three categories of lipids
triglycerides phospholipids sterols
*basic units of lipids are C, H, O
triglycerides
MOST COMMON LIPID (in both food and body)
95% of lipids found in food
functions-
add texture to baked goods make meats tender
stored as adipose tissue for energy
structure- glycerol and 3 fatty acid tails (E)
phospholipids
-synthesized by the liver
-provide structure for cell membrane
-used as emulsifier in foods
structure
-hydrophilic head (phosphate and glycerol)
-hydrophobic tail (saturated and unsaturated fatty acids)
sterols
made of four connecting rings of carbon and hydrogen
*do not contain glycerol or fatty acids
*do not provide energy
cholesterol is best known sterol
functions of lipids in the body
store and provide energy provide insulation
help manufacture steroids and bile play a role in
transporting fat-soluble nutrients in blood used to
manufacture major sex hormones key to structure of cell
membranes
fatty acids
structure
chain of carbon and hydrogen atoms with a carboxyl group at
the alpha end and a methyl group at omega end
*building blocks for triglycerides and phospholipids
saturated fatty acids
no double bonds all carbons are bound to hydrogen
solid at room temp higher melting point
unsaturated fatty acids
some carbons are held together with a double bond (fewer bonds
with hydrogen) monounsaturated fatty acid (MUFA)= 1 double
bond polyunsaturated fatty acid (PUFA)= at least 2 double
bonds tend to be liquid at room temp have a lower
melting point
cis form unsaturated
hydrogens on the same side of the double bond
trans form unsatured
hydrogen atoms are on opposite sides of double bond