Water absorption as a prediction tool for the application of hydrocolloids in potato starch-based bread

Abstract

To create visco-elastic networks in gluten-free doughs, hydrocolloids have been used most commonly to compensate for the lack of gluten. This study applies a prediction tool in form of an equation, considering the right water absorption level, to obtain optimised conditions for the use of six different hydrocolloids (guar gum, hydroxypropyl methylcellulose, locust bean gum, pectin, sodium alginate, xanthan gum). For this purpose, the water holding capacity of each hydrocolloid was determined and the water amount in the formulation was adjusted accordingly to it. The hydrocolloids were analysed in five concentrations (0.25%, 0.5%, 1%, 1.5%, 2.0%). Analysis of water adjusted doughs included rheological properties, pasting properties and the baking performance. With the aid of the prediction tool, it was possible to obtain bread-like products for each hydrocolloid. However, the various hydrocolloids showed different concentration levels, where they performed best. In this study, the main influencing factors on bread quality were linked to the charge and the molecular weight of the various hydrocolloids. The negative charge of some hydrocolloids was hypothesised to created repelling forces between it and the negatively charged phosphate groups of potato starches, affected those parameters. Bread baked with sodium alginate reached the highest specific volume at a concentration level of 1% and 2% xanthan gum had the softest breadcrumb. Based on the source of used hydrocolloid, the analysis of the rheological and pasting properties revealed connections between dough properties and bread quality parameters.