Evaluation of gelatinization thermal properties of various starches using dynamic viscoelasticity measurements in xanthan-gum gel matrices and rapid visco-analysis
2001
Sekine, M. (Saitama-ken. Government Office, Urawa (Japan)) | Horiuchi, H.
Gelatinization thermal properties of various starches were examined using rapid visco-analysis (RVA) and dynamic viscoelasticity measurement in the gel matrix(GDVM). These properties were compared with thermal properties of gelatinization endotherm (GE) obtained using differential scanning calorimetry. Onset temperature of RVA viscosity (R sub(o)) for root, glutinous grain and bean starches was higher than and correlated with peak temperature of GE (T sub(p)). R sub(o) for nonglutinous grain starches (NS), swelling power of which was relatively low, was considerably higher than and slightly correlated with Tp. Temperature, for which the maximum increase of RVA viscosity was obtained, was rather higher than and closely correlated with T sub(p) in starches except for NS. Onset temperature of G' in GDVM (G sub(o)) under 10% starch concentration was level with and correlated with T sub(p), and G sub(o) at 33% approached and correlated with initiation temperature of GE (T sub(i)). Go lowered when starch concentration increased, and was under T sub(i) for highly concentrated starch samples, due to detecting viscoelasticity change by moisture absorption of raw starches. The temperature, for which the maximum increase of G' was obtained, was just higher than and correlated with T sub(p) in all starches, irrespective of starch concentration. Peak temperatures of G' and RVA viscosity were higher than conclusion temperature of GE and weakly correlated with thermal properties of GE.
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