L7. LIPID PROPERTIES

1. Introduction:

Let's see how does a couple of drops of oil when the strips in water, ethanol and Esther.

-As the dye (Sudan III), we determine quantitad lipids that are in each type of milk, the more fat there are more change color.
-Let's see what effect the soap when you add to the mix water and oil.

2. Objectives:

-Test the solubility of lipids.

-Identify lipids in liquids compounds.

-Understand what are the effect of detergents.

3. Material:
-Test tube rack
-250mL beaker 
-Water
-6 test tube
-Cellulose paper
-Dropper
-Scissors
-Glass rod
-Olive oil
-Soap
-Milk with different fat content (semi-skimmed, full-cream...)
-Petroleum ether
-Ethanol
-SudanIII


4. Hypothesis:The most amount of milk fat (full cream milk) tenyirà more than that unless you cuantitat lipid (skimmed).The oil and water form a lipid monolayer, and the ether will dissolve the oil, and ethanol and water form micelles.Oil and water do not mix oil and form a monolayer, and the ester oil if you mix and oil and ethanol and oil do not mix form micelles.

5. Procedure:
1- Take three test tubes and add 2 mL of milk in each tube. In a whole milk, semi-skimmed milk in another and the last soymilk. Once we have milk in each tube add two drops of Sudan III staining with increased amount of milk lipids. Observe what happens.

2- Take another 3 test tubes and we put in a 1 mL of water, another 1 mL of ethanol and 1 mL of the final ether. Add in each two drops of oil. Observe how they act and every oil solvent.

3-Take a beaker of 250 mL and 100 mL of water are put. Add oil. Look what happens. Having observed the results, add soap. Stir, we see now?


6. Comments and conclusions:
Sudan III react more with the most amount of milk lipids, the whole milk.The solubility of water in the ethanol and ether mixed with oil.The right and the water does not dissolve, because oil is a lipid and lipid do not dissolve in water. The oil will form a monolayer on the surface of the glass, and when you add oil soap grouped to form droplets.First test tube water and oil-----> don't mixtSecond test tube, oil and ethanol-----> oil formed micellesThird test tube, oil and ether-----> ether (organic dissolvent) can disolve

7. Questions:
1.- From your observation, wich compounds can dissolve lipids? Ether can dissolve lipids

2.- Do the oil and water mix? What can you conclude about the polarity of the oil if you know that water is polar? No, they don't mix. So we ca conclude that the oil is apolar (non polar)
3.- Why is the olive oil liquid at room temperature? And why not the lard?Because oil is an insaturated acid, and lard not.

4.- Why does the lipid leave a translucent spot on paper? Because even if water has evaporate the lipid don't evaporate.

5.- Wich type of milk contains more lipids? Why? Full-cream milk, because in the experiment we have done we can see that they have more fat than the other milk types.

6.- Did the oil and water mix when you added the soap?No, they didn't.

7.- What did the soap do to the fat? Soap separated in micelles the fat.

8.- Can you think about process and locations were compounds like the soap would be important to an animal? Bile acids.