Sep 7, 2010

Food Test

Food tests and chromatography are techniques used for the recognition of biologically important chemical compounds. The use of these techniques is not limited only to the food industry. Detectives can use chromatography to analyse fibres found at a crime scene and when used in conjunction with sniffer dogs, gas chromatography is a common way to identify explosives in airports, it has also been used in schools to perform drug screening.
Why do we need two methods for identifying foods?
Food tests are less precise, they basically identify foods into the category of proteins, lipids, starch, cellulose, reducing sugars or non-reducing sugars, whereas paper chromatography can identify specific molecules, for example, finding out which amino acids or monosaccharides are contained in a mixture.

Three tips on food tests with sugars
1. To distinguish between reducing and non-reducing sugars, first test a sample for reducing sugars, to see if there are any present, if no positive result is achieved test for non-reducing sugars.
2. When testing for a reducing sugar it is not possible to distinguish between glucose and fructose, paper chromatography would need to be used.
3. When testing for a non-reducing sugar the solution will be neutralised when it stops fizzing.