Anthocyanins and Flavonoids

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Senyawa Fenol

1. Flavonoid : flavonol,flavanol,

flavanone,isoflavone,anthocyanin, dll

2. Asam phenol: asam elagat, asam tannat,

vanilin, dll

3. Asam Hidroksisinamat : asam kafeat, asam

klorogenat dll

4. Lignan

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Anthocyanin food color

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Anthocyanins

• Orange-red, red-blue colors

• Foods: strawberries, berries(blueberries, cherries, blackberries), grapes and some vegetables, such as egg-plant and avocado.

• Water soluble – form hydrogen bonds with water due to the presence of multiple hydroxyl groups.

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•natural acid-base indicators. • structure: Three phenol groups (benzene ring) with conjugated carboncarbon bonds and varyingnumbers of hydroxyl groups.•Glucose molecules bond to the oxygen atom on the second phenol group. •Anthocyanins are found in foods high in sugar content.

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Structure of Anthocyanin

Anthocyanin pigment is composed of aglicone (an anthocyanidin) esterified to one or more sugar

Aglicon/anthocyanidin

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• OH-more

bluish

• methoxyl groups

more redness

Effect of Substituents on the Color of Anthocyanidins.

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Anthocyanin at different pH

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O

OGlucose

OH

R

OH

R

OO+

OGlucose

OH

R

OH

R

HO

O+

OGlucose

OH

R

OH

R

OO+

OGlucose

OH

R

OH

R

HO

OH

BLUERED

COLORLESS COLORLESS

+H+

-H2O

-H+

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Stability of Anthocyanin

Unstable with -pH, -temperature -UV light and Fe3+ & Al 3+ ions. -high temperature during cooking, anthocyaninsdecompose

Most stable -at low pH (acid) - low temperature.

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At The position of equilibrium moves to the right, colorless.

- Blue quinonoidal base (A), stable at pH 6-7

- Red flavylium cation (AH+), stable at pH 1-2

- Colorless carbinol psuedobase (B), stable at pH 4-5

Colorless chalcone (C), stable at pH > 7 brown products

This is the reason that most colorants containing anthocyanins can

only be used at pH values < 4

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Anthocyanin can reacts with a bisulfite ion to form a

colorless 2-bisulfite adduct product

Ex: jams, dried fruits & dried vegetables

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FLAVONOID

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Flavonoid

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FLAVONOID

The basic flavonoid skeleton can have a large number of substitutions on it:-Hydroxylgroups-Sugars-e.g. glucose, galactose, rhamnose. most structures are glycosylated-Methylated-Acylated

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Sugars and hydroxyl groups increase the water solubility of flavonoids-Methyl and isopentyl groups make flavonoidslipophilc-If no sugar-AGLYCONE-With sugar-GLYCOSIDE

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Structures are very similar to those of anthocyanidins: But no positive charge on the oxygen atom and no double bonds in the C ring .

1. FlavAnols

Flavan-3-olAnthocyanidin

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FlavAnols: Catechin & Epicatechin

Green tea, Cocoa powder, Red wine

1. Powerful antioxidants2. Have beneficial effects on cardiac health, immunity and longevity

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2. FlavOnols

-The molecule has a double-bonded oxygen atom attached to position 4 (that’s why flavOnols). -They're still "-ols" because they retain the -OH group at position 3 like the flavAnols-The double-bonded oxygen atom, makes them like another class of flavonoids known as "flavones" (next)-Double bond in between C2 and C3 (C ring)

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FlavOnols

Example: •Quercetin in Onions•antioxidant effects

FlavOnols are mostly found as O-glycosides-

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3. FlavOnes

-Close to the flavOnols but not so widespread (celery, parsley and some herbs)-BUT Without the "-ol." there is no longer an -OH group at position 3 on the central ring

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4. Flavanones

High concentrations in citrus fruit

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Flavanones-No double bond between carbons 2 and 3 of the flavonestructure, and chiral center (C2)-A highly reactive structure ( a lot of substitutions)

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Flavanones-Ex. :Naringenin-An antioxidant flavanone from citrus species

-anti-inflammatory, anti-cancer, and liver protective effects

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5. Isoflavones (Isoflavonoids)

-Very similar to flavones, except that the B ring is attached to position 3 of the C ring, rather than to position 2 as in the flavone

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Isoflavones (Isoflavonoids)

-Found in leguminous plants (ex.: soybean)-Genistein, daidzein-phyto-oestrogens (can effect reproduction )

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Antioxidant activity

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1. Tanin terhidrolisis: td dari asam fenolatdan gula yg bisa di pecah dg asam, alkali dan enzim.

2. Tanin non-hidrolisis atau taninterkondensasi atau proanthocyanidins

Tannins

•present in the skins of red grapes •Have roles in the flavor profile of red wine.•Tanin bind proteins alivary to give astringency taste•Astringency also found in tea, wine

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