How Fiber and Gum Change Dough Properties
Research Context:
Sugar beet fiber (SBF) is used in food technology as a source of dietary fiber (DF). Due to its excellent functional and physiological properties, studies have been conducted on the use of SBF in products such as cookies, bread, spaghetti, extruded products, Frankfurter sausages, Turkish-type salami, and tarhana.
In the food industry, guar gum (GG) is also an innovative additive used in various products as a stabilizer and a source of dietary fiber. However, there is limited information in the literature about the rheological behavior of SBF and GG in wheat flour–dough systems.
Therefore, the present preliminary study was planned to examine the effects of incorporating SBF and GG on the rheological properties of wheat flour.
Rheological Analysis:
For the rheological analysis, commercial white wheat flour obtained from a local industrial mill (moisture 13.2%; ash 0.72%; protein 10.5% d.m.), guar gum, and salt were used. Fibrex (F) is a commercial sugar beet fiber product (67% dietary fiber) originating from Sweden.
Samples:
Control flour
Flour substituted with F at 3%, 6%, and 9%
Flour supplemented with GG at 0.5%, 1%, and 1.5%
The rheological properties of the dough were analyzed using Absograph 500 and Resistograph 500 instruments (Bastak Instruments, Ankara, Turkey).
Parameters obtained from Absograph 500:
Water absorption (WA, %)
Development time (DT, min)
Stability (ST, min)
Farinograph quality number (FQN)
Parameters obtained from Resistograph 500 (at 135 min):
Extensibility (Ex, mm)
Energy (A, cm²)
Tensile resistance (Rs, BU)
Maximum tensile resistance (Rm, BU)
Rs/Ex ratio
Rm/Ex ratio
Tests were conducted in duplicate, and the mean values are presented in a table.
Absograph Results:
For the control dough (without F or GG):
WA: 63.6%
DT: 0.9 min
FQN: 23
For the dough samples with F:
WA: 64.7–67.5%
DT: 1.0–7.8 min
FQN: 28–110
ST: 2.0–8.0 min
For the dough samples with GG:
WA: 65.9–69.9%
DT: 1.1–1.2 min
FQN: 22–29
Substitution of flour with F and GG decreased stability regardless of concentration. However, development time (DT) increased with increasing F content. The sample with 6% F showed the highest FQN value.
Resistograph Results:
For the control dough at 135 min:
Rs: 349 BU
Ex: 92 mm
These values indicate a weak-to-medium dough.
For the dough samples with F:
Rs: 706–742 BU
Ex: 79–112 mm
For the dough samples with GG:
Rs: 520–576 BU
Ex: 120–124 mm
Resting time was found to be important for the rheological behavior of the dough.
Table 1. Rheological parameter1 of wheat flour-F and wheat flour-GG dough
Higher addition of both F and GG substituted samples, which needed the highest rest time (135 min) in order to reach maximum resistance. The addition of F and GG to wheat flour brought some changes in the dough mixing behaviour as measured by Absograph 500 and Resistograph 500 and these absographic and resistographic characteristics of flour supplemented with F indicate that F supplemented flour can be used for making good quality bread. Results also indicate that incorporation of GG to the wheat flour increased the Ex value.
However, further researches are needed in order to determine the effects of incorporation of different levels of Fibrex and guar gum along with Fibrex on absographic and resistographic characteristics and to understand if Fibrex can be utilized with guar gum for value addition.
