Antioxidants in food: Myths and Truths

Natural antioxidants are part of today’s society’s daily diet, either intrinsically in some foods that we consume, or added to foods in order to delay oxidative rancidity and lengthen the shelf- life of the product.

But, what are antioxidants really? Why are antioxidants used in food? These are components whose function and main goal is to prevent the oxidation of food. According to Barry Halliwell, chief advisor to the president of the National University of Singapore and a specialist in biomedical research, the exact definition is, “substances that, are in low concentrations in respect to the biomolecules that they protect, prevent or reduce the damage suffered due to oxidation”. This makes antioxidants a key component for food, and relevant, since the industry relies on them to ensure that foods retain their quality for as long as possible.

We will now go over some of the myths related to antioxidants in food meant for humans, and we will analyse the reality about antioxidants.

Myth 1: All antioxidants are artificial

This is a statement that is quite widespread in some parts of society, since, unfortunately in food, especially when it comes to food additives, there is a great deal of ignorance. Sadly, some media are not very exhaustive when explaining the issue, creating confusion within society.

Another factor that has also influenced the spread of this myth is related to the existence of E numbers, since many people believe that these numbers correspond to synthetic ingredients.

However, the truth is that, in addition to synthetic antioxidants, there are various types of antioxidants that are 100% natural, such as Tocopherols, Rosemary Extract, Ascorbic Acid or Astaxanthin, among others, which have their corresponding E number and are presently used in many products of the food industry.

The truth is that natural antioxidants are being used more and more in industries such as food, dietetics, cosmetics, and more recently in animal nutrition, to the detriment of synthetic antioxidants, which are increasingly being questioned.

Myth 2: Antioxidants inhibit oxidation of food

The oxidation of fats is an irreversible process, so it is impossible to avoid it entirely. However, it can be delayed through the addition of antioxidants, which lengthen the shelf-life of the products. This is precisely one of the main reasons that leading companies in the food industry use natural antioxidants such as Tocopherols: to protect their products against oxidative rancidity.

Autoxidation is a chain reaction that consists of 3 phases: Initiation, Propagation and Termination. If antioxidants are added to the product during the first phase or before, it is possible to delay the rancidity of a product. However, once the propagation phase has finished, the process cannot be delayed, so it is known that once the second phase begins, the third phase of the oxidative process will inevitably occur.

So far, no miracle has been found to completely prevent the oxidation of foods and to make them last forever. What has been demonstrated over time and through different studies though, is the usefulness of using antioxidants in food to extend its shelf-life. This is of great importance to food manufacturers, as it gives their products a longer consumption margin.

Myth 3: Antioxidants do not withstand high temperatures

This belief is due to the fact that many food companies have only used synthetic antioxidants in the manufacturing of their products, so they only know the behaviour of these additives in processes that involve thermal processes, such as baking, cooking, or frying. However, many times those responsible for product development are unaware that there are certain natural antioxidants that are able to withstand high temperatures and can continue to protect the product against oxidation. It is known that some natural antioxidants like Tocopherols are more stable at high temperatures than some synthetics commonly used in the food industry, such as BHA, BHT or TBHQ.

The property of some natural antioxidants to “survive” a thermal process, that is, to remain present in the fat or oil, and to continue intact in the final product, where they continue to work by delaying rancidity in the final product is known as “Carry Through”.

There are several ways to check that an antioxidant is still present in a product after is has been subjected to high temperatures. There are several tests like the Rancimat Test, or the measurement of the Peroxides Index, which indicate that the antioxidant continues to exercise its technological function in the product, protecting it against rancidity.

Myth 4: There are very few types of natural antioxidants

Like the previous myth, this statement arises from the ignorance within the food industry about the fact that natural additives can be effective substitutes for certain synthetic compounds. This is because in the past, the use of synthetic compounds was prioritised. Among them, the most used in human food have been BHA, BHT, TBHQ and Propyl Galate, and in animal nutrition, other artificial compounds such as Ethoxyquin, which is being increasingly questioned, was used.

The truth is that over the centuries, nature has developed different compounds to prevent the oxidation of lipids. There are many types of natural antioxidants produced by plants in order to protect their own fats and / or oils. Many of these antioxidants have been identified but many others have not yet been discovered.

Tocopherols, Rosemary Extract and Ascorbic Acid are the natural antioxidants most used in the food industry, each with its own specific benefits and uses. In addition, many other naturally occurring antioxidants have been identified in plant sources and plant extracts, which can be in a variety of food applications.

Myth 5: Natural antioxidants are much more expensive than synthetics

At first glance it could be thought that this statement is 100% true, since, historically, synthetic antioxidants have always been cheaper than natural ones, especially if only the cost per kilo of the product is taken into account. However, at present, there are some types of natural antioxidants, such as Tocopherols, which in recent years have experienced a significant drop in prices, influenced both by a greater supply of the product and by the increase in efficient production.

Additionally, there are certain natural additives that have a higher antioxidant activity than synthetic ones in some specific uses, such as in frying processes, so the amount of product needed to achieve the same effect is lower. This, coupled with the fact that the recommended dosages are extremely low (between 0.03% and 0.3% of the fat part of the product), makes the economic impact on the cost of the final product minimal.

Lastly, although natural antioxidants are generally somewhat more expensive than synthetic ones (in price per kilo), the latter are being increasingly questioned by society, which is creating a demand for food producers to use products of natural origin. If we take into account the enormous economic impact that a food company can suffer if there is decrease in the demand for its product due to ingredients that do not reflect the market trends, the use of synthetic antioxidants may be much more expensive in the long run.

antioxidants in food

The perception that society has in relation to antioxidants in food

Because it is a technical field, much of society does deeply understand the functions of antioxidants and their application in food. This is why myths are generated around this issue, which may make society suspicious of antioxidant use. In fact, it should be just the opposite. Antioxidants are elements that help the conservation of food in a natural way, and can even provide a vitamin value for the consumer. The trend in the food industry, in line with the rest of society, is that more and more natural antioxidants are being used.

In short, the food industry is becoming focused on the processing of more natural foods, incorporating non-synthetic ingredients into their products, with the aim of making them healthier.