Throughout history, one of the biggest concerns of every group of people around the world has been finding ways to preserve food produced. Food preservation has advanced side by side with agriculture since ancient times, and over the centuries, we have found more and more ways to keep food edible for ever-longer periods.
This exploded with the birth of industrial chemistry in the 20th Century, leading to a huge range of new food additives and preservatives being discovered. Today, people around the globe rely on these preservatives when seeking safe food to eat. However, it is still useful to understand what these preservatives are, and the various methods by which they work.
The Major Types of Food Additives and Preservatives
Fundamentally, there are two basic types of food preservation: physical and chemical. Physical methods involve processes such as freezing or drying, often making significant changes to the food itself. Chemical methods are designed to preserve the food in its original state, as best as possible.
Chemical preservatives come in several different types:
- Anti-microbial preservatives
The most direct way to preserve food is to simply prevent it from spoiling. Anti-microbial agents prevent the growth of mold, bacteria, and other microbial life which would render the food unsafe to eat. These include benzoates, sorbates, propionates, and nitrates.
All of these are either acids, or salts derived from those acids. Acidic environments resist bacterial growth but can easily affect the flavor of the foods being preserved.
Another common method for preserving food is to prevent oxidation – the process of decay accelerated by exposure to oxygen in the atmosphere. Antioxidants are the most varied of the “families” of food additives and preservatives. These include vitamins (E and C), sulfites, and butylated hydroxyanisole.
Antioxidants are particularly effective at suppressing unwanted odors that can be caused by decay but cannot prevent bacterial growth.
III. Chelating agents
These are a sub-set of antioxidants that act via different means. Rather than directly inhibiting oxidation, chelating agents bind metal ions within foods to prevent decay. The most widely used chelating agent is citric acid, which is also the most common preservative in the world. This also includes most polyphosphates, which are effective anti-browning agents for fruits and vegetables.