Semi quantative estimation of glucose in foods.
Semi quantative estimation of glucose in foods.
ghost | 5743 Reads | Semi-quantative estimation of Sugars
Aim: Estimate the percentage content of reducing sugars in a series of foods.
Hypothesis:
Introduction: Reducing sugars can be detected with the use of Benedict’s reagent, higher concentrations of the sugar results in a darker colour of the solution containing Benedict’s reagent and the substance. Using this information we can construct a colour scale using varying concentrations of Glucose (a reducing sugar). With this scale we can semi-quantativly estimate the percentage of reducing sugars present in a given food type.
Prediction: I predict that the colour of the solution will darken as we use sweeter foods, especially the energy drink we shall be using.
Equipment: Benedict’s solution. Food types: 1.Lucazade (an energy drink). 2.Rice crispy squares. 3.Orange juice. 4.Flour. 5.Crisps 6.Pop (A fizzy drink). A Bunsen burner, with mat, tripod and gauze. Glucose solutions, of different concentrations: 2.0%, 1.0% 0.5%, 0.1%, 0.05%, 0.02% 0.01% Glass rod. Beaker( Large) Puppet Measuring cylinder Test tubes (13) Mortar and Pestle. Distilled water. Labels. Test tube rack.
Method:
Measure all quantity with a measuring cylinder and a peppet if nessesary.
Colour range test:
1.Get all the equiptment.
2.Place 3cm³ of each Glucose solution in a test tube 5cm³ of Benidicts reagent.
3. Place all the test tubes in the large beaker, half fill the large beaker with tap water.
4. Place the large beaker on the tripod, and light the Bunsen burner (Yellow
Flame).
5. Put Bunsen burner on mat with tripod in place and set the Bunsen burner to a blue flame.
6.Leave to boil until the solution changes colour, remove from flame for a few seconds if the bubbles cause the test tubes to move about vigorously.
7. Once the solutions have changed colour remove them from the flame and place them in a test tube rack.
Food test:
1. Get all the stated equipment.
2. Measure out 3cm³ of each liquid food and add to 5cm³ of Benidicts reagent. Label test tubes appropriately.
3. Crush up the solid foods if they are not already powder, and add to 3cm³ of
Distilled water, and then add to 5cm³ of Benedict’s solution.
4. Place 3cm³ of distilled water added to 5cm³ Benedict’s reagent in a test tube.
5. Place all the test tubes in the large beaker, half fill the large beaker with tap water.
6. Place the large beaker on the tripod, and light the Bunsen burner (Yellow
Flame).
7. Put Bunsen burner on mat with tripod in place and set the Bunsen burner to a blue flame.
8.Leave to boil until the solution changes colour, remove from flame for a few seconds if the bubbles cause the test tubes to move about vigorously.
9. Once the solutions have changed colour remove them from the flame and place them in a test tube rack.
10.Compare the results of the food tests against that of the Glucose solutions.
Results:
Glucose solution. (%) Food type 2.0 Rice crispies 1.0 Lucazade 0.5 Crisps 0.1 Orange Juice 0.05 X-Nothing 0.02 X-Notihng 0.01 POP
Conclusion: The rice crispies chewable square contained the most reducing sugars. I was surprised by the fact that the POP, seemed to only contain the equivalent of 0.01% glucose this is because these fizzy drinks usually are full of sugars to make them sweet. The turn out for Lucazade, an energy drink, fits, it’s high in sugar because it is designed to provide glucose for respiration.
Evaluation: use diabur 500 strips with invertase/ a ligth meter.