lipids-definition and classification Flashcards
T or F : Lipids are characterized by their hydrophobicity, insolubility in water and solubility in non-polar organic solvents.
T
Fats are made up of: A. Any alcohol esterified to fatty acids B. An alcohol with a single hydroxyl group esterified to a fatty acid C. Glycerol esterified to fatty acids
c
A substance that stabilizes an emulsion by increasing its kinetic stability is : A. Emulgent B. Emulsifier C. Surfactant D. All of them E. None of them
D
What are the three broad classes of lipids?
- simple lipids 2. compound lipids 3. derivied lipids
A diglyceride linked to a phosphate and a nitrogenous base is: A. Sphingolipid B. Phospholipid C. Glycolipid
B
In lecithin, the hydrophilic nitrogenous base is: A. Ethanolamine B. Serine C. Choline
C
T or F : Ceramide is a phospholipid
F
T or F : HDL contains more cholesterol than LDL
F
Carotenoids are important because of their: A. Nutritional value as precursors of Vitamin A B. Technological properties as natural food colorant C. Non of the above D. Both of the above
D
What are the three broad classes of lipids?
- Simple lipids 2. Compound lipids 3. Derived fatty acids (from simple lipids)
What are the simple lipids?
fatty acids esterified to an alcohol like triglycerides waxes
What are the compound lipids?
lipids conjugated to a non-lipid moiety like glycolipids, lipoproteins and phospholipids
Name the class of the following lipids groups : Fatty acids Fatty alcohols Hydrocarbons
Derived lipids
What will be the different in the melting point of a pure TG mixture and an edible fat
edible fat melts over a wider range of temperatures.
which one of the lipids could be considered for a low calorie fat replacer
waxes
Name the class of the following lipids : cholesterol, vitamin A.
waxes
What is the common source of phospholipids
soybean oil
Draw the structure of :
phosphatidylethanolamine
phosphatidylcholine
phosphatidylserine
phosphatidylinositol
What is a derived lipid
constituents that are derived from the simple or compound lipids categories and that still are hydrophobic.
T or F : longer-chain FFA have no flavour per se, but in the presence of mineral salts can give soapy flavour
t
Why should we discard an oil when the FFA gets to a certain point
because the FFA lower the smoke point (oil start to produce smoke).
What is added to TG mixture to form biodiesel?
methanol (CH3OH),
Why is milk fat solid?
because it is relatively saturated.
What can you conclude about this GC result
That there is a lot of saturated fat because the most predominant C16 in animal is C16:0 even if C16 can have double bonds.
Why are oils in the lauric group liquid at room T
because high portion of small chain (or medium) FA (C12)
True or False : Oils in the oleic-linoleic group doesn’t suffer from reversion
true because low amounts of C18:3
T or F : olive oil contains high amount of palmitic acid
true
What are would be bad for biodiesel? why?
soybean, linseed, castor and hempseed and perilla oil because they have high amounts of double bonds (3 double bonds) and so will polymerise.
Why does soybean oil wasn’t used in the past?
because of the high amounts of polynsaturated (linolenic) it suffers from reversion. No w it is processed to reduce the amount of polyunstaturation.
T or F : flaxseed oil is richer in omega-3 than fish oils
true.
What are the oils that contain omega-3?
wheat germ oil, soybean oil, hempseed oil, walnut oil, flaxseed oil and canola oil.
