## 4 Discussion
### Strategies to Improve Gluten-Free Dough Rheology and Bread Characteristics
#### 4.1.5 Hydrocolloids  
Section 3.3.4 highlights that hydrocolloids are widely used to improve dough rheology. Moreover, they seem to be an essential element in the production of high-quality products. In [PERSON] et al. (2016) [29], the authors reviewed the influence of hydrocolloids on gluten-free dough rheology and bread characteristics, and confirmed their role as structuring agents, imitating gluten network properties [13; 14; 17]. Moreover, [PERSON] et al. (2016) [29] confirmed their ability to improve food texture and viscoelastic characteristics. As reported in [13; 14; 15; 17], they act as water binders, extending the overall quality of products during storage, and delaying starch retrogradation [14]. However, although the benefits appear relatively clear, some questions remain. Which hydrocolloids perform best? At what dosage? Using what addition modality? How can we optimize any improvements? We begin with the first question--which hydrocolloids perform best? Here, it is important to highlight that the magnitude of the effect on dough and bread properties is a function of their chemical structure, the amount used, interactions with other ingredients, and process parameters [14; 15; 17; 29]. Nevertheless, HPMC and xanthan gum are the most commonly used, due to their superior effects on dough rheology and the quality of the final product [29]. They have been found to increase dough elastic and viscous moduli, increase dough viscosity, consistency and strength, increase the strength of gas cells, increase rheofermentographic indexes, and increase elasticity in doughs produced with rice, corn, and buckwheat flours [29]. Bread is reported to have higher specific volume (and the loaf resembles wheat bread), reduced crumb hardness, improved color, bigger gas cells and improved crumb porosity, increased moisture content, reduced water loss, reduced crumb firmness, slower staling kinetics, improved sensory properties, and higher consumer preference in panel tests [29]. These findings are supported by [22; 30; 31; 32; 33; 34; 35]. Turning to the second question--what is the correct dosage? In the context of HPMC and xanthan gum, it is very hard to determine the correct percentage, as it depends on several factors. The first is the optimum water content of the formulation (made up of flour, hydrocolloids, and other ingredients). As noted in Section 4.1.2 and by [PERSON] et al. (2018) [22], the optimum percentage must be evaluated by considering the WHC of individual ingredients (including the selected hydrocolloid). This observation is supported by [PERSON] et al. (2018) [30], who tested three HPMC levels (1%, 2%, 3%) and three hydration level (90%, 100%, 110%) to find the best HPMC percentage, and optimal water content for doughs and bread produced with rice flour. The analysis found that 2.2% HPMC,and optimum dough hydration of 110% was the best formulation to improve both dough rheology and bread characteristics. Finally, the authors highlighted that hydrocolloid viscosity and dough hydration played a key role in product quality. Other authors have examined the effect of HPMC on gluten-free doughs and bread. In [PERSON] et al. (2018) [31], the authors confirmed that HPMC improved dough rheology and bread characteristics in formulations based on rice and buckwheat flours. Unlike [PERSON] et al. (2018) [30], best performance was obtained with 1% HPMC and 100% water. This difference could be due to different flour characteristics (no buckwheat in [PERSON] et al. (2018) [30]), different water content (100% vs. 110%), and other breadmaking factors. With respect to xanthan gum, [PERSON] et al. (2010) [32] compared the effects of the addition of different hydrocolloids on batter properties and bread quality. Breads were made of rice, corn, and soy flours, with 158% water. The study tested several hydrocolloids (0.5%), such as carrageenan, alginate, xanthan gum, and carboxy methylcellulose.