Rheological, Baking and Sensory Characteristics of Bread from Wheat-Cassava Composite Dough

Uganda produces cassava, which has potential as a raw material for agro-industry. In this study, wheat flour was blended with high quality cassava flour in the ratios 100:0, 90:10; 80:20; 70:30; 60:40; 50:50 and 40:60 and the composite dough used to prepare bread. The doughs were subjected to rheological analysis using mixolab, consistograph and alveograph. Bread physical properties were measured and sensory qualities evaluated to correlate rheological characteristics of flour/dough with bread quality. Inclusion of cassava flour in the composite dough negatively affected the quality of the composite bread compared to the control. Bread volume (631.0 to 516.7 cm3) decreased, specific volume (2.065 to 1.574 cm3/g) decreased, bread density (0.49 to 0.63 g/cm3) increased. Mean scores for sensory quality parameters reduced: crust colour (6.88 to 4.63), taste (7.13 to 4.25), crumb texture (6.5 to 4.63) and overall acceptability (8.13 to 4.5). Bread quality was positively correlated with mixolab parameters protein weakening (C2), dough stability and dough development time (DDT); alveograph parameters tenacity (P) and deformation energy (W); and consistograph parameter maximum pressure (PrMax). Results showed that bread of acceptable quality can be processed using wheat composite containing 20 % cassava flour. Rheological properties can be used to assess suitability of flour for bread making.

ASPECTS REGARDING THE REPRESENTATION OF FARINOGRAPHIC CURVE TO ASSESS WHEAT FLOUR DOUGH BY MATHEMATICAL EQUATIONS

The Brabender farinograph is a device with which important indications for baking are obtained, namely: dough development time (DDT), water absorption (WA), dough stability time (DST), softening degree (SD), Farinograph Quality Number (FQN), important parameters for determining flour mixtures. These parameters are represented on the farinographic curve drawn during the farinograph test. Dough development or formation (formation of gluten) is represented by the ascending branch of the farinographic curve, which has a steep ascending slope, because time (expressed in minutes), fixed on the abscissa of the diagram, has relatively low values (about 1.2–3 min for regular flours), while consistency, fixed on the ordinate of the diagram, reaches the maximum value (peak time) of the dough. In comparison, the descending branch of the farinogram, which starts from the maximum value of the dough consistency (peak time), has a slow descending slope, because the kneading time is extended up to 20 minutes, and the consistency decreases relatively little. The paper presents the appreciation of this branch of the farinogram by mathematical equations for several types of doughs from wheat flour mixed with different percentages of salt.

Wheat rheological and Mixolab quality in relation to cropping systems and plant nutrition sources

The objective of this study was to evaluate the effect of cropping systems [integrated (INT) vs. organic (ORG)] and plant nutrition sources (synthetic in INT vs. approved organic in ORG) on analytical and rheological quality traits of winter wheat and its productivity. The results after 16 years of field experiments were evaluated. Pre-crop for winter wheat was N-fixing crop. Grain yield of winter wheat (6.8 t ha^–1 in INT, 6.5 t ha^–1 in ORG) did not differ significantly, while plant nutrition sources had an equal and positive effect on the yield. Crude protein quantity was higher in INT system by about 0.2%. The farinograph dough development time and dough stability were the longest for ORG and fertilised treatments. Mixolab quality indicators showed a clear distinction between ORG and INT systems and fertilisation in the protein and starch characteristics of the grain. The ORG reported longer Mixolab stability of the dough, mainly on fertilised treatment (8.8 min). Starch characteristics – torque C4 (amylolytic activity) and torque C5 (starch retrogradation) were higher for ORG system. Torque C2, protein weakening, was not affected by the cropping system. ORG system has the potential to achieve consistent, high-quality yields with significantly lower reliance on external inputs.

Selected Quality Attributes of Wheat Flour Added with Overozonized Wheat Flour

Overozonized wheat flour was added to unozonized wheat flour at three different ratios (M1: 1 : 1; M2: 1 : 2; and M3: 1 : 3), and the mixed flour was evaluated for quality properties, including pH, protein component, dough property, pasting property, and steamed bread quality. The pH of the mixed flour gradually increased as the addition content of overozonized flour decreased. The three mixed flour had higher insoluble polymeric protein (IPP) content than unozonized flour. Compared with overozonized flour, M1 and M2 flour did not show a significant difference in IPP content, but M3 flour exhibited a decreased IPP content. Three mixed flour had higher dough development time and dough stability time than both unozonized and overozonized flour, and there was no significant difference among three mixed flour in these two dough parameters. Peak, trough, and final viscosities of the three mixed flour were between those of unozonized and overozonized flour. Steamed bread of three mixed flour had larger specific volume and better texture than that of overozonized flour, with steamed bread of M3 flour showing the best attributes. Among the three mixed flour, M1 flour was the closest to overozonized flour in volatile compounds of steamed bread. These results suggested overozonized flour can be mixed with unozonized flour to decrease the deterioration of overozonization on the dough and food-making properties of wheat flour, but the mixing ratio should be taken into consideration to obtain a better quality.

Effect of selected Rwandan wheat varieties on the physicochemical characteristics of whole wheat flour

<p>The present study aimed to evaluate the effect of the wheat varieties newly introduced in Rwanda on the physicochemical characteristics of their whole wheat grains in order to know their potentials for processing. Gihundo wheat grain variety had the highest values for extraction yield (99.20 %), contents of ash (1.47 %) and total dietary fiber (15.97 %), water absorption capacity (89.00 %), dough development time (7.62 min) and brightness (84.67 %). For the same physicochemical characteristics, whole flour from Nyaruka wheat variety showed the lowest values for extraction yield (96.20%), water absorption capacity (80.00 %), dough development time (6.33 min) and brightness (80.33), while whole flour from Reberaho wheat variety exhibited the lowest values for the contents of ash (0.98 %) and total dietary fiber (12.44 %). The protein content ranged between 10.00 % and 10.85 % for whole flours from all wheat varieties. The results showed that whole flour from Gihundo wheat grain variety exhibited high values for most of the physicochemical characteristics determined in comparison to the other three varieties. It is important to select grains or flour from these wheat varieties newly introduced in Rwanda based on the individual cultivar because their derivative products could have a more desired quality.</p>

Nutritional and rheological evaluation of blends based on ora-pro-nóbis (Pereskia aculeata Miller) and wheat flour

This work aimed to evaluate the nutritional and rheological quality of ora-pro-nobis flour (OPNF) and its influence on the replacement of wheat flour (WF), through the analysis of physicochemical parameters, determination of phenolic compounds, antioxidant activity and rheological analyzes of wheat flour and mixtures with 10 to 30% OPNF. Flour blends with 10%, 20% and 30% of OPNF in substitution of WF in flour base were evaluated. The OPNF showed higher values of lipids (2.87%), proteins (18.29%), fibers (44.13%), ash (11.19%), minerals (Ca, Mg, K, Na, Fe and Zn), beta-carotene (71.37 µg 100 g-1), lycopene (25.02 µg 100 g-1), total chlorophyll (24.40 µg 100 g-1), ABTS radical-scavenging capacity (15.02 μmol Trolox eq. g-1) and DPPH (IC 50 = 33.30 μmol mL-1 extract) in relation to WF. The flour blends with 10%, 20% and 30% of OPNF showed a higher nutritional value and antioxidant activity proportional to the increase on OPNF concentration. The increasing on the concentration of OPNF in flour blends reduced the values of the gluten strength (P), tenacity (W), extensibility (L), water absorption and falling number. Moreover, it increased the values of dough development time, dough stability and water absorption. The results of rheological analyzes indicate that flour blends of OPNF (10%, 20% and 30%) with WF have characteristics suitable for use in biscuits, baked cakes and breads. The data from this study demonstrate the nutritional value and technological potential of OPNF for the development of food products.

Comparative Study on Protein Quality and Rheological Behavior of Different Wheat Species

The quantity and quality of protein and the rheological traits of wheat are crucial for processing flour in the baking industry, but there are few comparisons in the literature between old and modern wheat species. To help fill this gap, the baking quality characterization, gluten content, protein fraction composition, high molecular weight glutenin subunits, and rheological properties of ancient and modern wheat were determined and compared. These varieties were collected by the gene bank of the Crop Research Institute in Prague-Ruzyne and were grown in organically certified research areas in the Czech Republic. Results revealed differences in protein content and composition between varieties with different ploidy levels, as well as differences in development time and stability between einkorn and bread wheat varieties. Based on the proximity of their positions to the parameter quality in the principal components analysis, such as gluten content, gluten index (GI), Zeleny test, stability, dough development time (C1) and gliadin, the baking performances of cultivars were identified.

Effect of disulphide bonds and sulphhydryl concentrations on properties of wheat flour

Disulphide bonds and sulphhydryl concentrations were evaluated to determine the effects on rheological, thermodynamic, pasting, and dynamic rheological characteristics of mixed flours. Gluten samples, first treated with sodium sulphite of different concentrations, were added into flour at a 4% level, which had a significant impact on free sulphhydryl, disulphide bonds, and the ratio of the two indices. There was no relevance between the ratio and other parameters except for free sulphhydryl. The mixed flour doughs had reduced water absorption, dough development time, dough stability time as well as degree of weakening (P &lt; 0.05). Disulphide bonds were associated negatively with the rate of starch gelatinisation (C3–C2), peak, and setback and these characteristics were correlated strongly with dough development time, dough stability time, and progressive protein weakening (C2–C1). The stability of starch gelatinisation and cooking stability of mixed flours did not remain significantly different. The larger the concentration of sodium sulphite, the higher the peak, breakdown, final viscosity, and setback values, but there were no significant differences between samples. For all samples, storage modulus and loss modulus increased with increasing scanning frequency. For mixed doughs, the trend lines of moduli decreased with increasing levels of reduction in added gluten. There was no substantial effect on thermal properties of flours.

Milk thistle flour effect on dough rheological properties

The influence of the addition of partially defatted milk thistle seed flour was studied by analyzing the rheological properties of dough in order to further exploit the functionality of partially defatted milk thistle flour in bakery products. The rheological properties of dough were monitored using Mixolab 2 (Chopin Technologies, France). A rheofermentometer F4 (Chopin Technologies, France) was used to check the dough fermentation, and for the baking trials wheat flour, rye flour, and milk thistle flour were kept in the portion: 50:50:0 (control flour); 50:45:5; 50:40:10 and 50:35:15. The addition of different milk thistle flour in the mixtures resulted in a difference in the viscoelastic properties of the dough. The results showed a weakening of the gluten network in all trial mixtures evaluated. The dough development time values of the control flour were 1.20 min, while an addition of milk thistle flour in portions of 5, 10, and 15% increased these values to 1.30 min, 1.90 min, and 2,80 min, respectively. In addition to higher dough development time values, all trial mixtures exhibited also higher stability (5.07 min; 6.25 min and 8.03 min), when compared to the control flour (4.63 min). The trial mixture with 15% milk thistle flour had different characteristics of gelatinization and retrogradation. The rheofermentometer measured the dough characteristics during proofing, and the trial mixtures with the addition of MTF had a retention volume at approximately the same level as the control flour (WRF). The Volscan profiler was used to determine the bread volume and other parameters. All breads had high volume and specific volume values and can be rated as good, with good porosity and ratio. Mixtures containing 5%, 10% and 15% milk thistle flour added to wheat flour + rye flour maintained rheological parameters within the recommended limits for good technological behavior and, consequently, good quality of bakery products. From all of the above data, it can be stated that, with regard to their baking characteristics, these flour mixtures fall into the category of flours suitable for bakery products.

Development of Highly Nutritional Breads with By-Products of Chia (Salvia hispanica L.) Seeds

The effect of the incorporation of various types of residual chia flour (whole, semi-defatted and defatted, with or without mucilage) on the technological quality of bread was investigated. The various types of chia flour were used to substitute 5 and 10% wt/wt of wheat flour in the bread formulations. The water absorption, dough development time and stability of blends with the presence of mucilage and the incorporation of 10% wt/wt of chia flour demonstrated the highest values in comparison with the other ones. The specific volume of the flour variants with 5% wt/wt of chia flour with mucilage were similar to the control bread; while those formulated with chia flour without mucilage exhibited a lesser volume. The incorporation of 10% wt/wt of chia flour in the formulations caused a decrease in the technological quality of the bread as expected. The bread crust and crumb colour parameters were mainly influenced by the level of chia flour substitution, which resulted in a decrease in lightness and h values. The substitution of wheat flour with 5% wt/wt of chia flour counterparts with mucilage improved the technological quality of the breads. The different oil content of the chia flours did not show any significant influence on overall quality or texture.