- About your question
There is not really such a thing as a fermentation test; is it possible that you are confusing this with the Benedict's test, a process which tells us whether a sample contains reducing sugars, such as monosaccharides, or non-reducing sugars.
- How to perform a Benedict's test
Put your sample into a test tube and add about 20cm³ of Benedict's reagent, which can be made ready using sodium citrate, sodium carbonate and copper (II) sulfate.
Create a water bath by filling a beaker with some cold water. Using a Bunsen burner, tripod and gauze, heat it to around 80 degrees C, checking your thermometer occasionally.
When this is done, the beaker needs to be removed from the heat; you can do this by either turning off your gas supply (which is probably the safest option) or carefully removing the Bunsen burner. Never try to remove the beaker of water from the rest of your apparatus, as this is definitely a dangerous method, more so than the others.
Heat your sample by adding it to your water bath, leaving it for five minutes; should a brick red precipitate form then you know that your sample contains reducing sugars, as this is a positive result.
Should, however, a brick red precipitate not materialize upon performing the Benedict's test, you can run an investigation to see if your sample contains non-reducing sugars.
This is done by adding hydrochloric acid to your sample, and then performing the test described above again. This time, if the positive result for reducing sugar occurs, we can say that it contains non-reducing sugars, because of the addition of the acid.
There are many different food tests that can be carried out to see the type of biological molecules contained within a sample, from the emulsion test for the identification of lipids, to the Biuret test for the identification of proteins.