Differences between preservatives and antioxidants

Currently there are many miths related to antioxidants in food meant for humans, and one of them mantains that all food additives are bad and harmful to people’s health, however, the truth is that these products allow people to consume tasty, healthy and safe products.

In fact, the manufacture of food at the industrial level today is only possible thanks to the use of additives, and in that regard, companies should strive to use ingredients that, besides fulfilling their technological function, are safe for health and are regulated by food authorities, in order to offer consumers the highest quality products possible.

Currently in the food industry there is a wide variety of additives that are added to foods for purposes such as modifying or stabilising their organoleptic characteristics (e.g. colouring), stabilising certain physical characteristics (e.g. emulsifying), prolonging their shelf life (e.g. preservatives and antioxidants) or improve its components (e.g. acidity correctors). Since they are different components, it is important to learn about them and to know the characteristics that differentiate them from each other.

Two types of additives commonly used in the food industry are preservatives and antioxidants, however, oftentimes we confuse one with the other, and people are not completely clear about their meaning, their characteristics or their most common applications. In the next section, we will learn and differentiate these concepts, and we will see the differences between the two, as well as learn about their applications.

What are preservatives?

Preservatives are a type of additive whose purpose is to protect foods against microbial contamination, therefore preventing them from deteriorating from the growth of these unwanted microorganisms. This does not mean that the product will not deteriorate, since all foods have an expiration date, but they do help to delay deterioration. Preservatives are used in the food industry to delay the onset of fungi, bacteria and yeasts in processed foods ranging from baked goods to dairy and beverages.

What are antioxidants?

Antioxidants are additives capable of delaying or preventing rancidity of food due to oxidation, and therefore, lengthen the shelf life of products. They are very important in the food industry because they allow foods to conserve their nutritional properties and their quality levels. Antioxidants do not improve the quality of food, but it does help them to keep for a longer period of time. There is a wide variety of antioxidants from natural and synthetic origin, which are usually used in food. The most common uses of antioxidants are oils, margarines, confectionery, baked goods, pastries, snacks, cereals and sauces. Some natural antioxidants used in the food industry are Tocopherols, Ascorbic Acid or Rosemary Extract.

Differences between preservatives and antioxidants

Although both additives seek to extend the shelf life of the food preserving the quality of the product, its organoleptic characteristics and its nutritional properties, there are some differences that should be known to clarify which should be used and when.

Technological function

The first difference between preservatives and antioxidants lies in their technological function. As we have already mentioned, the former seek to prevent the proliferation of undesirable microorganisms in the product, while the latter are used to protect food from oxidative rancidity. Both are inhibitors of alterations in the product, but the preservatives are inhibitors of biological changes, and the antioxidants are inhibitors of chemical changes.

Products that contain water or fats

The second big difference is that preservatives are used in products that contain water, since it is in this environment where microorganisms such as fungi, bacteria and yeasts that deteriorate food arise and develop. Antioxidants, on the other hand, are incorporated into products that contain fats, to protect them from oxidation due to the impact of light, heat or other factors.

There are products such as fruits or drinks that do not have a percentage of fat in their composition; in that case it is recommended only to add preservatives to prevent deterioration. Additionally, products like oils lack water in their composition, which is why in this case it is advisable to use antioxidants. However, there are a lot of foods like bread, biscuits, margarine or sausages that have both water and oil in their ingredients, so in these cases it is common to see that food companies add both preservatives and antioxidants.


A third difference is the classification of these additives in relation to their labelling. For example, E-numbers are used at European level, where the preservatives correspond to the numbers between E-200 and E-299, and the antioxidants correspond to the numbers between E-300 and E-399. The E numbers are codes of the different additives, which are used to label them on food products. The number system originates from the International Numbering System (INS) as determined by Codex Alimentarius.

Codex Alimentarius is a compilation of standards, guidelines, codes of best practice, guides and other recommendations on food, food production and food safety, the purpose of which is to protect consumers by ensuring the availability of safe and high quality food.

Codex Alimentarius is a global benchmark for consumers, food producers and regulators. Its influence is recognised on all continents, as it has greatly contributed to protecting the health of consumers and ensuring best practices within the food industry.

How did food additives come about?

We go back to the era of the Roman Empire to find evidence of different ways to preserve food, such as using salt, algae and gelatines to make food more consistent, or using certain plant extracts to colour food. However, it is in the twentieth century that the idea of a food preservative begins to develop. These additives emerged with the aim of improving the quality of food and also to protect the health of consumers, especially as food began to require higher levels of production and transport across longer and longer distances.

At first, they were called “substances foreign to the composition of foods” but later they became known as “chemical food additives”. Although everything had been previously studied, it wasn’t until the mid-20th century that the foundations for the use of these substances were laid. Various congresses and meetings were held in which official bodies and experts from fields such as industry, science and law participated. After all the meetings, the foundations were finally laid for legislation, which has continued to evolve and adapt to new discoveries related to consumer health.

Food additives to extend shelf life

Food additives have been present in mankind for centuries, given the need for humans to preserve food. To date, it is hard to imagine the food industry without additives such as preservatives or antioxidants, because they allow foods to have a longer shelf life, entailing benefits for both consumers and producers.

The most substantial difference between a preservative and an antioxidant is that they are components that affect food differently. Both have a mission to keep food in good condition for a longer time, but do so in different manners.

In short, these are two different components that act differently and are used in products with different characteristics, but always with the aim of keeping the product in good condition for a longer period of time.

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