## 3 Results and Discussion
#### 3.2.5 Rheological Measurements  
The rheological alterations of OR and SP sourdoughs during fermentation and freezing are presented in Figures 4-7. G' represent the capability of materials to store the elastic deformation energy and G\" moduli represent the viscous portion of the materials [45]. In general, the G\" was lower than the G' in SP and OR fresh and frozen samples, indicating that the viscous properties of the sourdoughs increased while elastic behaviour decrease with the increasing hours of fermentation. This could be justified due to the possible _Lp_ exopolysaccharides production through sourdough  
Figure 3: SP and OR total flavonoids content during 24 h of fermentation. Small letters in common indicate no significant differences between OR and SP samples withdrawn at different moments; Big different letters indicate significant differences between SP and OR samples withdrawn at the same moment. ferentation, which could act as viscosifiers and texturizers, having pseudoplastic rheological behavior and being involved in the water-binding capacity of sourdoughs [27; 54; 82] reported that strains from _Lactobacillus_ genus could produce excopolsaccharides through sourdough fermentation. This is in agreement with [83] who confirmed that _Lactobacillus plantarum_ is able to produce excopolsaccharides in sourdough through fermentation. On the other side, [84] reported that LAB might produce 12\(\beta\)-glucan during the growth process and metabolism, which could positively influence the viscosity and the water holding capacity of quinoa flour. The low elastic properties of OR and SP fresh sourdoughs could be attributed to the starch degradation which might occur during fermentation [34]. [PERSON] et al. [82] confirmed the amyloid activity of _Lactobacillus plantarum_, activity which could influence the microstructure of quinoa starch and change the pasting properties of quinoa flour. SP 24 h frozen sample had the highest storage modulus (G') (23127.00 Pa) and loss modulus (G\") (6574.7 Pa) at a a final angular frequency of 628 rad s-1, while SP 24 h fresh sample had G' value of 0.06 Pa and G\" value of 1852.2 Pa, respectively, indicating that through freezing the elastic behaviour of quinoa sourdough improved due to the freeze-thaw stability of quinoa starch [50]. Another possible explanation for the G\" improvement through freezing could be the reorganization of hydrogen bonds of amylose and amylopectin during the cooling period [82]. In addition, OR 24 h frozen sample registered values of 4463.80 Pa and 1161.40 Pa for G' and G\", respectively, while OR 24 h fresh sample had values for G' and G\" of 0.09 Pa and 1252.4 Pa supporting the idea that through freezing the viscous features of sourdough improved. Gelation, water-holding, and foaming capacity represent the main technological applications of quinoa flour [52]. Water absorption capacity of quinoa flour is one of the most important physicochemical properties of carbohydrates content being influenced by the intermolecular association between starchy polymers [51]. Furthermore, this characteristics could influence the water loss in pastry or bakery final baked products [52]. Quinoa main carbohydrate is represented by starch having small granules (less than 3 \(\upmu\)m in diameter) and higher maximum viscosity and significant swelling power  
Figure 6: The storage (G’) and loss (G”) shear moduli for OR sourdough at different fermentation times: 0, 4, 8, 12, and 24 h.  
Figure 7: The storage (G’) and loss (G”) shear moduli for OR forzen sourdough at different fermentation times: 0, 4, 8, 12, and 24 h.  
compared with the barley and wheat starches [51]. Compared to the wheat flour, which has a gluten network, the gluten free flours network is mainly influenced by starch properties [84]. Due to its freeze-thaw stability, quinoa starch could be successfully used as an thickener in food manufacturing where resistance to retro degradation is desired. Likewise, quinoa starch is recomended for frozen baby food manufacturing proving good freeze-thawing stability.