The Sensational Science Behind Antioxidants: Testing Facts vs. Myths of popular antioxidant products

The Sensational Science Behind Antioxidants: Testing Facts vs. Myths of popular antioxidant products

Yesterday, you broke up into groups and selected a popular “antioxidant-rich” product

to endorse

Today you will chemically test the drinks to see if there’s truth to their marketing.

You are the Research & Development Team and the Marketing Team for your product.

Victims of Oxidation

Part I: The science behind antioxidants

Free radical with unpaired electron

Free radicals cause damage by oxidation

OO

Molecular OxygenO2

OO

OO

HH OO

O

H O

H

Add two H+

Add 3rd e-

Hydroxyl ion OH-

Add 1st e- Add 2nd e-

Superoxide radicalO2

-

Peroxide radicalO2

-2

Hydrogen peroxide

H2O2

Hydroxyl radicalOH

Add 4th e-O

H

Hydroxyl ion OH-

Add 2H+

O

H

H O

H

H

Water

Reactive Oxygen

Species

ROS

Oxidation occurs when one substance transfers one or more its electrons to another substance

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2O

Electrons lost to

“Catechol is oxidized by O2 to become benzoquinone”“Catechol loses its electrons to O2 to become benzoquinone”

Free radicals cause damage by oxidation

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2OPhenol Oxidase

Phenol Oxidase catalyzes the reaction that changes catechol, in the presence of O2, into benzoquinone

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2OPhenol Oxidase

Phenol Oxidase catalyzes the reaction that changes catechol, in the presence of O2, into benzoquinone

+Antioxidant!

X

Browning reactions are due to oxidation

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2OPhenol Oxidase

Phenol Oxidase catalyzes the reaction that changes catechol, in the presence of O2, into benzoquinone

Can any of these products inhibit the browning reaction in mushrooms?

BufferpH 7

100X Daily Dose of Vitamin C

x 10Controls:

1. Weigh mushroom2. Chop mushroom into

pieces and put into Ziploc bag

Multiply mass by 4 and add that amount of

buffer to the bag

3. Close bag tightly and mash gently with fingers

4. Wet the coffee filter with buffer and place over cup.

Use pipette to transfer mushroom extract to filter

Purifying mushroom oxidase

Perform the tests!

Spot test

1. Using the pipette, add two drops of mushroom oxidase to every square on your table.

2. Add the appropriate reactants to each square in the order they are listed

3. Once all the drops have been added to the 6 squares, start the timer.

4. Observe the reaction for 5 minutes, then answer the following questions.

Hint: Use a steady hand so that each drop is the same amount of liquid. Make sure the paper is level, so the drops do not move.

Time = 0 min

Time = 5 min

http://science-edu.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html

Double bonds absorb light

Light absorption is like a fingerprint for compounds

AbsorbanceReadout

0.430

Light Prism to disperse light

Wavelength selector

How does a spectrophotometer work?

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2O

0.5200.240

At Abs490 nm:

Spectrophotometer Test1. Label your test tubes #2, #4, #6 and buffer

blank

2. Add 4 ml of buffer to “buffer blank”. Place the tube into spectrophotometer holder and use the left knob to set the numbers in the absorbance window to 0.000.

3. Add the reactants for Tube #2—use correct pipettes for each reactant! Mix by tapping the test tube, and place tube into spectrophotometer. Start the timer and record absorbance at t=0 min.

4. Remove tube at t = 4:30 min and mix by tapping test tube. Record absorbance at t = 5 min.

5. Repeat steps 3-4 for each Tubes #4, #6.

There are many different ways to test for antioxidants

Our mushroom oxidase test may not be sensitive enough to pick up on antioxidant levels

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2OPhenol Oxidase

+Antioxidant!

X

CatecholColorless

+ ½O2

BenzoquinoneYellow-Brown

+ H2OPhenol Oxidase

+Antioxidant!

X

Your drink has antioxidants, but it may be very low amounts compared to

100X Daily Value of Vitamin C

Part II: The marketing behind antioxidants

Present a 3 minute marketing campaign that showcases:

Your knowledge on the mechanism and health benefits of antioxidants defense against free radicals.

Your product’s antioxidant test results.

Your opinion why your classmates should buy your antioxidant drink.

Edited by Ms. Theresa

(Instructor note: show a video clip of antioxidants in the media. In my presentation, I edited together a video of 9 different commercials, interviews on the topic of antioxidants)

1. Do not make scientific claims that you cannot back with evidence

2. Find a different approach to market the product

Much research has to be performed before claims can be made

Much research has to be performed before claims can be made

“I recommend pizza since it is a vegetable and

therefore has *tons* of antioxidants.”

I’m actually a real doctor! Google me!

The best marketing campaign was for:

The best scientific argument was made by:

Write-in: Based on the overall campaign and facts, I would consider buying:

Sample BallotWhich product is the best antioxidant drink on the market?

☐ 7-Up Antioxidant

☐ Activate Antioxidants

☐ FUZE Triple Berry

☐ Lipton Green Tea

☐ POM Wonderful

☐ Vitamin Water XXX

☐ Other ___________

☐ 7-Up Antioxidant

☐ Activate Antioxidants

☐ FUZE Triple Berry

☐ Lipton Green Tea

☐ POM Wonderful

☐ Vitamin Water XXX

☐ Other ___________