fragrances and skincare Flashcards
what is UVA
the longest wavelength and not absorbed by the ozone.
penetrates skin the deepest
what is UVB
responsible for sunburn, partially blocked by ozone layer
what is UVC
totally absorbed by earths atmosphere, only encountered through artificial radiation sources
what is UV light
high energy form of light present in sunlight which has enough energy to break bonds
what does overexposure to uv cause
sunburn and premature ageing
what does damage to dna casue
mutations which can result in cancerous growths
what is melanin
a pigment produced when skin is exposed to sunlight, causes skin to darken and stops skin from burning by absorbing some UV
what does sunblock do
provide a physical and chemical barrier stopping UV from reaching skin
what happens when UV breaks bonds
free radicals are formed
what are free radicals
highly reactive atoms or molecules due to the presence of unbonded electrons, they cause chain reactions
what is step 1 of chain reaction
initiation - a free radical is made
what is step 2 of chain reaction
propagation - the first free radical causes others to form
what is step 3 of chain reaction
termination - 2 free radicals react to reform a molecule
what are free radical scavengers
molecules which react with free radicals to prevent chain reactions, theyre added to cosmetics, plastics etc
what are good free radical scavengers
antioxidants eg vitamin c
what are essential oils
volatile and non-water soluble concentrated extracts of the aroma compounds from plants
whats the key compound of essential oils
terpenes
what do synthetic terpenes do
allow us to replicate the flavour/aroma of terpenes in perfumes and foods
what are terpenes
unsaturated compounds formed by joining isoprenes
isoprene structure
CH3
|
C CH2
/ \ /
CH2 C
how are isoprenes linked
head to tail or in a ring structure
why would terpenes be oxidised
to make some of the common aroma compounds in spices
what are terpenes containing oxygen or other functional groups called
terpenoids
what are common terpenoids
cloves, cinnamon, ginger
how are essential oils made
extraction of oil from plants using distillation
what is distillation
a serpatation technique based on different bps
