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Foodchem2 - midterm 2 > Natural pigments second midterm > Flashcards

Natural pigments second midterm Flashcards

1
Q

Carotenoids have a lot of ___ since they derive from ____ unit

A

conjugated double bonds isoprene

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2
Q

name a few carotenoids sources ?

A
  1. animal sources (crustaceans, milk fat, egg yolk, butter, salmonds, trouts) 2. vegetables like carrots 3. tomatoes 4. microbial (yeasts, mushrooms, algea) 5. vegetable oils
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3
Q

Draw the isoprene unit

A
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4
Q

true or false : some carotenoids can be found without double bonds

A

false, they all derive from isoprene units which contain double bonds so impossible

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5
Q

what will determine the extent at which the carotenoid is an antioxidant?

A

the lenght of the molecule (more double bonds)

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6
Q

what are the various hydrocarbon carotenoids seen

A

b-carotene
alpha-carotene
lycopene

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7
Q

when cleaved, alpha carotene yields ___ vitamin A
B-carotene yields ___ vitamin A

A

alpha carotene = 1

beta carotene = 2

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8
Q

Which molecule is this

A

alpha carotene

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9
Q

which molecule is this

A

beta-carotene

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10
Q

which molecule is this

A

lycopene

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11
Q

which molecule is this

A

vitamin A

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12
Q

lutein is a ____ carotenoid

A

oxycarotenoid

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13
Q

which molecule is this

A

lutein

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14
Q

what is the only difference between b-carotene and lutein

A

the presence of OH on the ring

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15
Q

does lutein has a vitamin A activity

A

no because of the presence of the OH on the ring

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16
Q

why does a-cartone yields only one vitamin A upon cleavage

A

because the position of the double bond on one of the ring is shifted

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17
Q

lycopene:- major pigment in ___ and ___

A

tomatoes & apricots

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18
Q

what is the difference between lycopene and b-and a-carotene

A

the ring in the lycopene is open (acyclic hydrocarbon caretnoid)

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19
Q

is lycopene symmetrical?

A

yes

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20
Q

what are the common oxy-carotenoids we saw in class?

A
  1. lutein
  2. canthaxanthin
  3. astaxanthin
  4. cryptoxanthin
  5. zeaxanthin
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21
Q

is lutein symmetrical

A

yes

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22
Q

what are the food sources of lutein

A

egg yolk, green leaves

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23
Q

which molecule is this

A

canthaxanthin (a la cantine on a des rigolos)

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24
Q

what is the difference between b-carotene and canthaxhantin

A

there is a =O on each rings

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25
Q

name food sources of canthaxanthin?

A
  1. microorganisms : mushroom
  2. plants and animal : red pepper, flamingo, shrimps
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26
Q

which one of the carotenoids can be commercially produce by chemical synthesis?

A

canthaxanthin

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27
Q

does canthaxanthin as a vitamin A activity?

A

no

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28
Q

which are the carotenoids with vitamin A activity?

A

alpha and beta-carotenoid
cryptoxanthin

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29
Q

what is the major carotenoid in salmonids and crustaceans?

A

astaxanthin

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30
Q

does astaxanthin as a vitamin A activity

A

no

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31
Q

which molecule is this

A

Astaxanthin (asteur qu’on a des rigolo ya aussi des hoe)

32
Q

what is the difference between astaxanthin and b-carotene?

A

presence of OH and =O

33
Q

is astaxanthin symetrical?

A

yes

34
Q

what is the major carotenoid pigment in peaches, yellow corn and egg yolk?

A

cryptoxanthin

35
Q

which molecule is this?

A

cryptoxanthin (OH tu t’es acheter une ring avec ta crypto?)

36
Q

what is the difference between cryptoxanthin and b-carotene?

A

presence of OH on one ring

37
Q

what is the difference between lutein and cryptoxanthin?

A

crypto as only one OH on one ring while lutein has 2

38
Q

does cryptoxanthin as vitamin A activity?

A

YESSS!!!

39
Q

what is the difference between b-carotene and zeaxanthin?

A

the zeaxanthin as 1 OH on each ring

40
Q

which pigment is this?

A

zeaxanthin (hoho zea aime leo)

41
Q

what are the major source of destruction of carotenoids?

A

-dehydration (lipooxygenase)
-oxygen
-light
heat

42
Q

is beta-carotene lost to cooking water?

A

not it is liposoluble

43
Q

what is this pigment?

A

anthoxcyanin

44
Q

anthocyanins are ___soluble

A

water

45
Q

what is the basic structure of anthocyanins?

A

the flavilium

46
Q

what is the color of anthocyanin?

A

blue, red, violet

47
Q

In nature, the anthoxyanins can have a maximum of ___ sugars attached to them

A

three

48
Q

why does anthocyanins exhibits different color?

A

because of the level of hydroxylation and sugars

49
Q

•Increasing ____ content increases redness.

A

methoxy (-OCH3)

50
Q

•Increasing hydroxy (-OH) content increases ___color

A

blue

51
Q

At acidic pH you get more ___ on anthocyanins and you favor ___ color

A

OH
red color

52
Q

At basic pH you get more ___ on anthocyanins and you favor ___ color

A

OCH3 (glycosid bonds)
blue color

53
Q

___ and __ enzymes remove the sugars from anthocyanins, thus destabilizing the molecule and causing loss of color

A

•Glucosidases or anthocyanases

54
Q

flavonoids are ___ soluble

A

water

55
Q

what is the difference in the basic structures between flavonoids and anthocyanins?

A
56
Q

what are the different class of flavonoids we saw in class?

A
  1. flavones
  2. isoflavones
  3. Flavonols
  4. flavonones
  5. Flavanonols
57
Q

which class of flavonoids is this

A

flavones (double bond from 2-3)

58
Q

which class of flavonoids is this

A

isoflavones (benzene ring is at C3)

59
Q

which class of flavonoids is this

A

flavonol (OH at position 3)

60
Q

which class of flavonoids is this

A

flavonones (like flavones but none double bond at C2-3)

61
Q

which class of flavonoids is this

A

flavonones (like flavonol byt without the double bond at C2-3).

62
Q

depending ____ and depending on ____, we can distinguish 5 type of flavonoids

A

where the ring A is attached to ring B
the nature of the bond between the C2 and C3

63
Q

which pigment is this : yellow in color, found in many fruits & vegetables (celery), and in chamomile tea. Has pleasant smell, and a bitter, astringent taste. Has calming effect and reduces anxiety in some people

A

apigenin (flavonoid)

64
Q

which pigment is this : colorless, found in many fruits. Vegetables, legumes (soy, alfalfa, peas). Has bitter taste and estrogenic effects. Protects against osteoporosis and menopause symptoms (hot flashes)

A

genistein

65
Q

which pigment is this : •yellow / brown in color. Ubiquitous; found in fruits, vegetables (onion), leaves & grains. Bitter / astringent taste (immature apples)

A

quercetin

66
Q

which pigment is this : colorless, found in many plant materials. Very bitter – responsible for bitter taste in grapefruits;

A

naringenin

67
Q

which pigment (flavonoids) is this : colorless and found mostly in leaves. Has bitter & astringent taste.

A

xeractinol

68
Q

betalaine are ___ soluble

A

water

69
Q

what are the two main colors of betalaine?

A

red and yellow

70
Q

how is called the red pigment of betalaine

A

betacyanin (betanin)

71
Q

how is called the yellow pigment of betalaine?

A

betaxanthin (vulgaxanthin)

72
Q

what is the major difference between betalaines and flavonoids and anthocyanins?

A

the difference from the anthocyanins and flavonoids is the presence of the nitrogen.

73
Q

Which pigment is this : solubility is based on the size

A

tannins

74
Q

what group of pigment is this pigment from?

A

quinone

75
Q

which class of pigment are we referring to : •Plant pigments with structural resemblance to flavonoids & quinones, i.e., glycosides;

A

xanthones

76
Q
A

Foodchem2 - midterm 2 (3 decks)

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