Common Types of Food Additives
Food additives are substances added to foods to enhance some of their natural qualities. Some additives keep foods fresher for longer or improve their safety. Others boost or maintain the food’s nutritional value. Finally, there are also additives that improve the appearance, texture or taste of foods.
There are two main categories of food additives:
- Direct additives. They are added to the food intentionally for a specific purpose. Direct additives are usually listed on the ingredient label of a food. Some of these additives may be listed collectively under headings such as artificial flavouring or spices. They are used to improve nutritional quality, preserve freshness, make food look or taste more appealing or assist in processing or preparing food.
- Indirect additives. These substances are typically present in trace amounts and become part of the food as a result of harvesting, processing, storage, packaging or other handling.
Why Food Additives Are Used
The benefits of food additives can be grouped into three major categories:
- Maintaining freshness or improving safety. Additives often serve as preservatives that help slow the damaging effects that oxygen, mold, bacteria, fungi or yeast can have on food. They include antioxidants and antimicrobials.
- Improving or maintaining nutritional value. These substances are added to foods to replace nutrients lost during processing (enriched foods) or simply to help boost a person’s intake of certain nutrients, including those that were not part of the original food (fortified foods). Such additives include vitamins, minerals and fiber. Enriched and fortified foods have helped to dramatically reduce diseases attributed to nutritional deficiencies such as goiter, pellagra, rickets and scurvy.
- Improving appearance, texture and taste. Natural and artificial colors are added to improve a food’s appearance. Emulsifiers help maintain a consistent texture of the food and keep it from separating whereas stabilizers and thickeners ensure a smooth, uniform texture. Anti-caking agents keep food from absorbing moisture so it does not clump together. And finally, sweeteners and spices (both natural and artificial) are used to enhance the food’s flavors.
Types of Food Additives
Examples of the most commonly used direct additives include:
Antioxidants. Oxidation causes rancidity and flavor changes in foods, fats, oils, alcohol and drugs. Antioxidants include vitamin C and E, sulphites, butylated hydroxyanisole and butylated hydroxytoluene. Sulfites may not be used on foods that are eaten raw (except grapes) because this may cause adverse reactions. They also cannot be used in foods that are important sources of thiamin (also known as vitamin B1), because they destroy this vitamin. Products that contain sulfites must indicate the additive on the labeling. This may be referred to as sodium sulfite, sodium bisulfite, sodium metabisulfite, sulfur dioxide or potassium metabisulfite.
Antimicrobial agents. Their role is to prevent the growth of microbes that may cause foodborne illness. They include salt and sugar, as the most commonly used antimicrobial agents, as well as potassium sorbate, sodium propionate and nitrates. For example, salt and sugar absorb water so that it is not available to microbes, while nitrates slow the decomposition of fats and inhibit bacterial growth.
Nutrient additives. Certain nutrients are sometimes added to maintain or enhance the nutritional quality of foods. Examples include folic acid (vitamin B9), niacin (B3), riboflavin (B2), thiamine (B1) or iron added to refined grains, the vitamins A and D added to milk, the iodine added to salt and the nutrients added to fortified breakfast cereals.
Natural and artificial flavors and flavor enhancers. These additives help foods taste better. Natural flavors include herbs, spices, fruits, fruit juices and essential oils. Some spices also provide antioxidant protection. Artificial flavors include artificial sweeteners. Flavor enhancers, such as monosodium glutamate, help bring out a food’s salty, sweet, sour or bitter taste.
Food preparation and processing additives. These substances help foods to maintain a desirable consistency. For instance, emulsifiers keep mayonnaise stable and allow powdered coffee cream to dissolve more easily. Gums, such as xanthan gum, are used to thicken foods and help form gels. Anti-caking agents prevent moisture from causing products to clump together, while leavening agents, such as yeast, release acids during heating that react with baking soda (sodium bicarbonate) to help foods to rise.
Colors. They include colors derived from natural pigments as well as synthetic colors. Color additives are very common in processed foods. They can be added to give appealing color to foods and beverages that normally lack an appealing color, enhance naturally occurring colors and offset color loss resulting from exposure to light, oxygen, temperature extremes, moisture and storage conditions.
Color additives can be divided into certified colors and colors exempt from certification. Certified colors are synthetic substances that provide more intense color to food and help create various hues. Most of certified colors do not change a food’s taste. Colors derived from natural sources are exempt from certification. They tend to be more expensive than certified colors and may alter the taste of a food.
Examples of artificial colors include two forms of blue (brilliant blue and indigotine), two yellows (tartrazine and sunset yellow), two reds (allura red and erythrosine) and a green (fast green). Natural-color additives include annatto (yellow), carotenoids (yellowish orange), caramel (yellowish brown), dehydrated beets (reddish brown) and grape skins (red, green).
Indirect additives may include tiny bits of plastic, paper, glass, tin and chemicals from processing, including:
Antibiotics. Antibiotics given to animals may be found in trace amounts in foods such as meat and milk. As a result, people allergic to antibiotics may experience an allergic reaction to such foods. For most other people, however, the levels of antibiotics in these foods are too small to pose a threat. The FDA in the US, for example, requires a specified time between the times an animal is treated with antibiotics and when the animal is slaughtered. This should ensure enough time for the drug to be metabolized in the animal’s body and excreted so that only a minimal amount is passed into food.
Hormones. In most countries of the world, hormones have been approved for use in food-producing animals. Traces of hormones, such as bovine growth hormone, may find their way into the meat and milk people consume. However, many experts argue that meat and milk from animals treated with hormones is as safe as that of untreated animals.
Acrylamide. This chemical compound forms when foods rich in carbohydrates are cooked at high temperatures (e.g., French fries). Acrylamide is classified as a potential occupational carcinogen, but scientists are unsure of whether or not there is enough acrylamide in foods to pose a risk of developing cancer.
Dioxins. Bleached paper used in packaging (e.g., milk cartons, frozen-food packages or paper plates) can be the source of food contamination with tiny quantities of dioxins. However, most experts believe that these amounts are too low to cause a health threat.
Microwave packaging. Packaging materials from microwave products that contain “active packaging” can sometimes be found in the foods. Also, packaging that simply holds the food when heated in a microwave may pass some of its components into the food. The FDA requires the manufacturers to prove that their packaging is safe for human consumption.
Methylene chloride. In some manufacturing processes, methylene chloride is used to remove caffeine from coffee, leaving traces of this chemical in the coffee. However, the levels that are present are believed to pose no threat to people who consume decaffeinated coffee. For those who remain concerned, decaffeinated coffee is also available in formulations obtained through different processes that do not use methylene chloride.