3.3.2.3 Shortening, aeration, plasticity and emulsification in fats Quiz: AQA Food Preparation and Nutrition, Unit 2

The 20 questions

1. What is shortening in pastry making?

   • Fat turning to steam in a hot oven so that the layers lift apart and the pastry flakes
   • Fat trapping air bubbles in a creamed mix so that the pastry rises well and feels light
   • Fat coating flour particles so long gluten strands cannot form, giving a crumbly texture
   • Fat dissolving in the water to form a thin, clear liquid that helps the pastry brown evenly

2. Which term describes a fat's ability to be shaped and spread over a range of temperatures?

   • Plasticity
   • Shortening
   • Aeration
   • Emulsification

3. What is emulsification?

   • Air bubbles trapped within a solid fat during the creaming process, which lift the cake mix
   • Sugar crystals melting to form a clear syrup that coats the bottom of the bowl as it stands
   • Water boiling away to leave dry steam inside a thick cake batter as it bakes in the oven
   • Tiny droplets of one liquid dispersed evenly through another, held in place by an emulsifier

4. Creaming butter and sugar for a Victoria sponge traps air in the fat. Which term describes this?

   • Denaturation
   • Dextrinisation
   • Caramelisation
   • Aeration

5. A mayonnaise separates when the oil is added too quickly. What is the most likely cause?

   • The yolk proteins gelatinised, which made the sauce far too thick to mix
   • The starch in the yolk dextrinised and thinned the sauce as it was whisked in the bowl
   • The oil was added faster than the egg yolk emulsifier could coat each droplet
   • The sugar caramelised in the bowl and turned the sauce brown and bitter

6. Why is cold fat rubbed into flour when making shortcrust pastry?

   • It caramelises the flour sugars so that the finished pastry turns golden
   • It melts into a liquid that dissolves the flour and forms a smooth dough
   • It denatures the flour protein so that the dough sets firm and dry
   • It coats the flour and keeps the fat in separate pieces, giving a short texture

7. Which fat is most suitable for a creaming method when making a rich sponge?

   • Chilled lard cut into cubes and never allowed to soften
   • Melted dark chocolate cooled to room temperature in a bowl
   • Cold, runny vegetable oil poured straight from the bottle
   • Softened butter or block margarine

8. What does a fat's shortening effect depend on when making a biscuit?

   • The amount of fat relative to the flour, and how little the dough is handled
   • The amount of sugar added, and whether it is sieved into the bowl first with the flour
   • The temperature of the oven, and the size of the tin used to bake
   • The colour of the fat, and how long it is left in the sun before use

9. A creamed sponge uses melted butter instead of creamed butter. Why is the cake likely to be denser?

   • More starch gelatinises, because melted fat dissolves into the flour
   • More sugar caramelises, because melted fat turns the sugar brown in the bowl before baking
   • More gluten forms, because melted fat activates the protein in the flour
   • Less air is trapped, because melted fat does not hold air as well as creamed fat

10. Why does the creaming method need the fat to be soft and at room temperature?

    • Soft fat holds air bubbles better, so the mixture aerates more effectively
    • Soft fat gelatinises, which thickens the batter before it is baked
    • Warm fat dissolves the flour, so the dough becomes smoother and firmer when it is chilled
    • Cold fat caramelises the sugar, which makes the cake browner on top

11. A salad dressing of oil and vinegar separates after standing. Why?

    • The sugar in the vinegar caramelises and sinks to the bottom of the jar
    • The protein in the vinegar denatures and sets into a firm, separate layer
    • The two liquids are not held in a stable emulsion without an emulsifier
    • The oil gelatinises the vinegar's starch, which makes the dressing thin

12. What does a cook add to oil and water to form a stable dressing?

    • A thickener such as cornflour, boiled briefly to gelatinise the starch
    • A tenderiser such as acid, left to stand overnight in the fridge
    • A raising agent such as bicarbonate of soda, stirred in at the end
    • An emulsifier such as mustard or egg yolk, whisked in

13. Why does a fat with good plasticity suit pastry that must be rolled out?

    • It stays spreadable and holds its shape when rolled, without cracking or melting
    • It caramelises under the rolling pin and turns the dough brown in patches
    • It turns to steam quickly and lifts the dough into separate layers
    • It dissolves the flour and makes the dough sticky and soft to handle

14. A creamed mixture curdles when eggs are added too quickly. Why?

    • The starch has gelatinised too early and turned the batter lumpy
    • The protein has coagulated and set the batter before it is baked
    • The sugar has caramelised and turned the batter bitter and grey
    • The fat and egg emulsion has broken, so the mixture separates

15. Which factor most improves the stability of an oil-in-water emulsion?

    • Adding a small amount of emulsifier and whisking the oil in gradually
    • Adding more sugar and boiling the mixture rapidly on the hob
    • Adding acid so that the oil droplets denature and set in place
    • Storing the sauce in a warm place so that the fat melts into the water

16. What does aeration in a fat-based mixture depend on?

    • Fat being worked so that tiny air bubbles are trapped and held in place
    • Fat being melted so that it dissolves and forms a smooth syrup
    • Fat being cooled quickly so that it sets into a firm, glossy gel
    • Fat being boiled until it turns to steam and leaves the mixture

17. A shortcrust pastry turns tough after the dough is overworked. Which error is most likely?

    • Chilling the dough, which gelatinises the starch in the flour and toughens it
    • Using too much fat, which caramelises and darkens the pastry as it bakes
    • Rubbing the fat in when it is too cold, which denatures the flour protein
    • Overworking the dough and adding too much water, which develops gluten

18. Which method makes a light, crumbly mixture for a crumble topping?

    • Creaming, where soft fat and sugar are beaten together until pale
    • Folding, where whisked egg white is gently combined with a mixture
    • Whisking, where eggs are beaten at high speed until they form peaks
    • Rubbing in, where cold fat is rubbed into flour with the fingertips

19. Why does a hollandaise sauce depend on an emulsion?

    • Butter and egg yolk gelatinise to thicken the sauce into a firm, cut gel
    • Butter and egg yolk caramelise to form a brown, bitter crust on the top
    • Butter and egg yolk dextrinise to form crisp golden flakes in the sauce
    • Butter and egg yolk form a stable emulsion that gives the sauce its smooth texture

20. In an oil-in-water emulsion, what is the oil?

    • The dispersed phase, present as tiny droplets spread through the water
    • The continuous phase, forming a solid layer that coats the bowl
    • The emulsifier, which is added as a separate solid ingredient
    • The air, present as bubbles trapped throughout the sauce

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