Have you ever looked at the ingredients on your microwave meal and wondered what dextrose and sodium nitrite are doing in your dinner?

These are some of the many chemicals used in processed foods - some are found in nature, but others can also be made in a laboratory. They’re used by food manufacturers for many reasons, from making sure rice doesn’t go mouldy, to ensuring yoghurt is low fat. But has the industry gone too far, adding too many synthetics to our food?

Graihagh Jackson meets three food scientists to find out what they're adding to our food, and why. Does it matter whether we use 'natural' or synthetic substances, why are some added ingredients not listed on the label, and how do these scientists ensure they are safe?

Plus, how do you bake cookies at 30,000 feet, and what does space smell like?

(Picture: A scientist picking up a plant leaf. Credit: Getty Images/BBC)