Isolation and characterization of hydrocolloids from monoi (Cissampelos pareira) leaves

Hydrocolloids from monoi leaves were extracted using cold water and precipitated with alcohol. The hydrocolloid fraction contained 49.7% anhydrouronic acid, and 4.24% methoxyl groups. Degree of esterification of 48.45% was calculated assuming that the methoxyl groups are attached to anhydrouronic acid only. Atomic force microscopy revealed that the monoi hydrocolloid consisted of linear chains with occasional long branches. The large variability in end-to-end lengths along individual chains suggested a wide molecular weight distribution. The monoi hydrocolloid fractions exhibited high viscosity with shear thinning characteristic. Increasing temperature decreased the viscosity and pseudoplasticity. However, the effect of temperature seemed to be reversible. Addition of NaCl (0–100 mM) or glucono-δ-lactone (0–1.2%) increased the viscosity and pseudoplasticity of the hydrocolloid.