skincare and fragrance

• UV radiation

  high energy form of light present in sunlight
• Effects of UV exposure

  UVA- wrinkles

  UVB- sun-burn
• Sun-screens

  Prevent UV from reaching the skin
• What elements can form free radicals

  Halogens
• Free radical reactions

  1) initiation- uses energy from UV light to break bonds

  2) propagation

  3) termination

  
• Free radicals

  Atoms with an unpaired electron that are highly reactive
• Free radical scavenger

  Molecules with unpaired electrons which can react with free radicals to form stable molecules => preventing chain reactions.

  Classes as anti-oxidants
• Examples of natural free radicals

  Vitamin C and E
• Essential oils

  Concentrated extract of volatile, non-water soluble (hydrophobic) aroma compounds from plants.
• Method to extract essential oils

  Steam distillation

  
• Uses of essential oils

  Perfumes, cosmetic products, cleaning products and flavourings in food
• What makes up essential oils

  Organic compounds (like ester) and terpenes
• Terpenes

  unsaturated compounds formed by joining together isoprene units
• Isoprene structure


  See diagram

  
• Method for working out how many molecules of isoprene in a terpene

  Total number of carbons/ 5
• Oxidation of terpenes

  Forms a terpenoid and hydrogen
• Why are terpenes NOT stored ground?

  Greater surface area => more oxidation.
• Use of terpenoid

  Responsible for distinct aroma of spices