1. Enzymatic Browning: Activity of Fruit Homogenates

2. Enzymatic Browning: Activity of Fruit Homogenates

3. Enzymatic Browning: Activity of Fruit Homogenates
* Control enzymatic browning by:
Heat
Elimination of O2
Control of PH
Use chemical inhibitors.

4. 1. Tissue extract preparation:
10g fruit +
100ml
distilled water

5. 1. Tissue extract preparation:
ICE
Buckner funnel

6. 2. Measurement oxidation rate: * at PH = 5 and 25ºC
Blank
0.5ml D.W.
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5
Set the wavelength to 420 nm

7. 2. Measurement oxidation rate: * at PH = 5 and 25ºC
Sample
Test
Mix Well
0.5ml enzyme solution
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Min A

8. 3. Effect of pH changes on enzyme activity: * at PH = ? and 25ºC
Sample
Test
Blank
0.5ml
D.W.
0.5ml enzyme solution
1ml 0.5M catechol
10ml 0.01M citrate buffer pH ? 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Min A

9. 4. Effect of added Sodium Bisulphite and Sodium Chloride on enzyme activity: a. Effect of added sodium chloride on enzyme activity:
Sample
Test
0.5ml enzyme solution
0.2ml conc. NaCL
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5
Blank
0.5ml D.W.
0.2ml conc. NaCL
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5

10. 4. Effect of added Sodium Bisulphite and Sodium Chloride on enzyme activity: b. Effect of added sodium bisulphate on enzyme activity:
Sample
Test
0.5ml enzyme solution
0.2ml conc. NaHSO4
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5
Blank
0.5ml D.W.
0.2ml conc. NaHSO4
1ml 0.5M catechol
10ml 0.01M citrate buffer pH 5

11. Results:
pH = 4
pH = 3
pH = 6
pH = 5
pH = 7

12. Results:
Activity
(A2min-A1min) pH 3 4 5 6 7
Samar A. Damiati