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Natural Antioxidants: Occurrence and Their Role in Food Preservation 69
VetBooks.ir 2.13 PHYTIC ACID

Phytic acid is one of the bioactive compounds that are being intensively
studied to evaluate their effects on health. It has been shown to have poten-
tial as anticancer agent which only affects malignant cells and does not
affect normal cells and tissues (Vucenik & Shamsuddin, 2003). Phytic
acid is a simple ranged carbohydrate with six phosphate groups attached to
each carbon (Shamsuddin, 2002). It serves as the major phosphorus storage
compound in plant in the seed, as well as being a natural antioxidant by its
chelating properties and reduction of the catalytic activities of many divalent
transition metals (Verghese et al., 2006). The chelation ability of phytic acid
with minerals has been suggested to have beneficial effects toward lowering
serum cholesterol and triglycerides and suppression of iron-mediated oxida-
tion (Lee et al., 2005). A variety of benefits of phytic acid on human health
has also been reported including its potential as an anti-cancer property in
soft tissue, colon, prostate, metastatic, and mammary cancers. It may also act
as an inhibitor for renal stone development (Dost & Tokul, 2006). In whole
grain cereals such as corn, wheat, and rice, the ranges of phytic acid is from
1.5 to 6.4% while defatted and dehulled oilseed meals such as soy, peanut,
and sesame contain 1.5% or more of the compound (Grases et al., 2004).
Phytic acid is primarily found in the outer layers (bran) of unpolished rice.
Phytin is a white amorphous powder, odorless and tasteless, almost insol-
uble in water, soluble in dilute mineral acids and in some organic acids. One
part phytin dissolves in 10 parts of 1 N hydrochloric acid and forms a clear
solution. According to some authors, phytin contains 36% organically bound
phosphoric acid. Upon heating with dilute acids, alkali, and water, phytin hydro-
lyzes to give o-phosphoric acid and the cyclitol myo-inositol as end products.
These are obtained together with some other products of semi-degradation.
Phytic acid (myo-inositol 1,2,3,4,5,6 hexakisphosphate) is the most abun-
dant form of phosphorus in rice and is virtually indigestible by humans or
non-ruminant livestock and hampers the nutritional value of rice and its
milling by-product rice bran (Larson et al., 2000). Studies have demonstrated
that the antinutrient effect of phytic acid can be manifested only when large
quantities of phytic acid are consumed in combination with a diet poor in
oligoelements (Shamsuddin & Vucenik, 2005). IP6 (phytic acid, phytin) is a
6-phosphate ester of inositol (Saad et al., 2011). It exists in almost all plants
as its mixed calcium and magnesium salts (phytin) and, especially, seeds and
grains contain it in a lot of amount.
It is considered as the storage of organic phosphates of plants with
60~90% of entire phosphorus quantity being in the form of phytin (Saad et