Controlling the rheological properties of wheat starch gels using Lepidium perfoliatum seed gum in steady and dynamic shear

In the present work, the influence of Lepidium perfoliatum seed gum (LPSG) addition in varied concentrations (0%, 0.25%, 0.5%, 0.75% and 1%, w/w) on dynamic and steady shear rheological properties of wheat starch dispersion (4%, /w) was examined. Comparison of the values of dynamic (G', G '', tau(y), tau(f), tan delta), shear-dependent (eta(a,50), eta(0), eta(infinity), tau, m) and time-dependent (eta(a,3s), k, eta(0), eta(infinity)) rheological parameters of the WS-LPSG mixtures with WS alone, indicated that the viscoelastic and flow properties of the mixtures were greatly affected by the addition of LPSG. According to the standard method provided by the National Dysphagia Diet (NDD), the WS and WS-LPSG gels were placed in the category of nectar-like (WS), honey-like (WS-0.25%LPSG, WS-0.5%LPSG and WS-0.75%LPSG) and spoon-thick (WS-1%LPSG) viscosity. In the simulated oral condition (SOC), the presence of saliva caused the increase of k value (10-81%), whilst decreased the values of eta(0) (43-95%) and eta(infinity)(68-96%). As the concentration of LPSG increased, less decrease in value of eta(a,3s) in the SOC was observed. The results of present study demonstrated the feasibility of manipulating the viscosity of the WS gels by addition of LPSG to be suitable for the individuals with varying degrees of swallowing difficulty. (C) 2019 Elsevier B.V. All rights reserved.