Lipid Flashcards
Is lipid hydrophobic or hydrophilic
hydrophobic
What are the 3 major classes?
simple lipids, compound lipids, derived lipids
What are the two categories of simple lipids?
fats ( triglycerides, edible fat/oils) and waxes (fatty alcohol esters and jojoba)
what are the 3 categories of compound lipids?
phospholipids (lecithin), glycolipids, lipoproteins
what are the 3 categories of derived lipids?
fatty acids, fatty alcohol, hydrocarbons (oxygenated derivatieves and flour/color compounds)
what is the definition of simple lipids?
esters of fatty acid connecte to an alcohol. The esters of fatty acid are connected to glycerol
what is the definition of compounds lipids?
conjugated to non-lipid moiety
what is the definition of derived lipids?
derived from simple/compound classes
what is another synonym of simple fat
triacylglycerol
What the term oil refers to?
Indice MP
refers to fat that have a low melting point and are liquid at room temperature. Fat is solid at room Temp
The most lipids found are
triglycerides
What is the difference between the melting point of a pure triacylglycerol and a typical edible fat
The edible fat melts over a much wider range of temperature because it consists of a mixture of many different pure triacylglycerol molecules, each with different melting points
What is an wax? Give some examples
esters of fatty acids esterified with an alcohol, other than glycerol.
EX: jojoba oil, bee’s wax
What are the applications of food use for waxes?
Largely used as sealing agents (cheese) and polishing agents (apple) Also being considered of potential low-calories food ingredient which give a “fatty sensation”but provides FEW CALORIES.
Apart from food, what other product could wax be used for ?
cosmetics
what are some compounds in the wax category?
complex alcohols such as cholesterol, esters of vitamin A or retinol
True or false
Waxes are important because they are biologically active
true
Compound lipids are made up with what
They are made up of a sigle lipid (generally the triglyceride type) conjugated to a non lipid molecule
What are phospholipids made of?
Is a triglycerides with one of thei fatty acid replaced with a non lipid moiety - phosphoric acid
Phosphoric acid is conjugated to what?
to some other non-lipid molecule
What is the basic structure of the non-lipid moiety
Indice : has a X
phosphatidic acid
X=OH
X is nitrogenous base
What is the structure for phosphatic acid
X=OH
what is the structure for phosphatidylethanolamine
X=O-CH2-CH2-NH2
What is the structure for phosphatilchoine
X=O-CH2-CH2-N(CH2)3
what is the structure for phosphatidulserine?
X=O-CH2-CH(NH2)-COOH
what is the structure for phosphatylinositol
hexagone with OH see slide 15
what are some common classes phospholipids
- lecithins (phosphatidyl choline)
- cephalins (phosphatidyl ethanolamines)
- phosphatidyl inositols
What are the % of lipid material found in food systems?
less than 5%
Phospholipids are commercially used for what? and give an exemple
commercially useful as emulsifiers - common source is soybean oil
Glyco- and sphingolipids are associated with what types of membranes?
memebrane lipids in both animals and plants
what are the structure of glycolipids and sphingolipids
combination of glycerol-like backbone, F.A, carbohydrate, and/or a nitrogenous group
True or false
glyco-sphingolipids have a lot of consequence to food scientist
False, they have little to do with food
what is the chemical composition of sphingolipids?
sphingosine
F.A
R-group
what types of glycolipid are found in cells
glycolipd and glycoprotein
what is the function of lipoprotein
they circulate in blood to carry lipids to tissues for metabolism or storage and they storage HDL (more protein) and LDL (more lipid)
what is the difference between the HDL and the LDL
HDL: high-density lipoprotein. It is considered good cholesterol. 1/3 of all blood-circulating cholesterol. Serve as a protective mechanism from the development of heart disease by carring away cholesterol from vessel walls and plaque to the liver disposal.
LDL: low-desnity lipoprotein. Bad cholesterol. It transports substances vital to cell function and development. When there is a lot it can be harmful - lead to blockages of arteries, plaque build up. Related to heart attach and stroke
T OR F
the actual structure of lipoproteins is rarely known
true
what are derived lipid
constituents taht are derived from the simple or compound lipid categories and that still retain their hydrophobic character
give the categories of derived lipids
- fatty acid
- fatty alcohol
- hydrocarbons and oxygenated derivatived therof
where are derived lipids found
food system
what are the difference between short and long F.A
short : flavour compounds, released by lipolysis . Long chain don’t have a flavour per se but in the presence of mineral salts it can give a soapy flavour
F.A Give their names
C4
C6
C8
C4: butyric acid
C6: caproic acid
C8: caprylic acid
true or false
In fatty alcohols short chains give flavours
true
what are terpernes
unsaturated hydrocarbons made of isoprene units
Terpenes are known of?
as components of the fragant oils obtained from leaves, flowers and fruits
what are the main constituents of essential oils
monoterpenes (10C, 2 isoprene unit ), sesquiterpenes (15C, 3 isoprene units)
what is the fundamental isoprenet unit
5 carbons
monoterpenes - 2 isoprene - 10 C
sesquiterpenes - 3 isoprene - 15 C
diterpenes - 4 isoprene - 20C
sesterterpenes- 5 isoprene - 25 C
triterpenes - 6 isoprene - 30 C
Lipid content can rise by 15-20% to serve what
as a commercial source for isolation of triacylglycerol and be sold as fats or oils
What is the nutritive importance of lipids
Fuel molecules (9kcal/g) and a source of fatty acids and vitamins Pleasant creamy or oily mouthfeel and the ability to solubilize many taste and aroma constituents of food
The 2 components (ipids) most interested in food systems are?
fats (95-96%) and phospholipds
in what form fatty acids are found
combined in the form of triglycerides (they assembled to the glycerol)
what are the 2 basic types of fatty acids
- saturated fatty acid (simplest and least reactive)
2. unsaturated fatty acid
true or false
fatty acids founds in nature tend to be even numbered
true
How many carbons there is in a short chain and a long chain of F.A? and what is there state
short chain F.A: C4-C12 and they are liquid at room temperature
longer chain F.A: more than C12 and they are solid
Who has a lower melting point: short chains or longer chains.
short chain has a lower melting point.
Give the melting point of butric acid (C4) lauric acid (C10) and myristic acid (C12)
Butric acid : -7.9
lauric acid : 44
myrictic acid: 54.4
Why does water solubility decreases with increasing in chain lenght
due to the increasing hydriohobicity
Fatty acids that have odd numbers are presented where
present in food only in traces
Which fatty acids (there is 2) that are found in milk and plants oils
pentadenoic (15C)
Heptadenoic (17C)
What are the most common unsaturated fatty acids
oleic, linoleic and linolenic
how many carbons and double bond there is with :
oleic acid
linoleic acid
linolenic acid
oleic acid: (18:1)
linoleic acid: (18:2)
linolenic acid : (18:3)
what are the 2 major systems to name staurated fatty acids
trivial names and systematic names
how can you name a an acid with a systematic way
the number of carbons (Greek numerical system) + suffix noic
ex:: penta(5C) + noic= pentanoic
what are the common name of : ethanoic (C2) butanoic (C4) hexanoic (C6) Octanoic (C8) Decanoic (C10) dodecanoic (C12) Tetradecanoic (C14) Hexadecanoic (C16) Octadecanoic (C18) Eicosanoic (C20) Docosanoic (C22)
- acetic
- butyric
- caproic
- caprylic
- capric
- lauric
- myristic
- palmitic
- stearic
- arachidonic
- behenic
How is the presence of a double bond indicated in nomenclature?
enoic
how is the name of these molecules:
C18:1
C18:2
C18:3
octadecenoic
octadecadienoic
octadecatrienoic
How is the name od these molecules given their position
C18:1 (9)
C18:2(9,12)
C18:3(9,12,15)
octadeca-9-enoic acid
octadeca-9,12-dienoic acid
octadeca-9,12,15-trienoic acid
In the IUPAC system from where is counted the double bond?
from the carboxyl end
If you have cis and trans configuration how can you write
C18:2(9c,12t)
octadeca-cis-9,trans-12-dienoic acid
What is the difference in the cis and trans form?
cis form: hydrogenes are on the same side of the carbon chain
trans form: the hydrogens are on opposite sides of the carbn chain
which conformation (cis or trans) is easier to pack? and which has a higher melting point?
trans and trans has also a higher melting point, because it packs more
Put in the correct other for melting point?
1= high
3=low
1) saturated
2) trans
3) cis
what happens regarding cis/trans during hydrogenation?
a side reaction in the conversion of the natural cis form to trans
what is the main mechanism for oils becoming plastic fats during hydrogenation?
cis -> trans
What is a positional isomerism?
the double bond is located on the fatty acid chain
What are the 2 forms of how the double bonds are situated?
unconjugated double bond: the double bonds are separed by a methylene group
conjugated double bonds: they are next to each other
