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A Taste of Chocolate

A Taste of Chocolate. Andrew Baik , Charmian Wu and Ruben Savizky Department of Chemistry, The Cooper Union 41 Cooper Square, New York, NY 10003. A Brief History of Chocolate. Maya – chocolate plantations around 600 A.D. Aztecs and Incas also used cocoa

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A Taste of Chocolate

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  1. A Taste of Chocolate Andrew Baik, Charmian Wu and Ruben Savizky Department of Chemistry, The Cooper Union 41 Cooper Square, New York, NY 10003

  2. A Brief History of Chocolate • Maya – chocolate plantations around 600 A.D. • Aztecs and Incas also used cocoa • Columbus brings chocolate to Europe around 1500 • Reserved for the aristocracy • Sugar was added, but it still did not appeal to most • Milk was added in 1727 by the British • Van Houten develops a cocoa process in 1828 which removes some of the fat from cocoa butter • Cocoa beans were pressed, milled and treated with alkali to generate a powder that could be dispersed in hot water or milk

  3. A Brief History of Chocolate • Fry designs a factory for producing eating chocolate in 1867 in the UK • Produced by using cocoa butter, sugar and cocoa nibs (cotyledons) • Run on steam power • Peter creates milk chocolate in 1875 in Switzerland • Lindt creates a smoother tasting chocolate in 1880 by making smaller particles using a conche • 1930 – white chocolate is made from sugar, milk powder and cocoa butter

  4. Chocolate manufacturing process

  5. In pictures (and German) • Harvest Bean cracking Fermentation Drying Roasting Milling Cocoa mass  Pressing or mixing  Molding

  6. Where does chocolate come from?

  7. Chemical composition of chocolate • Cocoa mass • Cocoa aroma

  8. Chemical composition of chocolate • 3 main types of fat • 40%% POS, 25% SOS and 20% POP • Cane sugar is a disaccharide of glucose and fructose • Lecithin is commonly from soy beans (phosphatidylcholine)

  9. Typical nutrition facts for chocolate (per 100g bar)

  10. Chemical analysis of chocolate • High-Pressure Liquid Chromatography (HPLC) • Separate and identify individual components of chocolate (methylxanthines) • Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FT-IR) • Spectroscopically distinguish various types of chocolate

  11. HPLC procedure • Dissolve chocolate in methanol/water • Pass through C18 SPE column • Inject into HPLC and analyze with a UV detector (l = 273 nm) • Establish concentrations using a calibration curve • Insert picture of HPLC

  12. HPLC Results • Insert HPLC spectrum for single caffeine standard

  13. HPLC Results • Insert HPLC spectrum for single theobromine standard

  14. HPLC Results • Explain chocolate sample (#, which peak is which, etc)

  15. ATR FT-IR procedure • Crush sample and analyze • Establish pattern recognition using Continuous Wavelet Transform (CWT) and Principal Component Analysis (PCA) • ATR FT-IR spectrum of sample 19

  16. ATR FT-IR results • Explain regions

  17. CWT results • Explain what was done

  18. PCA Analysis • Explain what was done • Show graph of results

  19. Methylxanthine content of various chocolates and beverages

  20. Health benefits to consuming chocolate • ORAC (Oxygen Radical Absorbance Capacity) of chocolate is the highest among known foods

  21. Conclusions • Comparisons of x vs y (caffeine vs dollars? Specific IR Peak vs dollars?) • Are there any trends in the cacao content • Did PCA tell us anything?

  22. References • Beckett, S. T., The Science of Chocolate, 2nd ed., RSC Publishing, UK, 2009 • http://www.barry-callebaut.com/1897 • http://www2.dpi.qld.gov.au/horticulture/6223.html • http://www.veryveryvegan.com/what-are-antioxidants/what-are-antioxidants-by-david-wolfe-jd • Include papers you have used (J Chem Ed for HPLC, others for IR, etc) – make sure citation is complete (see below): Lastname, X., Journal Name, Year, Issue, Page • Roth, K., Chem. UnsererZeit, 2005, 39, 416-428

  23. Acknowledgments • The Cooper Union • YashRisbud • Sarah Lerner • Victoria Heinz • Patrick Chiu • Volunteers at Chocolatefest • Science House • James Jorasch • Megan Kingery • Gabi de Wit • Dr. Stefan Koenig for knowledge of German, chemistry and chocolate!

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