lipids are another important class of nutrients that include fatty acids, phospholipids, steroids, and cholesterol
primary functions will be discussed further in lipid classifications
source of energy
Energy storage
Cell membrane component
Protection and insulation
Digestion and absorption
fatty acids consist of a long hydrophobic, non-polar hydrocarbon “tail”, and a hydrophilic polar carboxylic acid functional group at the “head”
natural fatty acids may be classified as
saturated fatty acids
unsaturated fatty acids
saturated fatty acids have no carbon-carbon double bonds
unsaturated fatty acids contain one or more double bonds in the hydrocarbon chain
lauric acid - a saturated fatty acid found in coconut oil
Oleic acid - an unsaturated fatty acid found in animal fat
essential fatty acids
Linoleic acid
Linolenic acid
Essential fatty acids are precursor in the sentences of prostaglandins. A group of lipids greatly affects a number of important physiological process.
trans fats or trans fatty acids can be formed through a process called hydrogenation, which makes the oil more solid
the cis and trans configurations influence the shape of fatty acid molecules
trans configuration that twist or kink produced by the double bond in the cis configuration is not observed
trans fats can be found in many food products such as
Cookies
Cakes
Savory snacks
classification of lipids
simple lipids
Complex lipids
steroids are simply lipids that have a backbone structure, consisting of four fused carbon rings
cholesterol is the most abundant steroid in animal tissues. It is composed of steroid backbone structure with hydroxyl group at one end and a branched hydrocarbon chain at the other.
cholesterol serves us
Base of other steroids
Male and female hormones
Vitamin D
Bile acid
The most abundant class of lipids in plants and animals is that triglycerides
triglycerides are composed of
Three fatty acids
Single glycerol
esterification is the reaction between an alcohol and a carboxylic acid that produces an ester and water
Triglycerides are the major lipids found in the blood
at room temperature, solid triglycerides usually of animal origin are called fats
liquid triglycerides, usually from plants are called oils
phospholipids are the fundamental building blocks of cellular membranes
phospholipids are have two distinct parts
Hydrophilic phosphate head
Long hydrophobic tail
lecithin is an example of phospholipid. It is a major component of cell membrane and this use as an modifying agent
lecithin is naturally found in
Egg yolks
nut
Whole grains
Soybeans
another phospholipid is cephalin, which is found in the cell membranes of the brain and tissue and in blood platelets
waxes are water-insoluble, low-melting solids that consist of a long chain fatty acid and a long chain, monohydroxy alcohol
Types of waxes
Beeswax
Chinese wax
Earwax
lanolin
shellac
Spermaceti
Vegetable wax
Phospholipids are made up of two fatty acids, glycerol, phosphate, and one simple organic molecule