Page 93 - Natural Antioxidants, Applications in Foods of Animal Origin

72 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir peroxidation of arachidonic acid driven by AA and iron. Substantial amount

of malondialdehyde arises from arachidonic acid in the presence of free iron
or of an iron–ADP chelate. However, the addition of phytate prevents this
iron-dependent generation of malondialdehyde. The magnitude of the effect
of chelating agents on OH formation does not directly correspond to that on
lipid peroxidation, suggesting that different reactions may be involved in the
two processes and that, during lipid peroxidation, iron may catalyze several
steps, for example, OH-dependent hydrogen abstraction, OH-independent
formation of lipid peroxides, and catalysis of the formation of the final alde-
hydic cleavage products. Phytic acid is an antioxidant and chelating agent.
It suppresses oxidative reactions catalyzed by iron. In plant seeds phytic
acid helps to reduce the oxidation of its components but when ingested by
humans it may reduce the risk of colon cancer and some other IBDs. The
addition of phytic acids to foods improves its shelf life. It is also used as
an antioxidant in many industrial applications. Toxicity studies of phytic
acid revealed that single-dose test acute oral LD is 0.9 g/kg in the case of
50
mouse and is 0.41 g/kg in the case of rat. Repeat-dose studies for 12 weeks,
a non-toxic amount is 300 mg/kg/day in the case of rat. Reverse mutation
test, chromosome aberration examination test, micronucleus test, all were
found to be negative.

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FIGURE 2.8 Structure of phytic acid.

2.13.2 FOOD APPLICATIONS OF PHYTIC ACID

Food applications of phytic acid includes, preservation of oils and fats in
tofu and deep-fried tofu; chelate action in miso, soy sauce, pickle, meat
industry products, canned foods, and soft drinks; browning prevention of