124
Fundamental of Antioxidants
Fundamental of Antioxidants
Antioxidants
• Free Radical Scavengers (Chain breaking antioxidants)
• Singlet Oxygen Quenchers • Metal Chelators • Encapsulation
Free Radical Scavengers Mechanisms of Action
Hydrogen dissociation energy
Reduction Potential
ROO•/ROOH 1000
PUFA•/PUFA-H 600
TOCOPHEROXYL•/TOCOPHEROL 500
ASCORBATE•/ASCORBATE 282
Buettner, 1993
Compounds with a high reduction potential can oxidize compounds with lower reduction potentials
Free Radical Scavengers Mechanisms of Action
• Act by lowering the energy of free radicals so they are less effective
Free Radical Scavengers Mechanisms of Action
♦ Each free radical
scavenger can inactivate 2 free radicals
Depletion of Rosemary Antioxidant and Formation of Hexanal in Corn Oil
Antioxidant Location
• Location, Location, Location????? • Antioxidant paradox was described by Porter
(1980) • A paradox was suggested because polar
antioxidant are most effective in bulk oils while nonpolar antioxidants are best described in oil-in-water emulsion
• The increase effectiveness of nonpolar antioxidants in oil-in-water emulsions is due to their ability to concentrate in the oil droplet or at the oil-water interface
α-tocopherol
Trolox
O
CH3
OH
CH3
CH3
H3CCH3CH3CH3
O
CH3
HO
H3C
CH3
CH3 O
OH
Bulk Corn Oil (Huang et al., 1996)
Trolox
Tocopherol
BULK OILS
Hydrophobic FRS Evenly distributed
Hydrophilic FRS Concentrated at surface
OIL
FREE RADICAL SCAVENGER
(FRS)
Air Air
Chen, et al.(2011) Crit Rev Food Sci Nutr 51:901-916
Reverse micelle Lamellar Mixed reverse micelle
Surface Active Components + Water = Association Colloids
Structures are on nano-scale so they do not scatter light
Emulsified Corn Oil (Huang et al., 1996)
Trolox
Tocopherol
Emulsified Oil
Nonpolar antioxidant Polar antioxidant
Commercially Available Free Radical Scavengers
Lipid Soluble BHT, BHA, TBHQ Tocopherols Rosemary Extract Surface Active Ascorbyl Palmitate Water Soluble Propyl Gallate (partial) Ascorbic Acid Grape Seed Extract
Synthetic Antioxidants
Water Solubility BHT = BHA < TBHQ < PG Often used in package liners Most limited to 0.02% of fat content
BHA vs BHT
• BHT less effective than BHA due to steric hinderence
• BHT more volatile than BHA
• BHA is listed on California Proposition 65 (reasonably anticipated to be a human carcinogen)
steric hinderence
TBHQ
• Often most effective synthetic antioxidant
• Works synergistically with citric acid
• Less steam volatile than BHA and BHT
• More regulatory restrictions especially in EU
Nu
mbe
r of
pu
blic
atio
ns
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
(1990-2013) Source WoS
Σ = 40 840 publications
Number of publications related to Antioxidants/phenolic compounds…
Courtesy of Pierre Villeneuve
Natural Free Radical Scavengers
One electron reduction potential (E°́) of the radical form of antioxidants.
Compounds E° ́ (mV)
PUFA (bis-allylic-H) o-Coumaric acid Ferulic acid b-coumaric acid p-Coumaric acid Uric acid pyrogallol Catechin EC Gallic acid Methyl gallate Sinapic acid Chlorogenic acid ECG 3,4-dihydroxylcinnamic acid Theaflavin digallate Caffeic acid Catechol 4-Methylcatechin 4-methylcatehol Theaflavin Taxifolin α-tocopherol Trolox EGC EGCG Myricetin Fisetin Quercetagetin Quercetin Ascorbic acid
600 596 595 590 590 590 575 570 570 560 560 556 550 550 540 540 534 530 520 520 510 500 500 480 430 430 360 330 330 330 282
Rosemary Antioxidants
CH3
CH3OH
HO
H3C CH3
COOH
H3C CH3
CCH3
CH3OH
HO
O
O
HO
OH
O
O
COOHOH
OH
CarnosolCarnosoic Acid
Rosmarinic Acid
Green Tea Extract
Reduction
Potential ROO•/ROOH 1000 PUFA•/PUFA-H 600 TOCOPHEROXYL•/TOCOPHEROL 500 ASCORBATE•/ASCORBATE 282
Antioxidant Interactions Free Radical Scavengers
AA
AAH TO
TOH LOO
LOOH NADH
NAD+
Compounds which do not strongly inhibit oxidation by themselves could be important to
oxidative processes if they are involved in recycling.
Propyl gallate in Tween 20 Stripped Corn Oil-in-Water Emulsions Huang and Frankel, 1997
Propyl gallate in Tween 20 Commercial Corn Oil-in-Water
Emulsions
Controlling Metals
♦Low concentrations in raw materials ♦Physical Separation ♦ Chelators
Chelators
♦Can Decrease Prooxidant Activity of Metals by: • Sterically Hinder Metal/Lipid or Hydroperoxide
Interactions • Decreasing Metal Solubility • Maintaining Metals in Their Oxidized Less
Reactive States • Partitioning Metals away from Lipid Surfaces
Commercially Available Chelators
• Organic Acids (citric) • EDTA • Polyphosphates • Proteins/Peptides
– pH must be above pKa of functional group – Activity is often dependent on metal:chelator
ratios
EDTA
Sodium Tripolyphosphate
Citric Acid
Common Food Chelators
• EDTA – pKa 1.7, 2.6, 6.3, 10.6 – Iron binding constant 1.2 x 1025
– Complex is anionic making it water soluble – Complex is highly bioavailable
Common Food Chelators
♦Citric Acid • pKa 3.1, 4.7 and 5.4 • Iron binding constant 1.5 x 1011
• Effective in bulk oils and high fat meats • Often prooxidative in oil-in-water emulsions
Common Food Chelators
♦Polyphosphates • pKa 0.8 and 2.0 • Iron binding constant 7.2 x 1022
• Effective in cooked meats • Often prooxidative in oil-in-water emulsions
Iron Chelation by Anionic Gums
Antioxidant activity of anionic gums
Challenges Alteration of viscosity Promote emulsion destabilization pKa around 4 Activity low at low pH
Siderophores
Enterobactin, catecholate siderophore
Ferrichrome hydroxamate siderophore
• Kraft has a patent • Might decrease iron bioavailability • Natural source available?
Chelating Active Packaging
Replace EDTA? Enable Additive Free Label Claim
Maintain Product Quality
US Provisional Appl. Ser. No. 61/570,417
Material Synthesis
Polypropylene (PP)
- COO-
- - -
- -
-
Poly(acrylic acid) (PAA)
-
Chelating monomer:
Acrylic acid oil
Fe2+
Fe2+ Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+ Fe2+
- - - - - - -
-
- -
- - - -
- - -
-
- - -
- -
- - -
- - -
- -
- -
- -
- - - -
- -
- -
- -
-
Fe2+
Fe2+
WATER
Non-migratory
Wavenumber (cm-1)1000 1200 1400 1600 1800 2000
Abso
rban
ce
0.00
.05
.10
.15
.20 PPPP-g-PAA
Material Characterization ATR-FTIR Spectroscopy
Storage time (day)
0 2 4 6 8 10 12 14
Lipi
d hy
drop
erox
ide
conc
entra
tion
(mm
ol/k
g oi
l)
-200
0
200
400
600
800
1000
PPPP-g-PAA
Storage time (day)
0 2 4 6 8 10 12 14
Hex
anal
con
cent
ratio
n (m
mol
/kg
oil)
-10
0
10
20
30
40
50
60
PPPP-g-PAA
Significant Lag Phase Extension
Storage time (days)
0 2 4 6 8 10 12 14
1000
800
600
400
200
0
-200
Lipi
d hy
drop
erox
ides
(mm
ol/k
g oi
l)
Storage time (days) 0 2 4 6 8 10 12 14
60
50
40
30
20
10
0
Hex
anal
(mm
ol/k
g oi
l)
Demonstration Lipid Oxidation
Multifunctional Antioxidants Flavonoids and Polyphenols
Fig. 1 The separation of groups of compunds of PYC by normal phase silica gel HPLC using an acidid polar solvent system and UV detection as described by Cheynier and coworkers <ce:cross-ref refid="BIB17"> [17]</ce:cross-ref> . Chemical structures of catech...
L Packer , G Rimbach , F Virgili
Antioxidant activity and biologic properties of a procyanidin-rich extract from pine ( pinus maritima ) bark, pycnogenol
Free Radical Biology and Medicine, Volume 27, Issues 5–6, 1999, 704 - 724
Metal Chelating by Flavonoids
Polyphenols generally have higher chelating capacity then monomers
Perron et al., 2010
Gallol groups have higher iron binding and iron oxidation rates than catechol analogs (Perron et al., 2010)
Flavonoids can promote iron oxidation and reductions
Fe3+ Reducing Activity (uM/min) of Galloyl Derivatives
pH 3.0 pH 7.0
Control 0 0
Methyl Gallate 9.56±0.31 0.17±0.03
Gallic Acid 11.6±0.89 0.24±0.05
PROOXIDANTS Metals
Fe+2 Fe+3 + LOOH + LO● + OH-
Electron Source e.g. Flavonoids
Iron Redox Cycling
Effect of water soluble antioxidants on oxidation of fish oil emulsion
Control
Grape seed extract
Flavonoids and Polyphenols in Grape Seed Extract
Mellen et al., 2010, Am Coll. Nutr. 29:469-475
Natural Antioxidants
♦Grape seed extract • Up to 95% flavonoids • Scavenge free radicals and chelate metals • Astringent Off-flavors • Trade source Gravinol (Kikkoman)
Multifunctional Antioxidants Proteins and Peptides
Alpha-Lactoalbumin http://www.acsu.buffalo.edu/~andersh/research/HAMLET.asp
Proteins as Antioxidants
Proteins as Antioxidants
♦Mechanisms • Metal Chelation
Chelation of Iron by Proteins
Proteins as Antioxidants
♦Mechanisms • Free radical scavenging
Continuous Phase β-Lg
Continuous Phase β-Lg
Residue Ratio(%) Buried? Met7 16.2 Trp19 0.0 Tyr20 27.7 Met24 0.0 Tyr42 8.6 Trp61 41.4 Phe82 0.9 Tyr99 18.3
Tyr102 7.2 Phe105 9.1 Met107 4.6 Phe136 0.1 Met145 9.6 His146 28.2 Phe151 7.0
Solvent Accessibility of amino acids in β-Lg
Altering the Solvent Accessibility of Amino Acids in β-Lg
Hydrolysis
Inhibition of Lipid Oxidation in a Menhaden Oil-in-Water Emulsion by β-Lg or Chymotrypsin Hydrolyzed β-Lg
0
2
4
6
8
10
12
14
16
18
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34Time (day)
Per
oxid
es (
mM
)
Control0.5 mg β-Lg/g oil2.5 mg β-Lg/g oil0.5 mg CTH/g oil2.5 mg CTH/g oil
Iron Chelating Activity of β-Lg and Chymotrypsin Hydrolyzed β-Lg
0
5 0
1 00
1 5 0
2 00
2 5 0
3 00
Treatment
[Fe]
, μM
1 mg/ml β-Lg
1 mg/ml CTH
Peroxyl Radical Scavenging Activity of β-Lg and Chymotrypsin Hydrolyzed β-Lg
0.0
0.2
0.4
0.6
0.8
1.0
0 10 20 30 40Time (min)
F/F0
Blank 7.5 μg/ml CTH 7.5 μg/ml β-Lg Fluorescein only
Heating
time (h) CP / G 1:0.5 CP / G 1:1 CP/G 1:2 CP
0 70.5±4.6a, A 70.7±4.8a, A 68.8±4.9a, A 72.4±4.8a, A
1 70.3±4.1a, A 62.5±5.2b, B 60.3±3.2b, B 69.8±3.6a, A
3 60.0±4.5b, B 51.7±3.7c, C 50.8±4.8c, C 68.0±5.3a, A
6 54.7±4.3c, B 44.0±3.4d, C 45.8±3.8d, C 69.8±5.2a, A
12 50.0±3.4c, B 40.1±4.0d, C 40.0±3.4e, C 71.0±4.9a, A
Bitterness Scores of Casein Peptides Maillard Products
Multifunctional Antioxidants
• Phospholipids/Lecithin – Inhibit oxidation by:
• Metal Chelation • Free radical scavenging • Formation of Maillard products • Increasing the efficiency of antioxidants (e.g.
tocopherols)
Food Science Department
DOPC/DOPE + α-tocopherol in bulk oil
In the presence of phospholipids reverse micelles - DOPC decreased the antioxidant activity of α-tocopherol
DOPE increased the antioxidant activity of α-tocopherol
Food Science Department
α-tocopherol
α-tocopherol quinone
?
2. DOPE regenerated α-tocopherol ?
DOPC
DOPE
1. DOPC/DOPE + α-tocopherol quinone 2. DOPC/DOPE + α-tocopherol
Food Science Department
PE/PC on α-tocopherol regeneration
DOPE headgroup, ethanolamine, can regenerate α-tocopherol.
Singlet Oxygen Quenchers • Quench singlet oxygen or interact with excited
photosensitizers • Carotenoids with > 9 double bonds are the
most active • Effective in nature but rarely used as food
antioxidant
β-Carotene
Photosensitizer Generated Singlet Oxygen
Photosensitizer (grd)
Photosensitizer (ext.)
Light
O2
1O2
Carotenoid (grd.)
Carotenoid (ext.)
Energy to Environment
How to Control Singlet Oxygen
♦Light blocking bottles
♦Remove photosensitizers • Oil refining
♦Metal Chelators
• Inhibit superoxide pathway
Light-induced generation of hydroperoxides and reducing agents
O2 Riboflavin
Light 1O2 + O2
- + Fe+3 O2 + Fe2+
+ LH LOOH Radicals
Other Methods to Inhibit Lipid Oxidation
Oxygen Concentrations
• Reduction of oxygen with processing equipment and packaging technologies • Vacuum • Modified atmosphere • Oxygen scavengers
• Must remove oxygen quickly in products which are oxidizing rapidly (e.g. cooked products)
Oxidation of fish oil with different dissolved oxygen concentrations
Encapsulation
Oils can be stabilized by embedding the oil in a dry matrix to inhibit oxygen exposure
P
W
A V
Each Particle
OD
V
R R B
Encapsulation
♦ Dried oils must have very low amounts of surface/exposed lipid to minimize oxidation
♦ Spray dried oils are very effective in: ♦ Powdered food systems ♦ Low moisture systems
Encapsulation Problem: In liquid-based foods, encapsulation can
dissolve leaving the lipid unprotected
P
W
A
Hydration
Hydrogenation
• Remove double bonds • Used to:
– Solid fat for baking and spreads – Increase oxidative stability of fats – Partial hydrogenation designed to decrease
concentration of most unsaturated fatty acid (e.g. 18:3) to increase oxidative stability and decrease fatty acids that produce volatile breakdown products with low sensory thresholds
Packaging to Inhibit Lipid Oxidation
Causes of Lipid Oxidation Packaging Control Strategies
Oxygen Low Oxygen Transmission Rate (glass, metal, some polymers)
Light Opaque materials (metal, some polymers)
Free Radicals ?? Metal ??
Properties of polymer packaging films
• Barrier Characteristics – Water Vapor Transmission Rate – Oxygen Permeability – Carbon Dioxide Permeability – Light transmission
food package environment
Oxygen Transmission Rates of Common Polymer Packaging Films
Material Oxygen Transmission Rate (cm3.mm/m2.day.atm at 23oC, 0%rh)
EVOH (ethylene vinyl alcohol) 0.02
PVDC (polyvinylidine chloride) 0.03
Cellophane 0.5
Nylon 6 1.02
PET (polyethylene terephthalate) 2.79
HDPE (high density polyethylene) 49.6
PP (polypropylene) 68.5
LDPE (low density polyethylene) 274
Permeability and Other Film Properties (1995)
Multilaminates
• Improve value & function of package material by using multiple materials in concert
PE FOIL PE PAPER PE
METALLIZED NYLON PE
ETHYLENE VINYL
ACETATE
DRY FOOD SEASONING
COFFEE
Migratory vs. Non-Migratory
Blending Coating Surface Grafted Non-migratory
Impregnate with antioxidant and let them volatilize into the foods
Chelating Active Packaging
Replace EDTA? Enable Additive Free Label Claim
Maintain Product Quality
US Provisional Appl. Ser. No. 61/570,417
Material Synthesis
Polypropylene (PP)
- COO-
- - -
- -
-
Poly(acrylic acid) (PAA)
-
Chelating monomer:
Acrylic acid oil
Fe2+
Fe2+ Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+
Fe2+ Fe2+
- - - - - - -
-
- -
- - - -
- - -
-
- - -
- -
- - -
- - -
- -
- -
- -
- - - -
- -
- -
- -
-
Fe2+
Fe2+
WATER
Non-migratory
Wavenumber (cm-1)1000 1200 1400 1600 1800 2000
Abso
rban
ce
0.00
.05
.10
.15
.20 PPPP-g-PAA
Material Characterization ATR-FTIR Spectroscopy
Storage time (day)
0 2 4 6 8 10 12 14
Lipi
d hy
drop
erox
ide
conc
entra
tion
(mm
ol/k
g oi
l)
-200
0
200
400
600
800
1000
PPPP-g-PAA
Storage time (day)
0 2 4 6 8 10 12 14
Hex
anal
con
cent
ratio
n (m
mol
/kg
oil)
-10
0
10
20
30
40
50
60
PPPP-g-PAA
Significant Lag Phase Extension
Storage time (days)
0 2 4 6 8 10 12 14
1000
800
600
400
200
0
-200
Lipi
d hy
drop
erox
ides
(mm
ol/k
g oi
l)
Storage time (days) 0 2 4 6 8 10 12 14
60
50
40
30
20
10
0
Hex
anal
(mm
ol/k
g oi
l)
Demonstration Lipid Oxidation
Antioxidant Application Strategies
Applying Antioxidant for Maximum Effectiveness
• Critical to optimize – Concentration – Interactions – Location – Stability
• Due to wide spread variations in food composition, it is difficult if not impossible to predict how antioxidants will work in different foods
Antioxidant Concentrations
• All antioxidants have a maximum concentrations of effectiveness – Chelators
• At low concentrations can increase metal solubility without decreasing reactivity = prooxidant
– Free radical scavengers • Activity very dependent on concentration
– Metal redox cycling – High or low antioxidant radical concentrations can promote
fatty acid oxidation
Prooxidant and Antioxidant Activity of Ascorbic Acid
Ascorbic Acid (mM)
TBA
RS
(nM
)
Decker and Hultin, 1990
Mechanism of Prooxidant and Antioxidant Activity
Fe+2 Fe+3 + LOOH + LO● + High Ascorbate Conc.
Low Ascorbate Conc. LOH + Dehydroascorbate
Prooxidant > Antioxidant Antioxidant > Prooxidant
Ascorbic Acid
Prooxidant and Antioxidant Activity of α-Tocopherol
% In
hbiti
on
Frankel, 1990
Mechanism of Prooxidant and Antioxidant Activity
α-Tocopherol
LOO• + α-Tocopherol LOOH + Fe+2
α-Tocopherol
LO• + Fe+3
α-Tocopherol quione
Antioxidant Stability and Reactivity
• Antioxidants must survive processing operation and interactions with other food components
• Antioxidants can be lost by: – Oxidation – Volatilization – Enzymatic degradation – Thermal Degradation
Antioxidant Stability and Reactivity
• Oxidation: – Antioxidants are more prone to oxidation than
fatty acids – If antioxidants are obtained in oil the oil must not
be oxidized – Antioxidants should be stored and treat like other
oxidizable lipids – Purified antioxidants tend to be very stable
Antioxidant Stability and Reactivity
• Volatilization – Antioxidants will be lost during
• Normal storage (evaporation) • Extrusion (steam distillation) • Frying (steam distillation)
– Antioxidants can also be introduced into foods by volatilization (packaging)
• Enzymatic Degradation – Phosphatases
Antioxidant Stability and Reactivity
• Thermal Degradation – Antioxidant Enzymes – Mallaird reaction
• Ascorbic acid • Amines (proteins and phospholipids) • Sulfhydryls
Antioxidant Stability and Reactivity
• Competing Reactions – Antioxidants can loose effectiveness by competing
reactions • Chelators and Calcium
– Dried products
• Singlet oxygen quenchers and singlet oxygen
Other Factors to Consider to Control Lipid Oxidation in Food
Systems
Oil Refining and Lipid Oxidation
♦The process of oil extraction and rendering promotes lipid oxidation • Activates lipase and lipoxygenase • Destroys or removes antioxidants • Increase oxygen exposure • Exposes lipids to high temperatures (rendering) • Releases and activates transition metals
♦Many steps of oil refining are designed to remove oxidation products and prooxidants
Steps of Oil Refining
♦Degumming ♦Neutralization ♦Bleaching ♦Deodorization ♦Winterization
Degumming ♦Removal of phospholipids by acid hydration
• Decrease foaming • Decrease water content • Decrease browning
♦Decrease phospholipids from 1-3% to less than 0.005%
♦Impact on oxidative stability • Aids in removal of prooxidative water • Removes some tocopherols and phenolics • Phospholipids are antioxidative
Neutralization
♦Oil mixed with caustic soda ♦FFA for water-soluble sodium salts that are
removed ♦Decreases FFA from 0.3-5% to less than
0.05%
Bleaching
♦Remove pigments with bleaching clays ♦Impact on oxidative stability
• Also removes residual FFA, phospholipids and hydroperoxides
• Removes photosensitizers • Performed under vacuum since bleaching clays
can promote oxidation ♦All bleaching clay must be removed or it
will promote oxidation
Deodorization
♦Remove off-flavors with steam distillation under vacuum.
♦Removes tocopherols and sterols which are sold as separate ingredients.
♦High temperatures decompose hydroperoxide thus decreasing peroxide value.
♦Following deodorization, 0.005-0.01% citric acid is added for stabilization.
Winterization
♦Decrease temperature to crystallize most saturated TAG
♦Crystals removed by filtration to produce liquid oil high in unsaturated fatty acids
♦Used to make salad oils that will not solidify in refrigerator
♦Decreases oxidative stability since increases unsaturation
Interesterification (IE)
♦Could be used to increase oxidative stability by increasing the level of saturated fatty acids on TAG
♦Oxidative stability of fatty acids at sn-2 are slightly higher so stereospecific IE could slow or increase oxidation
Chemical Esterification can Decreases Oxidative Stability
Adapted from Neff, Elagaimy and Mounts., 1994
Is Decreased Oxidative Stability due to Removal of Antioxidant or Addition of
Prooxidant? ♦Antioxidants
• Tocopherols – Can be lost during purification
Sample α-tocopherol
β-tocopherol
γ-tocopherol
δ-tocopherol
Total
Soybean Oil1
182 17 641 194 1033
IE Soybean Oil1
161(12%) 13 (24%) 571 (11%) 130 (33%) 875 (15%)
Is Decreased Oxidative Stability due to Removal of Antioxidant or
Addition of Prooxidant? • Antioxidants
– Tocopherols • Can be lost during purification • Can be chemically modified
Chemical Modification of Tocopherols during Interesterification
Reactive Site
Blocked
α-tocopherol
α-tocopherol-palmitate ester Adapted from Hamam and Shahidi, 2006
+ Palmitate
Formation of Minor Components by Interesterification
♦ Randomization increased MAG from 0 to 0.3% and DAG from 1.4 to 5.1%
♦ MAGs and DAG can increase lipid oxidation rates
Adapted from Wang, Jiang and
Hammond, 2005
Raw Material Quality ♦Impact on lipid oxidation (so many factors and
so little resources) • Lipid hydroperoxides • Metals • Free Fatty Acids • Temperature • Antioxidant concentrations
Raw Material Quality ♦Lipid Hydroperoxides are the substrate for
lipid oxidation ♦All lipids have hydroperoxides ♦Push for lower specs of hydroperoxide ♦Look for hydroperoxides in other ingredients
(e.g. emulsifiers)
Typical lipid hydroperoxide concentrations in food oils
Oil Peroxide Value
(Meq/kg) (mmol/kg)
Canola a 5.00 2.50
Coconut a 4.97 2.48
Corn b 3.93 1.96
Olive b 8.50 4.25
Extra virgin olive a 14.92 7.46
Peanut a 6.99 3.50
Palm kernel b 0.75 0.38
Palm olein a 7.99 4.00
Hydroperoxide concentrations in surfactants
Brij 10 4.0 uM/g Brij 35 13.7 uM/g Tween 20 16.8 uM/g Tween 40 11.6 uM/g SDS 0.6 uM/g DTAB 0.4 uM/g Lecithin 13.0 uM/g
Raw Material Quality ♦Transition metals are a major prooxidant for
lipid oxidation • All ingredients and have metals • Concentrations in the low ppb can promote
oxidation • Metals can come from unlikely sources
Sugar Beet Pectin = 1.91 ± 0.02 ppm Fe and 0.08 ± 0.00 ppm Cu Citrus Pectin = 0.13 ± 0.00 ppm iron and 0.04 ± 0.00 ppm copper
Raw Material Quality ♦Free fatty acids are a major prooxidants for
lipid oxidation • Crude Oils = 0.3-0.7% • Refined = < 0.05% • Rendered animal products ???
♦Foods/food ingredients can contain lipases which can further produce FFA
Raw Material Quality
♦Variations in antioxidants (know and unknown) can make it difficult to predict: • Inherent oxidative stability • Effect of added antioxidants
– Antioxidants have maximal levels of activity so adding more may not be effective
• Antioxidant interactions
Raw Material Quality Antioxidants
♦ Endogenous antioxidant concentration can vary widely Fat or oil Tocopherols
(% w/w)
Tocotrienols
(% w/w)
Soybean 0.13 + 0.03 0.009 + 0.01
Canola 0.07 + 0.01 NR
Corn 0.15 + 0.02 0.04 + 0.04
Cottonseed 0.09 + 0.00 0.003 + 0.003
Sunflower 0.07 + 0.01 0.03 + 0.03
Peanut 0.05 + 0.03 0.03 + 0.02
Olive 0.01 + 0.00 0.01 + 0.01
Palm kernel 0.0003 0.003 + 0.003
Raw Material Quality ♦ Endogenous antioxidant type can vary widely
Oil α β γ δ
High-erucic acid rapeseed 268 - 426 -
Canola 272 - 423 -
Soybean 116 34 737 275
Sunflower 613 17 19 -
Corn 134 18 412 39
Flax oil 26 - 213 9
Tocopherol Homolog Concentrations in Refined Oils
Raw Material Quality
♦Temperature ♦Oxidation rates typically follow Q10 kinetics
• For every 10 C increase, rate doubles
♦Will lead to oxidation of antioxidants first so quality parameters are not effected but oxidative stability decreases
♦Could result in variations in antioxidant concentrations of raw materials
♦Maintain lowest storage temperatures possible
Oxidation History ♦ Most lipid containing raw materials have oxidized during
their production ♦ Fish Oil
• Oxidation begins during rendering • Crude oil is steam distilled
– Removes volatile – Breaks down hydroperoxides
• Antioxidant Added ♦ Oil quality may be good but oil contains nonvolatile
oxidation products and has lower concentrations of endogenous antioxidants
Oxidation History
♦Refined oils contain nonvolatile oxidation products that are not removed by steam distillation = Core Aldehydes
♦Core aldehydes are potentially toxic and
prooxidative
Oxidative Stability of ω-3 Fatty Acid Delivery System With Algae Oil
Oxidative Stability of ω-3 Fatty Acid Delivery System With Menhaden Oil
