Natural food pigments Flashcards
State the food sources of anthocyanins
Fruits, vegetables and microorganisms.
State the food sources of flavonoids
Fruits, vegetables and microorganisms.
State the food sources of melanins
Shellfish, dried fruits, vegetables and microorganisms.
Give 6 natural food pigments
1- anthocyanins 2- flavonoids 3- melanins 4- chlorophyll 5- heme 6- carotenoids
Give three differences between chlorophyll a and b
a is :
- darker
- as a methyl group on C3 instead of a formyl
- absorbs at different wavelenghts
complete : under acidic and heat conditions, chlorophyll will lose the ____ and become ___ which is ___ (color)
Mg2+
Pheophytin
dull green
What color is pheophytin?
dull green
What color is pheophorbide?
brown
What color is chlorophyllide?
light green
complete : under acidic and heat conditions, chlorophyllide will lose the ____ and become ___ which is ___ (color)
Mg2+
pheophorbide
brown
complete : under the action of chlorophylase, chlorophyll will lose the ____ and become ___ which is ___ (color)
phytol
chlorophyllide
light green
complete : under the action of chlorophylase, pheophytin will lose the ____ and become ___ which is ___ (color)
phytol
pheophorbide
brown
complete : Fe also covalently linked to ____ in a ____ residue in globin (protein);
nitrogen
histidine
What are the differences between chlorophyll and heme?
- globin vs phytol side chain
- liposoluble vs hydrosoluble
- color red vs green
- Fe central atom vs mg
- side chain is linked to the fe in heme while it is on one of the pyroll in chlorophyll
What are the similarities between chlorophyll and heme?
- tetrapyroll ring
- metal ion as central atom
- massive side chain
why does cooking change the color of heme?
because the iron is oxidized (Fe2+ to Fe3+) and the proteins are denatured
When heme is red, the Fe is the ___ state and it is linked to ___.
reduced (Fe2+) and linked to oxygen.
The oxymyoglbin is ___ (color)
red
What is the name of the pigment formed when nitrite oxide is linked to the iron of the heme
nitrosomyoglobin
What is the state of the iron in nitrosomyoglobin?
reduced (Fe2+)
Ferric is when the Fe is in the state __ +
3+
Ferrous is when the Fe is in the state ___ +
2+
when Mb is in the presence of oxygen for a short time it will become ____ and the iron state will be ___
Mb-O2 (oxymyoglobin)
Fe2+
When Mb is in presence of H2O without oxygen is will be ___ (color) and the iron state will be ___
purple / blue
reduced (Fe2+)
when Mb is in the presence of oxygen for a long time it will become ____ and the iron state will be ___
metmyoglobin (Met-Mb)
ferric or oxidized (Fe3+)
What is the name of the brown pigment created when you cook cured meats
nitrosohemichrome
in nitrosomyoglobin the iron is in the state ___
Fe2+
nitrosohemichrome, the iron is in the state ___
Fe3+
Using redeucing agents containing ___ can lead to the formation of __
Sulfur (cystein)
sulfmyoglobin
