Physicochemical and structural properties of sago starch.

ABSTRACT

A comprehensive study was conducted to elucidate physicochemical and structural properties of sago starches. Two sago starch granules were oval in shape with an average diameter of 34.41 µm and had C-type polymorph with a crystallinity of about 28.13%. The amylose and resistant starch (RS) contents of two sago starches were higher than those of corn and potato starches. The two sago starches had a large amount of A and B1 chains (DP 6-24) which could form double helix structures. FTIR exhibited that the structure of two sago starches had a lower degree of order. The peak viscosity and breakdown of sago starch 2 were lower than corn starch, and the setback was higher than potato starch. Additionally, sago starches had lower gelatinization enthalpy and higher regeneration tendency. According to rheological results, sago starches showed lower shear thinning degree and thixotropy compared to corn and potato starches. Sago starch 1 gels represented the highest hardness, adhesiveness, springiness and cohesiveness, which could be used as potential food stabilizer. This study revealed the characteristics of two sago starches compared with other starches. The results indicated that the amylose content and amylopectin structures had significant influence on the physicochemical properties of sago starch.