Natural Antioxidants

71 Pages·2013·10.59 MB·English

Natural Antioxidants:
Maximizing Effectiveness for
Shelf-life Extension

Fereidoon Shahidi
University Research Professor
Department of Biochemistry
Memorial University of Newfoundland
St. John’s, NL, A1B 3X9, Canada
[email protected]
October 29, 2013 www.GlobalFoodForums.com/CleanLabel
ANTIOXIDANTS
Antioxidants are compounds that when present
in food or in the body at very low
concentrations, they delay , control or prevent
oxidative processes leading to food quality
deterioration or initiation and propagation of
degenerative diseases in the body.
Antioxidants in Food and non-
Food Applications
These are generally phenolic and polyphenolic in

nature
They are synthetic or natural

They are effective at low concentrations

They are non-toxic

They generally have good carry-through

properties
They are reasonable in cost

Antioxidants
Primary antioxidants: They are good free radical
scavengers and reducing agents
*Synthetic: BHA, BHT, TBHQ, PG
*Synthetic/Natural: ascorbic acid,
tocopherol
* Natural: mixed tocopherols, rosemary,
sage, green tea
Secondary antioxidants: EDTA, citric acid, etc
Antioxidants…
Synthetic antioxidants

OH OH
C( C H )
3 3
C( C H )
3 3
OC H 3 OC H 3 CH 2 OH CH 2 CO O ( C H 2 )1 4 CH 3
2-BHA 3-BHA H C OH H C OH
O O O O
O H OH OH
(H 3 C )3 C C( CH 3 )3 HO OH C( CH 3 ) 3
HO OH
HO OH
Ascorbic acid Ascorbyl palmitate
CH 3 CO O R OH
BHT Gallate TBHQ
ANTIOXIDANTS IN FOOD
Consumers now demand clean labels with no

artificial ingredients
Retailers expect longer shelf life and more

stability
Food processors can meet the needs of both

groups by using plant-derived natural extracts
Antioxidants…
Natural antioxidants

O H
O H
H O C O O H H O C H C H C O O H
O H O H
H O O HO O
p-hydroxybenzoic acid p-coumaric acid O H
O H O H
C H O O H O H
3
Epicatechine Epigallocatechine
H O C H C H C O O H
H O C O O H
O H O H
H O
Vanillic acid Caffeic acid O H O H
C H 3 O C H 3 O H O O H O O O H
H O C O O H H O C H C H C OO H O C O H O C O H
O H
O H O
O
C H 3 O Syringic acid Ferulic acid O H O H
O H
O H
Epicatechine gallate Epigallocatechine
gallate
Antioxidants…
Natural antioxidants

O H
OH
HO
HO
HOOC O R1
C
HO
O
R O
2
CH
Carnosic Acid Carnosol 3
Tocopherols
O H
O H
C O O H R
1
HO
HO
O O O H
C
R O
O O 2
CH
3
O H
Tocotrienols
Rosmanol Rosmarinic acid
Over 5000 polyphenolics have been identified in
different plants

7000

s
n
6000
o
i
t
a
c
5000
i Total
l No of Publications
b
u
p 4000

f 24, 021
o

r
3000
e
b
m
u 2000
N
1000
0
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 1 1
9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2
Number of publications related to polyphenols/antioxidants (1989-2011)
(SciFinder)
Plant Phenolics
They are present in plants to protect them

against herbivours, attack by micro-organisms,
and other preditors
To protect plants from stress under sunlight

To participate in wound-healing process

To attract polinators

Others
