Page 383 - Natural Antioxidants, Applications in Foods of Animal Origin

362 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir manufactured food products; modifications of the taste, color, and general

organoleptic characteristics; high production costs; etc.) are responsible for
the scarce actual exploitation of this potential solution (Samaranayaka &
Li-Chan, 2011).

9.3.2 SYNTHETIC ANTIOXIDANTS

Natural antioxidants show some disadvantages: Low antioxidant activity
(antioxidants should ideally be active at low concentrations, 0.01–0.02%),
and the fact that most of them are insoluble in water. In addition, antioxi-
dants must be stable during the food processing operations (carry through
effect) in order to show all their activity in the processed foods throughout
the storage process. Synthetic antioxidants comply with all these require-
ments and are abundantly used as food additives. We will review shortly the
synthetic molecules most used in the food industry:
BHA (tertiary-butyl-4-hydroxyanisole) (C H O ): It is a mix of two
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isomers (2-tertiary-butyl-4-hydroxyanisole and 3-tertiary-butyl-4-hydroxy-
anisole) obtained from 4-methoxyphenol and isobutylene. The conjugated
aromatic ring from its molecule captures free radicals, sequestering them
and preventing the propagation in the oxidation processes. Approved as
food additive with the reference number E320 it is commercialized under
various trade names. Specifications have been defined in the EU legislation
in Directive 2008/128/EC and by the Joint FAO/WHO Expert Committee on
Food Additives (JECFA). The purity is specified to be not less than 98.5% of
tertiary-butyl-4-hydroxyanisole and not less than 85% of the 3-tertiary-butyl-
4-hydroxyanisole isomer.
BHT (tertiary-butyl-4-hydroxytoluene) (C H O): It is a non-coloring,
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odorless, white solid matter. As the BHA, it is a chemical derivative of
phenol with similar sequestering capacity of the free radicals due to the
conjugated aromatic ring. It is approved as food additive with the reference
number E321.
Tert-butylhydroquinone (TBHQ) (C H O ): It is approved as food addi-
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tive with the reference number E319. Addition to foods does not modify
color or flavor, being very effective in the enhancing of the storage life.
Ascorbyl palmitate (C H O ): It is an ester formed from ascorbic
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acid and palmitic acid resulting in a fat-soluble form of the ascorbic acid.
Contrary to the other synthetic antioxidants, its metabolism is not suspected
to generate metabolites with a potential toxic effect. Ascorbyl palmitate is
known to be broken down (through the digestive process) into ascorbic acid