Synthesis and characterization of acetylated cassava starch with different degrees of substitution

Fil: Trela, Valeria Daiana. Universidad Nacional de Misiones. Instituto de Materiales de Misiones; Argentina. Fil: Trela, Valeria Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Materiales de Misiones; Argentina. Fil: Trela, Valeria Daiana. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Fil: Ramallo, Ana Laura. Universidad Nacional de Misiones. Instituto de Materiales de Misiones; Argentina. Fil: Ramallo, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Materiales de Misiones; Argentina. Fil: Ramallo, Ana Laura. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Fil: Albani, Oscar Alfredo. Universidad Nacional de Misiones. Instituto de Materiales de Misiones; Argentina. Fil: Albani, Oscar Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Materiales de Misiones; Argentina. Fil: Albani, Oscar Alfredo. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Acetylated cassava starch with low and medium degrees of substitution (DS) were synthesized. Also, the effect of DS on swelling power, solubility, morphological properties, gelatinization temperature, paste clarity and moisture sorption were studied. Swelling power and solubility in water between 50oC and 90°C were determined. Acetylated cassava starches with low DS showed an increased in both parameters, while at higher DS values a reduction of them was observed. Maximum swelling power values were measured in acetylated starch with DS of 0.2 and maximum solubility was registered at DS of 0.72. Equilibrium moisture content values from sorption isotherms presented a good fit using the GAB model (R2>0.96). SEM micrographs showed that as acetyl groups are incorporated the granules suffer surface changes and eventually lose their structure at DS of 1.5. Clarity of acetylated starch pastes with low DS was lighter than native starch paste. In addition, the increase in DS produced a reduction in gelatinization temperature.