Physicochemical properties of food grade acetylated cocoyam (Xanthosoma sagittifolium) starches

A. O. Tijani, Celestina Ibitayo Omohimi, L. O. Sanni, E. K. Oke
2016 Croatian Journal of Food Science and Technology  
Starch was isolated from cocoyam (Xanthosoma sagittifolium). It was further modified by acetylation using NaOH and NaHCO 3 at room temperature (28±3 ºC). The pasting and physicochemical properties of the native and modified starches were then studied. Pasting properties of the alkaline modified cocoyam starches showed higher peak viscosities (245.92-256.96 RVU) compared to low peak viscosity (215.5 RVU) of the native starch. The modified starches were characterized by higher setback viscosities
more » ... setback viscosities (112.79-110.17 RVU) in relation to native starch (105.88 RVU). Similarly, the alkaline modified starches had lower gelatinization time (4.47-4.50 min) compared to the native starch (4.60 min). Other functional properties, notably solubility and swelling power of the modified starches, showed higher swelling power (4.0-6.9%) and solubility indices (4.0-4.8%) compared to the native starch with lower swelling power (2.7%) and solubility index (0.9%). The degree of acetylation and substitution for cocoyam starches was 2.1-2.4 and 0.08-0.09 respectively. The study shows that starch acetylated with NaOH and NaHCO 3 has better properties than native cocoyam starch and therefore it can be concluded that acetylated cocoyam starch produced under these conditions may be used as an alternative food grade starch additive for industrial purposes thereby encouraging import substitution.
doi:10.17508/cjfst.2016.8.2.02 fatcat:rbuc3mcofjelnpjbti2k3dkwia