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.

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