Download - ANTIOKSIDAN BTM
ANTIOXIDANT
KULIAH BAHAN TAMBAHAN MAKANANTEKNOLOGI INDUSTRI PANGAN
UNIVERSITAS PADJADJARAN2011
PENGERTIAN
Substansi yang dapat menetralisir radikal bebas dan mencegah kerusakan yang ditimbulkan o/ radikal bebas dengan melengkapi kekurangan elektron yg dimiliki radikal bebas dan menghambat terjadinya reaksi berantai dari pembentukan radikal bebas yg dpt menimbulkan stres oksidatif
Antioxidant O-2, 1O2, .OH, H2O2,
Cu, Fe. R•, RO•, ROO •
R•, RO•, ROO•,
1O2, O-2,
-OH, H2O2,
Cu, Fe
Prooxidant Jail
Are you ready to fight the attack of prooxidants?
Antioxidants in Food
Antioxidants aim to:• prevent food containing fat or oil from going rancid due to oxidation, i.e. developing an unpleasant odour or flavour;
• prevent the browning of cut fruit, vegetables and fruit juices (and so increase shelf life and appearance).
Preventive Antioxidants
Superoxide dismutase Catalase Glutathione peroxidase Singlet oxygen quencher Transition metal chelators (EDTA)
Preventive antioxidants minimize the formation of initiating radicals
Minimization of Lipid Oxidation
If a compound inhibits the formation of free alkyl radicals in the initiation step, or if the chemical compound interrupts the propagation of the free radical chain, the compound can delay the start or slow the chemical reaction rate of lipid oxidation.
The initiation of free radical formation can be delayed by the use of metal chelating agents, singlet oxygen inhibitors, and peroxide stabilizers.
The propagation of free radical chain reaction can be minimized by the donation of hydrogen from the antioxidants and the metal chelating agents.
14 13 12 11 10 9
- H
CH2 CH CH CH2 CH CH CH2 R(CH2)3CH3
Initiation
13 12 11 10 9
+ 3O2
(C H2)4
C H3 C H C H C H C H C H
2RC H
Mechanism of Antioxidant
Metal
Energy
Reactive oxygen species
Lipoxygenase
Substrate effect
Oxygen consumption,
Conjugated diene
Electron spin resonance
mv
K=109/sec
(K= 10o M-1sec-1) + H from RH (triglyceride)
(CH2)4CH3 CH CH CH CH CH2 RCH
O
O
Propagation
13 12 11 10 9
OHC(CH3)
3
OCH3
from
01000mv
0 300-500mv
(K= 107 M-1sec-1)
R.
OC(CH3)
3
OCH3
.
- OH
CH CH CH CH CH CH2 R(CH2)4CH3
O
O
H
(C H2)4
C H3 C H C H C H C H C H2 RC H
O
C H 3 (C H 2)4 C HO
13 12 11 10 9
13 12 11 10 9
Termination
Most reactive oxygen speciesPeroxide value
(C H2
)3
C H3 C H3
0mv
Sensory evaluation
Volatile compounds
Transition Metal
0mv
Kinds of Antioxidants
Natural antioxidants:(a) senyawa antioksidan yang sudah ada dari satu atau dua komponen makanan(b) senyawa antioksidan yang terbentuk dari reaksi-reaksi selama proses pengolahan(c) senyawa antioksidan yang diisolasi dari sumber alami dan ditambahkan ke makanan sebagai bahan tambahan pangan.
Antioksidan Alami
1.Tocopherols (delta>gamma>beta>alpha)
2.Flavonoid 3.Ascorbic Acid 4. Sesamol 4.Gossypol
Radical scavenging antioxidants break free radical chain reaction by donating hydrogen to free radicals
SYNTETIC ANTIOXIDANTS
BHA (Butylated hydroxy anisole)
BHA is a mixture of two isomers. Referred to as a 'hindered phenol' because of the proximity of the tertiary butyl group to the hydroxyl group. This may hinder the effectiveness in vegetable oils, but increase the 'carry through' potency for which BHA is known.
Uses: Lard, shortenings, vegetable oils, cereals, package liners, potato products, dry soups, chewing gum, etc. Usually in combination with other primary antioxidants.
OH
C(CH3)3
OCH3
Butylated Hydroxy Anisole
BHT (Butylated hydroxy toluene)
Butylated hydroxy toluene is also a 'sterically hindered' phenol Susceptible to loss through volatilization in high temperature applications.
Uses: Lard, shortening, vegetable oils, cereals, animal feeds, etc. Usually used in combination with BHA or BHT and citric acid.
Sinergic used with BHA & low price
C(CH3)3(CH3)3C
CH3
OH
Butylated hidroxy toluene
Propyl Gallate
Three hydroxyl groups make it very reactive. Lower solubility. Tend to chelate trace minerals such as iron and form colored complexes. Are heat labile, especially under alkaline conditions.
Uses: Lard, shortening, vegetable oils, cereals, package liners, animal feeds, etc. Used alone and in combination with BHA or PG and citric acid.
OH
OHOH
COOC3H7Propyl Galat
TBHQ (Tertiary-butylatedhydroquinone)
Tertiary-butylatedhydroquinone is an extremely potent antioxidant. Had been used extensively in non food applications prior to gaining approval in food.
Uses: Lard, cottonseed oil, potato chips, corn flakes
kemampuan antioksidan sangat baik pada penggorengan tetapi rendah pada pembakaran.
OH
C(CH3)3
OHTBHQ
Combination Antioxidants Combinations
Antioxidants are usually combined to take advantage of their differing properties.
For example BHA may be combined with PG and citric acid. The citrate chelates metals, the propyl gallate provides a high level of initial protection while the BHA has good carry through properties.
Reasons for Combinations Take advantage of different properties Allow for better control and accuracy May provide synergistic effects Combinations may provide more complete distribution in
some foods More convenient to handle
Synergism in Lipid Oxidation
Synergism occurs when mixtures of antioxidants produce a more pronounced activity than the sum of the activities of the individual antioxidants when used separately.
To have maximum efficiency, primary antioxidants are often used in combination with (1) other phenolic antioxidants, or with (2) various metal chelating agents.
Jenis Antioksidan Berdasarkan Mekanisme Kerja Antioksidan primer Antioksidan sekunder
Antioksidan Primer
Merupakan antioksidan yang berfungsi sebagai pemberi atom hidrogen.
Senyawa ini dapat memberikan atom hidrogen secara cepat ke radikal lipida (R*, ROO*) atau mengubahnya ke bentuk lebih stabil.
Sementara turunan radikal antioksidan (A*) tersebut memiliki keadaan lebih stabil dibanding radikal lipida.
Mekanisme Kerja Antioksidan Primer
(a) pemberian hidrogen (b) pemberian elektron (c) penambahan lipida pada cincin aromatik
antioksidan (d) pembentukan kompleks antara lipida dan
cincin aromatik antioksidan.
Reaksi Penghambatan antioksidan
primer terhadap radikal lipida: Inisiasi : R* + AH RH + A*
Radikal lipida
Propagasi : ROO* + AH ROOH +
A*
Antioksidan Sekunder
Merupakan antioksidan yang berfungsi memperlambat laju autooksidasi dengan berbagai mekanisme diluar mekanisme pemutusan rantai autooksidasi dengan pengubahan radikal lipida ke bentuk lebih stabil.
Mekanisme Kerja Antioksidan Sekunder
Antioksidan sekunder ini bekerja dengan satu atau lebih mekanisme berikut
(a) memberikan suasana asam pada medium (sistem makanan)
(b) meregenerasi antioksidan utama (c) mengkelat atau mendeaktifkan kontaminan
logam prooksidan (d) menangkap oksigen (e) mengikat singlet oksigen dan mengubahnya
ke bentuk triplet oksigen.
Metode Analisis Antioksidan
Metode Kualitatif Uji Warna Spektrofotometri IR DPPH (Diphenyl pycril Hidrazil)
Metode Kuantitatif Metode ORAC (Oxygen Radical Absorbance
Capacity) Iodimetri dan iodometri
Factors Affecting the Efficiency of Antioxidant
1. Activation energy of antioxidants to
donate hydrogen should be low
2. Oxidation potential should be high
3. Reduction potential should be low
4. Stability to pH and processing.
5. Solubility in oil should be .
Antioxidant Safety
Total concentration of authorized antioxidants added singly or in combination, must not exceed 200 parts per million by weight
on the basis of fat content of the food.
Possible Future Antioxidants
1. Polymeric antioxidant.
2. Antioxidant attached to the packaging materials.
3. Development of new, non-absorbable polymeric
antioxidants for use in foods.
Ideal Antioxidants
•No harmful physiological effects
•Not contribute an objectionable flavor, odor, or color to the fat
•Effective in low concentration
•Fat-soluble
•Carry-through effect No destruction during processing
•Readily-available
•Economical
•Non-adsorbable, if possible