Identification of Unknown Carbohydrates Using Various Biochemical Techniques
Practical Assessment LO1
Introduction:
The experiment conducted involved subjecting six samples of unknown carbohydrates to different methods of identification, this is involved several reagents including Benedict’s reagent, Barfoed’s reagent and iodine solution, these reagents provided the investigation with credible and accurate results as the reagents stated above give good indicative results to the types of carbohydrates present.
Carbohydrates come in several different forms e.g. Starch is a polysaccharide and consists of thousands of monosaccharide sub-units which form a chain – polysaccharides (poly – many) are not readily soluble in water but react with iodine …show more content…
Aldehyde Oxidation (University, n.d.)
Glucose Testing Strip (Diastix®) – Test 5
Objective – Using glucose test strips to determine carbohydrate samples, this method of analysis is dependent on the concentration of glucose, the downside to this is the test could produce a false negative if the concentration is too low to stimulate a reaction from the test strip.
A test strip was stirred into a sample being tested allowing 30 seconds for the glucose test strip to react, if the strip turns green-brown within 30 seconds, the sugar is glucose.
Iodine Test – Test 6 (This test was carried out last)
Objective – To test for polysaccharides using iodine solution.
5 drops of Iodine Solution was added to each sample, if the colour of the sample being tested changed from brown to blue-black this indicates a positive test for polysaccharides, if the colour did not change this concludes in a negative result for polysaccharides.
(Iodine reacts with amylose present in starch and forms a blue black colour, iodine molecules enter the coiled amylose and form a starch-iodine complex (linear triiodide ion complex, see figure 2.). Figure 2. Linear Starch (amylose) /Iodine complex.
(Arora, 2012)
Results:
Figure 3. Results Table
Test A B C D E
Practical Assessment LO1
Introduction:
The experiment conducted involved subjecting six samples of unknown carbohydrates to different methods of identification, this is involved several reagents including Benedict’s reagent, Barfoed’s reagent and iodine solution, these reagents provided the investigation with credible and accurate results as the reagents stated above give good indicative results to the types of carbohydrates present.
Carbohydrates come in several different forms e.g. Starch is a polysaccharide and consists of thousands of monosaccharide sub-units which form a chain – polysaccharides (poly – many) are not readily soluble in water but react with iodine …show more content…
Aldehyde Oxidation (University, n.d.)
Glucose Testing Strip (Diastix®) – Test 5
Objective – Using glucose test strips to determine carbohydrate samples, this method of analysis is dependent on the concentration of glucose, the downside to this is the test could produce a false negative if the concentration is too low to stimulate a reaction from the test strip.
A test strip was stirred into a sample being tested allowing 30 seconds for the glucose test strip to react, if the strip turns green-brown within 30 seconds, the sugar is glucose.
Iodine Test – Test 6 (This test was carried out last)
Objective – To test for polysaccharides using iodine solution.
5 drops of Iodine Solution was added to each sample, if the colour of the sample being tested changed from brown to blue-black this indicates a positive test for polysaccharides, if the colour did not change this concludes in a negative result for polysaccharides.
(Iodine reacts with amylose present in starch and forms a blue black colour, iodine molecules enter the coiled amylose and form a starch-iodine complex (linear triiodide ion complex, see figure 2.). Figure 2. Linear Starch (amylose) /Iodine complex.
(Arora, 2012)
Results:
Figure 3. Results Table
Test A B C D E