Properties of Bread and Cakes

Question 1

What does a viscoelastic material behave like over a short timescale and what does it behave like over a long timescale?

Answer 1

Short timescale: an elastic solid, springing back e.g., bread dough

Long timescale: a viscous liquid flowing slowly

Question 2

Are these hydrophilic or hydrophobic?

1. Water
2. Fat
3. Salt
4. Starch
5. Air

Answer 2

1. Hydrophilic
2. Hydrophobic
3. Hydrophilic
4. Hydrophilic
5. Hydrophobic

Question 3

What will cake crumb look like if leavening takes place too soon and if it takes place too late?

Answer 3

Too soon – the cake will collapse before the starch gelatinises and will be pasty.
Too late – the structure will set before the cake rises and will be dense.

Question 4

What happens if there is too little gluten development in pastry and what happens if there is too much?

Answer 4

Too little – it will be too crumbly.

Too much – it will be too hard.

Question 5

What effect does increasing baking time and/or temperature have on biscuits?

Answer 5

It drives out more water, makes them crisper, increases shelf life, increases flavour and browning.

Question 6

Describe the roles and effects of developed gluten in bread

Answer 6

In bread developed gluten is the continuous phase in the dough. It holds all the other ingredients and the bubbles. Gluten development should be complete, though gluten that is too strong can limit dough extensibility and loaf volume.

Question 7

Describe the roles and effects of developed gluten in semi-sweet biscuit

Answer 7

In semi-sweet biscuits there is partial gluten development that is responsible for their crispness. Excessive gluten development can interfere with shaping.

Question 8

Describe the roles and effects of developed gluten in short-crust pastry

Answer 8

Short crust pastry requires little gluten development. It needs just enough to make the pastry strong enough to avoid breaking up in the final product, but still retain “melt in the mouth” texture. Excessive handling can produce too much gluten development resulting in a hard pastry.

Question 9

What are colligative properties?

Answer 9

They are properties, such as boiling point, due to the number of molecules.

Question 10

What is the difference between the crystal and glass (amorphous state)?

Answer 10

A crystal is more organised than the glassy state for which there are interfering substances preventing a crystalline arrangement of sucrose molecules.