Tomato skin

TOMATO SKIN

If you bite an unripe green tomato and then a nice, red tomato, like this physicist, you will immediately feel the difference. 
 
Frédéric JAMME – Physicist INRA / Synchrotron SOLEIL – Ligne SMIS 
The green tomato has a firmer skin than the red one. 

 
The difference in texture is due to changes taking place on a molecular scale as the tomato ripens. 


 
Frédéric JAMME 
Combinations of molecular assemblies will disassemble and change the texture of the tomato skin. 


 
Scientists want to use infrared radiation to find out exactly how these molecular assemblies change. 


 
Frédéric JAMME 
Using infrared microscopy, we can look at every point on the wall of my tomato's cell to determine the chemical composition, and compare different samples of red and green tomato which are changing in order to find differences in these chemical compositions and assemblies of chemical groups. 

 
To understand infrared microscopy, you need to know that a molecule vibrates at its own frequency, which changes when the molecule binds with others. 
The infrared beam lets us observe these changes. 
A scientist might sum up this procedure by saying: show me how you vibrate, I'll know what kind of molecule you are and which other molecules you are joined with. 
In this case, the scientist can determine the exact location of sugars in the wall of the tomato.

  
Frédéric JAMME 
I can then superimpose the chemical image on the visible image to show the sugars along my tomato wall cells. 


 
Because the SOLEIL Synchrotron produces such a fine and intense infrared beam, scientists hope to observe the finest molecular transformations in a tomato skin as it goes from green to red. 


 
Frédéric JAMME 
Other research groups can then improve tomato transport or the taste of the tomato.