Effects of Substrate Concentration on Debranched Recrystallized Starch from Three Different Sources

Three kinds of debranched recrystallized starches from different sources (common corn starch, tapioca starch and pea starch) were used to investigate the effect of substrate concentration on the morphology, size, crystal structure, thermal properties, gel properties and other functional properties. The results showed that the surface of native starch was smooth without pores, and the integrity of debranched recrystallized starches were all destroyed and not significantly affected by concentration. The particle size increased with the increase of substrate concentration. The relative crystallinity of three types of debranched recrystallized starches decreased and then increased with the increase of substrate concentration. Compared with native starch, the storage modulus (G') of the three modified starches was higher than the loss modulus (G"), the gel strength was enhanced, and the thermal stability and degree of order (DO) all decreased while the degree of double helicity (DD) increased. The modified corn starch and tapioca starch showed weak viscoelasticity at lower substrate concentration (6%, 10%), whereas pea starch showed higher viscoelasticity at medium substrate concentration (10%, 14%). The value of DD decreased with increasing substrate concentration (except for 18% sample with substrate concentration). The thermal stability improved with the increase of substrate concentration but was still lower than that of the native starch. It follows that the ideal debranched recrystallized starches could be obtained selectively by adjusting the substrate concentration, which will provide ideas for the integrated utilization of different kinds of starches.