Download food chemistry - Genome Discovery

FOOD CHEMISTRY
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
Fifth lecture
13/August/2012
Goals
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Structural arrangements of different Gums:
Carrageenans,
Guar gum,
Carbogum,
Xanthan,
and Gum arabic
Composition
Physico-chemical properties of Gums
Applications of Gums in food industry
Polysaccharides
Carrageenans
Ionic Gums
March 5, 2004.
Southern Bio-products Conference
Carrageenan
• Carrageenan
– obtained by extraction with
water or alkaline water of certain
Rhodo phyceae (red seaweed).
• It is a hydrocolloid
– consisting mainly of the
potassium, sodium, magnesium,
and calcium sulfate esters of
galactose and 3.6-anhydrogalactose copolymers.
3 types: Kappa, lambda, iota
– nonhomogeneous
polysaccharides
Three types of Carrageenans
Carrageenans
• Kappa
• Lambda
Structural changes of Carrageenans at different
temperatures
Hot
Cold
Cold
Gelation
Ca 2+
double helices are believed to
double-helical structures
nest
In a hot solution, the polymer molecules are in a coiled state. As the solution is cooled, they
intertwine in double-helical structures.
coiled state
As the solution is cooled further, the double helices are believed to nest together with the aid of
potassium or calcium ions.
Comparisons of different
Carrageenans
• Characteristics
Kappa
Iota
Lambda
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Solubility
20° C water
80° C milk
20° C milk
Gelation
no
yes
no
no
yes
no
yes
yes
thickens
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With addition of:
K+
Ca++
None
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Stability
Freeze – thaw
pH > 5
Syneresis
Salt tolerance
no
stable
yes
poor
yes
stable
no
good
yes
stable
no
good
Protein - Carrageenan Interactions
• Protein (milk) with a negative charge
Protein (milk) with a positive charge
• Reacts with casein milk protein
•The thickening effect of kappa-carrageenans in milk is 5–10 times greater than
it is in water.
•Useful in the preparation of chocolate milk, icecream, evoporated milk etc.
Carrageenan: Application of
carrageenan in meat protection
• 3 categories of meat:
1. pale, soft, and exudative (PSE)
• Due to postmortem generation of lactic acid
2. dark, firm, and dry or non-exudative (DFD)
3. "normal" meat
• acceptable
• subjectively between PSE meat and DFD meat
• Function: Carrageenan + soy protein:
– Prevents occurrence of PSE meat
Concept:
Use of carrageenan is to hold water and maintain water content, and therefore
softness of meat products, such as sausages, during the cooking.
Carrageenan softens meats
• Carrageenan is a water-soluble polymer, also known
as a gum, that is used as a fat substitute in
processed meats and can be found in condensed
milk and some soy milk products.
• Normally, fat serves the purpose of maintaining
softness, but because of the binding power of
carrageenan for protein and its high affinity for
water,
• Carrageenans can be used to replace in part this
function of natural animal fat in lean products.
… However
• Carrageenan may cause stomach
lesions, cancer
• Strawberry cheesecake like this may be
stabilized and thickened with
carrageenan.
• Containers of pudding, ice cream, yogurt, or
cottage cheese may include the ingredient
carrageenan, a thickener derived from red
seaweed.
• For decades, it has been presumed to be safe
to eat, but new research from a medical doctor
on the faculty of the University of Iowa shows
that presumption may be wrong.
March 5, 2004.
Typical Dairy Applications of Carrageenan
• Typical Dairy Applications of Carrageenan
• Milk Gels
• Cooked flans (open pastry filled with fruit or custard) or custards
(Sweetened mixture of milk and eggs baked, boiled or frozen)
– Gelation
K, K + I
• Cooked prepared custards
– Thickening
– Gelation K, I, L
• Pudding & Pie Fillings
• Dry mix cooked with milk
– Level starch gelatinization
• Ready-to-eat
– Syneresis control, bodying
Typical Dairy Applications of Carrageenan
• Whipped products
– Whipped cream Stabilize overrun
– Aerosol whipped cream
• Stabilize overrun & emulsion
• Cold prepared Milks
– Instant Breakfast
• Suspension, bodying agent
– Shakes
• Suspension, bodying
Carrageenan: Summary
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Structure:
Galactose backbone
Ester sulfate gives negative charge
Properties:
Gels with potassium (Kappa)
Gels with calcium (Iota)
Non-gelling (Lambda)
Applications:
Good stabilizer for milk proteins
Suspender for chocolate in milk
Part of ice cream stabilizer mix
Water gels
Questions
• Commercial carragennan contains:
1. Kappa
2. Iota
3. Lamda
4. a mixture of above
• The viscosity of carrageen is quite stable over a wide
range of pH values because
• 1. sulfate half-ester groups are always ionized
• 2. Phosphate groups are never ionized
• 3. Phosphate groups are always ionized
• 4. Nitro groups are always ionized
Questions
• Lambda carragennan contains:
1. the maximum no. of sulfates
2. the lowest no. of sulfates
3. only one sulfate
4. none
• Carrageen softens meat due to its
• 1. binding power for protein
• 2. high affinity for water
• 3. both
Non-ionic Gums
•Guar gum
&
Carobgum
•Guar gum
Guar Gum
Guar gum is the ground endosperm of seeds
Guar gum
Monomer: galactose, mannose (galactomannan)
Bonding: -1,6/-1,4
Galactose
Mannose
Glucose
Guar gum
Monomer: galactose, mannose (galactomannan)
Bonding: -1,6/-1,4
a main chain of b-D-mannopyranosyl units joined by (1-- 4) bonds with single-unit a-Dgalactopyranosyl branches attached at O-6
Galactose
Mannose
Mannose
Guar Gum
• It produces the highest viscosity of any natural, commercial gum
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Galactomannan (Mannose (1-4) + Galactose (1-6) every other Mannose
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Galactomannans consist of MW 220,000 ± 20,000
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Particle size affects viscosity and hydration
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Cold water swelling - Turbid solutions
Guar Gum
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Hydration increased by heating
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High water binding
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High viscosity form - up to 100,000 CP
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Low viscosity from - up to 10,000 CP
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Modifies properties when used with:
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Carrageenan
Xanthan
Guar Gum
• Characteristic of different grades of Guar Gum
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Grade
Coarse
Medium
Fine
Powder
Cold Viscosity.
2,700
3,800
4,000
4,300
Hydration Rate
Slow
Moderate
Fast
V. Fast
Dispersability
Excellent
Excellent
Fair
Poor
Food Uses
Ice cream
prevents ice crystal formation,
slows meltdown,
improves heat shock resistance
Salad dressing
viscosity
Cheese
improves spreading
Guar gum uses in food industry
• Ice creams: Smooth creamy texture
• Bakery products: Texture, moisture retention
• Noodles: Moisture retention, machine runnability
• Beverages: mouth feel
• Meat: Binder, absorb water
• Dressings: Thickener, emulsion stabilizer
Carobgum
Carobgum
Carobgum is the ground
endosperm of seeds
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Carobgum
• Carobgum
– obtained from the endosperm
of the Carob or locust seed
(Ceratonia siliqua).
March 5, 2004.
Southern Bio-products Conference
Seed Gum
Carobgum
Monomer: galactose, mannose (galactomannan)
Bonding:
-1,4/-1,6 (branch)
Carob Gum
Galactose
Mannose
Galactomannan (D-Mannose (1-4) with Galactose (1-6) every 4th
mannose
Carobgum
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Galactomannan (D-Mannose (1-4) with Galactose (1-6) every 4th mannose
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Molecular weight 330,000 ±30,000
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Neutral - relatively unaffected by ions, pH.
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Not soluble in cold water
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Fully hydrated if heated 10 minutes at 80° C
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Solutions are turbid, off-white
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Modify properties of
– Carrageenan
– Xanthan Gum
Carobgum
• retards ice crystal growth
• shows viscosity synergy with xanthan.
March 5, 2004.
Southern Bio-products Conference
Guar gum and Carobgum
Gums-Guar gum and Carobgum
B) Non-ionic gums
• Guar gum and Carobgum
– No effect of pH and ions (salts)
since they are uncharged
– Guar gum has galactose sidegroups on every other mannose
unit (2 monnose:1 galactose) while
carobgum does not have uniform
distribution (4 mannose:1galactose)
or irregular
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Gums-Guar gum and Carobgum
Carbogum
Gums-Guar gum and Carobgum
B) Non-ionic gums
• Guar gum and Carobgum:
– Guar gum : soluble in hot/cold water;
very viscous solutions at 1% ; and it
forms gels and films at 2-3%
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Guar gum produces the highest viscosity of any
natural, commercial gum
Used in Ground meats, salad dressings and
sauces……
– Carobgum: Soluble at 80/90oC; very
viscous solutions; Synergises with
xanthan gum or carrageenan
• Used as a Binder in meat products and
in frozen desserts
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Questions
Guar gum and carbogum are examples for:
1. Ionic gums
2. Non-ionic gums
3. Both
4. None
pH and ions can change the property of Guar gum and carbogum
1.
2.
3.
4.
True
False
Only pH
Only ions