The term ‘food additives’ is commonly understood to mean that group of substances which, having no particular nutritional importance, when added to a food preserve its quality or develop certain characteristics or properties. Also excluded from the category are all those substances that are accidentally found in food, such as various pollutants and product processing residues, but sometimes nutrients added specifically for the same purposes as other additives are included. The difference between food additives and processing aids should also be clarified. The latter are in fact substances that do not appear in the composition of the food at the end of its preparation, but are used during its preparation.

Legalisation of food additives

It is well known among most consumers that food additives can be toxic, especially if they are taken in large quantities. This is why the use of these products is strictly regulated. In truth, not all additives have documented toxic properties, but then again, although all those currently authorised for food preparation are subject to strict controls, there is not always a guarantee that they do not harm the body. In fact, some of them can be highly allergenic and the possible deleterious effects on health of others are not yet known.

Justification for the use of additives

  The legislation clearly states what reasons must justify the use of additives in the preparation of foodstuffs. Well, the three minimum requirements are:

1. technical necessity of the food additive: if a foodstuff can be prepared without the use of additives, it must be dispensed with. If, on the other hand, it cannot be done without it, then the additive is said to be technically necessary and its use is authorised;
2. inability of the additive to mislead the consumer: some additives, such as colourings, may lead the consumer to think that one product is fresher, more wholesome or simply better than another when in fact it is not. If an additive can change the appearance, smell or taste of the food to such an extent that it misleads the purchaser, it may not be used;
3. safety: the additive must be non-toxic. As mentioned before, however, there is never a guarantee that the intake of a given additive will not give rise to unpleasant allergic reactions or other deleterious effects on health in the short, medium or long term.

Mandatory additive-free foods

  There are, by law, certain foods that cannot be prepared using food additives of any kind. These foods are summarised in the following list:

• fresh buttermilk;
• creme fraiche;
• unfruited kefir;
• milk;
• non-fruity whey;
• natural yoghurt;
• quark;
• non-fruity sour milk;
• sour cream;
• eggs;
• fresh potatoes;
• fresh vegetables;
• seeds and sprouts;
• fresh fruit (except glossy apples, bananas and surface-treated lemons);
• fresh mushrooms;
• pulses;
• cereals;
• cereal flakes;
• dried pasta;
• rice (not quick-cooking rice);
• walnuts;
• seeds;
• pure vegetable oil (refined olive oil can be enriched with vitamin E);
• honey;
• coffee powder;
• natural mineral water and spring water.

The ADI

  For all products intended for food consumption that can be prepared using additives, the ADI (Acceptable Daily Intake) represents the amount of a given substance used as a food additive that could theoretically be consumed daily without harm to health. The ADI is expressed in milligrams per kilogram of body weight (mg/kg) and is valid for individuals of all ages and both sexes. Some authors criticise the ADI on the grounds that it is not a reliable basis for assessing the toxicity risk of an additive. Regardless of this, however, at present the only way to estimate this risk is to use the ADI. Of course, the best thing to do would be to try to avoid consuming foods containing food additives altogether, with the possible exception of nutrients (such as vitamins), but this suggestion is often difficult to apply in practice, both on the part of manufacturers and consumers.

The Code

  In Europe, most food additives can be listed in codedform on food packaging. This type of wording is authorised since some additives have a very long name and are therefore difficult to state in full on the packaging. The code consists of a number, usually three digits, preceded by the capital letter E (standing for Europe) and sometimes followed by a lower case letter.

Classes of food additives

We now come to the specific treatment of each of the products. They are:

1. colourants;
2. stabilising dyes;
3. preservatives;
4. acidity regulators;
5. antioxidants;
6. stabilisers;
7. sweeteners;
8. sweeteners;
9. phosphates;
10. humidifiers;
11. anti-caking agents;
12. leavening agents;
13. release agents;
14. flavour enhancers;
15. coating agents;
16. solvents;
17. resistance agents.

Dyes

  Dyes, as the term itself suggests, are additives used to modify the natural colour of a food, for example to embellish certain confectionery products. They are classified into two distinct categories: surface colourings, which are inedible, and edible colourings. Of these, only the latter may be added directly to food, while the former must only be added to those parts of the food that are not intended for consumption (e.g. the rind of cheeses). The code representing non-edible colours shows the letter C instead of the letter E. According to the latest legal provisions, only certain foodstuffs may be treated with colours. These are listed below:

• icings and sugar products, with the exception of liquorice and products prepared with milk, butter, honey, eggs, malt, caramel, cocoa, chocolate and coffee;
• cocktail cherries;
• candied fruit, with the exception of candied orange and lemon peels;
• packaged ice creams;
• marzipan and marzipan-like products;
• fish-egg products;
• jarred shrimps;
• canned salmon fillets;
• low-calorie jams;
• creams and jellies;
• puddings;
• sweet sauces and soups, with the exception of cocoa products, chocolate, eggs and caramelised sugar;
• effervescent drinks;
• packaged drinks;
• margarine and semi-fat margarine;
• sliced cheeses of medium consistency;
• herbal liqueurs;
• industrial honey;
• strawberry, raspberry and cherry preserves.

Current legislation obliges manufacturers to specify on the product packaging in clear letters the fact that it has been prepared with dyes. In addition, the list of ingredients must specify the dye used.

Stabilising dyes

  Stabilising dyes represent a special class of dyes that, while not possessing the ability to change the natural colouring of the product, can prevent this colouring from being lost during processing.

Preservatives

  Preservatives are substances which, when added to food, act by chemically binding to it and preventing or slowing down its deterioration due to microbiological causes. It is necessary to specify that not all microbiologicalinterventions in food are to be considered as spoilage. On the contrary, they are sometimes necessary processes for the correct ripening of the food, following which the food will acquire digestibility or flavour characteristics that it did not possess before. Now, the micro-organisms that can act on a food by deteriorating it are of various types: we recall fungi, ferments and bacteria. Most preservatives only have their effect against the first two, while only two preservatives exist to prevent bacterial spoilage: benzoic acid and ethyl parahydroxybenzoate. To ensure the protection of food against any micro-organism, several preservatives are very often used simultaneously. In this case, the ADI for each preservative must decrease the more preservatives are used at the same time. More specifically, if two preservatives are used, the ADI of each of them must be halved, whereas if three preservatives are used, the ADI of each of the three will be one third of the original one. Their use must be notified on the product packaging and on the list of ingredients, specifying only in the latter the preservative used. The preservatives par excellence are undoubtedly nitrites and nitrates. They, if consumed in high quantities (unfortunately, the ADI is not very difficult to exceed) can have carcinogenic capacities, due to the endogenous production of nitrosamines to which they give rise. Nitrates, on the other hand, are not toxic per se, but within the body they are easily and frequently converted into nitrites. Other noteworthy preservatives are acids, which act in a very peculiar way: by lowering the pH of the food, they make it unsuitable for the proliferation of those micro-organisms that facilitate deterioration. The law does not oblige the manufacturer to specify the type of acid used to prepare the food.

Acidity regulators

  Acidity regulators are special substances that have the ability to keep the pH of the food constant without changing it. Again, the manufacturer is free not to specify the acidity regulator he has chosen to use in the preparation of the food.

Antioxidants

  Antioxidants can also be considered a special class of preservatives, since their use is intended to preserve food from natural oxidation due to contact with air. As a result of oxidation, food loses vitamins A and C, fat tends to go rancid and, through the action of the enzyme polyphenol oxidase, fruit and vegetables lose their colour. The action that antioxidants perform is only valid for a limited time, after which they lose all their power. In some cases they can even cancel out oxidations already in progress. As with synthetic preservatives, antioxidants can also be used in combination. In this way, the required amount of each antioxidant substance is minimal and the combination is less toxic. Some antioxidants are of natural origin (such as vitamins. These are non-toxic) and others are synthetic.

Stabilisers

  Stabilisers are additives used to preserve or improve the structure of a food. They can be classified into thickeners, gelling agents and emulsifiers. Thickeners and gelling agents, in contrast to emulsifiers, are not fat-soluble, however, due to their particular chemical-physical structure, they are able to retain water molecules within a kind of envelope. Products with thickeners and gelling agents, therefore, swell and acquire a gelatinous consistency when in contact with water. Speaking of thickeners, a special note is deserved by modified starches, which consist, trivially, of synthetically produced starches. The use of synthetic starches is justified by the fact that they are more stable at high and low temperatures than natural starches. Now, in addition to the three classes of stabilisers discussed here, there are two further types of these substances, one intended to stabilise cloudy drinks and the other to act on foamy foods. The former are used in the preparation of certain fruit juices. The purpose of these additives is to prevent small fruit particles in the juices from settling. The latter, on the other hand, are used to preserve the stability characteristics of cakes and various bakery products that contain ingredients in the form of foam. It should be made clear that food manufacturers are not obliged to specify the type of stabiliser used during the preparation of the product, but must indicate, in a general way, that this class of additives has been used and, more specifically, whether the food is enriched with modified starches.

Sweeteners

  Sweeteners are special sweetening substances that can be used as an alternative to ordinary sugar. They are very similar to monosaccharides but possess a hydroxyl function (one oxygen atom double bonded to one hydrogen atom) instead of a carbonyl function (one oxygen atom double bonded to one carbon atom, which in turn is bonded to two other atoms). They are therefore polyols. Despite their structural similarities to monosaccharides, they are absorbed at a slower rate than simple sugars. This, it is thought, could be the reason for their partial malabsorption, which can sometimes result in a laxative effect if the 20-30g/day polyhydrate intake is exceeded. In fact, although they can be assimilated and broken down entirely in the small intestine, the partially unaltered ones reach other intestinal tracts where they subtract water and cause diarrhoea. Precisely for this reason, products containing more than 10% sweeteners must by law bear a warning on the label that in excessive doses they may have laxative effects. They also have the peculiarity that they do not alter (at least very sensitively) insulin levels. They are therefore particularly suitable for products prepared for diabetics. Some sweeteners have a lower sweetening power than common sugar (sucrose), but provide fewer calories. By way of example, lactylol has a sweetening power equal to 25% of that of ordinary sugar and provides 2.4kcal/g; the sweetening power of isomalt is 50% of that of sucrose, while providing 2kcal/g; finally, maltilol has a sweetening power equal to 90% of that of ordinary sugar and provides 2.4kcal/g. Another kind of sweeteners also have the power to increase the sweetness of a food and are used as an alternative to ordinary sugar, but in a different way. The substantial difference lies in the fact that they have little or no energy content. Moreover, these substances have enormous sweetening power, so only a small amount is needed to sweeten a food. For example, saccharin has a sweetening power 200-450 times that of ordinary sugar, while thaumatin has one that exceeds that of sucrose by as much as 2000 times. Several sweeteners are usually used in combination, especially saccharin and cyclamate in a ratio of 1 to 10. In this way, the sweetening power of each individual substance is increased. According to some nutritionists, however, the organism that perceives the taste of sweetness ‘prepares’ itself to assimilate carbohydrates; if these are then denied to it because synthetic sweeteners have been used, it will react with the onset of appetite and the tendency to crave sugar. Foods that are fortified with sweetening substances must be labelled ‘sweetened’ or ‘with sweetener’ on the label and, in the product’s list of ingredients, the sweetener substance used in its preparation must be specifically mentioned. Some sweeteners are heat-resistant and therefore suitable for addition to hot food or food requiring heat during preparation, while others are not and can only be used for the preparation of cold food. The former include acesulfame-K, cyclamate and saccharin, while the latter include aspartame, thaumatin and, more generally, all those whose chemical structure consists of protein bonds.

Phosphates

  Phosphates can be used for very different purposes. Their use, regardless of purpose, must be clearly indicated in the list of ingredients on the product label.

Humidifiers

  Humectants are special substances which, by virtue of their chemical and physical properties, prevent the product from drying out. They are used especially in the production of cakes and various baked goods.

Anti-caking agents

  Anti-caking agents are used to prevent two different parts of the same product from sticking together (e.g. salt and icing sugar).

Leavening agents

  Leavening agents are used to make a food product swell by increasing its volume. This swelling is due to the carbon dioxide (CO₂ ) produced by the fungi in the yeast.

Release agents

  Release agents are used to keep two different products within the same package separate. An example would be sliced bread, or some candies sold inside tubes.

Flavour enhancers

  Some products tend to lose their flavour during processing. To prevent this process, manufacturers are legally allowed to add substances called flavour enhancers to these products. They are used especially for some dehydrated soups sold in pouches. According to some authors, the use of these additives may not only preserve the flavour of a food while it is being processed, but also increase it very significantly. This could lead consumers accustomed to foods with flavour enhancers (or, more generally, to very tasty foods) to a desensitisation of the taste buds and consequently to losing the ability to enjoy less tasty foods. Some also suggest a partial papillary desensitisation in the context of a single meal: starting a meal from particularly tasty foods would invalidate the possibility of fully enjoying the taste of the more delicate ones eaten immediately afterwards. For this reason, it would be desirable to start the meal with milder-tasting foods (such as certain cheeses) and finish with stronger-tasting ones (such as certain peach products).

Coating agents

  Some foods, after a longer or shorter storage period, tend to lose flavour. To prevent this from happening, the manufacturer can add so-called coating agents to such foods, i.e. substances that, by preventing the evaporation of the water contained in the food, can enable it to be stored for longer.

Solvents

  Solvents are used to facilitate the task of another additive. More precisely, food solvents dissolve and dilute an additive with the food itself.

Agents of resistance

  Resistance agents have basically two uses: the first is related to maintaining the structure of fruit and vegetables, while the second is related to combining with gelling agents. In the latter case, its task is to consolidate the gelled structure produced with the help of the gelling agent.

Authorised food additives

A table summarising the special characteristics of additives that are authorised for food production follows (Source: ‘Additives and preservatives’ by Elmadfa I.; Muskat E.; Fritsche D.; 2008. Modified).

Legend:

— = non-harmful substance, therefore no ADI value

* = data not available.