analisis pangan (karbohidrat)

7/28/2019 Analisis pangan (karbohidrat)

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Analisis karbohidratBagian 1


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overview

Pendahuluan

Preparasi Sampel

Mono- dan Oligosakarida

Polisakarida

Dietray Fiber


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Water

Protein

Carbohydrate

Lipida

Vitamin &Mineral

Komponen Alami: Komponen Tambahan:

Emulsifier

Antioxidant

Preservative

Thickener

Sweetener

Etc.

MUTU & KEAMANAN

PANGAN

Enzim

Antioksidan

Asam

Pigmen Citarasa


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Pendahuluan

Karbohidrat merupakan komponendalam makanan yang merupakansumber energi utama bagi organismehidup.

senyawa organik yang terdiri dari bahanekstrak tanpa nitrogen (BETN ) dan seratkasar, unsurnya terdiri dari karbon (C),hidrogen (H) dan oksigen (O).

senyawa polihidroksi aldehid ataupolihhidroksi keton (CnH2nOn). Berdasarkan jumlah monomer

penyusunnya, dapat dikelompokkan mjd

mono-, di-, oli-, dan polisakarida.


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Pendahuluan


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Pendahuluan

Monosakarida mungkin dapat bergabung satu samalain, dengan mengambil satu molekul air untuk tiapgabungan, menghasilkan, di-, tri-, atau polisakaridayang mengandung 2,3 atau lebih monosakarida.

KH dibagi menjadi 2 golongan gula (mono-tetrasakarida) dan non-gula (homopolisakarida,heteropolisakarida).

HOMOPOLISAKARIDE Pentosan

Heksosan

HETEROPOLISAKARIDE Hemiselulose

Gummi

Musilage

Zat Peptik

Mukopolisakaride dari hewan


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CARBOHYDRATECx(H2O)y

Mono

saccharides

POLY

SACCHARIDES

Di

saccharides

Hexose (C-6)

Pentose (C-5)

a. D-Glucose

b. D-Galactose

c. D-Mannose

d. D-Fructose

1. Xylose2. Arabinose

3. Ribose

Sucrose (a+d)

Lactose (a+b)

Maltose (a+a) -> a Cellobiose (a+a) ->b

Oligo

saccharides

Rafinose (b+a+d)

Stachyose (b+b+a+d)

Verbacose

Cellulose (-> a)

Starch (-> a)

Chitin

Agar (->b)

Carrageenan (->b)

Alginat


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Pendahuluan

Humans can digest only sucrose,lactose, maltooligosaccharides/maltodextrins, and starch. All aredigested with enzymes found in the small

intestine. Hanya amilum (jenis polisakarida) yg

dpat dicerna manusia. Nondigestible polysaccharides can be

divided into soluble and insolubleclasses. Along with lignin and othernondigestible, nonabsorbed substances,they make up dietary fiber (sbgkomponen tambahan dlm produkpangan)


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POLYSACCHARIDES

STARCH NON-STARCH

POLYSACCHARIDES

Alginate

Carrageenan

Agar

Furcellaran

Daratan:

Cellulose

Pectin

Perairan:

Chitosan

Gum

Lainnya

Lainnya


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Struktur Kimia

C

OH

H

C

C

C

C

C

H

H

H

HO

OH

OH

H

H

O

H OH

=

OH

HO

OH

OHOH

H

CH2OH

H

H

a-D-Glukosa

123

4

5

6

1

2

3

4

5

6

a-D-Glukosa(Aldosa)

(Aldohexose)

Gugus Karbonil (CO)

Gugus Aldehid (CHO) = gugus reduksi

Atom C asimetris terjauh dari karbonil (CO)Sebagai dasar penamaan D (OH dikanan) dan

L (OH di kiri)

H

OH

1

b

Atom C Chiral


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Struktur Kimia


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Struktur Kimia

C

OH

H

C

C

C

C

C

H

H

H

HO

OH

OH

H

H

O

H OH

=

OH

HO

OH

OHOH

H

CH2OH

H

H

a-D-GlukosaKonfigurasi Haworth

123

4

5

6

1

2

3

4

5

6

Aldehydo-D-Glukose

C

OH

H

C

C

C

C

C

H

H

H

HO

OH

O

H

H OH

H OH

1

2

3

4

5

6

a-D-Glucopyranosa


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Struktur Kimia

C

OH

H

C

C

C

C

C

H

H

H

HO

OH

OH

H

H

O

H OH

=1

2

3

4

5

6

a-D-Glukosa(Aldosa)

Gugus Karbonil (CO)


C

OH

H

C

C

C

C

C

H

H

H

HO

OH

OH

H

H

OH

H OH

1

2

3

4

5

6

H

Reduksi

Sorbitol

Na-Amalgam

Li-Al-hydride

hydrogenation


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Struktur Kimia

C

OH

H

C

C

C

C

C

H

H

H

HO

OH

OH

H

H

O

H OH

=1

2

3

4

5

6

a-D-Glukosa(Aldosa)

(Hexose)

(C6H12O6)

Gugus Karbonil (CO)


C

O

H

C

C

C

C

C

H

H

HO

OH

OH

H

H

OH

H OH

1

2

3

4

5

6

H

=

a-D-Fruktosa(Ketosa)

(Hexulose)

(C6H12O6)

Gugus Keton

R

O

H

C

CHO

=

R = H AldehydeR = CH2OH

Keton

Saccharose group


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Struktur Kimia

Carbonyl group

Keton Aldehid

Aldehydes are readily oxidised to

carboxylic acids:

If copper (II) (blue Cu2+) is used as

the oxidising agent it is converted intocopper (I) which forms red copper

oxide (Cu2O) as a precipitate. This is

how Benedicts reagent and Fehlings

solution are used to test for aldehydes

and reducing sugars.


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OH

HO

OH

OHOH

H

CH2OH

OH

HOOHOH

OH

H

CH2OH

OHO

H

OH

OHOH

H

CH2OH

H

H

HH

H

H

a-D-Glukosa

a-D-Manosa

a-D-Galaktosa

O

OH

CH2

OHOHCH2

H

OH

OH

H

1

23

4

5

6

1

2

34

5

6

a-D-Fructose

H

MONOSAKARIDA

a a

a a


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OH

HO

OH

OHO

H

CH2OH

H

H

a-D-Maltosa(Glukosa-a-(14)-Glukosa)

OH

OH

OHOH

H

CH2OH

H

H

DISAKARIDA

a-D-Glukosa a-D-Glukosa

terdiri atas 2 molekul glukosa

dari hydrolysis pati oleh b-amylase gula reduksi


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O

LactosaGalaktose-b-(14)-Glukosa)

OH

OH

OHOH

H

CH2OH

H

H

DISAKARIDA

a-D-Glukosa

terdiri atas Galaktosa dan Glukosa

terdapat pada susu :

Mamalia : 2 8.5%

Cow and Goat : 4.5 4.8%

Human : 7 %

gula reduksi

OHO

H

OH

OHH

CH2OH

H

H

a-D-Galaktosa


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SukrosaGlukosa-a-(12)-Fruktosa)

DISAKARIDA

terdiri atas Glukosa dan Fruktosa

terdapat pada cane atau beet

gula non-reduksi

table sugar

OH

HO

OH

OH O

H

CH2OH

H

H

a-D-Glukosa

O

OH

CH2OHOHCH

2

OH

OH

H

1

2

34

5

6

a-D-Fructose

H


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OHOH O

H

CH2OH

H

OH

OH

OHH

CH2OH

H

H

CELLULOSE

a-D-Glukosa a-D-Glukosa

n

POLISAKARIDA

ikatan-b-(14)-Glikosidik)OH

OHO

A

A

B

B O1 4

2

1

4

4

1


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POLISAKARIDA


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POLISAKARIDA


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Pendahuluan

Evolution of analytical methods for carbohydrates hasfollowed the succession:

qualitative color tests, adaptation of the color test for reducingsugars based on reduction of Cu(II) to Cu(I) (Fehling test) toquantitation of reducing sugars,

qualitative paper chromatography,

quantitative paper chromatography, gas chromatography (GC) of derivatized sugars,

qualitative and quantitative thin layer chromatography,

enzymic methods, and

highperformance liquid chromatography (HPLC).

nuclear magnetic resonance,

near-infrared (NIR) spectrometry,

antibodies (Immunoassays)

Fluorescence spectrometry

CE dan MS


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Pendahuluan

Pelabelan (FDA): Total carbohydrate calculated by subtraction of

the sums of the weights ofcrude protein, total fat,moisture, and ash in a serving from the totalweight of the food in a serving.

Othercarbohydrate (formerlycalledcomplex carbohydrate) is obtained bycalculating the difference between the amount oftotalcarbohydrate and the sum of the amountsof dietary fiber and sugars.

Sugars are defined as the sum of all freemonosaccharides (D-glucose and -fructose)and disaccharides [sucrose, lactose, and maltose(if a maltodextrin or glucose/corn syrup has beenadded)]


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Pendahuluan

Total KH = 100% - (% crude protein + %crude fat + kadar air + kadar abu)

KH kompleks = total KH (serat pangan+ gula)

Serat pangan = jenis KH yang tidak bisadicerna (selulose, hemiselulose danpolisakaride lain yang berfungsi sebagai

bahan pelindung tanaman, serta lignin) Gula = jumlah monosakarida bebas +

disakarida/ maltodextrin


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Preparasi Sampel

vacuum oven and drying to constant

weight at 55C and 1mm Hg pressure

Soxhlet extractor

Removed

contaminants

M d T t l Ph l lf i


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Mono- dan

Oligosakarid

aMetodeanalisis

Totalkarbohidrat

Phenol-sulfuricmethod

Total reducingsugar

Somogyi-Nelsonmethod

Metodekhusus

HPLC

GC

Enzimatis

MS

TLC

CE

Total Carbohydrate: Phenol


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Total Carbohydrate: Phenol-

Sulfuric

Acid Method Prinsip KH didigesti dgn asam danatau suhu panas, tjd reaksi dehidrasi,

menghasilkan turunan furan. Lalu

dikondensasi dgn senyawa fenolik(fenol, resorsinol, naphtol) dan amin

aromatis (anilin)

Total Carbohydrate: Phenol


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Total Carbohydrate: Phenol-

Sulfuric

Acid Method

Prosedur umum :1. A clear, aqueous solution of carbohydrate(s) is

transferred using a pipette into a small tube. A blankof water also is prepared.

2. An aqueous solution of phenol is added, and thecontents are mixed.

3. Concentrated sulfuric acid is added rapidly to the tubeso that the stream produces good mixing. The tube isagitated. (Adding the sulfuric acid to the waterproduces considerable heat.) A yellow-orange colorresults.

4. Absorbance is measured at 490 nm.5. The average absorbance of the blanks is subtracted,

and the amount of sugar is determined by referenceto a standard curve. D-glucose is used to prepare thestandard curve.


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Total Reducing Sugar: Somogyi-

Nelson Method Prinsip terjadi reaksi reduksi-oksidasi.

Gula pereduksi yaitu gula ygmengandung gugus aldehid (donorelektron/ reduktor) mengalami oksidasi,

menghasilkan gugus asam karboksilat. Gugus keton merupakan gula pereduksi

yg lemah.

The SomogyiNelson method is basedon the reduction of Cu(II) ions to Cu(I)ions by reducing sugars.


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Total Reducing Sugar: Somogyi-

Nelson Method Prosedur umum:1. A solution of copper(II) sulfate and an alkaline

buffer are added by pipettes to a solution ofreducing sugars(s) and a water blank.

2. The resulting solution is heated in a boilingwater bath.

3. A reagent prepared by mixing solutions ofacidic ammonium molybdate and sodiumarsenate is added.

4. After mixing, dilution, and remixing, absorbanceis measured at 520 nm.

5. After subtracting the absorbance of the reagentblank, the A250 is converted into glucoseequivalents using a standard plot of

micrograms of glucose vs absorbance

analisis pangan (karbohidrat)

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