engleski

Preparation and characterization of acetylated tapioca starches

Tapioca starch was acetylated to evaluate the effect on the thermal, retrogradation, rheological and textural properties of starch. Modification was carried out with 4, 6 and 8 % (w/w) of acetic anhydride. The degree of substitution (DS) increased proportionally with the concentration of acetic anhydride used. The acetylation of tapioca starch decreased the transition temperatures and enthalpy of gelatinization and increased swelling power and solubility. The retrogradation of native and modified starches was measured by DSC after 7 and 14 days of storage at 4 and 25 °C. Results showed that the acetylation considerably diminished the retrogradation in starch gels and enthalpy of retrogradation decreased as the DS increased among the modified starches. The acetylation also decreased viscosity and consistency of starch pastes, as well as hardness and adhesiveness of starch gels.

acetylation; tapioca starch; gelatinization; retrogradation; rheology

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