1. Physical Properties of Starch

2. B-3.02 -- Physical Properties of Starch
Considerations
Five properties to consider when choosing a starch for food preparation:
Retrogradation
Viscosity
Stability
Opacity vs. Translucency
Texture
B Physical Properties of Starch

3. B-3.02-Physical Properties of Starch
Retrogradation
Firming of a gel during cooling and standing
Amylose-amylose bonding
Desirable when forming a gel
Undesirable when gel cracks upon standing
Cracks in a custard pie
Effect of acids:
Breaks down starches and weaken gels.
Should be added to a starch mixture after it has thickened.
B-3.02-Physical Properties of Starch

4. B-3.02 -- Physical Properties of Starch
Retrogradation
Syneresis
Water leaking from a gel due to prolonged storage.
B Physical Properties of Starch

5. B-3.02 -- Physical Properties of Starch
Viscosity
Resistance of a mixture to flow
Starches hold their shape, resist flow
Example -- flow of water vs. starch paste
More starch, greater resistance to flow
Amylose vs. amylopectin
B Physical Properties of Starch

6. B-3.02 -- Physical Properties of Starch
Stability
The ability of a thickened mixture to remain constant over time and temperature changes
Freezing
Heating
Waxy maize starch
Flour
Cornstarch
B Physical Properties of Starch

7. Opacity vs. Translucency
How much an object blocks light
Wheat starch
Good for sauces and soups
Translucency
How much light can pass through an object
Cornstarch, potato starch, arrowroot
Good for fruit sauces, pie fillings, glazes
B Physical Properties of Starch

8. B-3.02 -- Physical Properties of Starch
Texture
Consider type of starch
Gritty vs. smooth texture
Mouthfeel
B Physical Properties of Starch