Carry out positive food tests for protein, fat, glucose and starch. We will then use these techniques to identify food groups in as range of foods.

Chemical Test on Food

Science Coursework

Aim: The aim of this experiment is to carry out positive food tests for protein, fat, glucose and starch. We will then use these techniques to identify food groups in as range of foods.

Risk Assessment:

Physical Hazards

Avoid chemicals such as Sodium Hydroxide to touch your skin as it may damage the tissue in our skin.
Were safety goggles to protect our from unexpected splashes of chemicals getting into our eyes.

Chemical Hazards

Avoid accidents such as spilling the chemical as it may get our clothes and stain it or burn it. (E.g. the iodine which we will use for the starch test will permanently stain cloths.
Do not attempt to sniff or drink any of the chemicals used in this experiment as they could be toxic and may poison you.

Biological Hazards

There are no biological hazards in this experiment.

Potential Errors:

The potential errors that could occur when we are going to conduct this experiment could be to do with contaminating the food that we are going to test because the apparatuses for this experiment may not be clean enough or the food could go out of date and lose it’s glucose or protein etc.

Results Table:

The crosses or ticks that are squared are the correct results which we should have got in the experiment.

Anomalous Results:

The Anomalous results are shown on the ...

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Potential Errors:

Results Table:

The crosses or ticks that are squared are the correct results which we should have got in the experiment.

Anomalous Results:

The Anomalous results are shown on the results table above. The experiment for these results was conducted by other groups of pupils from our lab. In the group that I was in we experimented on biscuits. The results we found that was close to being anomalous was that in our glucose test the colour only changed to orange and didn’t change further to brick-red. This was probably because the hot water started to cool down.

Problems Encountered:

The problem that we encountered that may have been the reason to give us these odd results was not to be able to use a continuous supply of heat to the boiling water in our test for glucose, so the water may have turned slightly cooler, therefore slowing down the reaction and the colour change.

Evaluation:

Strengths

The experiment was carried out very easily as there was not any difficult eye-level measuring involved.
Except for the glucose test the others were very simple because we just had to put the drops of the required chemicals onto the foods to get our result, where as in the glucose test we had to add the benedict’s solution on the glucose that heat it to get our result.
We carried out the experiment very quickly because the pupils in our lab were split into groups and each group just tested on one type of food.

Weaknesses

We were unable to use the glass tubes which were required for this experiment but instead we had to use small trays in which it was very difficult to deal with the chemicals.
The equipment we used looked unclean and contaminated.
Some of the food that the other groups tested did not give a clear result because they had gone off.

Sources of Errors

In the group that I was conducting the experiment with we did not identify any errors but that group near to us was carrying out the tests on an apple. The apple had gone off therefore there was no glucose present in that apple. This gave the anomalous result which is shown on the results table on the previous page.

The method of these tests were very easy to carry out and does not need any amending but to overcome these errors in future experiments we should use new packed up food that will only be opened at the start of the experiment. We should also be provided with the required equipment that has been thoroughly cleaned and sterilised by the science technician.

Argha Sarkar 10E