The mechanisms of various hydrocolloids regulating the quality and starch digestibility of whole rye bread

Summary The in vitro effects of six hydrophilic colloids on bread flour properties, rheological properties, water distribution, microstructure, baking quality and starch digestibility were examined. The incorporation of xanthan gum (XG), hydroxypropyl methylcellulose (HPMC), apple pectin powder (APCT) and Curdlan gum (CDL) into rye dough was observed to enhance the gluten network and reduce the gelatinisation and ageing. The addition of APCT and CDL improved softness and ductility and resulted in more complete and orderly protein network of the rye dough than when XG, trehalose (THL) and CDL were added. The addition of THL and XG increased the specific volume, softened the texture of the rye bread and decreased the blood glucose index by approximately 5%. In conclusion, the addition of six common hydrophilic colloids may enhance the quality of bread, albeit with a reduction in the in vitro starch digestibility of rye bread. In the process of making rye bread with added hydrophilic colloids, the hydrophilic colloids will bind with the proteins and starch in rye to strengthen the gluten network structure and improve the quality of the bread.