Lipids Flashcards
liquid in room temperature
oil
meaning of lipid
great
fat-like
composition of lipids
fatty acids
glycerol
hydrophobic
no charges
equal sharing of electrons
soluble in organic solvents
non-polar
Characteristics of Lipids
means great or fat-like made up of fatty acids and glycerol non-polar soluble in organic solvents energy storage for the cell
partly ionic, positive charge,
polar
lipid-solvents or fat-solvents
ether, chloroform, benzene and acetone
Solvents used in solubility of coconut oil
water conc. HCl conc. NaOH cold alcohol hot alcohol chloroform
solubility of coconut oil in water
insoluble
solubility of coconut oil in conc. HCl
insoluble
solubility of coconut oil in conc. NaOH
insoluble
solubility of coconut oil in cold alcohol
insoluble
solubility of coconut oil in hot alcohol
insoluble
solubility of coconut oil in chloroform
soluble
are non-volatile
Fats
Oils when brought in contact with a substance like paper, it penetrates through it producing a:
translucent spot
the spot of grease can never absorb enough______ to vaporize
heat
When the liquid is inside the sheet of paper, it diffracts light -
Translucent Phenomenon
affect the rate of evaporation of oil.
The difference in molecular weight and number of double bonds
The longer the carbon chain and the fewer the double bonds
The longer the time it evaporates
to evaporate a lot longer
because they are composed of many single carbon bonds that make the substance less volatile
Saturated fatty acid
composed of one or more double bonds.
The double bonds make the fat more volatile.
Unsaturated fats
result of Coconut oil in Formation of translucent spot
saturated fatty acid
less volatile and thicker spot
result of Anise oil in Formation of translucent spot
unsaturated FA
more volatile, thinner spot
Color of fresh coconut oil
yellow
Color of coconut oil after exposure
brown
Odor of fresh coconut oil
oil-like
Odor of coconut oil after exposure
rancid
Reaction of fresh coconut oil to litmus paper
Neutral
Reaction of coconut oil after exposure to litmus paper
Acidic
Acidity is due to:
- Oxidation of the double bonds of glycerol
- Hydrolytic change with the production of FA with the formation of volatile aldehyde. This condition is called rancidity
refers to the spoilage of a food in such a way that it becomes undesirable (and usually unsafe) for consumption, having unpleasant smell or taste.
Rancidity
the ability of the molecule to come in intimate contact with the material acted upon
Surface tension
is used to detect the presence of glycerol or fat
when fat is treated strongly in the presence of a dehydrating agent like potassium bisulphate (KHSO4), the glycerol portion of the molecule is dehydrated to form an unsaturated aldehyde, acrolein that has a pungent irritating odor.
Acrolein
is a process by which you mix two liquids that are ordinarily immiscible (formation of globules)
Emulsification
must be present to stabilise the emulsion
Emulsifying agent
solid room temperature
fats
Serve as emulsifier of egg
Lecithin
Emulsifiers
Na2CO3
Egg albumin
Reagents of TT1 in Emulsification of Oils
Coconut oil + H2O
Reaction of TT1 in Emulsification of Oils
shake: Formed 2 layers with H2O on top
settle: coconut oil on top
Reagents of TT2 in Emulsification of Oils
Coconut oil + Na2CO3 + H2O
Reaction of TT2 in Emulsification of Oils
Formed a milky white solution
Reagents of TT3 in Emulsification of Oils
Rancid oil + Na2CO3 + H2O
Reaction of TT3 in Emulsification of Oils
Formed a milky solution without precipitate
Reagents of TT4 in Emulsification of Oils
Egg albumin + coconut oil
Reaction of TT4 in Emulsification of Oils
Formed milky solution with precipitate but with foam
is the hydrolysis of an ester under basic conditions to form an alcohol and the salt of a carboxylic acid
It produces soap and glycerol, usually from fats and lye
It involves metallic alkali base (usually NaOH and KOH) hydrolysis of triglycerides, which are esters of FA, to form the sodium salt of carboxylate.
Saponification
dehydrating agent in saponification of lard
KOH dissolved in ethanol and neutralised FA in the lard
Alkaline
alcoholic potash
Production of saponification of lard
Soap
Glycerol
Source of soap and glycerol
Fats
Lye
Metallic alkali base used in saponification
NaOH
KOH
Used in the experiment to produce hard soap
Alcoholic potash
Na2CO3
Dehydrating agent in acrolein formation
KHSO4
Procedure in formation of translucent spot
- Place 1 drop of coconut oil on a piece of paper
- Note formation of translucent spot
- Allow to evaporate
- Repeat procedure 1-3 with anise oil
Procedure of reactions of fats
- Place 2 ml of coconut oil in test tube
- Test with red and blue litmus paper
- Allow oil to stand uncovered until next lab period
- Note any change in coconut oil during next lab period
- Test with red and blue litmus
Procedure in effects of fats on surface tension
- Fill clean pipette with water up to 0 ml mark using aspirator bulb
- Hold pipette vertically and cover top end with thumb
- Gradually release the thumb to allow water to flow by drops
- Count number of drops in one minute
- Clean pipette with acetone and allow to dry up
- Fill with coconut oil
- Drain oil
- Fill pipette with water, repeat procedure 1-4
Procedure in acrolein formation
- Place potassium bisulfate in test tube
- Add a drop of coconut oil and heat
- Note odor produced
Procedure in emulsification of fats TT1
- Add drop of coconut oil to water and shake
2. Allow to stand and record result
Procedure emulsion TT2
- Add drop of Na2CO3 to water
2. Add drop of fresh coconut oil and shake. Record and compare
Procedure emulsification TT3
- Add drop of Na2CO3 to water
2. Add drop of rancid oil and shake, observe emulsion produced
Procedure emulsification TT4
- Add drop of coconut oil to dilute albumin solution
- Observe nature of emulsion
- Compare
Procedure of saponification of lard
- Place lard on erlenmeyer flask
- Add 50 ml alcoholic potash
- Warm in water bath till saponification is complete
- Transfer solution to evaporating dish
- Heat in water bath until alcohol is driven off
- Acidify with dilute HCl and cool
- Remove fatty acid
- Neutralize solution with na2co3
- Evaporate to dryness
- Extract residue with alcohol
- Remove alcohol by evaporation on water bath until consistency is syrupy