notes Flashcards
What are Lipids?
They include all biological compounds that are not soluble in water but can be soluble in organic solvents such as chloroform, methane, ether or benzene.
What do lipids include?
Fats, Oils, some vitamins, hormones and most nonprotein components of cell membranes
What do lipids include?
They include all biological compounds that are not soluble in water but can be soluble in organic solvents such as chloroform, methane, ether or benzene.
Include: Fats, Oils, some vitamins, hormones and most nonprotein components of cell membranes
What are lipids?
Lipids can be defined as fatty acids and their derivatives as well as substances related to biosythetically or functionally to said compounds
Classification?
Lipids fall into two groups and the subgroups.
Saponifiable:
- Simple lipids (Fats, oils & waxes)
- Compound lipids (Phospholipids, Glycolipids)
Nonsaponifiable
- Steroids (sterols, hormones)
Fats?
Lipids which are solid at room temp
Oils?
Lipids which are fluid/liquid are room temp
Function of fat in the body?
- Energy source especially for muscles
- Energy reserve
- Major component of cell membranes
- Nourishes hair and skin
- Insulates the body from temperature extremes
- Cushins vital organs to protect them
Functions fats and oils in food?
- Integral part of the human diet
- Calorie rich food: 9kcal/g
- Carry fat-soluble citations and essential fatty acids
- Provide satiety
- Contribute to flavour either good or bad (Eg. unique olive oil flavour and rancid bean off flavours)
- Contribute to texture (Crispy, creamy ect)
What is satiety?
Gives you the feeling of fullness
Structure of fats and oils?
(see other notes for more detail)
- They are triacylglycerols or triglycerides
- Comprise about 95% of lipids in food and the human body
- Glycerol + 3 fatty acids = Triglycerides + H2O
Classification of fatty acids
They are classified into Saturated and unsaturated
Unsaturated fats include Mono and polyunsaturated fats
Structure of fatty acids
- Fatty acids are usually liner comprising of even no. of carbon rings ranging from 4-24 carbons
(see other notes)
Saturated vs. Unsaturated fatty acids
- In general, saturated fatty acid is a straight molecule
- The double bond in an unsaturated fatty acid produced the kink in the molecule -> this happen due to the double bond been unable to rotate
- Saturated triglycerides pack closely together
- Attractive forces in saturated fatty acids give them a high melting point
- unsaturated fatty acid molecules cannot pack closely together because of cis double bonds (causes kinks)
- Intermolecular forces are weaker and less energy is required to operate molecules so lower melting point
Omega 3 vs. 6 fatty acids
- Based on the location of double bonds. “omega number”
- Omega no. is the number of c atoms between the double bond and the terminal methyl group.
- Omega 3 fatty acid
- Omega 6 fatty acid
Cis and trans Fatty Acids?
Unsaturated fatty acids can exist in either the cis or trans form depending on the configuration of the hydrogen atoms attached to the carbon atoms joined by the double bonds.
cis Fatty Acids
– If the hydrogen atoms are on the same side of the carbon chain, the arrangement is called cis.
trans Fatty Acids
– If the hydrogen atoms are on opposite sides of the carbon chain, the arrangement is called trans
- The Kink in the carbon chain is much more pronounced in the cis isomer then the trans. For this reason the cis fatty acids do not solidify as easily as trans
and cannot line up as easy
Trans fats health concern?
Fatty acids with trans double bonds usually occur as a result of processing (ie hydrogenation) but can occur naturally in ruminant fats.
trans Fatty acids are thought to play a part in lowering high density lipoprotein ie HDL (also referred to as good cholesterol) and increasing low density lipoprotein (LDL).
LDL is known to contribute plaque formation in arteries leading to the potential for a myocardial infarction.
Position of double bonds in fatty acids?
- Methylene interrupted
Polyunsaturated fatty acids where the double bonds are operated by a CH2 unit
-CH=CH-CH2-CH=CH= - Conjugated
Polysaturated fatty acids where the double bonds are operated by a singe bond
-CH2-CH2=CH-CH2=CH-