Relation between polymer transitions and the extensional viscosity of dough systems during thermal stabilization assessed by lubricated squeezing flow

Strain-dependent assessment of dough’s polymer structure and functionality during the baking process

“…Therefore, the reenforcing effect of strain hardening is seen to accomplish for the effects of the higher gas void fraction in yeasted dough. Additional knowledge, underlining the yeast-induced extension of the protein network during the early baking phase in terms of a decreasing protein strand width and increasing average protein strand length, has been reported earlier by accessing the protein network structure by Confocal Laser Scanning Microscopy [21]. The strain hardening effect might further be supported by additional effects, such as altered structures in the dough matrix itself.…”

“…It is furthermore hypothesized that starch, being clustered in nodes, might be more accessible to water as the granules are not further embedded in the gluten network. Thus, an accelerated starch gelatinization process could take place in yeasted doughs and the formation of a continuous network of gelatinized starch is more likely to be formed in the nodes [21]. Confirmatory indications were found by accessing the extend of the starch gelatinization process in yeasted and non-yeasted wheat dough systems using Differential Scanning Calorimetry during thermal treatment, where a slightly accelerated starch gelatinization process was observed in yeasted dough systems [21].…”

“…The sample preparation was performed similar to [21] and will be described in the following section. After the kneading process, the dough samples were sheeted to the desired sample height and cut using a cylindrical cutter (45 mm diameter).…”

“…The dough systems used in this work are standard non-yeasted wheat dough and yeasted wheat dough. In comparison to the standard wheat dough system, the microstructure of yeasted dough has been shown to be less branched, as the microstructure of yeasted dough is markedly affected by the degrading effects of yeast fermentation [10,21]. Beside this, secondary yeast metabolites were not shown to affect the network structure or functionality significantly [10].…”

“…In inline fermentation, uniaxial expansion of the sample must be enabled to avoid overfilling effects. In extensional rheology, a suitable technique for inline fermentation, heating and rheometry using lubricated squeezing flow was formerly suggested by [21]. Regarding shear rheology, inline fermentation is even more desirable, as sample transfer-and especially sample loading-can cause a degassing of the fermented dough sample.…”