The influence of arabinogalactan on wheat dough development during mixing and leaving process

Arabinogalactan (AG) is very promising as a functional additive to foodstuff. The objective of this research was to evaluate the influence of AG content on structural development of wheat dough during mixing and leavening processes. Dough was prepared from wheat flour enriched with 1 - 5 % of AG. The used AG was of plant origin, specifically harvested larch trees. Dough without AG was used as control. The farinograph characteristics of wheat flour dough enriched with AG provided useful information on the modifying effects of those additions on the behaviour of the dough during its development and mixing. The water absorption capacity was increased each time the AG proportion increased. The dough development time was significantly higher (p < 0.05) in the AG enriched doughs than in the control, whereas the Mixing Tolerance Index and elasticity was significantly less (p < 0.05) for control in relation to AG enriched doughs which indicates that the enrichment with AG may weaken the dough. Microstructure of doughs was investigated by means of Scanning Electron Microscopy. Dough with high contents of AG had a more compact microstructure compared with doughs with no or low levels of added AG. The leavening kinetic was investigated by monitoring the variation of volume vs time by means of Image Analysis. The dough was continuously photographed during leavening stage. The area and centre of mass were determined by an Image tool software and the sample volume was calculated. Experimental results showed that the addition of AG influenced the final volume of dough, mainly at high AG contents. As the AG content increased, the volume expansion of the dough was higher than the volume expansion of control. The experimental evidences are of special importance when formulating novel and functional bakery products.