Can pasting in N‐methyl morpholine N‐oxide (NMMO) differentiate between tapioca starches?

Abstract

Three tapioca starches that showed very similar pasting behavior in water, as demonstrated using rapid visco analysis (RVA) and differential scanning calorimetry (DSC), can be distinguished from each other when pasted in the organic solvent N‐methyl morpholine N‐oxide (NMMO). In a 78% NMMO‐ 22% water solvent the end viscosities after extensive pasting (15 min at 95°C) were different (starch concentrations used were 2.5 and 5%). These differences were not obvious if the complex viscosity of the pasted samples were measured. Further heating of the 78% NMMO pasted samples increased the viscosity and may indicate that the original pasting may not completely dissolve the samples. It is suggested that pasting in the NMMO solvent may identify samples that will process differently due to differences in structure and/or composition, which is not easily identified by other methods.