Lecture
Antioxidants are substances that extend the shelf life
of food products by protecting them from spoilage (rancidity of
fats and discoloration) caused by oxidation [2, 5].
Significant amounts of antioxidants are found in various plants. Phenols and polyphenols, found in fruits, vegetables and tea, reduce the risk
of cancer occurrence. It has been found that a 2% solution of quercetin and
a 4% solution of rutin inhibit tumor growth.
Only one antioxidant may be used in a single product, not counting synergists. In Ukraine, the following antioxidants and synergists are permitted
without restriction: ascorbic acid (E300), sodium ascorbate
(E301), ascorbyl palmitate (E304), ascorbyl stearate (E305), a concentrate of a mixture of tocopherols (E306), α-tocopherol (E307), γ-tocopherol (E308),
δ-tocopherol (E309), heated isoascorbate (E316), butylated hydroxyanisole (E320),
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butylated hydroxytoluene (E321), lecithins (E322).
Ascorbic acid (E300) has antioxidant properties and
is able to prevent the oxidation of fats, fat emulsions and dried milk. In
studies on the storage of butter, a higher antioxidant activity of ascorbic acid was found compared with other ingredients. When studying the effect of ascorbic acid (0.025%) on
sunflower oil, it was found that it increases its resistance to oxidation by a factor of 1.9. The results of studies of radical exchange reactions between self-oxidizing polyunsaturated lipids and ascorbic
acid made it possible to establish the mechanism of radical exchange and molecular chain termination by antioxidants. This can be used to
inhibit the oxidation of polyunsaturated lipids. Ascorbic acid is preferably used together with other additives. For example, it exhibits high antioxidant activity with β-tocopherol, vitamin P,
as well as with many types of medicinal-technical raw materials and their extracts.
Ascorbyl palmitate (a derivative of ascorbic acid, E304) increases
the resistance of sunflower oil to oxidation by a factor of 1.7; it is permitted
for use in Ukraine. In addition to E300 and E304, sodium ascorbate (E301) and ascorbyl stearate (E305) are also permitted for use in
Ukraine.
Tocopherols (E307-E309) are widespread in nature. They do not have toxic, teratogenic, mutagenic or carcinogenic properties. In
animal lipids only α-tocopherol is found, whereas in plant lipids
4 isomers of tocopherol and the corresponding tocotrienols are found. The resistance of oils and
fats to oxidation depends on the tocopherol content and fatty
acid composition.
It is believed that the tocopherol content in hydrogenated fats is sufficient for their
stabilization, because α-tocopherol has a high rate constant of inhibition. The most promising direction for increasing the oxidative
stability of hydrogenated fats is reducing the initiation rate by removing prooxidants. Ferrum and cuprum ions cause the decomposition of α- and γ-tocopherol. Ascorbic acid completely inhibits the action of cuprum ions on
α- and γ-tocopherol. The presence of citric acid increases the resistance of α- and γ-tocopherols to the action of ferrum ions, whereas ascorbic acid completely
suppresses this effect. Tocopherols are permitted for use in Ukraine.
Phospholipids (lecithins, E322) play a significant role in the
human body. They can terminate chains in reactions with peroxide radicals and act as synergists of natural antioxidants. They are able to
form weakly active complexes with heavy metals, regenerate
phenolic antioxidants, and inactivate free radicals during the formation of peroxides. Permitted for use in Ukraine.
Butylated hydroxyanisole (E320) – is a phenolic-type antioxidant
consisting of a mixture of two isomers. Butylated hydroxyanisole may have a toxic effect on the body. With prolonged administration of 500 mg/kg of butylated hydroxyanisole, changes in lipid
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metabolism were observed in experimental animals. The Joint FAO/WHO Expert Committee on Food Additives
established a temporary acceptable daily intake of butylated hydroxyanisole at a level of up to 0.5 mg/kg body weight, and a conditionally acceptable level of 0.5-2 mg/kg
body weight. Permitted for use in Ukraine.
Butylated hydroxytoluene (ionol, E321) (3.11) – an antioxidant used in the food industry to slow down the oxidation of rendered animal fats and salted fatback. Butylated hydroxytoluene may have a toxic effect on the human body.
The LD50 of butylated hydroxytoluene for rats when administered orally
is 1700-1900 mg/kg body weight. Prolonged oral administration of butylated hydroxytoluene at a dose of 2-3% of total food intake (or 1-1.5 g/kg
body weight) led to the development of pathological changes in internal organs and
accumulation of butylated hydroxytoluene in adipose tissue. With prolonged administration of 500 mg/kg of butylated hydroxytoluene, a change in lipid metabolism was observed in experimental animals.
The Joint FAO/WHO Expert Committee on Food Additives noted that ionol enhances the carcinogenic action of certain other chemical substances.
The phenomenon of its «promotion» of carcinogenesis in various organs attracts
serious attention from oncologists. The mechanisms of action remain not fully elucidated. Permitted for use in Ukraine.
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