Study on the Effect of Enzymatic Purification on Rheological Properties of Balangu Seed (Lallemantia royleana) Gum

Food gums are a class of food additives playing various roles, such as thickening, gelling and stabilizing of the food aqueous solutions. The aim of this study was to investigation rheological properties of protein-free Balangu seed gum. For this purpose, balangu seed gum was prepared and after its enzymatic hydrolysis, protein-free Balangu was prepared and the rheological properties of balangu seed gum and protein-free balangu seed gum were evaluated in terms of different parameters such as intrinsic viscosity, steady shear flow properties (shear dependence and time dependence tests) and dynamic rehology properties (stress sweep and frequency sweep tests). The results showed that balangu and protein-free balangu seed gums at 1% w/w had shear-thinning and weak gel-like behavior, and indicated the random coil conformation in dilute region. Considering correlation coefficient (0.998), the Herschel–Bulkley model was selected to describe the rheological behavior of Balangu and protein-free balangu seed gum solutions. In the time-dependent test, the balangu and protein-free balangu seed gums showed same ability to create the structure and the amount of thixotropy. The results of dynamic rheological test showed the storage modulus curve was located higher than the loss modulus in the linear region, indicating semi-gel or semi-solid behavior in Balangu and protein-free balangu seed gum. Hydrolysis and decreasing protein content did not significantly affect viscoelastic behavior of balangu seed gum