Natural tocopherols were one of the first liposoluble antioxidants isolated from plants. Due to its high concentration and habitual presence in vegetable oils and other plants with high concentration of lipids, Tocopherol is the most common antioxidant in nature.
Most vegetable oils contain a mix of Tocopherols between 0.5% and 0.1%, but because of the refining processes, the oils lose most of the natural tocopherols present. Due to this, sometimes it is necessary to add Tocopherols at the end of the refining process to ensure that the oils have a good stability and to prevent their oxidation.
Tocopherols prevent oxidation of lipids by stopping the free radical chain reactions by yielding a hydrogen atom to a hydroperoxide radical. The result of this reaction is a relatively stable Tocopherol derivative (Tocopheryl) radical which does not continue the chain reaction.
Tocopherols exist in nature as a mixture of four different isomers: Alpha, Beta, Gamma and Delta. The antioxidant activity of each isomer is different as is its vitamin power. Numerous studies show that the antioxidant capacity lies mainly in the gamma and delta isomers, and are practically non-existent in the alpha and beta isomers.
Tocopherols are a powerful natural antioxidant widely used in the food industry, as well as in cosmetics or animal nutrition, due to its great ability to prevent against oxidative rancidity, extending the shelf life of food products.
Food shelf life is defined as the period from production to expiration, the end of the life of a food is when it exceeds the levels of microbiological contamination and loses its physical-chemical and organoleptic qualities. This definition was set by the European Parliament and the Council of 20 March 2000 related to the approximation of the laws of the Member States relating to the labelling, presentation and advertising of foods.
See the article The most commonly used methods for determining food shelf life for more information on shelf life.
9 reasons to choose natural tocopherols
Here are nine reasons to choose tocopherol-based antioxidants for the food industry:
- It is a 100% natural ingredient
As we have previously explained, Tocopherols are present in a large quantity of vegetable oils, and are obtained from distillates of these oils by physical methods without the use of solvents, which can alter their natural composition. This characteristic is of paramount importance for the food industry, and because of this the Tocopherols can be used without limitations in practically the whole world. In addition, this is increasingly valuable for consumers, who are more and more searching for foods that are healthy and do not use artificial ingredients.
- Availability in various raw materials
It is possible to find Tocopherols that come from diverse sources, however in the food industry the most used are soybean oil and sunflower oil. The composition of the 4 isomers of Tocopherol varies among the different sources of origin, with soybean Tocopherols showing a higher antioxidant activity due to their higher concentration of gamma and delta isomers. On the other hand, the Tocopherols from sunflower origin have a higher concentration of Alfa Tocopherol (Vitamin E).
Over the centuries, nature has developed different compounds to prevent the oxidation of lipids, with Tocopherols being one of the most powerful natural antioxidants. This antioxidant is very effective in protecting fats against oxidation and rancidity, so every day it is used by more and more food companies to protect their products. It is common to find mixtures of Tocopherols in concentrations between 30% and 90%.
- No organoleptic effects on the product
It should be noted that due to the low doses in which Tocopherols are used (between 0.03% and 0.3% of the fat portion of the product), they have no effect on the colour, taste or smell of the final product, which is something that is highly valued by the food industry.
- Stability at high temperatures
Tocopherols have an important structural difference in respect to synthetic antioxidants, providing them with a number of advantages. This difference is its long lipid side chain, which greatly decreases the volatility of Tocopherol. Volatility in antioxidants is directly related to their stability during the food production process. This is a very important feature, especially when using antioxidants to protect food during processes that involve high temperatures, such as baking or frying.
- Double protection
“Carry through” is the property that some antioxidants have to “survive” a process of frying; in other words, it is the ability to remain in the oil and thus pass to the final product, where they continue to exercise their antioxidant function, delaying rancidity of said final product. Highly volatile antioxidants tend to evaporate at different stages of the manufacturing process, leaving less antioxidant in the product. The result is a high cost and difficulty in controlling the optimum level of antioxidant remaining in the final product.
- Ease of incorporation into a product
Because antioxidants cannot reverse the process of self-oxidation of food but only prevent it, it is important that both when they are added and that their distribution to the lipid medium is homogeneous. Natural Tocopherols are 100% miscible in all fats and oils, unlike the synthetic antioxidants, with which it is sometimes necessary to use solvents such as propylene glycol.
- Ecological products
Another differentiating factor of this natural antioxidant is that its use is permitted in organic products. This is thanks to the low doses of Tocopherols that are used to protect against oxidation, which do not exceed the limits established by regulation for this type of product.
- Food safety
Natural Tocopherols are a safe, effective and easy-to-transport antioxidant. In addition, since they are not toxic components, there are no limits to their use and they are permitted in practically every country in the world. In contrast, certain synthetic antioxidants are limited or even banned in food meant for human consumption, because there is evidence to suggest that high doses may be harmful to health. On the other hand, Tocopherols have GRAS status (Generally Recognized As Safe), an FDA-approved mark, an assurance that they are safe to use as food additives.
Choosing the ideal antioxidant to extend the shelf life of a food depends on various factors such as the type of application, compatibility, production process, regulatory guidelines or the impact of external factors such as packaging or storage conditions. That is why food manufacturers should be aware of all these elements when selecting an antioxidant to protect their products. Antioxidants based on natural Tocopherols are presented as a suitable and very effective solution due to their multiple properties and benefits compared to other alternatives in the market.