Food Lab Report
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Food Lab Report
Purpose: Test for presence of starch, protein, glucose or vitamin C in our chosen food sample. I accomplished this task by following various procedures which gave me a result to see if my test was negative or positive.
Hypothesis:
Test for Starch: Tested raisin bread: before testing the bread I was expecting to have a positive result, and see a sign of starch in the bread.
Test for Protein: Tested an orange: before testing the orange I knew that we would find a presence of protein in it.
Test for Glucose: Tested sugar: I knew that we would find glucose in the sugar after the tests.
Test for Vitamin C: Tested orange juice: I knew that we would find a presence of vitamin C in orange juice.
Materials:
Salt, spot plate, iodine, starch, food sample (raisin bread, orange juice, sugar and orange), Benedict’s solution, Biuret solution, broth solution, test tube, droppers, test tube holder, H2O, beaker, test tube rack, wash bottle, hot plate and micropipets.
Procedure:
Test for protein: I added about 1cm of salt solution to a test tube. Then I added 1cm of broth solution to a new test tube. Finally I added 2ml of Biuret solution to each test tube. Then I recorded my observations. I repeated these steps again but this time with my food sample to see if it was negative or positive.
Test for starch: First off, I added a few drops of salt solution into a spot plate. Then I added a few drops of Iodine solution to the sample. I then recorded my observations. These tests showed me what a positive reaction of starch looks like. I then proceeded by repeating these steps but this time around, with my food sample.
Test for glucose: First off, I added about 1cm of salt solution to one of the test tubes. Then I added about 1cm of glucose to a new test tube. Then I added 10 drops of Benedict’s solution to each test tube and let each one stand in a bath of boiling water for 1 minute. I then recorded my observations, and repeated these test with my chosen food sample to see if it had a presence of glucose in it.
Test for vitamin C: I Added 1ml of starch solution into a test tube. Then I added exactly 3 drops of Iodine solution to the test tube and stirred and mixed it. I then recorded my observations. After that I added 3 drops of vitamin C to the test tube and swirled it. I then repeated these steps with the food sample in it to see if it contained vitamin C
Observations:
I noticed many changes in colour once I mixed substances together; I also noticed some changes in texture. For example in one of the labs, I had a very dark and purplish liquid, once I added another substance in the mix, it became clear and a light purple. I didn’t notice any changes in smell or any scents at all; I also didn’t hear anything when I was doing these labs.
Discussions:
Question: What is a false positive?
Answer: A false positive is when you get a positive result for a certain substance in your food, but it actually isn’t in it, it was a mistake because something went wrong and gave you a false positive result.
Question: What might have caused a false positive?
Answer: one very likely cause may have been the bad measurement of certain substances either leading to an overdose or an under dose of what was asked. Main problem was somewhere in the instructions you didn’t read or follow something properly. Also you may have let in sit either in hot water or just on the counter longer or shorter than instructed. Lastly you may have mixed the wrong substance in the mix.
Conclusion: In conclusion by following the various procedures and steps, I was able to determine whether my chosen food sample was either negative (not containing a certain substance) or positive (containing a certain substance).
References: Text book, Brain, Lab observation sheet, Equipment sheet on website, procedures sheets (4) on website.
By: Gabriel McConnery