Lorenzo+and+Adam

For follow-up work: The chocolate that was allowed to sit's melting point will increase while the chocolate that was melted and allowed to re-solidify will have a lower melting point. || http://maryeaudet.hubpages.com/hub/How-To-Make-Chocolate-From-Scratch Crystal Structures of 1,3-Distearoyl-2-oleoylglycerol and Cocoa Butter J. Phys. Chem. B, 2004 , 108  (40), pp 15450–15453 @http://www.esrf.eu/UsersAndScience/Publications/Highlights/2004/SCM/SCM8 || 1.Taste different types of chocolate (based on price). 2.Heat and melt the different types of chocolate (individually) in a pan. 3. Allow the chocolate to melt completely, then turn heat off. 4. Allow chocolate to re-harden 5. Taste again 6. Record and difference in appearance and/or taste.
 * Project Topic: || Crystal Structure of Chocolate ||
 * Chemistry Concept: || Triglyceride structure, melting points to determine crystal structure ||
 * Hypothesis: || The higher the grade of chocolate, the higher the crystal structure form will be
 * Journal Article(s): || http://www.practicalchemistry.org/experiments/chocolate-and-structure,122,EX.html
 * Lab Procedure: || Pre-Lab:

Lab: Phase 1 1. Goal: see how the difference in price, brand, etc. affects the crystal structure of the chocolate (there are 6 forms). 2. To determine the form each chocolate is in, record melting point of each brand. Each melting point will correspond to one of the six forms. 3. Record how the price, brand, etc. affects the form of the chocolate. Phase 2 1. Goal: Make your own chocolate 2. Attempt to achieve a chocolate that is both stable and tastes good. 3. Keep in mind that in order to achieve form VI, form V chocolate must sit at room temperature for up to 4 months.

Lab (follow-up work) Phase 1 1. Find sample of Cadbury chocolate in cabinet (untouched for approximately 2 months) 2. Insert a portion of the chocolate sample in the capillary tube to observe melting point. 3. Record melting point and compare to the results of the original lab (original melting point: 34 C)

Phase 2 1. Boil water in a beaker over a Bunsen burner. 2. Place sample of Cadbury chocolate in a test tube and place in the hot water bath. 3. Allow for the chocolate to melt completely. 4. Immediately remove chocolate from the test tube and pour into petri dish. 5. Allow time for the chocolate to re-harden. 6. Place a sample in a capillary tube and observe melting point. 7. Compare melting point to the melting point received in the original experiment (original melting point: 34 C) || 2. Melting Point Apparatus (to detect and record melting point of the various chocolates). 3. Unsure of what chemicals will be used in creating our own chocolate. 4. Bunsen burner || Chemicals/Reaction: || Hot Liquids || CRYSTAL STRUCTURE OF CHOCOLATE Lorenzo Pavoloni, Adam Lurie It has been the one of the major goals of chocolate producers and manufacturers since the beginning of time: to find a perfectly stable, low-cost, and rich-tasting chocolate. The flavor, appearance, and overall quality of chocolate stem from the crystal structure; the more complex the structure, the better tasting it is. To test and learn about the crystal structures of chocolate, the pre-lab consisted of tasting, melting, and re-hardening a sample of chocolate to see if and how the flavor (and therefore crystal structure) was affected. The crystal structure melted, and reformed in a new way, causing the chocolate to lose its sweetness. The next phase of the experiment consisted of testing five chocolates in the melting point apparatus. Through melting point, the form (quality) of chocolate can be found. The hypothesis of the lab is: the higher the melting point, the higher the complexity of the crystal structure of the chocolate, and the better the flavor; therefore, quality increases as the melting point increases. Intermolecular forces, stronger in chocolates of higher form and quality, support the chocolate’s complex structure, raising the melting point. Cadbury brand chocolate had the highest melting point (34 degrees C). The other chocolates followed closely at melting points around 33 degrees Celsius. When cross-checked against price, it was found that price is not an accurate measure of the quality (complexity of crystal structure) of chocolate. Follow-up work included allowing a sample of Cadbury (form V chocolate) to sit at room temperature for approximately 2 months. This sample's melting point was observed to have increased .7 degrees C after the two-month period. Phase two of the follow up work also included melting a sample of Cadbury and allowing it to re-harden. The melting point of this sample, when tested, was found to have decreased by .2 degrees. The melting point of the cacao nibs themselves (a main ingredient in the production of chocolate) exceeded 40 degrees C (much greater than the melting point of the individual chocolates). Chocolate manufacturers must take into account these factors in order to create a stable and delicious chocolate. Future works will include attempting to create a stable, high-quality, and savory chocolate using common household ingredients and equipment.
 * Apparatus and Chemicals Needed: || 1. Pre-lab can be done at home.
 * Safety Information and
 * Other Information: || None ||


 * Keywords **: Melting Point Apparatus, Cacao Nibs, Crystal Structure and Form (I-VI), Intermolecular Forces, hot water bath.

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