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Crystal control in ice cream - Alternatives to ice-binding proteins

Q: What is the ice-binding surface of antifreeze gelatin peptides?

The flat oxygen triad plane, in which the 3 oxygens forming the triad are thought to form hydrogen bonds to the water molecules in the prism face of the ice crystal nuclei.

Q: Why do only small gelatin peptides show antifreeze properties?

The small peptides might form stiff rods, sticking to the ice crystal with their oxygen triad planes. Larger peptides, > 4 kDa, are expected to lose stiffness and are less efficient in covering the ice crystal surface, due to steric hindrance.

5 important questions on Crystal control in ice cream - Alternatives to ice-binding proteins

What can be an alternative to IBPs?

Gelatin hydrolysates. The small peptides produced can bind to ice crystals and have antifreeze properties.

What is the primary sequence of gelatin?

Glycine (33%)
Proline or hydroxyl proline (33%)
Other amino acids (33%)

What size do gelatin molecules need to have to have anti freezing properties?

< 3 kDa

What is the ice-binding surface of antifreeze gelatin peptides?

The flat oxygen triad plane, in which the 3 oxygens forming the triad are thought to form hydrogen bonds to the water molecules in the prism face of the ice crystal nuclei.

Why do only small gelatin peptides show antifreeze properties?

The small peptides might form stiff rods, sticking to the ice crystal with their oxygen triad planes. Larger peptides, > 4 kDa, are expected to lose stiffness and are less efficient in covering the ice crystal surface, due to steric hindrance.

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Chemical aspects

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