## 3 Main Findings
### Ingredients and Their Effects on Gluten-Free Dough Rheology and Bread Quality
#### 3.3.3 Conventional and Alternative Sources of Protein  
Several studies have examined the addition of alternative protein sources. The first distinction relates to the type of protein, which can be divided into \"conventional\" (egg, dairy, soy, etc.) and \"alternative\" (insets and legumes). The latter, in addition to any technological improvements, reduces environmental pressure, and meets increasing demand for sustainable protein. Like other improvers, the aim of protein addition is to reinforce the dough structure, with the help of cross-linking enzymes. An additional benefit is improved nutritional content [13]. Generally, protein addition decreases dough peak viscosity, final viscosity, and setback, due to starch dilution [13; 14; 15; 17]. Soybean protein isolates and solid egg whites have been found to significantly increase the storage modulus of rice-based, gluten-free doughs [13]. However, the latter authors report that although loaf specific volume and crumb hardness were better when using solid egg white,its addition did not modify the elastic modulus. At the same time, while the addition of soybean protein did increase the elastic modulus, crumb hardness was poorer. These findings were supported by [PERSON] et al. (2008) [14], who highlighted that the addition of soy protein to gluten-free formulations enhanced crumb grain, bread volume, and the overall bread score. Consistent with [PERSON] and [PERSON] (2015) [13], the latter study found that the addition of egg protein resulted in the formation of a film-like continuous structure (similar to wheat gluten); the effect was enhanced by the addition of transglutaminase, which catalyzed cross-linking. A very interesting development is reported by [PERSON] and [PERSON] (2012) [17], who tested the use of processed storage proteins from tropical cereals such as maize and sorghum. The latter authors report that zein, the maize prolamin protein, and kafirin, the sorghum prolamin, exhibit viscoelastic (gluten-like) properties if suitably plasticized with a lipid, such as oleic acid. However, at normal kneading temperature, these proteins exist in a glassy state, and must be mixed at a higher temperature to be effective. In other work, [PERSON] et al. (2008) [14] highlighted that the addition of dairy ingredients such as demineralized whey powder, a powdered skimmed milk substitute, skimmed milk powder, sodium caseinate, and milk protein isolate significantly improved the nutritional content, volume, appearance, and sensory properties of breads, due to their ability to form stable networks. However, the use of dairy ingredients as an improver is not recommended, as approximately 50% of people with celiac disease are also lactose intolerant. From an environmental point of view, alternative protein sources are more sustainable than those mentioned above. The literature reports several studies that test the suitability and effectiveness of flour made from different insects. The first critical issue relates to safety. An early study ([PERSON] et al. (2020)) [18] examined the potential microbial, chemical, physical, and allergenic risks related to the breeding, transformation, and consumption of insects. Regarding microbial risk, the authors noted that, although neither _Salmonella_ spp. nor _Listeria monocytogenes_ have been detected, particular attention needs to be paid to this aspect [18]. Chemical and allergenic risks are also worrying, and they observed that care needs to be given with respect to breeding (chemical risk), and food labeling (allergenic risk) [18]. Nevertheless, although insects are still not globally accepted as food--the European Community has only recently recognized them as a novel food [19]--it seems that, if due precautions are taken during production, the use of insect floors is very promising [18; 20]. The latter observation is confirmed by [PERSON] et al.