physical properties of fats and oils

Question 1

T or F : There can be as little as 10% “solids” in a fat that still retain a solid character.

Answer 1

T

Question 2

What are the forces that holds the crystals together?

Answer 2

Van der waals

Question 3

On what factor is depedant the plasticity of fats

Answer 3

temperature and fatty acid composition

Question 4

Fats don’t have sharp melting point because:
A. They consist of different TG with different melting points
B. Because the 3D network of crystals delay melting of some fat crystals
C. None of the above
D. Both of the above

Answer 4

a

Question 5

Put the different polymorphic forms in order of increasing stability

Answer 5

alpha (α), beta prime (β’), and beta (β) forms

Question 6

From a functionality perspective, β’ crystals are very undesirable because they are large and grainy.

Answer 6

false, it is the β that is grainy.

Question 7

The preferred crystal type in margarine is: : A. Alpha crystals, because it gives the product better spreadability
B. Beta prime crystals, because it gives the product better spreadability and a creamy mouth feel
C. Beta crystals, because they give the product a desirable degree of solidness

Answer 7

B

Question 8

What is dialometry?

Answer 8

Measure of the solid fat contnet. This technique is based on the measurement of the change in specific volume (the inverse of density) per unit temperature. A sample of the fat is simply placed in a reservoir, with a capillary attached, and the expansion of the fat is measured as the temperature is changed in specific increments.

Question 9

Butter has a sharp solid fat content curve, which means: 
A.	It melts fast
B.	It releases flavors fast
C.	None of the above
D.	Both of the above

Answer 9

both

Question 10

What is consistency?

Answer 10

Consistency is the apparent hardness at a temperature

Question 11

Beta-prime crystals → ____ amount of ____ air bubbles

Answer 11

large amount of small air bubbles

Question 12

Beta crystals → ____ amount of ____ air bubbles

Answer 12

small amount of large air bubbles

Question 13

How are produced low to zero trans margarines?

Answer 13

produced by interesterifying a blend of liquid oil and a fully hydrogenated oil.

Question 14

The melting range of a confectionary fat depends on :

Answer 14

1- FA composition

2- crystallization

Question 15

80% of cocoa butter is ___ triglyceride.

Answer 15

disaturated

Question 16

What is the fatty acid in SN-2 position in most of the TG of cocoa butter?

Answer 16

oleic acid

Question 17

A crunchy chocolate is obtained when cocoa butter forms: 
A.	Small alpha crystals
B.	Small beta prime crystals
C.	Small beta crystals
D.	Large beta crystals

Answer 17

small beta cystals

Question 18

When fat is cooled quickly it forms thin, leaf-like crystals. This form is:

Answer 18

alpha

Question 19

Beta prime crystals are preferred for chocolate:

Answer 19

false, it is beta

Question 20

Fat blooms are ___ type of crystal

Answer 20

Studies on fat bloom indicate that the bloom consists of large, single cocoa butter crystals or collections of crystals of the stable Beta form of cocoa butte

Question 21

The technique that is based on the measurement of the change in specific volume per unit temperature is called

Answer 21

dilatometry

Question 22

Why is milk fat often added to chocolate

Answer 22

because the milk fat tends to be in the beta-prime crystal type and it is cheap in comparision to cocoa butter.