Antioxidants
Antioxidants are chemical compounds that provide stability
to fats and oils by delaying oxidation reactions. Antioxidants
do not stop oxidation; they merely slow the reaction down.
Generally, antioxidants only involve oil-soluble ingredients
but there are some water-soluble antioxidants such as ascorbates.
What causes oxidation?
The degree of saturation of
the fat or oil. Saturated fats such as animal fats tend
to be much more stable than unsaturated
vegetable oils. The greater the number of unsaturated carbon
bonds, the more sites there are for oxidation.
Catalysts such as metal ions significantly influence oxidation.
These may be found in other ingredients, processing equipment
or even packaging.
Oxidation is also influenced by exposure to light, heat,
oxygen or enzyme activity.
While
manufacturers can minimise the introduction of metal ions,
and remove oxygen with technologies such as gas flushing,
rancidity will usually occur in food products containing
unsaturated fats, especially once the oxidative resistance
of products is broken down.
Oil-soluble antioxidants can be
grouped into two categories:
Natural antioxidants
Synthetically manufactured antioxidants
HWL offers two
forms of natural antioxidants:
Vitamin
E from ADM
OxyLess
Vitamin E
Mixed Tocopherols are the most common forms of vitamin
E - for use in fats, oils and a wide range of fat-containing
food and feed products. Mixes of the natural forms of
D-forms of alpha, beta, gamma and delta to Tocopherols
are available. HWL usually stocks products such as MTS
70, which contains a minimum of 700 mg/g of mixed Tocopherols.
D alpha Tocopherol.
D alpha Tocopherol is the form of Tocopherol that is retained
better in human tissues. It is the only form of Alpha
Tocopherol found in nature. The low viscosity and high
concentration make D alpha Tocopherol ideal for soft
gel capsules.
D alpha Tocopherol acetate.
The esters of D alpha Tocopherol have reduced susceptibility
to degradation when exposed to air or elevated processing
temperatures. These particular benefits allow for flexibility
in product formulations. It is D alpha Tocopherol acetate
that is being used by ADM in developing water-dispersible
and water-soluble products.
D alpha Tocopherol succinate.
These products are available in powder form.
Water-soluble antioxidants
Ascorbic acid is
a valuable antioxidant in water-based systems and will
preferentially degrade to protect the
food system, especially where there is the risk of enzymatic
browning. However, in some systems it can degrade to furfural
and form brown pigments, so shelf life testing is imperative.
Ascorbic acid is readily soluble in water, but will degrade
quickly to dehydroascorbic acid (DHA), when mixed with
oxygen.
Sodium Erythorbate is the sodium salt of iso-ascorbic acid
(also known as erythorbic acid) and can be used to slow
the rate of enzymatic browning in food products where the
acidic impact of ascorbic acid is not appropriate. In meat
curing, it controls and accelerates the nitrite curing
reaction and maintains the bright red colour in meats.
It is used in frankfurters, hams and bacon and is often
used in guacamole, beverages and fruit products.
Citric acid can also act as a sequesterant
for metals and can reduce the rate of oxidation by binding
with potential
oxidation catalysts.
| ANTIOXIDANT |
|
| VITAMIN E |
Natural antioxidant available in oil and water oil
soluble forms, derived from soy |
| ROSEMARY EXTRACT |
Oil soluble natural antioxidant |
| ASCORBIC ACID |
Water soluble antioxidant, well suited to fruit systems |
| SODIUM ERYTHORBATE |
Water-soluble antioxidant, also used in meat products. |
| CITRIC ACID |
Sequesterent used to reduce effect of oxidation catalysts. |
Back to the top |