Over the last 2 weeks we have been concentrating on some popular food additives and their reason for being added to our foods. Those food additives are described in terms, which are not always clear. Let's clarify some of them. BUFFERS; Are substances which can hold the acid-alkali balance at a constant level no matter what other ingredients you add to the product. ANTI-CAKING AGENTS; Are substances added to foods such as icing sugar, salt or powdered milk to help them flow freely and prevent the particles to stick together. ANTI-FOAMING AGENT; Are added to prevent excessive frothing or boiling, or to reduce the formation of scum. ANTIOXIDANTS; Normally fats and oils become oxidized when they are exposed to the atmosphere and become rancid and a health hazard. The addition of antioxidants prevents the process of oxidation. Antioxidants are also added to prevent discoloration in fruits. AZO DYES; An azo dye has a particular chemical structure of the atoms in its molecule to which a proportion of the population is sensitive. About 1/5 of people who are allergic to aspirin are also allergic to azo dyes. They are added to foods for color ( Tartrazine is an example ). BASES; Used to increase the alkalinity of a product. Sometimes added to react with acids to give off carbon dioxide gas for aerating purposes. CHELATING SUBSTANCES; When the acid/alkali ratio exceeds a particular limit or the ratio of traces of metal to one another exceeds a particular level, the trace metals may be precipitated out. The addition of chelating substance retains the trace elements in the food solution by bonding them on to an amino acid. EMULSIFIERS; Bring together oil and water and mix them so that they do not separate out in layers. Some emulsifiers are plant gums, some are chemicals and others are synthetic produced derivatives of natural products. PRESERVATIVES; Are substances which inhibit the growth of bacteria, fungi and viruses within foods and thus prevent the spoilage of these foods. Gases such as sulphur dioxide, organic and inorganic acids, phosphates and nitrates are all preservatives. PROPELLANTS; Gases or volatile liquids used in aerosol sprays to expel the content when the button is pressed. RELEASE AGENTS; Added to the machinery or coated on the food to prevent the food from sticking to the equipment such as molds, conveyors, pans, tins and packages. STABILISERS; Similar in function to emulsifiers and thickeners. They serve to protect the droplets in an emulsion from collision with one another and consequently negate their tendency to separate out. SYNERGISTS; Are substances which are capable of increasing or enhancing the effect of another substance. In the context of food additives, synergists are usually used to enhance the effect of antioxidants. These synergists include tartaric acid, citric acid, potassium and sodium salts. THICKENERS; Add to the viscosity of a food. Most of the thickeners are of plant origin such as seaweed or algae derivatives or substances produced from cellulose capable of forming a gel. To round off our understanding of food labeling, next week we will explore artificial sweeteners, then I will get off the subject, I promise!