Identification of Unknown Carbohydrates Using Various Biochemical Tests

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Identification of Unknown Carbohydrates using various biochemical tests

Date of experiment: 11/10/2012
Name of Student: Vicki Marshall

A series of biochemical tests was carried out to identify unknown carbohydrates. There were six carbohydrates that needed to be identified; they have been randomly labelled A-F. The carbohydrates are glucose, fructose, maltose, lactose, sucrose and starch. There was six tests that were carried out to help identify them, these were: Iodine Test, Solubility in Water, Benedict’s test, Acid Hydrolysis, Barfoed test and Diastix test. Aim

The aim of the experiment which was carried out was to identify the unknown carbohydrates by subjecting them to a series of biochemical tests. The tests were as follows: Iodine, Solubility, Benedict’s, Acid Hydrolysis, Diastix and Barfoed test. Methods

There was 1g of each solid carbohydrate contained in bottles labelled A-F, 10ml of deionised water was added to each bottle using a measuring syringe. The bottles were shaked well to ensure that the carbohydrates were complete dissolved. The solubility of each carbohydrates was recorded and the solutions were retains for further testing. If the carbohydrates dissolved completely in water to give a clear view, this meant they were either a monosaccharide or a disaccharide, if the solution was cloudy then it was a polysaccharide. The next test that was carried out was the Iodine Test. 15 drops of solution and 5 drops of iodine were added to a test tube and observed for any colour change. This was repeated for each carbohydrate. If the solution turned blue-black, the carbohydrate is starch. Carbohydrate E turned blue-black while the others had no colour change therefore it was concluded that Carbohydrate E was identified as starch. As Carbohydrate E was identified as starch, there were no further tests required on this solution. The third test that was completed was the Benedict’s test. In this test, 40 drops of each solution...
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