Page 172 - Natural Antioxidants, Applications in Foods of Animal Origin

Natural Antioxidants: Control of Oxidation in Fish and Fish Products 151
VetBooks.ir the metal or by occupying all its coordination sites. Examples include:

ethylene diaminetetraacetic acid (EDTA) and polyphosphatases.
• Secondary antioxidants function by breaking down HPOs formed
during lipid oxidation into stable products. Examples include: dilauryl
theodipropionate and thiodipropionic acid(Naidu, 2010).

BHT and BHA are the most prevalent synthetic antioxidants in food.
Chemically, they are monohydric phenol with BHA consisting of two
isomers 3-tertiary butyl 4-hydroxyanisole and 2-tertiary butyl 4-hydroxy-
anisol in the ratio 9:1. It is available as white waxy flakes, while BHT is a
white crystalline solid and both are extremely soluble in fats but not in water
as a result of their phenolic structure with bulky hydrocarbon side chains.
Because of their carry through properties, both compounds can withstand
various processing steps such as baking and frying as well as maintaining
their functionality(Devlieghere et al., 2004). They are effective in protecting

the flavor and color of foods.
The FDA stated that the presence of synthetic antioxidants used in foods
be mentioned on food labels with an explanation of their intended usage.
Their permissible levels in food is decided on the basis of the fat content
of the food and usually limited to 0.02% total antioxidants (Naidu, 2010).

When used within recommended levels, they have shown to prevent lipid
deterioration in food thereby extending the shelf life of foods. Even though
at current levels of intake, synthetic antioxidants seem to pose no reason-
able threat to health, but long-term ingestion may aid in modifying the
acute toxicity of several carcinogenic and mutagenic chemicals and lead
to chronic side effects. Therefore, in recent time, there has been growing
concern over possible carcinogenic effects of synthetic antioxidants in
foods. BHA, TBHQ, as well as other synthetic antioxidants are no longer
allowed for food application in Japan and a number of other countries
although still in use at recommended levels in certain countries; there is
a general desire to replace synthetic antioxidants with natural ingredients
(Venkatesh, 2011).

4.4.2 NATURAL ANTIOXIDANTS

The mention of natural antioxidants brings about an association with spices
and herbs, in that they are utilized by-product developers as replacements for
synthetic antioxidants. However, other natural products such as nuts, cereals,
oilseeds, legumes, animal products, and microbial products can serve as