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Food Chem 2 > Food Pigments > Flashcards

Food Pigments Flashcards

1
Q

Where can we find chlorophyll in foods

A

Green vegatvles, root vegetables and fruits

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2
Q

What is the structure of chlorophyll

A

Tetrapyrrole

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3
Q

What is the difference between chlorophyll a and b

A

The absorbance of the wavelength
Chlorophyll b has a 475 nm
Chlorophyll a is at 670 nm and because of this difference they have different colors chlorophyll a is darker and it is the most present

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4
Q

Chlorophyll
- colour
- solubility

A

Green and water insoluble

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5
Q

If chlorophyll lost a photos what molecule would form

A

Chlorophyllide

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6
Q

Chlorophyllide
- colour
- solubility

A

Water soluble and green

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7
Q

If chlorophyll loss Mg what molecule would form

A

Pheophytin

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8
Q

Pheophytin
Color
Solubility

A

Dark brown colour and water insoluble

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9
Q

If Pheophytin loss payroll what it would form

A

Pheophorbide

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10
Q

Pheophorbide
Color
Solubility

A

Soluble and brown Color

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11
Q

True or false
Chlorophyll is a fat soluble

A

True

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12
Q

How can you destroy chlorophyll

A
  • By heating under acidic condition
  • It is degraded by various enzymes such as chlorophylase and lipoxidase
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13
Q

Give 2 examples of heme pigments

A

Myoglobin and hemoglobin

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14
Q

What is heme pigments responsible for

A

Red colors of muscle

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15
Q

Major food sources of heme pigments

A

Meats and fish

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16
Q

Myoglobin structure

A

4 N’s in the 4 purple molecules covalently linked to central iron atom

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17
Q

True or false
4 myoglobins form 1 hemoglobin

A

True

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18
Q

What is oxymyoglobin

A

Bright red colour of fresh meats and the iron is present as ferrous form

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19
Q

What happens when you heat oxymyoglobin

A

Change te texture and color

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20
Q

What is the advantage and disadvantage with rare vs well done meat

A

Rare meat has more iron and so it is easily absorbed compared to well done meat. However, well done meat is better for energy because rate meat is difficult to digest

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21
Q

What colour is metmyoglobin

A

Brownish colour

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22
Q

What happens when we storage a meat

A

Gradual oxidation forming dark brain color

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23
Q

What happens when we cook meat

A

Denatures proteins
Oxidation of Fe2+ to Fe3+
Formation of dark color

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24
Q

Hemoglobin and myoblobin are what type of compound

A

Tetrapyrrole

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25
Q

Where is found carotenoid pigments

A

Plants, animals and Microorganisms

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26
Q

What color is carotenoid

A

Yellow, orange and red orange colors in plants and animals

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27
Q

Give examples of carotenoids foods from fruits and vegetables

A

Carrots
Peppers
Cantaloupe
Watermelon
Oranges

28
Q

Give animal source examples of carotenoids

A

Milk fat, egg yolk, butter, salmonid, crustacean

29
Q

How animals can have a carotenoid part

A

The pigment will deposit of the fat and it will give the color

30
Q

Give an microbial source example of caratenoid

A

Fungi, yeast, algae

31
Q

Why the microorganisms Phaffia is used as a feed supplement for farmed animals

A

1) rich in pigment
2) easier to cultivate
4) don’t cause environmental concern

32
Q

In which form ( cis or trans) are carotenoid found in the most? And what happens when you heat trans form

A

Trans form is the most found and when you heat it will go from trans to via and it will have a change of color

33
Q

What is the structure of carotenoids

A

5C compound - isoprene

34
Q

Can carotenoid be cyclic

A

Yes

35
Q

What are the 3 sources of carotenoids

A

1) extraction from natural sources
2) chemicals synthesis
3) biosynthesis/ microbial fermentation

36
Q

Explain for caratenoids are available from extraction from natural sources

A

Extraction entails adding the source material to a solvent such as acetone which is able to extract both water soluble and fat soluble components. After the acetone step the non polar carotenoids are extracted further with non polar solvents such as petroleum either to leave behind the water soluble proteins peptides, amino acids and surfaces

37
Q

How much carbon does a carotenoid gas

A

40 carbons

38
Q

What isopentenyl 5 pyrophosphate can do

A

Grows or polymerize to form the various carotenoid compounds we find in nature

39
Q

How is beta carotene formed

A

Retinal + beta retinyltriohenykphospjonium chloride

40
Q

What is the difference of beta and alpha carotene

A

Is the double bond on one of the cyclic form

41
Q

What happens if we do the hydrolysis ( couper) of beta carotene

A

We obtain 2 molecules of vitamin A

42
Q

We know that beta carotene can make 2 vitamins A. How much vitamin A can the alpha carotene make

A

1 vitamin a because the alpha carotene is not symmetrical

43
Q

Where is lycopene found

A

Major pigments in tomatoes and apricots

44
Q

What is the molecular structure of lycopene

A

It is symmetrical but the ring structures are open so it cannot do vit A

45
Q

Can lycopene has vit A activity

A

No

46
Q

True or false
Lycopene is a potent antioxidants

A

True

47
Q

What is the chemical structure of lutein

A

Symmetrical
It has an OH in the cyclic group

48
Q

Lutein can make vit a true or false

A

False because lutein has a OH on its cyclic group so we cannot form vit A

49
Q

Is lutein more a potent antioxidants than beta carotene

A

True because it has the oxygen which makes more potent

50
Q

Give some examples of oxy carotenoids

A

Lutein
Canthaxanthin
Astaxanthin
Cruptoxanthin
Zeaxanthin

51
Q

What is the source of lutein

A

Green leaves and egg yolk

52
Q

Where is canthaxanthin found

A

Plants, microorganisms, animals

53
Q

How is canthaxanthin used

A

As a feed supplement for cultured salmonidé and imitation of seafood products

54
Q

Does canthaxanthin has vit A act

A

No

55
Q

Where au is astaxanthin found

A

Salmonids, crustaceans

56
Q

Does astaxanthin has a vitamin a activity

A

No

57
Q

If we give animals canthaxanthin and another group of animals astaxanthin which of the group will have a more intense color

A

Astaxanthin - more stable

58
Q

Where can you find cryptoxanthin

A

Peaches, yellow corn and egg yolk

59
Q

How is the chemical structure of cryotoxanthin

A

Similar to carotene but it has an OH function on one of the cyclic carbons

60
Q

True or false
Cryptoxanthin cannot make vitamin a activity

A

False it can make one vitamin A

61
Q

Where is found zeaxanthin

A

Yellow corn, egg gold wifely distributed in nature

62
Q

How is the chemical structure of zeaxanthin- can it make vitamin A

A

It has an OH in the cyclic carbons so it cannot make vitamin a

63
Q

What are some of the application of carotenoids

A

1) food colorant : put on oats, margarine
2) forticagion
3) biochemical/ pharmaceutical : treat cancers
4) cosmetics

64
Q

What is the major cause of distraction of carotenoids

A
  • oxygen and light
  • dehydration
65
Q

True or false
Is carotenoids lost by cooking water

A

False it is NOT lost

Food Chem 2 (5 decks)

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