Enzymatic Browning: Activity of Fruit Homogenates

1
Enzymatic BrowningActivity of Fruit Homogenates
2
Enzymatic BrowningActivity of Fruit Homogenates
3
Enzymatic BrowningActivity 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 0 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 0 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