This document presents information about oxidation, free radicals, and antioxidants. It discusses how oxidation contributes to diseases and food deterioration. Free radicals are unstable molecules that can cause oxidation. Antioxidants prevent oxidation by donating electrons to free radicals. The document outlines various natural and synthetic antioxidants, how they work, and their health benefits. It also discusses regulations around approved food antioxidants and trends in antioxidant research.

1. Presented by: Mr. Prasanna Prakash Bhalerao
M.Tech 2nd yr
North Maharashtra University, Jalgaon.

2. Introduction
 Oxidation: chemical reaction that involves transfer
of electrons from one compound to other.
 Contributes to diseases such as cancer, heart
disease.
 Oxidation causes loss of flavour and colour in
foods.
 To prevent oxidation antioxidants are used.

3. Free Radicals
“any species capable of independent existent that
contains one or more unpaired electrons”
Example :
Radicals can be formed by…
1. The LOSS of a single electron from a non-radical, or
by the GAIN of a single electron by a non-radical
2. The breakage of covalent bond ‘homolytic fission’
A B A + B

  H2O H + OH 
Example :
Hydroxyl radical ( OH)O


H
 

4. Free Radicals and Diseases
 Cancer
 Inflammation/Infection
 Ischemia-reperfusion injury
 Neurodegenerative diseases
 Cardiovascular diseases
 Aging
 Others (e.g., drug/chemical-induced toxicity, etc)

5. Lipid Peroxidation
1. Initiation of first-chain reaction
• Abstraction of H+ by ROS (•
OH)
• Formation of lipid radical (LH•
)
• Formation of peroxyl radical (LOO•
, ROO•
)
2. Propagation
• H+ abstraction by lipid peroxyl radical (LOO•
)
3. Termination
• Radical interaction non-radical product

6. •
Molecular rearrangement
Conjugated diene
Lipid hydroperoxide
Cyclic peroxide
Cyclic endoperoxide
•
•-H
Hydrogen abstraction
I
•
O
O
O
O
H
•H
O2 Oxygen uptake
Peroxy radical: abstract
H• rom another fatty acid
causing an autocatalytic
chain reactions
P
I
P
Initiation
Propagation
(LH•)
(LOO•)

7. Antioxidants
Antioxidants are the compounds that prevent oxidation.
They delay autoxidation by inhibiting formation of free
radicals
They prevent oxidation by donating electrons from their
hydroxyl [-OH] group
Free radical binds with hydroxyl group and result in stable
double bond

8. Methods of producing stable foods
without adding antioxidants
Technique Method
Elimination of oxygen
Packaging under nitrogen,
Packaging with vacuum
Packaging with oxygen scavenger
Elimination of sensitive
substances
Replacement of polyunsaturated
oil with oils which are less
unsaturated and more stable such
as olive oil or palm oil

9. Decreasing the rate of
oxidation
Storage at low temperature
Storage in dark
Use of fats and oils that
contains oxidised products
and heavy metals.
Use of ingredients that are
naturally rich in antioxidants

10. Inhibiting oxidation
1. Minimize influence of physical factors (air, light,
higher temperature) during processing and storage.
2. Inhibit autoxidation: chain breaking and preventive
inhibitor.

11. Chain breaking antioxidants
 Chain breaking antioxidant radical AH scavenge free
radical (LOO*, LO*) and forming antioxidant radical
A*
 LOO* + AH LOOH + A*
 LO* + AH LOH + A*

12. Antioxidant class Mechanism Examples
Proper antioxidants
Inactivating lipid
free radicals
Phenolic compounds
Hydroperoxide
stabilizers
Preventing
decomposition of
hydroperoxides into
free radicals
Phenolic compounds
Synergists
Promoting activity
of proper
antioxidants
Citric acid, ascorbic
acid

13. Metal chelators
Binding heavy
metals into inactive
compounds
Phosphoric acid,
Maillard
compounds, citric
acid
Singlet oxygen
quenchers
Transforming singlet
oxygen into triplet
oxygen
Carotenes
Substances reducing
hydroperoxides
Reducing
hydroperoxides in a
non-radical way
Proteins, amino acids

14. History of antioxidants

15. Natural antioxidants.
Ascorbic acid Vitamin E β-carotene
Flavonoid Anthocyanin Polyphenols

16. Natural antioxidants
Compound Source
Vitamin C Citrus fruits
Vitamin E
(Tocopherol)
Cereal grains, oil, green vegetables
β-carotene Carrot, papaya
Flavonoids Tea, red wine, vegetables
Anthocyanin High in Red wine, blueberry,
blackberry,
Polyphenols Tea, grape juice
Lycopene Tomato, watermelon etc
coQ10 Wheat bran, fish.

17. BENEFITS OF NATURAL
ANTIOXIDANTS
Antioxidant Benefits Mode of action
Vitamin C Prevents Cancer
and heart disease
Inhibits oxidation
of DNA
Tocopherol/
Vitamin E
Prevents oxidation
of lipids
Passed through
liver and delivered
to adipose (fat)
tissue.
Vitamin A Prevents oxidation Passed through
liver and deposited
in adipose tissue

18. BENEFITS OF NATURAL
ANTIOXIDANTS CONTD…..
Lycopene Retards cancer
formation
Binds with surface
membrane protein
of damaged cells
Polyphenols Prevents build up
of plaques
Prevents oxidation
of LDL molecules.

19. Classification of antioxidants
Antioxidants
Synthetic
Priamary Secondary
NaturalNatural

20. Ascorbic acidAntioxidant function:
Donate e- quenches free radical, and generating
double bond.

21. β-carotene, Lycopene, Vitamin A
Antioxidant function:
Donates double bond to prevent oxidation

22. Radical terminator:
(BHA, BHT, TBHQ, PG, DG, OG)
Antioxidant function:
Transfer of e- from phenol group.

23. Synthetic antioxidants
Synthetic
antioxidants
Priamary
Free radical
terminators
Oxygen
scavengers
Chelating
agents
SecondarySecondary

24. Cellular Defense Mechanisms Isolation of generation sites of reactive oxygen
species
 Inhibition of propagation phase of reactive oxygen
species
 Scavenging of reactive oxygen species
 Repair of the damage caused by reactive oxygen
species

25. Natural and synthetic antioxidants
Synthetic antioxidants Natural antioxidants
Inexpensive Expensive
Widely applied Use restricted to some products
Medium to high antioxidant activity Wide ranging antioxidant activity
Increasing safety concern Perceived as innocuous substance
Use banned for some of them Increasing use and expanding
applications
Low water solubility Broad range of solubility
Decreasing interest Increasing interest

26. Laws and
regulations for
antioxidants
Food item Antioxidants Specification
Bread and
biscuit
Ascorbic acid GMP
Snacks and
sweets
BHA
TBHQ
200 ppm max
Chewing gum BHA 250 ppm max
Carbonated
water
TBHQ
BHA
0.01 % max
Oil and fats Ascorbic acid,
PG, OG, DG
BHA
TBHQ
100 ppm max
200 ppm max
200 ppm max
Frozen fish Sodium and
pottasium
ascorbic acid
1 gm/kg

27. FDA
Specifications.
Compound
name
Limits Use
BHA
Less than 200
mg/kg
Cereals,
chewing gums,
vegetable oil,
bakery
products
BHT
Less than 100
mg/kg
Cereals,
chewing gums,
bakery,
beverages
PG, OG, DG
Less than 200
mg/kg
Vegetable oil,
snacks,
confectionary
EDTA -
Salads,
processed
fruits and

28. BHA Hypertrophy of liver,
lung proliferation
BHT Cell proliferation
PG Damage to heart

29. Future trends
 Develop products susceptible to lipid oxidation.
 Improving Methods of preventing oxidative
detoriation.
 Develop novel antioxidants which are stable at all
processing conditions.
 Develop new antioxidant from natural sources.

30. Conclusion
 Antioxidants provide several beneficial health
benefits, they also have potential toxic effects if not
consumed in proper fashion.
 Antioxidants as functional foods.

31. References
 Abuja P M et al. (1998), ‘Antioxidant and prooxidant activities of
elderberry (Sambucusnigra) extract in low-density lipoprotein
oxidation’, J Agric Food Chem, 46,4091–4096.
 AlSaikhan M. S. (1995), ‘Antioxidant activity and total phenolics
in different genotypes of potato (SolanumtuberosumL)’, J
FoodSci, 60.
 Brewer M.S (2011), ‘Natural Antioxidants: Sources, Compounds,
Mechanisms of Action, and Potential Applications’,
Comprehensive Reviews in Food Science and Food Safety, 10,
221-248.
 Brieskorn C H and Domling H-J (1969), ‘Carnosolsäure, der
wichtigeantioxidativwirksameInhaltsstoff des Rosmarin- und
Salbeiblattes’, Z LebensmittelUntersuchForsch, 141,10–16.

32. References contd…..
 Frank M.D (2005), ‘A Review of Antioxidants and Alzheimer’s Disease’,
Annals of Clinical Psychiatry, 17, 269–286.
 Frankel E N (1998), ‘Lipid Oxidation’, Dundee, The Oily Press.
 Gardner H W, (1989), ‘Oxygen radical chemistry of polyunsaturated
fatty acids’, Free Rad. Biol Med, 7, 65–86.
 Linde H (1964), ‘EinneuesDiterpenausSalvia officinalisL und
eineNotizzurKonstitution von Pikrosalvin’, HelvChimActa, 1361234–
1239.
 Lolinger J (1991), ‘The use of antioxidants in foods’, in: Free Radicals
and Food Additives,
 Madhavi D L et al. (1996), ‘Food Antioxidants’, New York, Marcel
Dekker.
 Meyer A.S et al.(1997) ‘Inhibition of human low-density lipoprotein
oxidation in relation to composition of phenolic antioxidants in grapes
(Vitisvinifera)’, J Agric Food Chem, 45, 1638–43.

33. Contd…………
 Msagati Titus A. M. (2013) ‘Chemistry of Food Additives and Preservatives’, Chemistry of
Food Additives and Preservatives, First Edition, John Wiley & Sons, Ltd. Page 1-32.
 Nakatani N and Inatani R (1981), ‘Structure of rosmanol a new antioxidant from rosemary
(RosmarinusofficinalisL)’, AgricBiolChem, 452385–2386.
 Nawar W. W. (1985), ‘Lipids in Food Chemistry’, Fenema O R (ed.), New York, Marcel.
 Neff W E et al., (1994), ‘Oxidative stability of purified canola oil triacylglycerols with
altered fatty acid compositions as affected by triacylglycerol composition and structure’, J
Amer OilChemSoc, 71 1101.
 Noguchi N et al. (1999), ‘Chemistry of active oxygen species and antioxidants’, in:
Antioxidant Status, Diet, Nutrition and Health, Papas A M (ed.), Boca Raton, CRC Press,
page, 3–20.
 Onyeneho S N and Hettiaranchchy N S (1993), ‘Antioxidant activity, fatty acid and
phenolic acid compositions of potato peels’, J Sci Food Agric, 62, 345–350.
 Podsedek A, (2007), ‘Natural antioxidants and antioxidant capacity of Brassica
vegetables: A review’, LWT, 40, 1–11.
 Pokorny J (1991), ‘Natural antioxidants for food use’, Trends in Food SciTechnol, 223–227.
 Prabhasankar P and Nanditha B (2009), ‘Antioxidants in Bakery Products: A
Review’,Critical Reviews in Food Science and Nutrition, 49, 1–27.

34. Contd….
 Robards K, (1987), ‘Analytical Chemistry of Synthetic Food AntioxidantsA Review’, ANALYST, 112, 933-
943.

 Schyvens C, (2014), ‘Antioxidants’, Encyclopedia of Food Safety, 455-458.

 Seifried H.E (2007), ‘A review of the interaction among dietary antioxidants and reactive oxygen
species’ Journal of Nutritional Biochemistry, 18, 567–579.

 Simic M G et al. (1992), ‘Mechanism of lipid oxidative processes and their inhibition’, in: Lipid
Oxidation in Food,ACS Symposium Series, No 500, St Angelo A J (ed.), Washington, ACS Press, page
14–32.

 Sindhi V et al. (2013), ‘Potential applications of antioxidants: A review’ Journal of pharmacy research,
7, 828-835.

 Tamura H and Yamagami A (1994), ‘Antioxidant activity of monoacylatedanthocyanins isolated from
Muscat Bailey A grape’, J Agric Food Chem, 42, 1612–1615.

 Valenzuela A et al. (1996), ‘Synthetic and natural antioxidants: food quality protectors’, Grasas y
Aceites, 47, 86–96.


35. THANK
YOU………..