Enzymatic Browning:Activity of Fruit Homogenates

Enzymatic Browning:Activity of Fruit Homogenates

Enzymatic Browning:Activity of Fruit Homogenates

* Control enzymatic browning by:

• Heat• Elimination of O2

• Control of PH

• Use chemical inhibitors.

1 .Tissue extract preparation:

10g fruit+

100ml distilled water

1 .Tissue extract preparation:

ICEBuckner funnel

2 .Measurement oxidation rate:* at PH = 5 and 25ºC

10ml 0.01M citrate buffer pH 5

1ml 0.5M catechol0.5ml D.W.

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Set the wavelength to 420 nm

2 .Measurement oxidation rate:* at PH = 5 and 25ºC

10ml 0.01M citrate buffer pH 5

1ml 0.5M catechol0.5ml enzyme solution

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A

Mix WellSample

Test

3 .Effect of pH changes on enzyme activity:* at PH = ? and 25ºC

10ml 0.01M citrate buffer pH?

1ml 0.5M catechol0.5ml enzyme solution

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A

Blank0.5ml

D.W.

SampleTest

4. Effect of added Sodium Bisulphite and Sodium Chloride on enzyme activity: a. Effect of added sodium chloride on enzyme activity:

0.5ml enzyme solution

0.5ml D.W.0.2ml conc. NaCL

0.2ml conc. NaCL1ml 0.5M catechol

10ml 0.01M citrate buffer pH 5

SampleTest

Blank

1ml 0.5M catechol

10ml 0.01M citrate buffer pH 5

4. Effect of added Sodium Bisulphite and Sodium Chloride on enzyme activity: b. Effect of added sodium bisulphate on enzyme activity:

0.5ml enzyme solution

0.5ml D.W.0.2ml conc. NaHSO4

0.2ml conc. NaHSO4

1ml 0.5M catechol

10ml 0.01M citrate buffer pH 5

SampleTest

Blank

1ml 0.5M catechol

10ml 0.01M citrate buffer pH 5

Results:

Time

Ab

s.

Time

Ab

s.Time

Ab

s.

TimeA

bs.

pH = 3 pH = 4

pH = 5 pH = 6

Time

Ab

s.

pH = 7

Results:

pHA2

min -

A1mi

n

pHActivity

( A2min-A1min)

3

4

5

6

7

Samar A. Damiati