Summary: Chemistry

Read the summary and the most important questions on Chemistry

• 1 Chemistry behind colour changes

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• What is the colour of the pigments with the spectra above? an what pigments might these spectra represent?

  First one is yellow/ orange. carotenoid
  Second one is green. chlorophyll

• 1.1 Caramelization

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• What is the difference in starting compounds of caramelization and the maillard reaction?

  caramelsiation: reducing sugar
  maillard reaction: amino compound

• When can you make caramel of sugar or sugar syrup?

  You need:
  

  • persons of acid or alkaline catalysts 
  • low water activity
  • high temperature

• What are the different reactions happening in caramelization?

  • Enolization
  • Dehydration
  • oxidation
  • Fission
  • Aldol concdensation

• Why are there differences in caramelization temrpature?

  these sugars consist out of pyranose and furanose ring sugars. Pyranose has one C more and therefore more stable. You need less energy to open the furnaces ring. 
  Also disacharides need more energy to open and therefore a higher temperature. 

• Hoe does the enolization step in caramel go?

  Dit is een acid catalysed reaction with mono schrods. 
  De dubble band verplaats van de O naar de 2e C. 
  Dit zorgt voor molecular diversity. 

• What happens during the dehydration step?

  A H is extracted from the molecule. and you get different round components.

• What is formed during the dehydration step?

  Aroma compounds

• Which monosaccharides yield more products in dehydration, aldoses or ketoses?

  Ketoses since the reaction can go 2 ways in the elongation reaction. Therefore you get a bigger variaty of products in the dehydration reaction.

• What happens in the oxidation reaction of caramelization?

  The enodial formed with the elongation reaction is very reactive. 
  In an oxidation reaction the H of the two upper C goes of and a double C bond is formed.