Flashcards in Lipids lecture 1 Deck (64)
What is olestra?
"fat free fat"
a FA attached to a sugar
can't be metabolized
chemical characterization of lipids?
insolubility of in water
soluble in non polar organic solvents
3 classes of lipids?
categories of simple lipids?
fats and waxes
types of compound lipids?
what are simple lipids?
esters of FA connected to an alcohol
types of derived lipids?
what are fats (simple lipids)?
esters of FA connected to glycerol
R1 R2 R3 are FA (short to long chain aliphatic hydrocarbons with a COOH group at one end)
oil vs fat?
oil: low mp and liquid at room temp
fat: solid at room temp
percent of triglycerides in extractable lipid material in biological systems and in lipid that we consume?
melting profile of pure triglyceride vs edible fat?
triacylglycerol has a very sharp melting point
edible fat melts over a wider range of temp because it is a mixture of different triacylglycerol molecules
chemical structure of waxes?
FA esterified with a simple fatty alcohol (other than glycerol)
aliphatic alcohol + FA = wax
what is a true wax
FA esterified to a SIMPLE fatty alcohol
uses of waxes?
sources of wax?
sealing agents (cheese)
polishing agents (apples)
sources: injojoba oil, beesewax
jojoba oil structure and use?
structure: linear esters of mono unsat long chain FA esterified to fatty alcohols
use: cosmetics. low cal ingredient (not digested readily)
structure of cholesterol?
FA esterified to a complex alcohol
what are compound lipids? types?
simple lipid conjugated to a non lipid
structure of phospholipids?
what is the base structure?
what are the different phosphatidic acid molecule examples?
triglycerides with one FA replaced with a nonlipid moiety - phosphoric acid
base structure = phosphatidic acid (when X=OH)
other phospholipids: X=nitrogenous base
classes of phospholipids
1. lecithins (phosphatidyl cholines)
2. Cephalins (phosphatidyl ethanolamines): phosphatidic acid conjugated to ethanolamine (x=OH-CH2-CH2-NH2)
3. Phosphatidyl inositols: non nitrogenous group + phosphatidic acid
hydrophilicity of phospholipids?
how much is found in food systems?
contains both hydrophobic and hydrophillic groups
thus, good emulsifier (ie soybean oil )
in food systems: comprises <5% of lipid material
what are glycolipids and sphingo lipids?
examples of glycolipids in cell membranes?
in cell membrane lipids in plants and animals
complex structure: combination of glycerol backbone, FA, carb, nitrogenous group
ex in cell membranes: glycoproteins, glycolipid, glycocalix
role and structure of lipoproteins?
circulates in blood to carry lipids to tissues for metabolism or storage
HDL and LDL (different sizes and levels of protein, fat and cholesterol)
inside: triglyceride + cholesterol esters
outside: phospholipid + cholesterol + apolipoprotin
LDL vs HDL?
HDL: good. accounts for 1/3 of blood circulating cholesterol. protective to heart disease
LDL: excess = plaque in blood vessels = artery blockages
what are derived lipids?
derived from simple of compound lipid categories. Still retains hydrophobic character
types of derived lipids (3)
Role in food systems?
1. fatty acids
2. fatty alcohols
3. hydrocarbons and oxygenated derivatives
role in food systems: major role in functionality
structure of fatty acids (as type of derived lipids)?
short to long chain aliphatic hydrocarbons w/ COOH group at one end
what are short chain FA important for?
can be released by lipolysis
butyric acid (C3)
Caproic acid (c6)
caprylic acid (c8) --> rancid cheese flavor
what can presence of FFA do?
lower the smoke point of edible oils when used for frying
do long chain free fatty acids have flavour?
but can give soapy flavour in presence of mineral salts