The eVect of structurally diVerent bacterial homoexopolysaccharides on gluten-free bread quality and their properties to act as hydrocolloids was investigated. Furthermore, exopolysaccharides (EPS) were analyzed structurally by asymmetrical Xow Weld Xow fractionation and methylation analysis. Breads were made of buckwheat and rice Xour with EPS of Lactobacillus (L.) curvatus TMW 1.624, L. reuteri TMW 1.106, L. animalis TMW 1.971, and L. sanfranciscensis TMW 1.392 or hydroxypropylmethylcellulose (HPMC) at 1 % w/w Xour base. Waterholding capacity, speciWc volume, crumb analysis, baking loss, moisture content, and crumb hardness were determined. Only HPMC and the glucan of L. curvatus TMW 1.624 retained water, and all supplements increased the speciWc volume. Furthermore, crumb hardness was decreased by additives to diVerent extents. The moisture content, baking loss, and crumb Wrmness were improved most by dextran of L. curvatus TMW 1.624. Structure analysis of EPS revealed that L. animalis TMW 1.971 produces a fructan and a glucan and that the dextran of L. curvatus TMW 1.624 had highest molecular weight of analyzed EPS, ranging from 118 to 242 MDa. A methylation analysis demonstrated diVerences in branching. Dextran of L. reuteri TMW 1.106 is branched in position 4 (18-19 %), whereas dextran of L. curvatus TMW 1.624 is branched in position 3 (8-9 %). Overall, this study gives insight into structure function relations of diVerent EPS. A structure function relation is suggested in which high weight average molar mass (Mw) and branching at position 3 of the glucose monomer foster a compact conformation of the molecule, which enables an increased water-binding capacity and promotes superior (structural) eVects in gluten-free breads. The dextran of L. curvatus TMW 1.624 was the most promising candidate for applications in gluten-free bread quality improvements as it retains its size distribution and root mean square even with increasing Mw and forms an increasingly compact molecule.

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