STEM Electrophoresis with Food Dyes

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

2. Instructors - Bio-Rad Curriculum and Training Specialists Sherri Andrews, Ph.D., Eastern US sherri_andrews@bio-rad.com Damon Tighe, Western US damon_tighe@bio-rad.com Leigh Brown, M.A., Central US leigh_brown@bio-rad.com

3. 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

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

5. NH3+ - - - - - - - - - O HO CH2 C CH2 OH CH3 C - O- CH2 OH + + + + + + + + + Apply an electrical charge + Electricity can be used to separate molecules by charge Acetate ions Tris ions

6. Sieves can be used to separate materials by their size

7. Electrophoresis separates molecules by CHARGE and SIZE Electrophoresis means “to carry with electricity” Molecular sieve Electricity

8. Food dyes – What have you recently eaten?… Did you eat any cheddar cheese? Was it orange? Starbucks Strawberry Frapuccino?

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

10. 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

11. 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

12. FD&C Dyes and Natural dyes FD&C Synthetic Dyes FD&C Red 40 or FD&C Red 40 Lake FD&C Yellow 6 or FD&C Yellow 6 Lake FD&C Yellow 5 or FD&C Yellow 5 Lake FD&C Blue 1 or FD&C Blue 1 Lake FD&C Blue 2 or FD&C Blue 2 Lake FD&C Red 3 or FD&C Red 3 Lake FD&C Green 3 or FD&C Green 3 Lake Natural Dyes Beetroot 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)

13. Food dyes in the news

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

15. So how do we design an electrophoresis chamber to separate food dyes? Dye Electrophoresis Commercial versus built box comparisons

16. 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 Best electrode material Understanding the chemistry of metals in salt solutions, physics of conductivity and currents Conducts well, has low reactivity, inexpensive Measurements Analysis Best gel matrix Conducts electricity, moldable, inexpensive, non-toxic, correct pore size Polymer chemistry, melting points, gelling properties

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

18. Dye extraction from candies

19. Building and running your electrophoresis system to separate the dyes

20. Building and running your electrophoresis system to separate the dyes

21. Building and running your electrophoresis system to separate the dyes

22. Building and running your electrophoresis system to separate the dyes

23. Building and running your electrophoresis system to separate the dyes

24. Extensions Copper electrode • 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 Gelatin matrix