Effect of presence of sulphurdioxide on acetylation and sorption isotherm of acetylated starches from cultivars of cassava

• Treatment with SO2 reduced the degree of acetylation relative to untreated starches.
• Choice of cultivar is of importance and influences application in the food industry.
• Monolayer value (Vm) for storage stability ranged from 1.05% to 9.16%.
• With adequate storage condition, acetylated starches can be applied in frozen foods.

Starches from cultivars of cassava were modified with acetic anhydride. Treatment with sulphurdioxide was compared with native. The starches were evaluated for functional properties and moisture isotherms were calculated.Addition of 3.5% acetic anhydride resulted in starches with DS of 1.66% and 3.25% in sweet and bitter cultivars. Sweet starch alone will be applicable for food. Least gelation concentrations for the native were 14% and 10% against 6% and 8% acetylated samples, respectively. Degree of substitution (DS) was reduced with SO2 by 45% and 39% in sweet and bitter cultivar with 150 mg/kg starch, respectively. Swelling power and solubility increased with DS. Exudates from samples varied. Monolayer values of the starches were between 1.05% and 9.16% under 18 °C and 30 °C that simulated distribution and storage. R2 value of water adsorbed and water activity ranged from 50% to 97%. X-ray patterns were not disrupted.