Abstract
Adding a certain proportion of Pleurotus eryngii can improve the nutritional value of wheat-flour foods and enhance the utilization of this mushroom. In this research, partial wheat flour was substituted with P. eryngii powder (PEP) or soluble polysaccharide (SPPE) at different addition levels, and the effects of PEP and SPPE on the rheological and microstructural properties of dough were investigated. Farinographic assay results suggested that PEP significantly (p < 0.05) increased the water absorption of wheat flour but decreased the development time and stability of dough significantly (p < 0.05). Furthermore, it was capable of providing weaker extensographic characteristics and harder dough with the increasing of PEP addition levels. The dynamic oscillatory tests indicated that the PEP addition approximately increased the storage (G') and loss (G″) moduli in the entire frequency range, while the tan δ roughly decreased with the increasing of PEP addition levels, which could be attributed to the low solubility and strong water-trapping capacity of the dietary fiber in PEP. Due to the good water solubility and easy formation of hydrogen bonds, the addition of SPPE had inconsistent results with the PEP addition. The inner microstructure of dough showed that the continuity of gluten networks had been disrupted by PEP and SPPE addition and then resulted in a weaker extension and harder dough. This research could provide a foundation for the application of PEP in wheat-flour foods, and PEP addition levels of 2.5%-5.0% are recommended.