effects of high temperature
or HP processing on protein gelation with
relationships to free sulfhydryl content,
surface hydrophobicity,
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Method: HP and Heat Processing
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 1 % (w/v) RPI slurry was prepared in 50mMTris–
HCl buffer (pH 7.5) with stirring at 4 °C for 12 h.
 For HP treatment, the RPI slurrywas sealed in a
polyethylene bag and then subjected to a 4-l HP
reactor unit equipped with temperature and
pressure regulation as transmitting medium of
water, followed by freeze-drying and storage at
−20 °C until needed for further analysis.
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Method: Design of experiment
• Trial 1: HP was operated at 200, 400, and
600 MPa for 15 min each while the
temperature was kept at 25 °C.
• Trial 2: the RPI slurry was heated in a
water bath at 60, 80, and 100 °C for 15
min.
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Method: Determination of responses
 Free Sulfhydryl Content (M/g protein)
 Surface Hydrophobicity (So)
 Gelation properties: least gelation
concentration (LGC), Hardness (N), .
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Results: 
Free Sulfhydryl Content (M/g protein)
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200 MPa: a significant (p<0.05)
increase, which probably reflects
pressureinduced exposure of
inaccessible thiol groups buried
within the hydrophobic interior.
400 – 600 MPa: a progressive
decrease in free SH groups, which
may be due to formation of disulfide
bonds as pressure-induced protein–
protein interactions intensified.
Heat had stronger effects on Free
Sulfhydryl Content when compared
to HP treatments
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Results: 
Surface Hydrophobicity (So) 
So of RPI was significantly (p<0.05) increased
following HP and thermal treatments, which
suggests that the native protein had a higher
degree of globular (folded) structure when
compared to the treated samples.
The higher protein unfolding efficiency of HP
treatment may be due to the effective ability to
disrupt hydrogen bonds that hold proteins in a
folded state.
HP had a stronger effect on Surface
Hydrophobicity (So) when compared to Heat.
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Results: 
Gelation properties
LGC of RPI was significantly (p<0.05)
decreased from 15 to 6 % by HP
treatment, while heat treatment
decreased LGC from 15 to 10 %.
The unfolded proteins are then able to
interact through hydrophobic bonding to
increase strength of resultant gel
networks and reduce amount of proteins
required to form the gel, i.e., decreased
LGC.
Conclusions
• Overall, pressure treatments (200–600
MPa) were better than heat treatments
(60–100 °C) to modify the structure and
improve gelation properties of RPI.
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Jam
Jelly
Confectionery
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Other Applications
 Surface activity and emulsifying properties
 Hydrocolloids as edible films and coatings
 Hydrocolloids as fat replacers
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NỘI DUNG
1. Giới thiệu chung về chất keo
2. Một số chất keo sử dụng làm phụ gia TP
3. Modification
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Why do we modify food hydrocolloids ? 
• Some native hydrocolloids have often
been reported to present a number of
undesired properties, including is
insolubility in cold water, crumbling after
heating, and loss of viscosity,
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Starch
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Cấu tạo hóa họcTINH BỘT
Hydrogen bonds 104
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Rheological propertiesSTARCH
Heating Cooling
Reassociation 
of Amylose
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Three categories of digestible starches are distinguished
by the rate at which glucose is formed and absorbed in the
blood
 Rapidly digestible starches (RDS) are hydrolysed in the
small intestine within the first 20 min of digestion.
 Slowly digestible starches (SDS) acquire more time to
degrade.
 Resistant starch (RS) generally escapes digestion in the
small intestine and passes through the large intestine as
dietary fiber for fermentation by bacteria, where it helps
to maintain colon health and protect against disease
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Starch modificatiion
• Starch modifications are a means of altering
the structure and affecting the hydrogen
bonding in a controllable manner to enhance
and extend their application. The alterations
take place at the molecular level, with little or
no change taking place in the superficial
appearance of the granule. Therefore, the
botanical origin of the starch may still be
identified microscopically
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Hạt tinh bột khoai tây ở thời điểm trước và sau biến 
tính bằng enzyme amylase
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Biến tính tinh bột
(Starch modification)
TINH BỘT
 Phương pháp vật lý
 Phương pháp hóa học
 Phương pháp hóa sinh (enzyme)
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Biến tính tinh bột
(Starch modification)
TINH BỘT
 Phương pháp vật lý
 Phương pháp hóa học
 Phương pháp hóa sinh (enzyme)
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp vật lý: Tiền hồ hóa (Pre-gelatinisation)
 Mục đích: pregelatinisation is designed to remove the
necessity for cooking.
 Phương pháp: tinh bột ban đầu được hồ hóa trong một
lượng thừa nước, sau đó sấy để tách ẩm.
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Drum Drying
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Production of pre-gelatinized wheat starch
Wheat starch was first dispersed in cold water (10%
w/w, starch in water), then, it was dried using a twin
drum drier (Model Benton Harbor, USA) at drum speed
of 5 rpm, steam pressure of 5 bar, clearance between
the drums of 0.4 mm and the surface temperature was
158 °C. The dried starch sheet with moisture content
of 7.3% ± 0.2 (dry weight basis) was milled using a
laboratory mill and then sieved to obtain a powder with
particle size of 150-250 μm. The PGS was packed in
polyethylene bags and stored at room temperature for
further experiments.
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Twin Drum Drier
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Pre-gelatinized Wheat Starch
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Pre-gelatinized Wheat Starch
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Pre-gelatinized Wheat Starch
A cold water viscosity of 3833 centi Poise (cP) was observed for PGS at 25 ºC, while
no peak was seen for the native starch at this temperature. For the latter, a peak
viscosity of 2011 cP was observed at 95 ºC when the sample was held for 11 min.
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 The PGS had the ability to increase the
viscosity at temperatures below
gelatinization temperature of native starch.
At high temperatures, however, the native
starch was able to increase the viscosity.
 Moreover, if PGS is heated and then
cooled down, it produces lower final
viscosity than native starch.
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Pre-gelatinized Wheat Starch
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Keywords
Imitation cheese
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Keywords
Imitation cheese
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Imitation (analogue) cheese products may be classifed as
cheese substitutes or imitations, which partly or wholly
substitute or imitate cheese and in which milk fat, milk protein
or both are partially or wholly replaced by non-milk-based
components, principally of vegetable origin.
Ingredients such as rennet casein, vegetable oils or fats,
salts, acids and Xavourings are generally used in the
manufacture of imitation cheese.
Rennet casein: Due to its high cost, considerable eVort has
been vested in the partial replacement of casein with
cheaper ingredients, of which, starch has been the most
effective low-cost casein substitute
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Objectives
• The objective of this study is to investigate
the eVects of pre-gelatinised starches on
the rheology, meltability and
microstructure of imitation cheese.
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Materials & methods: imitation cheese 
Water 48%
Renet casein/PG starch 24.5%
Vegetable fat 26%
Emusifying salt (trisodium citrate,
citric acid, disodium phosphate) 2.18%
Sodium chloride 1.67%
Sorbic acid 0.1%
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Control
PG maize 
PG waxy maize 
PG wheat
PG potato
PG rice
Rennet casein
replacing 15%
of the rennet
casein by PGS
 Micro-structure
 Melt 
 Hardness
 Dynamic rheology
 Viscosity
Results
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Micro - structure
PGS had poorer fat emulsification. Imitation
cheese products containing pre-gelatinized
starches had larger fat globule size distributions
(especially rice or waxy-maize starch).
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The G’ of all products
decreased signiWcantly (P ·
0.05) with increasing
measuring temperature from
22 to 85 °C, due to melting of
the vegetable fat and
softening of the protein
matrix.
Imitation cheese containing
potato starch had the highest
G’ values in the temperature
ranges 55–85 °C, which was
possibly due to extensive
starch retrogradation
impeding the Xow of casein.
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All products containing
starch had significantly
lower tan values at 22 °C
(ranging from 0.36 - 0.02
for waxy-maize to 0.42 -
0.013 for rice starch-
containing imitation
cheese) compared to the
control imitation cheese
(0.44 - 0.012), indicating
more elastic (less
viscoelastic) structural
behaviour compared to the
control.
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The replacement of 15% of the protein in the
dispersions with pre-gelatinised starches
resulted in increases in apparent viscosity in
the order rice starch (26.3 - 1.2 mPa s) >
waxy-maize (24.6 - 0.4 mPa s) > wheat
(22.2 - 0.5 mPa s) > potato (21.6 - 0.6 mPa
s) > maize (20.0 - 0.5 mPa s) starch.
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Biến tính tinh bột
(Starch modification)
TINH BỘT
 Phương pháp vật lý
 Phương pháp hóa học
 Phương pháp hóa sinh (enzyme)
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp hóa học:
 Acid hydrolysis
 Oxidation
 Cross-linking
 Stabilisation
 Lipophilic substitution
 Dextrinisation
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp hóa học:
Acid hydrolysis
 When the starch is heated beyond its gelatinisation temperature the granules
rupture quickly.
 A lower hot viscosity due to the increase in the ratio of smaller, linear
molecules
 A stronger gel develops on cooling (set-back)
Water/alcol
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp hóa học:
Oxidation
Alkaline 
hypochlorite
 The relatively bulky carboxyl (COOH) and carbonyl (C=O) groups are
introduced together the bulky groups disrupts any tendency towards
re-association (set back) of the shorter chains reduce the gel strength.
 Partial depolymerisation of the starch chains a significantly reduced
hot viscosity.
 Bleaching 135
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 Độ nhớt khi hạt tinh trương nở cực đại
 Tính bền nhiệt: sự thay đổi độ nhớt ở nhiệt độ cao
 Tốc độ hồ hóa
 Độ bền gel: độ nhớt khi tạo gel
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp hóa học:
Cross - linking
Distarch phosphates
Distarch adipates
Cross – linking
Replacement of the hydrogen bonding between starch chains by stronger, more permanent,
covalent bonds: typically one cross-link per 100–3000 anhydroglucose units of the starch:
 The swelling of the starch granule is inhibited;
 The starch becomes more resistant to gelatinisation;
 Heat and shear stability over their parent native starches.
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acetate-adipate 
starch.
distarch phosphate
Biến tính tinh bột
(Starch modification)
TINH BỘT
Stabilisation
Phương pháp hóa học:
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 Bulky groups are substituted onto the starch to take up space and
hinder (steric hindrance) any tendency for dispersed (cooked), linear
fragments to re-align and retrograde (freezethaw cycles).
 Degree of Substitution (DS): is a measure of the number of substituents
per 100 anhydroglucose units (those with DS below 0.2 are typically
used).
 Easy cooking, particularly useful in low-moisture environments and
where the moisture level is restricted by competition from co-
ingredients.
Acetylated
Hydroxypropylated
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E1420: acetylated starch
 Độ nhớt khi hạt tinh trương nở cực đại
 Tính bền nhiệt: sự thay đổi độ nhớt ở nhiệt độ cao
 Tốc độ hồ hóa
 Độ bền gel: độ nhớt khi tạo gel
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Lipophilic substitution
Phương pháp hóa học:
Hydrocarbon chain
The glucose part of starch binds the water
while the lipophilic part binds the oil 
emulsion stabilisation.
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Dextrinisation
Phương pháp hóa học:
 (a) Depolymerisation: dry roasting the starch either
alone, making use of its natural 10–20% moisture
content, or in the presence of catalytic quantities of acid.
 (b) Recombination: in a branched manner.
(a) (b)
Biến tính tinh bột
(Starch modification)
TINH BỘT
Combination treatments are used to achieve the
desired objective:
Cross-linking/Stabilisation
Cross-linking/Stabilisation/Pregelatinisation
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 Độ nhớt khi hạt tinh trương nở cực đại
 sự thay đổi độ nhớt ở nhiệt độ cao
 Tốc độ hồ hóa
 Độ bền gel: độ nhớt khi tạo gel
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E1412: distarch phosphate (Cross-linking)
E1414: acetylated distarch phosphate (Cross-linking/Stabilisation)
E1422: acetylated distarch adipate (Cross-linking/Stabilisation)
 Độ nhớt khi hạt tinh
trương nở cực đại
 Tính bền nhiệt: sự thay
đổi độ nhớt ở nhiệt độ cao
 Tốc độ hồ hóa
 Độ bền gel: độ nhớt khi
tạo gel
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Biến tính tinh bột
(Starch modification)
TINH BỘT
 Phương pháp vật lý
 Phương pháp hóa học
 Phương pháp hóa sinh
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Biến tính tinh bột
(Starch modification)
TINH BỘT
Phương pháp hóa sinh
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Dextrose Equivalent (DE):
Biến tính tinh bột
(Starch modification)
TINH BỘT
 DE = 100: dextrose (glucose)
 DE = 0: starch
 DE = 50: maltose
 DE < 20: maltodextrin
 DE = 20 ÷ 100: glucose syrup
Phương pháp hóa sinh
Bai bao dual starch
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