Shed light on benzene reactivity in fizzy drinks – Education in Chemistry

Download this

Use the starter slide with your class to help them think about uses of organic substances and their risks.


Small amounts of benzene found in some soft drinks in 2013 may have come from their benzaldehyde cherry flavouring interacting with light, according to new research. Benzaldehyde is one of the world’s most widely used food flavourings. It can simulate both almond and cherry flavours and odours, and it occurs naturally in many fruit extracts.

Up to 4.6 µg of benzene per litre was found in some drinks. That’s a tiny amount – most people breathe in about 200 µg of benzene each day. However, there is no safe level of exposure. The recommended level for drinking water in Germany is up to 1 µg of benzene per litre.

Experiments with a variety of lamps found that the longer benzaldehyde was exposed to light, and the more intense the light, the greater the levels of benzene were that formed. The researchers also found the reaction didn’t occur in dark red cherry juice – and so they reason that the colour acts as a light filter and prevents the formation of benzene.

Read the full story in Chemistry World.