Macromolecules Standard Qualitative Tests and Testing Your Own Food

Qualitative Detecting if a substance is present You dont know how much

SAFETY IF A SOLID, cut into little pieces Rinse razor blades under water, do not wipe across the blade Put used blades at the end of the period in the used beaker on the cart

Goggles and Apron Chemicals are caustic to your eyes Iodine stains

When it asks for… Dropper FullJust squeeze to fill dropper and release Exact amounts are not important 1 dropper full = drops

Pasteur Pipets

NEVER EVER NEVER, hold a filled pipet upside down…or hold on its side… You contaminate the bulb

For 5mL and 10 mL ACID SUCROSE

Controls Positive Control Absolutely expect to see the result Use the substance (starch, glucose, etc.) Negative Control Absolutely expect to NOT see the result (may use water )

Lab Objective: Describe the test that indicates the presence of most small sugars.

Recording Benedicts Results - blue no sugar + blue/green trace ++ green little sugar +++ yellow some sugar ++++ orange/red much sugar

Benedicts Sugar Test

Lab Objectives: Describe the test that indicates the presence of starch. IODINE IS POISONOUS!!!

Iodine Test negative positive

Lab Objective: Define hydrolysis and give an example of the hydrolysis of carbohydrates. ANIMATION LINKS: Animation: Enzyme Action and the Hydrolysis of Sucrose Animation: Enzyme Action and the Hydrolysis of Sucrose Hydrolysing starch WHFoods: How Does Digestion Work and How Can I Improve Mine? (Animated graphics)WHFoods: How Does Digestion Work and How Can I Improve Mine? (Animated graphics)

Hydrolysis break with water to make monomers

Lab Objective: Give examples of the formation/ breakdown of a: monosaccharide disaccharide polysaccharide

Lab Objective: Name the monosaccharide components of sucrose and starch.

Polysaccharide Disaccharide (sucrose) Monosaccharide (glucose)

Two Common Monosaccharides

Simple Sugars Called monosaccharides primary function = energy Your SAMPLE will be glucose

Disaccharide Double Sugar Combined simple sugars YOUR SAMPLE WILL BE SUCROSE

Disaccharide

Now Lets Demonstrate how Digestion Might Work Click Here Howstuffworks "The Digestive System"Howstuffworks "The Digestive System"

Tube 1- blue (-) still sucrose, a disaccharide Tube 2- heat broke bonds –so tested orange (+) for glucose 2 1

Tube 3 Negative for because it is starch (a polysaccharide) STARCH

Polysaccharides Shorter sugars link together to form complex sugars Your starch sample will be POTATO STARCH

glucose

Tube 4 Starch Not heated – so it would be (+) for iodine, blue- black

Tube 5 Heated 5 minutes – added Benedicts Starch may just start to break down, so just a little (+) for glucose or (-) starch did not break down yet here

Tube 6 Heated 5 minutes added Iodine Brown – somewhat broken down – so just partially (+) for starch Tube 6

Tube 7 Heated 15 minutes Added Benedicts (for a glucose test) Starch is broken down to its monomers, glucose Tube 7

Tube 8 Heated 15 minutes – Tested for starch Negative, because it is broken down to glucose TUBE 8

Explain Benedicts test on sucrose AT first sucrose is (-) with Benedicts because it is a disaccharide. After hydrolysis (heating and acid), the monosaccharide glucose is (+)

Explain the iodine test with starch At first starch is (+) with iodine. After hydrolysis, the starch breaks down to glucose and tests (-) with iodine.

Explain Benedicts with starch. At first starch would be (-) for it is not glucose, but is a polysaccharide. After hydrolysis, glucose is formed when the bonds break.

Why does hydrolysis of starch take longer than of sucrose? Starch is a polysaccharide, more bonds to break. Sucrose is a disaccharide.

Cellulose

Dehydration Synthesis take out water to make macromolecule

Complex Carbohydrates Starch -storage in plants Cellulose -fiber Glycogen-storage in animals

Testing for Fats and Proteins Read Lipids Intro p. 9 and answer the questions to the left (3) Read Proteins Intro p. 10 and answer the questions to the right (3) Mrs. Sheldon will demonstrate the Separation of Butter lab.

Fat Test with Brown Paper Translucent (light can go through) = + fat test

Protein Test with Biurets

Describe the Protein Test Biurets is what color? Blue In the presence of a protein it will turn what color? purple

Biurets turns purple in the presence of protein Neg. Lots Slight

Separation of Butter Clarification is removing lipid part (water insoluble) from non- lipid part (water-soluble). Why do it? Clarifying butter raises the smoke point from 250 o F to 350 o F.

Emulsion Oil droplets (micelles) are formed in water- soluble substances Oil is non-water- soluble

Heat breaks up the Emulsion- separates the butter Ghee A common food fat in India, ghee is produced from boiled buffalo milk. Its manufacture is similar to that of butter oil. It can be kept for months, or years, without refrigeration, and has a more intense flavor than butter or butter oil.

Clarified Butter (Ghee) separated into: Protein foam on top skimmed off Next layer = clarified butter Bottom layer = milk solids - flavor

BRING IN FOODS TO TEST We can grind, chop, dilute them to make them dissolve in water We will run all the tests on them

While you Wait… Do exercises from the handouts: –Lipid Crossword –Exercise 6 –Exercise 7 –If you have trouble, use text CD