Bài giảng Chất keo thực phẩm Mạc Xuân Hòa: Tổng hợp kiến thức

8/1/2016

CHẤT KEO THỰC PHẨM

(Food hydrocolloids)

Giảng viên: Mạc Xuân Hòa

1. Giới thiệu chung về chất keo

2. Một số chất keo sử dụng làm phụ gia TP

3. Modification

NỘI DUNG

8/1/2016

1. Giới thiệu chung về chất keo

2. Một số chất keo sử dụng làm phụ gia TP

3. Modification

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 flow behaviour food system namely, properties of (viscosity) and mechanical solid property (texture)  to modify its sensory properties.

NỘI DUNG

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Kích thước cấu tử hòa tan

Dung dịch keo (10-4 - 10-6 mm ) Dung dịch 1 pha (<10-6 mm ) Huyền phù (1 - 10-2 mm )

Đông tụ

pH Nhiệt độ Lực ion,…

Nguồn gốc

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Functional properties

• Thickening (basic)

• Gelling (basic)

• Emulsifying

• Controlling the crystal growth of ice and sugar

• …….

1. Giới thiệu chung về chất keo

2. Một số chất keo sử dụng làm phụ gia TP

 Thickening agent/Thickener

 Gelling agent

NỘI DUNG

8/1/2016

1. Giới thiệu chung về chất keo

2. Một số chất keo sử dụng làm phụ gia TP

 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.

NỘI DUNG

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Examples of food products containing hydrocolloids

Gravies

Soups

Salad dressings

Toppings

Sauces

Process of thickening

In dilute dispersion,

the individual molecules of

hydrocolloids can move freely and do not exhibit

thickening.

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,…

Mark-Houwink equation

 M: the molecular weight

 K, α: the parameters of Mark-Houwink equation

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 thinning meaning that apparent exhibit shear viscosity decreases with increasing shear rate.

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Shear thining

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.

Khi C>C* độ nhớt (viscosity) và tốc độ cắt (shear rate) có 17 quan hệ như dạng đường cong ở trên.

Amylose will have a higher intrinsic viscosity

than amylopectin.

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Regulations

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Xanthan Gum

(E415)

 Nguồn gốc

 Cấu tạo hóa học

 Tính chất

 Ứng dụng

XANTHAN GUM

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 Nguồn gốc

 Cấu tạo hóa học

 Tính chất

 Ứng dụng

XANTHAN GUM

Nguồn gốc

 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.

XANTHAN GUM

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 Nguồn gốc

 Cấu tạo hóa học

 Tính chất

 Ứng dụng

XANTHAN GUM

Cấu tạo hóa học

Xanthan gum is a linear (1 

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)

terminal mannose unit and

(12) to a second mannose that

connects to the backbone.

XANTHAN GUM

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 Nguồn gốc

 Cấu tạo hóa học

 Tính chất

 Ứng dụng

XANTHAN GUM

Tính chất

Xanthan gum is widely used as a rheology control

agent

for aqueous systems:

Increasing viscosity

(thickening)

 Stabilizing emulsions

 Preventing the settling of solids

XANTHAN GUM

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Tính chất

 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

XANTHAN GUM

suspending properties during long-term storage at elevated

temperature as it does at ambient conditions.

 It imparts excellent freeze/thaw stability to most compositions.

Tính chất

XANTHAN GUM

Complex aggregates, with weak intermolecular forces

 High viscosity at low shear rates (suspension stabilising

properties)

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Tính chất

XANTHAN GUM

Tính chất

XANTHAN GUM

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Tính chất

The viscosity remains nearly constant between pH 2 and pH 12

XANTHAN GUM

Tính chất 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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 Nguồn gốc

 Cấu tạo hóa học

 Tính chất

 Ứng dụng

XANTHAN GUM

Ứng dụng

XANTHAN GUM

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.

Introduction

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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,

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.

Method: Preparation of yogurt

Cow's milk

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0.01%

0.005%

Soy milk

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, rheological, microbiological, microstructural and sensory properties.

0.007%

Treat ment I Treat ment II Treat ment III Treat ment I Treat ment II Treat ment III Treat ment I Treat ment II Treat ment III Treat ment I 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

Method: Rheological properties

• Viscosity:

Method: Rheological properties

• Curd tension:

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Method: Rheological properties

• Syneresis:

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.

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Results:

Viscosity of yogurt and soy yogurt during fermentation

 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

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 gum at (I) with xanthan

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

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).

8/1/2016

1. Giới thiệu chung về chất keo

2. Một số chất keo sử dụng làm phụ gia TP

 Thickening agent/Thickener

 Gelling agent

NỘI DUNG

Gels are…

 A three-dimensional network that

traps or

immobilizes water within it

to form a rigid

structure

Gels are…

 A form of matter

intermediate

between solid and liquid and show

mechanical rigidity.

 A viscoelastic system with a ‘storage

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modulus’ (G′) larger than the ‘loss

modulus’ (G″).

Rheology of gels

Fluid-like

Solid-like

What is  ? Phase angle

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

Silly putty

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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

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

Junction zones

 Cation mediated cross-linking

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Process of gelling: ‘junction zones’

CONDITIONS OF GEL FORMATION

• Type of hydrocolloids

• Concentration of Gelling Agent

• Conditions at which “junction zones” can

be formed:

temperature,

ionic strength,

high pressure,…

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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∗.

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

Conditions at which “junction zones” can be formed:

 Temperature: agar, gelatin,..

 Ionic

strength:

alginate,

pectin,

carrageenan,..

 pH

 Pressure

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%

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

Ca2+

Alginate gel formation

DUNG DỊCH GEL

Conditions at which “junction zones” can be formed:

 Temperature: agar, gelatin,..

 Ionic

strength:

alginate,

pectin,

carrageenan,..

 pH

 Pressure

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High Methoxyl Pectin

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;

DUNG DỊCH GEL (hydrogen bonds)

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

combination with

increased

temperature):

usually applied to form protein gels

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Keywords

 Rapeseed

 Protein isolate

Bodybuilder

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Introduction

propertie

food

groups

(SH)

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• Heat and high pressure can improve gelation protein: increased exposure of hydrophobic and (structure sulfhydryl modification).

Introduction

• 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.

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,…

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.

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), ….

Results: Free Sulfhydryl Content (M/g protein)

exposure

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(p<0.05) 200 MPa: a significant increase, which probably reflects pressureinduced 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

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.

stronger

on Surface

effect

HP had Hydrophobicity (So) when compared to Heat.

Results: Gelation properties

heat

LGC of RPI was significantly (p<0.05) decreased from 15 to 6 % by HP treatment, treatment while decreased LGC from 15 to 10 %.

resultant

strength

The unfolded proteins are then able to interact through hydrophobic bonding to increase 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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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

Why do we modify food hydrocolloids ?

• Some native hydrocolloids have often

been reported to present a number of

undesired

properties,

including

insolubility in cold water, crumbling after

heating, and loss of viscosity,…

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Starch

103

TINH BỘT

Cấu tạo hóa học

104

Hydrogen bonds

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STARCH

Rheological properties

Reassociation of Amylose

Heating

Cooling

105

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

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to maintain colon health and protect against disease

Starch modificatiion

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• 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

107

Hạt tinh bột khoai tây ở thời điểm trước và sau biến tính bằng enzyme amylase

108

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TINH BỘT

Biến tính tinh bột (Starch modification)

 Phương pháp vật lý

 Phương pháp hóa học

 Phương pháp hóa sinh (enzyme)

109

TINH BỘT

Biến tính tinh bột (Starch modification)

 Phương pháp vật lý

 Phương pháp hóa học

 Phương pháp hóa sinh (enzyme)

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TINH BỘT

Biến tính tinh bột (Starch modification)

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

111

Drum Drying

112

lượng thừa nước, sau đó sấy để tách ẩm.

113

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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

115

Pre-gelatinized Wheat Starch

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Pre-gelatinized Wheat Starch

117

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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Pre-gelatinized Wheat Starch

temperatures

 The PGS had the ability to increase the viscosity 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 final it produces lower

cooled down, viscosity than native starch.

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120

Keywords

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Imitation cheese

121

Keywords

Imitation cheese

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.

122

Rennet casein: Due to its high cost, considerable eVort has replacement of casein with been vested in the partial cheaper ingredients, of which, starch has been the most effective low-cost casein substitute

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

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Water 48%

Renet casein/PG starch 24.5%

Vegetable fat 26%

(trisodium citrate, 2.18% Emusifying salt citric acid, disodium phosphate)

Sodium chloride 1.67%

Sorbic acid 0.1%

Control

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PG maize

Rennet casein

PG waxy maize

 Micro-structure  Melt  Hardness  Dynamic rheology  Viscosity

PG wheat

PG potato

PG rice

rennet replacing 15% the of casein by PGS

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).

128

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of all

with

vegetable fat the of products The G’ decreased signiWcantly (P · 0.05) increasing measuring temperature from 22 to 85 °C, due to melting of and the softening protein matrix.

129

products

had

rice

containing All starch significantly lower tan values at 22 °C (ranging from 0.36 - 0.02 for waxy-maize to 0.42 - starch- 0.013 for imitation containing cheese) compared to the imitation cheese control indicating (0.44 - 0.012), (less elastic more viscoelastic) structural behaviour compared to the control.

130

Imitation cheese containing potato starch had the highest G’ values in the temperature ranges 55–85 °C, which was possibly due to extensive retrogradation starch impeding the Xow of casein.

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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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TINH BỘT

Biến tính tinh bột (Starch modification)

 Phương pháp vật lý

 Phương pháp hóa học

 Phương pháp hóa sinh (enzyme)

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TINH BỘT

Biến tính tinh bột (Starch modification)

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

Water/alcol

 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

134

 A stronger gel develops on cooling (set-back)

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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.

135

 Bleaching

136

 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

Cross – linking

Distarch phosphates Distarch adipates

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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distarch phosphate

acetate-adipate starch.

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Biến tính tinh bột (Starch modification)

TINH BỘT Phương pháp hóa học: Stabilisation

Acetylated Hydroxypropylated

 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).

in low-moisture environments and is restricted by competition from co-

 Easy cooking, particularly useful where the moisture level ingredients.

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E1420: acetylated starch

141

Biến tính tinh bột (Starch modification)

TINH BỘT Phương pháp hóa học: Lipophilic substitution

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 Phương pháp hóa học: Dextrinisation

(b)

(a)

 (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.

143

TINH BỘT

Biến tính tinh bột (Starch modification)

Combination treatments are used to achieve the

desired objective:

 Cross-linking/Stabilisation

 Cross-linking/Stabilisation/Pregelatinisation

144

145

 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

 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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E1412: distarch phosphate (Cross-linking)

E1414: acetylated distarch phosphate (Cross-linking/Stabilisation)

E1422: acetylated distarch adipate (Cross-linking/Stabilisation)

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TINH BỘT

Biến tính tinh bột (Starch modification)

 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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Biến tính tinh bột (Starch modification)

TINH BỘT Phương pháp hóa sinh

 DE = 100: dextrose (glucose)

 DE = 0: starch

 DE = 50: maltose

 DE < 20: maltodextrin

 DE = 20 ÷ 100: glucose syrup

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Bai bao dual starch

150

Dextrose Equivalent (DE):

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Bài giảng Chất keo thực phẩm - Mạc Xuân Hòa

Bài giảng Chất keo thực phẩm do Mạc Xuân Hòa biên soạn cung cấp cho người học các kiến thức: Giới thiệu chung về chất keo, một số chất keo sử dụng làm phụ gia thực phẩm, modification. Mời các bạn cùng tham khảo nội dung chi tiết.

Chủ đề:

CHẤT KEO THỰC PHẨM

(Food hydrocolloids)

Đông tụ

pH Nhiệt độ Lực ion,…

Nguồn gốc

Functional properties

Gravies

Soups

Salad dressings

Toppings

Sauces

Factors effecting thickening properties

Shear thining

Xanthan Gum

Nguồn gốc

Cấu tạo hóa học

Tính chất

Tính chất

suspending properties during long-term storage at elevated

Tính chất

Tính chất

Tính chất

Tính chất

Tính chất Synergistic Effect

Ứng dụng

0.01%

0.005%

0.007%

Results:

 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.

Results: Viscosity of yogurt and soy yogurt during fermentation

modulus’ (G′) larger than the ‘loss

modulus’ (G″).

Process of gelling: physical association

Process of gelling: ‘junction zones’

CONDITIONS OF GEL FORMATION

Type and Concentration of hydrocolloids

Conditions at which “junction zones” can be formed:

GELATIN

Sol

AGAR

Gelling temperature: around 380C

Melting temperature: around 850C

Gelling concentration: between 0,5 – 2%

carrageenan,..

Low Methoxyl Pectin

High Methoxyl Pectin

• Heat and high pressure can improve gelation protein: increased exposure of hydrophobic and (structure sulfhydryl modification).

Method: Determination of responses

Jam

Jelly

Confectionery

Why do we modify food hydrocolloids ?

Starch

TINH BỘT

Cấu tạo hóa học

STARCH

Rheological properties

Reassociation of Amylose

Heating

Cooling

TINH BỘT

Biến tính tinh bột (Starch modification)

TINH BỘT

Biến tính tinh bột (Starch modification)

TINH BỘT

Biến tính tinh bột (Starch modification)

Production of pre-gelatinized wheat starch

Twin Drum Drier

Pre-gelatinized Wheat Starch

Pre-gelatinized Wheat Starch

Pre-gelatinized Wheat Starch

Pre-gelatinized Wheat Starch

Imitation cheese

Imitation cheese

Results

Micro - structure