oxidation of food

• in a ketone the carbonyl group is NEVER on the first carbon, and the systematic name needs the number of the carbonyl group
• in aldehydes the carbonyl group is ALWAYS on the first carbon
• what functional group do aldehydes and ketones contain?


  carbonyl
• label the table

  A) 1 alcohol

  B) aldehyde

  C) carboxylic acid

  D) 2 alcohol

  E) ketone

  F) no oxidation

  G) 3 alcohol

  H) no oxidation

  
• what are free radical scavengers?

  Free radical scavengers are molecules which can react with free radicals to form stable molecules and prevent chain reactions.
• Summary of free radical chain reactions:

  1. initiation
  2. propagation
  3. termination
• Initiation: Step that starts the reaction – breaking bond forming two free radicals (2 free radicals on RHS)
• Propagation: Keeps the reaction going, more radicals form allowing the reaction to continue (hence chain reaction) (1 free radical on each side)
• Termination: Radicals are needed for this process to work, two radicals colliding to form a stable compound therefore ‘terminates’ the process. (2 free radicals on LHS)
• When UV light breaks bonds, free radicals are formed.
• Free radicals are the atoms formed which have unpaired electrons and, as a result, are highly reactive.
• Ultraviolet radiation (UV) is a high-energy form of light present in sunlight.
• Exposure to UV light can result in molecules gaining enough energy for bonds to be broken
• This is the process responsible for sunburn and skin cancer also contributes to aging of the skin.
• Sun-block products prevent UV light reaching the skin.
• Terpenes can be oxidised within plants producing some of the compounds responsible for the distinctive aroma of spices.
• The general formula for terpenes is (C5H8)n where n is the number of linked isoprene units
• You need to divide the total number of carbons by 5 to work out the number of isoprene units
• The isoprene units may be linked together "head to tail" to form linear terpene or they may be arranged to form cyclic terpenes.
• Terpenes are key components in most essential oils
• Terpenes are unsaturated compounds formed by joining together isoprene (2-methylbuta-1,3-diene) units. The molecular formula for these isoprene units is C5H8