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Flashcards in Emulsions Deck (27):
1

Give three common examples of where you might find emulsions

1. Food

2. Cosmetics

3. Paint

2

Which 2 substances can emulsions be made from?

Water and oil

3

What, broadly speaking, are emulsions made up of?

Lots of DROPLETS of one liquid SUSPENDED in another liquid.

4

Give 2 examples of emulsions using oil and water

A...
1. Oil-in-water emulsion (oil droplets suspended in water)

or a...
2. Water-in-oil emulsion (water droplets suspended in oil)

5

Complete the sentence:

Emulsions are _______ than either oil or water.

Emulsions are THICKER than either oil or water.

6

Give an example of an everyday emulsion and what it is made of

Mayonnaise

SUNFLOWER (or olive) oil, and VINEGAR

7

What do the physical properties of emulsions make them suited for? Example?

Lots of uses in foods e.g. as salad dressings and sauces

8

How is a salad dressing made?

By shaking olive oil and vinegar together forming an EMULSION that COATS salad better than PLAIN oil or PLAIN vinegar

9

Generally, how does having more oil in an oil-in-water emulsion affect its density?

The MORE oil, the THICKER the emulsion

10

Give an example of an oil-in-water emulsion with not much oil and a lot of water, and the percentages of oil

Milk / cream

Full-fat: 3%
Single cream: 18%
Double cream: 50% - (technically doesn't have a lot more water than oil but nm)

11

What extra ingredient (besides oil and water), do the oil-in-water emulsions WHIPPED CREAM and ICE CREAM both contain?

Air

12

Why does WHIPPED CREAM contain air?

To give it a FLUFFY, frothy consistency for use as TOPPING

13

Why does ICE CREAM contain air?

To give it a SOFTER TEXTURE, which makes it easier to SCOOP out of a tub

14

What kind of COSMETIC is usually an oil-in-water emulsions?

Moisturising lotion (moisturiser)

15

Why are most MOISTURISERS emulsions?

Because the SMOOTH texture of an emulsion makes it easy to RUB into the skin

16

Basically, what do emulsifiers do?

Help OIL and WATER mix

17

Why do some foods contain emulsifiers?

To help oil and water mix

18

Complete the sentence:

Oil and water mixtures naturally ______ ___ .

Oil and water mixtures naturally SEPARATE OUT .

19

Complete the sentence:

Emulsifiers are molecules with one part that's attracted to ______ and another part that's attracted to _____ or ____ .

Emulsifiers are molecules with one part that's attracted to WATER and another part that's attracted to OIL or FAT .

20

What is the bit of an emulsifier that's attracted to WATER called?

Hydrophilic

21

What is the bit of an emulsifier that's attracted to OIL called?

Hydrophobic

22

What do the HYDROPHILIC ends of each emulsifier molecule latch onto?

Water MOLECULES

23

What do the HYDROPHOBIC ends of each emulsifier molecule latch onto?

Oil MOLECULES

24

State the 3 points explaining what happens when you shake oil and water together with an emulsifier

1. The oil forms droplets, SURROUNDED by a coating of EMULSIFIER, with the HYDROPHILIC end facing OUTWARDS.

2. Other oil droplets are REPELLED by the HYDROPHILIC bit of the emulsifier, while water molecules LATCH onto it.

3. This stops the emulsion separating out.

25

What are the 2 pros of using emulsifiers?

1. They STOP emulsions from SEPARATING out, giving them a longer SHELF LIFE

2. They allow food companies to produce food that's lower in FAT but still has a GOOD TEXTURE

26

What is the downside of using emulsifiers? (give specific example)

Some people are ALLERGIC to certain emulsifiers.

E.g. EGG YOLKS

27

In an emulsion what does NOT happen to a liquid in another liquid?

One liquid is not DISSOLVED in another liquid - it is SUSPENDED!!!