n°14 January 1998
GLUCOSE OXIDASE INFLUENCE ON DOUGH’S BEHAVIOUR
These tests have been made in order to study the influence of glucose oxidase on the
Pr MAX measurement at constant hydration (CH), on dough behaviour during mixing at adapted hydration
(AH), on the Alveographic parameters at CH and AH.
METHOD
Measurement are done using the following glucose oxidase concentrations : 0%, 0,02%, 0,03%,
0,04% and 0,08%. Premixes are done using 1 Kg of flour with calculated quantities of glucose oxidase in
order to obtain the desired concentrations. For all tests, salt water (25 g/l) is used.
For each concentration, the following tests are performed :
CHOPIN CONSISTOGRAPH
- Constant hydration Consistograph test is made in order to measure the maximum
pressure (Pr MAX), thus the water absorption capacity using to obtain a target consistency.
The amount of sodium chloride solution which is added depends of the flour moisture
content. For each test, the hydration is the same, only the glucose oxidase concentration changes.
The maximum pressure is the main parameter because it is directly linked to the water
absorption capacity of the flour.
- Adapted hydration Consistograph test is used in order to be sure the target consistency is
obtained and to study the dough behaviour during mixing (T Pr MAX, Tolerance, 250 seconds Drop and
450 seconds Drop).
The hydration could be different, it depends on the water absorption capacity which is determined during
constant hydration Consistograph test for each concentration of glucose oxidase.
CHOPIN ALVEOGRAPH
- Constant hydration Alveographic test is made in order to determinate the evolution of
parameters (P, L, G, W, P/L, Ie) as a function of concentration of glucose oxidase.
- Adapted hydration Alveographic test (new prtocol) is made to study the glucose oxidase
influence on parameters T, A, Ex, Fb, T/A and Iec.
RESULTS
CHOPIN CONSISTOGRAPH
PROTOCOL
CH
AH
PARAMETERS
PrMAX (mb)
T PrMAX (sec)
HYDHA
T PrMAX HA (sec)
TOLERANCE (sec)
D 250 (mb)
D 450 (mb)
0,000%
2438,5
179
53,1
150
228
246,5
967
0,020%
2383,5
180,5
52
147
300
114
674,5
0,030%
2238,5
147
50,5
136
312
100,5
639
0,040%
2142,5
217
50,9
139,5
305,5
106,5
639,5
0,080%
2070,5
170,5
50,6
123
312
150
660
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CHOPIN ALVEOGRAPH
PROTOCOL
CH
AH
PARAMETERS
P
G
P/L
Ie
W
T
Ex
T/A
Iec
Fb
0,000%
108
16,7
1,91
60,3
250
90
18,6
1,28
61,4
248
0,020%
171
10,6
7,56
171
135
14,1
3,36
55,8
235
0,030%
175
11,4
6,68
208
179
11,1
7,22
198
0,040%
175
11,1
7,05
198
172
10,7
7,38
179
0,080%
142
11,5
5,25
178
173
10,8
7,36
168
OBSERVATIONS
CHOPIN CONSISTOGRAPH
Ø At constant hydration, the Pr MAX decreases (thus the used hydration for adapted
hydration protocol decreases in function of the glucose oxidase addition)
Ø The evolution of the T for Pr MAX does not follow a clear tendency.
Ø At adapted hydration, an increase of the tolerance and a decrease of drops at 250 and
450 seconds are noticeable when we add higher glucose oxidase quantity.
Ü The glucose oxidase is an oxidoreductase which with oxygen and water catalyses the
transformation of glucose into gluconic acid and hydrogen peroxide.
It activates the reduced ascorbic acid form too (the used flour already contains ascorbic acid).
The ascorbic acid has an action in the transformation of thiol groups into disulfid bonds. This effect
induces a reinforcement of proteinic network.
At constant hydration, the decrease of the Pr MAX is linked to the catalase action (catalase is
contained in the preparation of used glucose oxidase). The catalase allows the transformation of
hydrogen peroxide into water and oxygen.
CHOPIN ALVEOGRAPH
Ø The evolution of parameters for the two protocol is the same.
Ø The pressure and tenacity increase (the tenacity increase is more higher than the
pressure increase.
Ø The swelling and the extensibility decrease (the ratio P/L and T/A increase a lot).
Ø The lengthes curves are too small for the calcul of the elasticity index at constant and
adapted hydration.
Ø The baking strength decreases when addition of glucose oxidase is higher.
Ü The reinforcement of the proteinic network induces a noticeable increase of the pressure
and the tenacity on Alveograph. We can notice that the evolution of dough tenacity is more important at
adapted hydration. This phenomenon can be explained by the correction of the amount of salt water
which takes in account the quantity of water formed by the catalase action.
The tenacity increases to the detriment to the extensibility (which decreases).
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CONCLUSION
The complex glucose oxidase action is noticeable on Consistograph and Alveograph. The
ptoteinic network reinforcement is noticeable on the one hand by the parameters tolerance and drops
and on the other hand by the alveographic parameters pressure and tenacity.
When the doses are too high the glucose oxidase induces an increase of the extensibility to
the detriment to the elasticity.
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