Studies on Physicochemical and Structural Properties of Marshmallow (Althaea Officinalis) Seed Mucilage

Marshmallow (Althaea officinalis) belonging to Malvaceae family possesses mucilage containing cells in stem, petiole, petals and seeds showing antimicrobial activity, anti-inflammatory, immunomodulatory effects among others. In this study, in order to determine the characteristics of marshmallow seed mucilage, as a potential new source of hydrocolloid, some instrument methods (Scanning Electron Microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, etc.) were used and viscosity of mucilage was determined. SEM analysis showed that the mucilage had an amorphous structure and disordered particle size. Mucilage solution at pH of 7 had negative charge; zeta potential of -22.4 mV, electrical conductivity of -1.753 mS /cm and particle size being 255.1 d.nm. Its glass transition temperature (Tg) was 37.9 °C and the melting process started at 34.3 °C to 182.2 °C. An endothermal peak was observed at 92.6°C. Heat of infusion was 199.19 J/g. The most important functional groups identified by FTIR were an asymmetric stretching of double-bond (C=0) in the deprotonated carboxylated groups at 14.3 and 1627 cm^-1 vibratory stretching ring of pyranose at 1280 cm^-1 and 1115 cm^-1 as well as glycoside bonds at 617 and 780 cm^-1. Marshmallow seed mucilage solution showed a shear–thinning (pseudoplastic) behavior and the most predominant elements found in the mucilage were carbon (26.59%), potassium (26.39%).