Enriching Wheat Flour Dough with Dietary Fibers: A Structure–Function Relationship Investigation

This study investigated the impact of high-level replacement (from 2.5% to 10%) of dietary pea fiber (PF), insoluble wheat straw fiber (IWF), and carboxymethylcellulose (CMC) on wheat flour dough characteristics. IWF included 92.96% cellulose, whereas hemicellulose comprised the majority of PF's insoluble fibers (38.12%), followed by CMC (28.90%). FTIR data from lyophilized enriched dough samples showed that PF and IWF interacted with gluten proteins, improving gluten network structuration, but the CMC hindered it. Furthermore, FTIR data showed that the addition of IWF induced partial gluten dehydration. Doughs with a high DF content showed higher water absorption and resistance to extension but lower extensibility than the control. Dynamic rheology demonstrated that PF and IWF raised the elastic and viscous moduli while decreasing the loss factor, whereas CMC had the reverse effect, supporting structural results. TGA data indicated that CMC reduced the dough thermal stability by destroying the gluten network but IWF and PF increased it. The results revealed that PF and IWF, when added to wheat flour dough, interacted with gluten proteins, enhancing the dough's quality for baking applications. Conversely, the CMC degraded the dough by preventing the formation of the gluten network.