Abstract
Edible canna starch (Thai-green canna) was cross-linked with different concentrations (0.005%, 0.01%, 0.05%, 0.1%, 0.2%, and 0.5%) of sodium trimetaphosphate (STMP) at 40°C, pH 5.5 for 2 h. Modified starches contained 0.032% – 0.042% of phosphorus content. Scanning electron micrographs showed that the granular size and shape of the modified starch granules were similar to those of the native starch granules. Investigation on pasting properties of 6% w/w starch using Rapid Visco Analyzer (RVA) revealed that peak viscosities of cross-linked starches increased with increasing concentration of STMP from 0.005% to 0.05%, but decreased when concentration of STMP was further increased (from 0.1% to 0.5%). Most of the modified starches exhibited lower setback. Stability of the cross-linked starches to low pH was not improved, whereas that to high shear was superior when compared to the native starch. Starches modified with 0.01% – 0.05% STMP had higher freeze-thaw stability than the native starch.
Keywords
Canna starch; Modification; Cross-linking; Sodium trimetaphosphate
