STEM Electrophoresis with Food Dyes Bio-Rad Biotechnology Explorer™ IDEA and STEM Kits

STEM Electrophoresis with Food DyesBio-Rad Biotechnology Explorer™ IDEA and STEM Kits

Biotechnology Explorer™ | explorer.bio-rad.com2

Instructors - Bio-Rad Curriculum and Training Specialists

Sherri Andrews, Ph.D., Eastern US

[email protected]

Damon Tighe, Western US

[email protected]

Leigh Brown, M.A., Central US

[email protected]


Why Use Bio-Rad?

Guaranteed to work

Easy to prep

Cost Effective per student group

Easy, inexpensive first exposure to electrophoresis

Independent inquiry opportunities for what dyes are present in food items, what is the charge of the dyes, can they be separated based on charge/size?

Engineering inquiry with STEM kit ranging from optimizing metal composition and diameter for electrodes, gel matrix composition, buffer composition, etc.

Extensions including paper chromatography, spectroscopy, and researching food dyes commonly used


Separation technology: How do you separate two or more compounds from each other?

Materials to be Separated Property Used to Separate Components

Explanation

Iron filings from other metals Magnetism Iron filings will be attracted to a magnet while other metals will not

Salt from sand Solubility Salt will dissolve in water and can be separated from the sand

Caffeine from coffee beans Solubility A solvent is used that selectively dissolves the caffeine (such as dichloromethane or ethyl acetate) but not most of the remaining coffee oils

Ethanol from fermented grain Boiling point Ethanol will boil off at a lower temperature than the other components of the fermented grain

Wheat from chaff Density Wheat kernels are more dense and will fall to the ground while chaff can be blow away by the wind

Tea from tea leaves Size Filtration can be used to separate the liquid extract from the large tea leaves


Electricity can be used to separate molecules by charge

Acetate ions Tris ions- +

+

-

+

--

-

-

+

+

+

+

- ---

+ ++

Apply an electrical charge

CH3 CO

O-

HO CH2 C CH2 OH

NH3+

CH2 OH


Sieves can be used to separate materials by their size


Electrophoresis separates molecules by CHARGE and SIZE

Molecular sieve

Electricity

Electrophoresis means “to carry with electricity”


Food dyes – What have you recently eaten?…

Did you eat any cheddar cheese? Was it orange?

Starbucks Strawberry Frapuccino?


Food dyes – Color tells our brains about foods. What flavor is this Skittle?


Food dyes – We have been dying our foods for hundreds of years

In the early 1800s some cheese and cayenne pepper was colored with LEAD tetroxide

Pickles with COPPER sulfate

Green tea with COPPER carbonate


Food dyes - Regulation

There was NO control or regulations on food dyes until the early 1900s in the US

•Food and Drug Administration (1902)•Due to public outcry over adulterated foods •Upton Sinclair – The Jungle (1906)•Elixir sulfanilamide Poisoning, 100 dead (1937)

Food Drug and Cosmetics Act (1938) •Synthetic Dyes – Seven approved for use•Natural Dyes (derived from plants or animals) can also be used and are not regulated


FD&C Dyes and Natural dyes

FD&C Synthetic Dyes

FD&C Red 40 or FD&C Red 40 LakeFD&C Yellow 6 or FD&C Yellow 6 LakeFD&C Yellow 5 or FD&C Yellow 5 LakeFD&C Blue 1 or FD&C Blue 1 LakeFD&C Blue 2 or FD&C Blue 2 LakeFD&C Red 3 or FD&C Red 3 LakeFD&C Green 3 or FD&C Green 3 Lake

Natural DyesBeetroot red or betanin (from beets)Curcumin (from tumeric)Caramel coloring (from sugar)Annatto (seeds of achiote trees)Carminic acid, carmine, or cochineal (from ground up beetle abdomens)Lycopene (from tomatoes, watermelons, papayas, and red carrots)


Food dyes in the news


Food dyes have an intrinsic SIZE and CHARGE and thus can be separated using Electrophoresis

Food dye Molecular weight

Charge

FD&C Blue 1 792.86 -2

FD&C Yellow 5 534.37 -3

FD&C Yellow 6 452.37 -2

FD&C Red 40 496.43 -2

Carminic Acid 492.38 0

Beetroot red 551.48 +1


So how do we design an electrophoresis chamber to separate food dyes?

Dye Electrophoresis Commercial versus built box comparisons


Combining Science, Engineering and Math to Develop a Separation Technology

Engineering – Design parameter based; no single “correct answer”

Science – Hypothesis driven; try to find specific cause/effect

Conducts well, has low reactivity, inexpensive

Understanding the chemistry of metals in salt solutions, physics of conductivity and currents

Best electrode material

Best gel matrix

Conducts electricity, moldable, inexpensive, non-toxic, correct pore size

Polymer chemistry, melting points, gelling properties

Mea

sure

men

ts

An

alys

is


What are some of the design factors we want to think about?


Dye extraction from candies


Building and running your electrophoresis system to separate the dyes










Extensions

Paper chromatography Spectroscopy Food diary Electrochemistry study

– pH changes at the cathode and anode– Effect of material choice for electrode

Optimization of STEM box system– Electrode material choice and thickness– Different materials for gel thickness– Impact of TAE Concentration and Volume– Gel percentages

Copper electrode

Gelatin matrix

Documents

STEM Electrophoresis with Food Dyes Bio-Rad Biotechnology Explorer™ IDEA and STEM Kits