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Food Constituent Tests. Research question: What are the substances that make up foods such as potatoes, egg yolk, apples and oil?

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Introduction

Food tests Introduction: Reducing sugars, starch (a polysaccharide), lipids and proteins make up large a portion of our daily diet. To test for the presence of these substances, certain tests should be made. In this report I will mention these tests and their results. Research question: What are the substances that make up foods such as potatoes, egg yolk, apples and oil? Apparatus: * Test tubes * Samples of a potato, egg yolk, apple and oil * Bunsen burner * Beaker * Benedicts solution * Iodine solution * Ethanol * Biuret solutoin Method: (For reducing sugars) ...read more.

Middle

(For proteins) Add a sample of egg yolk into the test tube, then add a few drops of biuret solution and observe. Results: Test for... Test Result Reducing sugars (With apple sample) Benedict solution Solution turned red-brown Starch (With potato sample) Iodine solution Blue/black color Lipid (With oil) Equal amounts of ethanol, oil and water Milky white solution Protein (With egg yolk) Add biuret solution to protein Purple solution Discussion: In the reducing sugar test, the solution turned red-brown. This is because, as the name suggests, reducing sugar reduced the copper (II) ...read more.

Conclusion

Hence, an emulsion of tiny droplets of water reflects light and results in a white solution. In the protein test, the result was a purple solution, this is because peptide bonds are present which form a purple color with copper(II) ions. Evaluation: In these experiments, I tried to make it as accurate as possible by doing the following: * Adding equal amounts of food samples and solutions However, the experiment could have been better if I: * Used a different pipette for each solution as the different solutions might have mixed inside the pipette. Conclusion: After doing this experiment, I can conclude that egg yolk mostly consists of proteins, apples mostly contain reducing sugars, potatoes are mostly starch, and cooking oil mostly contains fats. ?? ?? ?? ?? ...read more.

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