Testing for Reducing sugars, non-reducing sugars, starch, lipids and proteins.
Testing for reducing sugars, non-reducing sugars, starch, lipids and proteins in unknown substances:
Our aim: was to find out which substances from our five samples have reducing sugars present to determine what they may be for example; they could be monosacchrides or disaccharides. This was carried out by using Benedict’s test.
To find out which substances from our five samples were non-reducing sugars, since some disaccharides are reducing sugars and this would be carried out by using Benedict’s test.
To find out which substances had starch present using iodine
To find out which substances were lipids using the emulsion test
To test for proteins in the substances using the biuret test
Context of the experiments:
The context of this experiment was that we were interested in finding out what biological compounds we were dealing with as we had no idea what each substance was and all samples looked the same therefore we had to carry out a series of tests to figure out what structures they were made of.
Some simple sugars, including glucose, can be made to reduce blue copper sulphate to red copper oxide. This reaction can be used as a test for some sugars. Copper sulphate is mixed with other chemicals to be used as Benedict’s solution which is used in the test. This was the test for reducing sugars.
If the reducing sugar test comes out as negative (no colour change), the non-reducing sugar test can be done. The non-reducing sugar test works because if there is any sucrose present (which is a non-reducing sugar, that we are testing for), it is broken down into those monosaccharides, which can be tested for using the ordinary reducing sugar test. A positive result therefore means non-reducing sugars are present on the original sample.
Starch is easily detected in substances by its ability to change the colour of the iodine in potassium iodide solution from yellow to blue-black.
Lipids do not dissolve in water, but do dissolve in ethanol. This
Our aim: was to find out which substances from our five samples have reducing sugars present to determine what they may be for example; they could be monosacchrides or disaccharides. This was carried out by using Benedict’s test.
To find out which substances from our five samples were non-reducing sugars, since some disaccharides are reducing sugars and this would be carried out by using Benedict’s test.
To find out which substances had starch present using iodine
To find out which substances were lipids using the emulsion test
To test for proteins in the substances using the biuret test
Context of the experiments:
The context of this experiment was that we were interested in finding out what biological compounds we were dealing with as we had no idea what each substance was and all samples looked the same therefore we had to carry out a series of tests to figure out what structures they were made of.
Some simple sugars, including glucose, can be made to reduce blue copper sulphate to red copper oxide. This reaction can be used as a test for some sugars. Copper sulphate is mixed with other chemicals to be used as Benedict’s solution which is used in the test. This was the test for reducing sugars.
If the reducing sugar test comes out as negative (no colour change), the non-reducing sugar test can be done. The non-reducing sugar test works because if there is any sucrose present (which is a non-reducing sugar, that we are testing for), it is broken down into those monosaccharides, which can be tested for using the ordinary reducing sugar test. A positive result therefore means non-reducing sugars are present on the original sample.
Starch is easily detected in substances by its ability to change the colour of the iodine in potassium iodide solution from yellow to blue-black.
Lipids do not dissolve in water, but do dissolve in ethanol. This