Some interesting aspects of the science of chocolate.

Polymorphs of chocolate

• Actually polymorphs of cocoa butter
• Most comprehensive text currently (4 April 2012) on WP: Cocoa butter#Physical properties, needs sources
• See Polymorphism (materials science) for general information on polymorphism
• One type of chocolate bloom is called fat bloom and involves some sort of unwanted transformation between crystalline polymorphs of cocoa butter
• Related topics:
  • Recrystallization (chemistry)
  • Chocolate#Tempering
  • Melting point
  • Co-crystal
  • Crystal structure
  • Phase transition
  • Freezing-point depression

Journal articles

• K. Sato, "Crystallization behaviour of fats and lipids — a review", Chem. Eng. Sci. (2001) 56, 2255–2265
• C. Loisel, G. Keller, G. Lecq, C. Bourgaux, M. Ollivon, "Phase transitions and polymorphism of cocoa butter", J. Am. Oil Chem. Soc. (1998) 75, 425–439
• B. J. D. Le Révérend, P. J. Fryer, S. Coles, S. Bakalis, "A Method to Qualify and Quantify the Crystalline State of Cocoa Butter in Industrial Chocolate", J. Am. Oil Chem. Soc. (2010) 87, 239–246
• H. Schenk, R. Peschar, "Understanding the structure of chocolate", Radiation Phys. Chem. (2004) 71, 829–835
• R. Peschar, M. M. Pop, D. J. A. De Ridder, J. B. van Mechelen, R. A. J. Driessen, H. Schenk, "Crystal Structures of 1,3-Distearoyl-2-oleoylglycerol and Cocoa Butter in the β(V) Phase Reveal the Driving Force Behind the Occurrence of Fat Bloom on Chocolate", J. Phys. Chem. B (2004) 108, 15450–15453
• R. Campos, M. Ollivon, A. G. Marangoni, "Molecular Composition Dynamics and Structure of Cocoa Butter", Cryst. Growth Des. (2010) 10, 205–217
• A. G. Marangoni, S. E. McGauley, "Relationship between Crystallization Behavior and Structure in Cocoa Butter", Cryst. Growth Des. (2003) 3, 95–108

Triacylglycerols found in cocoa butter

Triacylglycerols (TGAs) and are also known as triglycerides. They are fatty acid tri esters of glycerol. If they are solid at room temperature, they are called fats, and if they are liquids they are called oils.

Their three-letter abbreviations denote the fatty acid side chain ( acyl group). For example, ABC would refer to acyl group A bonded (via oxygen) to carbon #1 of glycerol, acyl group B on carbon #2 and acyl group C on carbon #3.

Fatty acid side chain abbreviations

• O: oleoyl group from oleic acid
• P: palmitoyl group from palmitic acid
• S: stearoyl group from stearic acid
• L: linoleoyl group from linoleic acid
• B: behenoyl group from behenic acid

Major components of cocoa butter

• POP: 1,3-dipalmitoyl-2-oleoyl-glycerol
• POS: 1-palmitoyl-2-oleoyl-3-stearoyl-glycerol
• SOS: 1,3-stearoyl-2-oleoyl-glycerol

Minor components of cocoa butter

• OOO: 1,2,3-trioleoyl-glycerol, synonymous with triolein and glyceryl trioleate
• PPP: 1,2,3-tripalmitoyl-glycerol, synonymous with tripalmitin and glyceryl tripalmitate
• POO: 1-palmitoyl-2,3-dioleoyl-glycerol

Related TGAs

• SSS: 1,2,3-tristearoyl-glycerol, synonymous with stearin and glyceryl tristearate
• LLL: 1,2,3-trilinoleoyl-glycerol, synonymous with linolein and glyceryl trilinoleate
• Many others at Category:Triglycerides

Top Google hits for "the science of chocolate"

• http://www.guardian.co.uk/science/punctuated-equilibrium/2011/apr/11/1
• http://www.exploratorium.edu/chocolate/
• http://www.rsc.org/shop/books/2008/9780854049707.asp
• http://www.bbc.co.uk/search/chocolate
• http://www.scienceinschool.org/2006/issue2/chocchemistry
• http://www.amazon.co.uk/The-Science-Chocolate-S-T-Beckett/dp/0854049703