# The Clean Label Concept: Novel Approaches in Gluten-Free Breadmaking
## 6 Gluten Substitutes  
Most often, gluten-free products use hydrocolloids to perform the function of the gluten network. These long-chain biopolymers with high water-binding ability are usually plant secretions (e.g., guar gum), substances produced by microorganisms (xanthan), or plant materials modified by chemical and physical methods (cellulose derivatives). However, all are classified as food additives under the provisions of the food law and have E numbers in accordance with the EU regulation no 1333/2008 [1]. The number of such stabilizers and thickeners can be applied in the production of high quality gluten-freebread, including gelatinin [40], hydroxypropyl methylcellulose (HPMC) [41; 42; 43; 44], sodium carboxy methyl cellulose (CMC) [40; 45], psyllium [41; 43], \(\beta\)-D-glucan [45; 46], pectin [45], carrageenanan [40], and xanthan [41; 42; 45; 47]. An adequate water content as well correct water distribution in the matrix is essential when producing different gluten-free breads. It was found that higher hydration level has a positive impact on the specific volume and height of the loaf as well as on crumb firmness. The interactions of HPMC and water have a strong effect on crumb grain structure [44]. In formulas with a high water content, studies confirmed an association of batter consistency and bread volume. A number of factors and conditions are involved in the process such as the type and amount of hydrocolloids added, the amount of water added, and the interactions between the hydrocolloid and batter ingredients. [40; 41]. [PERSON] et al. [42] found that hydrocolloids impact on gluten-free model systems may vary depending on the raw ingredients used. HPMC improved the volume of teff and maize breads while decreasing the size of rice breads. The volume of buckwheat bread did not change. The usage of xanthan had a negative impact on the loaf volume of all studied breads. The addition of HPMC had a positive effect on crumb hardness of each and every bread type. The crumb hardness of the teff and buckwheat breads was increased by the addition of xanthan gum. The opposite effect was observed in the case of maize breads, whereas xanthan gum had no impact on rice bread crumb hardness. Table 2 summarises the impact of thickeners on volume and crumb hardness depending on the raw material. Crumb grain characteristics such as the surface area of cells and cell wall thickness were also influenced by the hydrocolloids. [PERSON] et al. [45] reported that the influence of specific hydrocolloids on bread quality depended on the type and the amount. The high rigidity of doughs bearing xanthan had a twofold impact on breads characteristics. A negative effect was observed on loaf volumes, and a positive one on the elasticity of the crumb. The usage of \(\beta\)-D-glucan had a beneficial outcome in terms of bread loaf volume at both addition levels. An improved porosity was observed using 1% of \(\beta\)-d-glucan. Agarose at concentrations of up to 1% also had a positive effect on loaf volume. The formulations bearing 1% of CMC or 2% of pectin resulted in breads with substantially improved breads characteristics such as volumes, crumb porosity and elasticity [45]. Table 3 summarises the impact of thickeners on volume, porosity and crumb elasticity depending on the dosage. [PERSON] et al. [44] report that water has a greater effect on the quality of GF bread than HPMC. Of the substances mentioned above, only psyllium and \(\beta\)-d-glucan can be considered as potential replacements for gluten in clean label formulations. The other substances have E numbers, which many consumers associate with artificial additives and chemicals.