Natural antioxidants for food applications

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19 February 2021

Natural antioxidants for food applications

An introduction on ingredients and clean labeling 

Consumers are demanding ‘cleaner’ labels whilst retailers demand longer shelf lives. The use of natural antioxidants such as tocopherols and rosemary extracts can solve these problems simultaneously. Below is an introduction of the ingredients.


Vitamin E and its homologues

Natural tocopherol is not a single substance but is a mixture of 8 forms (homologues) namely, Alpha (α), Beta (β), Gamma (γ) and Delta (δ) Tocopherol and 4 tocotrienol homologues (γ, δ, β, α). There are in fact a total of 8 homologues of vitamin E and choosing the right tocopherol for your application is important. Tocopherol can be used as a vitamin or as an antioxidant. The ‘In vitro’ or antioxidant potency of tocopherol is in the order delta > gamma > beta > alpha

As a result, tocopherols high in delta and gamma tocopherol are preferred for antioxidant activity in fats and oils. Alpha tocopherols however have superior vitamin E potency. Vitablend provides both high alpha-tocopherol products in various forms for in vivo and fortification use in foods, and natural mixed tocopherol (Tocoblend®) high in delta and gamma homologues for stabilizing fats and oils.

Natural mixed tocopherols
Natural mixed tocopherols are extracted from vegetable oils and are suitable for the stabilization of food products that contain fat and oil susceptible to rancidity. In a simple rancimat test to test the oxidative stability of oils a mixed tocopherol was seen to be nearly twice as effective at preventing oxidation developing than a single alpha tocopherol.

Vitablend markets natural mixed tocopherols under the brand name Tocoblend®, they are available as either a free-flowing powder form or as easy to pour liquids. Applications include oils and fats, essential oils, mayonnaise, baked products, infant milk formula, and other food applications where a more natural antioxidant is a preference to the use of synthetics.

Labeling and GM of tocopherols
As soya is the preferred source, it is important to source mixed tocopherols that are non-GM, and IP (identity preserved) certification is the best way to certify this. Tocoblend® is available as IP ensuring confidence in all stages of use that the material is not of GM origin. True mixed tocopherols from soy oil, E306, as offered with Tocoblend® are also permanently exempt from allergen declaration.

Rosemary extracts

Rosemary extracts in the Food Industry
Rosemary extracts are produced from the rosemary plant Rosmarinus with subsequent extraction and standardization ensuring consistency of quality. It is the phenolic compounds extracted from rosemary that are responsible for the antioxidant property of this plant. The antioxidant capacity of rosemary extracts is based on their content of phenolic diterpenes which are fat-soluble, notably carnosic acid and carnosol. These diterpenes can be further oxidized on exposure to elevated temperatures, however, their capability to prevent oxidation is maintained. The oxidation products formed are active and can protect oils during frying and have carryover activity into the fried products. This means rosemary extracts can prevent oxidation both of the frying oil and after frying in the final product. Rosemary also liberates a water-soluble extract, rosmarinic acid which is also widely used in the food industry.

Why use Rosemary Extract?
Being derived from a natural source, the unrefined rosemary extracts offer effective antioxidant properties whilst still retaining a natural label. Rosemary extract is stable up to 200 °C and is one of the most heat-resistant antioxidants, retaining all its antioxidant properties up to this temperature.

Unrefined Rosemary extracts
The unrefined rosemary extracts retain the color and aroma of rosemary, which in many cases is desired. They maintain a high complement of the active phenolic compounds at 20 – 22% in the RE form and importantly the high content of carnosic acid within these. The liquid version is a 15% dilution of the unrefined powder.

Refined Rosemary extracts
In certain applications, the incorporation of an unrefined rosemary extract may be undesirable possibly due to the color or the odor it may have. By refining the rosemary extracts we can provide an odorless amber liquid or pale brown powder. However, there is no loss of the all-important phenolics, the “workhorses” for antioxidant and color protection. Rosemary refined liquid for example is the best demonstration of a refined rosemary extract. It is water dispersible and oil-soluble and doesn’t produce a glaze or taste.

Labeling and dosing of Rosemary extracts

When used as an antioxidant, Rosemary extracts may be declared simply as “Natural antioxidant rosemary extract” or “Natural antioxidant E 392.” Please note that regulation changes frequently. The maximum level is also regulated, you find the data for the EU in the EU Food Additives database. For instance, in potato chips, the maximum limit is 50 mg/kg, which is the same as for frying oils, excluding olive oil.