Investigating Chocolate Copyright © 2012 Board of Trustees, University of Illinois. All rights reserved.

2 Background Chocolate is a multi- billion dollar a year business. Very popular worldwide.

3 Background Chocolate contains flavanols Flavanol--an antioxidant May also help improve vascular health Found in other foods

4 Background Chocolate has a shelf life. When it “blooms” it is much less desirable. Research being done in this area.

5 What is bloom? Has whitish look Crystals become larger May not taste as smooth or as good

6 Some questions Do storage conditions affect rate of bloom? Can chocolate be engineered to extend shelf life and storage conditions?

7 Focus for Today Do storage conditions affect rate of bloom? Three tests: Crystal size Color Taste

8 Testing for crystal size Microscope, but what kind? Light microscope, can’t see chocolate crystals

9 Testing for crystal size Microscope, but what kind? Scanning Electron Microscope (SEM), but may change crystals

10 Testing for crystal size Microscope, but what kind? Atomic Force Microscope (AFM), gives molecular resolution without affecting sample

11 How does AFM work? Very good probe can see a single atom – but 3D resolution still off Probe rides along surface of object

12 How does a AFM work? Measure movement of probe – but how?

13 Testing crystal size Look at AFM pictures provided

14 Testing for color What does it look like? What color is it? Are there any white patches?

15 May not taste as good Taste! Consider texture – smooth taste should have only small crystals Consider volatiles – small taste molecules are present and not bound to larger molecules