1. Lecture XVIII Charged PS’s - Carrageenan & Agar
Fucellaran
Lecture #18 - Charged PS’s - Carrageenan, Fucellaran, Agar (Seaweed PSs)

2. Marine Algae Classification
Phaeophyceae
(Brown algae)
Rhodophyceae
(Red algae)
Genus
Ascophyllum
Laminaria
Macrocystis
Lessonia
Durvillaea
Eucheuma
Gigartina
Furcellaria
Chondrus
Gracilaria
Gelidium
Hydrocolloid
Alginates
Carrageenan
Agar

4. Red Seaweed PSs Common structural features of Red Seaweed Galactans
Complements of FMC Corp
Common structural features of Red Seaweed Galactans

5. Red Seaweed PSs

6. Charged PS’s - Agar History Oriental cuisine
A.K.A., Japanese isinglass, Chinese isinglass, Seaweed isinglass, Japanese gelatin, etc.
Since 1882
1st seaweed extract used

7. Charged PS’s - Agar Manufacture/ Production
Japanese
Agar Diver
Seaweed collection
Sold as dried gel
Production
Extract - hot water
Freeze-thaw
Dry, grind, pack

8. Charged PS’s - Agar Structure (Agarose)
CH2OH O OH O O O
CH2 OH OH O n

9. UniqueProperties of Agar I
Solubility - only > 85oC
Viscosity
Insoluble at R.T.
“Kelated” agar hydrates at lower temps
Very low vis at elevated temps

10. UniqueProperties of Agar II
Solubility - only > 85oC
Viscosity
Very low vis at elevated temps
Gelation
Very strong gels at low conc.
Hysteresis - set at oC - melt <85oC
Brittle texture
LBG increases gel strength

11. Major Food Applications of Agar
Icings
Glazes
Piping jellies
Japanese desserts & confections
(Media pour plates)
Regulatory Status - GRAS

12. Piping jelly used to write this…

13. Benefits vs other Hydrocolloids
Strongest gelling agent/lowest conc
Hysteresis - gel/setting points
Low viscosity hot/high solids
Liabilities vs other Hydrocolloids
Sporadic Supply problems
High Cost
Insoluble cold

14. Charged PS’s - Carrageenans
Background
“Carrageenan” = family of PSs
Chondrus crispis - NE shores of US & Canada
a.k.a. “Irish Moss”
Furcellaran - developed in Denmark - WW II
a.k.a. “Danish Agar
Furcellaria fastigiata - similar to kappa-Carr

15. Cross Section of Red Seaweed
Carrageenan is located in the cell wall and intercellular matrix between the cellulosic fibers
During manufacturing, carrageenan is extracted to achieve good solubility in applications
Courtesy of FMC Corp

16. Carrageenan Extract Manufacturing Process
Alcohol precipitation:
Complete extract range
Cold soluble grades
KCl precipitation + freezing:
Good dispersibility
Good color
A second extract range
KCl precipitation + pressing:
Very limited extract range
Courtesy of FMC Corp

17. Repeating units of Main Carrageenan Types
Kappa
Gal-4-sulfate
+ 3, 6 AG OH
CH2OH
O3SO O
CH2
CH2OH
CH2
O3SO OH O
OSO3
Iota
Gal-4-sulfate
+ 3, 6 AG-2-sulfate
Lambda
Gal-2-sulfate
+ Gal-2,6-sulfate
CH2OH HO O
CH2OSO3 OH
OSO3
Courtesy of FMC Corp

18. UniqueProperties of Carrageenan(s)
General Properties
Protein reactivity (complexation)
Gelation
Heat reversible, ion aided

19. Comparative Properties of Carrageenans
Courtesy of FMC Corp

20. Gelation Mechanism of Carrageenan
Cool
Cool
Heat
Heat
Double helix formed
Gel
Random coil
Solution
Aggregated double helices
Hard gel
Kappa
- high temperatures - intermediate step - final gel
Iota
- high temperatures - final gel -
Lambda
- all temperatures
Courtesy of FMC Corp

21. Change in Comformation of Carrageenan Molecules
-SO3 here produces kinks in chain
Change in Comformation of Carrageenan Molecules
-SO3 here prevents helix formation completely
Courtesy of FMC Corp

22. Texture of Carrageenan Gels
2% Kappa carrageenan
2% Iota carrageenan
Courtesy of FMC Corp

23. Combinations of Kappa & Iota Carrageenan Are Used to Obtain a Desired Texture
Fracture Points
50/50
Blend
Increasing Strength
Iota
Carrageenan
Increasing Elasticity
Courtesy of FMC Corp

24. k-Carrageenan Galactomannan Synergism Complements of FMC Corp

25. Interaction of protein-Carrageenan Molecules
Decreasing pH
> pI -->
at pI -->
Interaction of protein-Carrageenan Molecules
< pI -->
< pI -->
Courtesy of FMC Corp

26. Interaction of protein-Carrageenan Molecules
Stable Complex
Ppt
Ppt
Interaction of protein-Carrageenan Molecules
Courtesy of FMC Corp

27. Carrageenan Gelation in Milk, a 2-Step Process
sol
Step 1.
At high temperatures, carrageenan reacts electrostatically with kappa casein
Step 2.
On cooling, carrageenan chains interact, creating a network
Casein micelle with kappa casein on the surface
Carrageenan chains
Cooling

28. Complements of FMC Corp
Carrageenan Milk Gels
Kappa
Lambda
Iota
All carrageenans have ‘milk reactivity’
Properties of gels vary considerably
Complements of FMC Corp

29. Complements of FMC Corp

31. Complements of FMC Corp

32. Functions of Carrageenan in Chocolate Milk
Carrageenan imparts suspension and body in chocolate milk due to both water gel and milk gel potential.
Cocoa suspension is mainly due to carrageenan-carrageenan helix formation during cooling which forms a weak gel matrix, entrapping the cocoa particles.
Carrageenan-Protein interactions account for the viscosity development, mouthfeel and body of the finished chocolate milk.
Carrageenan is the only soluble hydrocolloid capable of permanently suspending cocoa in chocolate milk.
Other gum/starch combinations will temporarily suspend cocoa due to viscosity effects. However, these blends impart a heavy body and may leave a gummy film on the tongue which coats flavor receptors.

34. Benefits vs other Hydrocolloids
Protein reactivity
Extremely efficient stabilizer in milk
Heat reversible gelation
Good clarity

35. Liabilities vs other Hydrocolloids
Poor acid stability unless gelled
Gels tend to be brittle and weep
Undesired gelation w/ high protein
Sporadic supply problems
Regulatory Status - GRAS