The effect of high hydrostatic pressure treatment on the molecular structure of starches with different amylose content

- Pressurized starches demonstrated distinct changes in hydrodynamic parameters.
- The greatest molecular degradation occurred upon treatment of waxy maize starch.
- Both α-1,4- and α-1,6-glycosidic bonds were split upon pressurization.
- Structural changes were more determined by starch origin than by pressurization.

The effect of high hydrostatic pressure processing (650 MPa/9 min) on molecular mass distribution, and hydrodynamic and structural parameters of amylose (maize, sorghum, Hylon VII) and amylopectin (waxy maize, amaranth) starches was studied. The starches were characterized by high-performance size-exclusion chromatography (HPSEC) equipped with static light scattering and refractive index detectors and by Fourier Transform Infrared (FTIR) spectroscopy. Significant changes were observed in molecular mass distribution of pressurized waxy maize starch. Changes in branches/branch frequency, intrinsic viscosity, and radius of gyration were observed for all treated starches. The combination of SEC and FTIR data showed that α-1,6-glycosidic bonds are more frequently split in pressurized amaranth, Hylon VII, and waxy maize starch, while in sorghum and maize starches, the α-1,4 bonds are most commonly split. Our results show that the structural changes found for pressurized starches were more strongly determined by the starch origin than by the processing applied.