The most common macromolecules found in living organisms are carbohydrates , lipids, proteins and nucleic acids. Briefly, the meaning of macromolecules is that they normally contain two or more molecules in them and their main functions are to store energy, information and much more. Most foods are known to be combinations of macromolecules. While some of these compounds can be detected by taste tests, many cannot. Scientists then use certain tests to determine the presence of macromolecules. To determine the type of macaromolecules present in a certain type of food sample,various test can be done .The tests performed were, iodine testing for starch and glycogen, Benedict’s test for reducing sugars,schultz’ solution for cellulose, Phloroglucinol to test for lignin ,Xantoproitec test and Biuret’s test for protein.And for lipid , Sudan 3 test and emulsion test was conducted. Depending on the test performed, certain results acquired, clearly identified the macromolecules present in each food sample. With the aid of the results from the lab, the unknown solution will also be determined.
To test for starch, the starch test has been conducted with the use of dilute iodine. When a few drops of Iodine solution was dripped into the test tube with starch solution, the iodine solution changes colour from yellow to dark blue. This determines the presence of starch. When starch is presence, the iodine lodges itself in the helical structure of the polysaccharide chain to give it a black blue colour.
Dilute Iodine was dripped onto a thin slice of potato to test for the presence of starch. Dark blue colouration forms on the potato slice indicating the presence of starch. The Iodine solution traps itself in the helical structure of the polysaccharide to form dark blue colour.
To test for the presence of glucose, Benedict’s solution was used to test for reducing sugars. Benedict’s reagent is clear blue due to the copper...
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