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Natural food pigments Flashcards

1
Q

chlorophyll is a ______ compound

A

pyrrole ( 5 member ring with nitrogen )

4 come together with central Mg atom

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2
Q

chlorophyll is a ______ compound

A

pyrrole ( 5 member ring with nitrogen )

4 come together with central Mg atom

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3
Q

side chain of Chlorophyll

A

PHYTOL

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4
Q

characteristic of phytol

A

insoluble in water

hydrocarbon chain

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5
Q

difference in chlorophyl a vs b

A

a has a meyth group

b has a formyl ( aldehyde)

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6
Q

b tends to be _______ whereas a is ______

A

b- brighter

a- darker

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7
Q

when chlorophyll is heated in presence of an acid it turns to _______ , and loses the Mg atom

A

Pheophytin

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8
Q

characteristics of pheophytin

A

water insoluble, brown pigment

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9
Q

when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes

A

pheophorbide

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10
Q

when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes

A

pheophorbide

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11
Q

side chain of Chlorophyll

A

PHYTOL

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12
Q

characteristic of phytol

A

insoluble in water

hydrocarbon chain

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13
Q

difference in chlorophyl a vs b

A

a has a meyth group

b has a formyl ( aldehyde)

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14
Q

b tends to be _______ whereas a is ______

A

b- brighter

a- darker

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15
Q

when chlorophyll is heated in presence of an acid it turns to _______ , and loses the Mg atom

A

Pheophytin

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16
Q

how many nitrogen atoms in chlorophyll?

A

4

- tetrapyrrole ring

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17
Q

when chlorophyl loses phytol side chain

A

chlorophyllide ( neon green )

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18
Q

when chlorophyllide loses Mg, of pheophytin loses photos ( so chlorophyl has neither Mg or photos side chain) it becomes

A

pheophorbide

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19
Q

what enzyme cleaves the ester bond between chlorophyl molecule and phytol?

A

chlorophyllase

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20
Q

what does chlorophyllase do?

A

cleaves the ester bond between chlorophyl molecule and phytol

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21
Q

how does chlorophyll get converted to chlorophyllide?

A

loss of phytol group with chlorophyllose enzyme

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22
Q

side chain on chlorophyl

A

phytol ( 20 hydrocarbon side chain)

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23
Q

how many nitrogen atoms in chlorophyll?

A

4

- tetrapyrrole ring

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24
Q

what happens when we expose chlorophylls to light and oxygen?

A

bleaching, de-colourizing

25
carotenoids
yellow, orange or ret fat-soluble pigment
26
anthyocyanins
red, purple and blue plant pigment - antioxidant -
27
Flavoniods
simular to anythycyanins- but less intense colour
28
tannis
in plants and bark of trees, light shades to dark brown- flavour compound
29
chlorophyl a is better at absorbing light at what wavelength?
600-700
30
chlorophyl b is better at absorbing light at what wavelength?
400-500
31
chlorophyll is water soluble or fat soluble?
fat
32
2 heme pigments?
myoglobin and hemogloin
33
protein part of heme pigment?
globin
34
chlorophyll has ____ side chain, whereas heme has _____ side chain
phytol, | protein
35
what kind of molecules are myoglobin and hemoglobin
tetrapyrrole
36
myoglobin is a single_______ chain
polypeptide
37
Hemoglobin pigment in ?
blood vessels
38
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)
39
Metmyoglobin
oxidized form of myoglobin water is bound instead of oxygen Fe2+--> Fe3+
40
how many Myoglobin make up one hemoglobin molecule?
Hb is made of 4 Mb sub-units
41
chlorophyll has ____ side chain, whereas heme has _____ side chain
phytol, | protein
42
Fe has a coronation number of?
6 ( it can accept 6 lone pairs)
43
Myoglobin pigment in ____
muscle tissue
44
if protein deficit choose what steak?
well-done- protein is denatured and easily digested
45
Oxymyoglobin
oxygenated form of myoglobin Fe in Fe2+ form (same as Mb) bright red colour
46
Metmyoglobin
oxidized form of myoglobin water is bound instead of oxygen Fe2+--> Fe3+
47
cooking and heating can cause ______ in meat
oxidation of iron
48
rare steak =
Fe2+ form, which is better absorbed, globing NOT denatured- harder to digest
49
well-done steak =
Fe3+ which is harder to absorb, but globing is denatured so easier to digest
50
structure of carotenoids
5 carbon compound - isoprene repeating units - variety, for example could be exclusively hydrocarbon or oxy-carotenoids, cyclic or acyclic
51
if protein deficit choose what steak?
well-done- protein is denatured and easily digested
52
hemichrome pigment
when meat is heated will turn to this light brown colour
53
what results from the curing of meats with nitrites?
red colour nitrosomyoglobin
54
what results when you cook cured meats?
- protein denatures - Fe2+ oxidized - brown pigment called nitrosohemichrome
55
what can be used to reverse the oxidation of meats?
reducing agents | - unacceptable formation of sulfmyoglobin with SH containing reducing agents
56
carotenoid pigments
yellow, orange and red- coloured pigments
57
structure of carotenoids
5 carbon compound - isoprene repeating units - variety, for example could be exclusively hydrocarbon or oxy-carotenoids, cyclic or acyclic
58
compound in carotenoids?
isoprene

Food chemistry 2 (7 decks)

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