physical properties of fats and oils Flashcards
T or F : There can be as little as 10% “solids” in a fat that still retain a solid character.
T
What are the forces that holds the crystals together?
Van der waals
On what factor is depedant the plasticity of fats
temperature and fatty acid composition
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
a
Put the different polymorphic forms in order of increasing stability
alpha (α), beta prime (β’), and beta (β) forms
From a functionality perspective, β’ crystals are very undesirable because they are large and grainy.
false, it is the β that is grainy.
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
B
What is dialometry?
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.
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
both
What is consistency?
Consistency is the apparent hardness at a temperature
Beta-prime crystals → ____ amount of ____ air bubbles
large amount of small air bubbles
Beta crystals → ____ amount of ____ air bubbles
small amount of large air bubbles
How are produced low to zero trans margarines?
produced by interesterifying a blend of liquid oil and a fully hydrogenated oil.
The melting range of a confectionary fat depends on :
1- FA composition
2- crystallization
80% of cocoa butter is ___ triglyceride.
disaturated
What is the fatty acid in SN-2 position in most of the TG of cocoa butter?
oleic acid
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
small beta cystals
When fat is cooled quickly it forms thin, leaf-like crystals. This form is:
alpha
Beta prime crystals are preferred for chocolate:
false, it is beta
Fat blooms are ___ type of crystal
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
The technique that is based on the measurement of the change in specific volume per unit temperature is called
dilatometry
Why is milk fat often added to chocolate
because the milk fat tends to be in the beta-prime crystal type and it is cheap in comparision to cocoa butter.
