Selective modification of wheat bran affects its impact on gluten-starch dough rheology, microstructure and bread volume

Abstract

Wheat bran incorporation in bread has multiple health benefits, but also a detrimental effect on overall bread quality. Bran is hypothesised to withdraw water from gluten, resulting in less optimal viscoelastic dough properties and a lower gas retention capacity, in turn resulting in a decreased bread loaf volume. In this study, wheat bran samples having different water retention capacities were produced and used to investigate this hypothesis. Gluten-starch model systems were used and the effect of substitution of part of the starch by bran in combination with different water absorptions and mixing times was evaluated. The properties of the gluten network in the doughs were investigated using rheological and microstructural analyses and these properties were linked to the final bread loaf volume. A proper gluten network microstructure, as visualised with CLSM, could be achieved in the presence of wheat bran. However, significant effects of the type of wheat bran, water absorption and mixing time on dough rheology and loaf volume were observed. Wheat bran addition decreased the strain hardening of dough despite optimisation of water absorption and mixing time. The deleterious effect of wheat bran on dough rheology increased by adding modified wheat bran with high water retention capacity and surface area. The results indicate that dynamic water redistribution after mixing and gas cell incorporation can have an effect on dough rheology when wheat bran is added to dough. The strain hardening behaviour of dough proved itself a valuable predictor of bread loaf volume also in the presence of (modified) wheat bran.

Water Absorption Capacity Determines the Functionality of Vital Gluten Related to Specific Bread Volume

“…In weak wheat flour, mainly starch and gluten molecules were part of the gluten network. In contrast, the baking mixture had additional ingredients such as oilseeds, which are likely to affect the interaction of gluten molecules to a greater degree than shown recently for, e.g., wheat bran [ 25 ]. It is reasonable to assume that gluten polymers had a wider distance to each other, which limited their interconnection so that only restricted formation of covalent bonds may take place.…”

Wheat Bran Modifications for Enhanced Nutrition and Functionality in Selected Food Products

“…In most studies where size reduction was paired with other pretreatment methods, milling preceded other processes such as hydrothermal and fermentation [ 30 , 37 , 46 ], and enzymatic treatment [ 39 , 45 ]. However, wet superfine grinding increased the surface area and strong water retention capacity of WB compared to native bran and thereby reduced the deleterious effect of WB on gluten development [ 56 ]. A combination of superfine grinding with steam explosion [ 40 ] increased hydration properties of WB and improved gluten development in the dough.…”

Development of a New Pasta Product by the Incorporation of Chestnut Flour and Bee Pollen

“…Property (Units) (1) FC4 (2) FC4-C50 (3) FC4-P10 (4) FC4-C50P10 (5) Water activity (dimensionless) 0. (6) 82.15 76.24 74.82 74.09 (1) dm = dry matter.…”

“…(4) Egg formulation with 10% pollen powder. (5) Egg formulation with 50% chestnut flour and 10% pollen powder. (6) Calculated by difference based on mean values of other components of dry matter.…”

“…Pasta can be, generally, made from durum wheat semolina or soft wheat flour to which water is added and then subjected to various mechanical actions to obtain the final texture [3]. When wheat flour is kneaded and hydrated, its proteins form a network called gluten, which endows the paste its capacities of extensibility, elasticity, tenacity, cohesion and gas retention [4,5]. The hydrothermal treatment of pasta allows the gelatinization of starch and the crosslinking of proteins.…”