Natural food pigments Flashcards
chlorophyll is a ______ compound
pyrrole ( 5 member ring with nitrogen )
4 come together with central Mg atom
chlorophyll is a ______ compound
pyrrole ( 5 member ring with nitrogen )
4 come together with central Mg atom
side chain of Chlorophyll
PHYTOL
characteristic of phytol
insoluble in water
hydrocarbon chain
difference in chlorophyl a vs b
a has a meyth group
b has a formyl ( aldehyde)
b tends to be _______ whereas a is ______
b- brighter
a- darker
when chlorophyll is heated in presence of an acid it turns to _______ , and loses the Mg atom
Pheophytin
characteristics of pheophytin
water insoluble, brown pigment
when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes
pheophorbide
when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes
pheophorbide
side chain of Chlorophyll
PHYTOL
characteristic of phytol
insoluble in water
hydrocarbon chain
difference in chlorophyl a vs b
a has a meyth group
b has a formyl ( aldehyde)
b tends to be _______ whereas a is ______
b- brighter
a- darker
when chlorophyll is heated in presence of an acid it turns to _______ , and loses the Mg atom
Pheophytin
how many nitrogen atoms in chlorophyll?
4
- tetrapyrrole ring
when chlorophyl loses phytol side chain
chlorophyllide ( neon green )
when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes
pheophorbide
what enzyme cleaves the ester bond between chlorophyl molecule and phytol?
chlorophyllase
what does chlorophyllase do?
cleaves the ester bond between chlorophyl molecule and phytol
how does chlorophyll get converted to chlorophyllide?
loss of phytol group with chlorophyllose enzyme
side chain on chlorophyl
phytol ( 20 hydrocarbon side chain)
how many nitrogen atoms in chlorophyll?
4
- tetrapyrrole ring
what happens when we expose chlorophylls to light and oxygen?
bleaching, de-colourizing
carotenoids
yellow, orange or ret fat-soluble pigment
anthyocyanins
red, purple and blue plant pigment
- antioxidant
-
Flavoniods
simular to anythycyanins- but less intense colour
tannis
in plants and bark of trees, light shades to dark brown- flavour compound
chlorophyl a is better at absorbing light at what wavelength?
600-700
chlorophyl b is better at absorbing light at what wavelength?
400-500
chlorophyll is water soluble or fat soluble?
fat
2 heme pigments?
myoglobin and hemogloin
protein part of heme pigment?
globin
chlorophyll has ____ side chain, whereas heme has _____ side chain
phytol,
protein
what kind of molecules are myoglobin and hemoglobin
tetrapyrrole
myoglobin is a single_______ chain
polypeptide
Hemoglobin pigment in ?
blood vessels
Fe is also ______ linked to a _____ in a ________ residue in globin
covalently linked to a N in a histidine residue in the globing part ( protein part)
Metmyoglobin
oxidized form of myoglobin
water is bound instead of oxygen
Fe2+–> Fe3+
how many Myoglobin make up one hemoglobin molecule?
Hb is made of 4 Mb sub-units
chlorophyll has ____ side chain, whereas heme has _____ side chain
phytol,
protein
Fe has a coronation number of?
6 ( it can accept 6 lone pairs)
Myoglobin pigment in ____
muscle tissue
if protein deficit choose what steak?
well-done- protein is denatured and easily digested
Oxymyoglobin
oxygenated form of myoglobin
Fe in Fe2+ form (same as Mb)
bright red colour
Metmyoglobin
oxidized form of myoglobin
water is bound instead of oxygen
Fe2+–> Fe3+
cooking and heating can cause ______ in meat
oxidation of iron
rare steak =
Fe2+ form, which is better absorbed, globing NOT denatured- harder to digest
well-done steak =
Fe3+ which is harder to absorb, but globing is denatured so easier to digest
structure of carotenoids
5 carbon compound
- isoprene repeating units
- variety, for example could be exclusively hydrocarbon or oxy-carotenoids, cyclic or acyclic
if protein deficit choose what steak?
well-done- protein is denatured and easily digested
hemichrome pigment
when meat is heated will turn to this light brown colour
what results from the curing of meats with nitrites?
red colour nitrosomyoglobin
what results when you cook cured meats?
- protein denatures
- Fe2+ oxidized
- brown pigment called nitrosohemichrome
what can be used to reverse the oxidation of meats?
reducing agents
- unacceptable formation of sulfmyoglobin with SH containing reducing agents
carotenoid pigments
yellow, orange and red- coloured pigments
structure of carotenoids
5 carbon compound
- isoprene repeating units
- variety, for example could be exclusively hydrocarbon or oxy-carotenoids, cyclic or acyclic
compound in carotenoids?
isoprene