Carrageenan

Question 1

Carrageenan in food structuring:

Answer 1

• Very divers in chemical structure and functional properties.
• Frequently used stabiliser and gelling agent.
• Properties depend on molecular structure and food environment.

Question 2

Extraction of carrageenans:

Answer 2

Red seaweeds–> alkaline/water extraction–> Different types of carrageenans

Question 3

Types of carrageenans:

Answer 3

1. OSO3 kappa (galactose + anhydrogalactose)
2. OSO3 iota (galactose + anhydrogalactose)
3. OSO3 lambda ( do not have anhydrogalactose)

Question 4

Solubility properties of different carrageenans:

Answer 4

• In hot water you can solubilize all the three carrageenans.
• Lambda is soluble in all conditions.
• Cold water: kapa and iota, behave different because the sodium salt is quite soluble but the calcium or the potassium salt may be insoluble or give some dispersion.
• Cold milk: kappa and iota insoluble.
• Concentration sugar: kappa soluble hot, iota difficulty soluble.
• Concentration salt: kappa insoluble, iota soluble hot.

Question 5

Gelation of carrageenans are thermoreversibles, 1. Random coils –>heating. 2. ordered domains (double helices) –>K+. 3. Aggregated domains. TRUE OR FALSE?

Answer 5

TRUE

Question 6

Different gelation of kappa- and iota-carrageenan:

Answer 6

1. Kappa carrageenan gel: you have potassium ions, you will end up with a very firm brittle shell, which you can break easily but is quite stiff.
2. Iota-carrageenan: with calcium, you end up with an elastic gel which is very flexible and in fact can be moved around easily.

Question 7

Gelling mechanism of different carrageenans:

• Freeze/thaw stability
• Synergistic effect with locust bean gum:

Answer 7

• Freeze/thaw stability: kappa and lambda not stability in frozen products.
• Synergistic effect with locust bean gum: kappa and iota yes, lambda n

Question 7

Carrageenan – protein interactions

Answer 7

1. In case of the pH of milk, high pH (»pka), protein may be charged, negatively, and the carrageenan is also negatively charge (SO4-), you do not have repulsion but you have a bridging of the calcium Ca 2+ and a stabilization, association with different molecules.
2. Low pH(

Question 8

Gelation of kappa-carrageenan and milk protein. Applications?

Answer 8

• Chocolate milk: prevention of fat droplet separation and stabilization of
  cocoa particles.
  -Fresh cheese: prevent syneresis

Question 9

Why is carrageenan often used in meat applications?

Answer 9

Carrageenan in brine (salmuera) is:

• Quite soluble in water
• After cooking: binds water and soluble proteins upon cooking, preventing cooking loss, preventing migration of the proteins into the cooking water.