Morphological, structural and physicochemical properties of rice starch nanoparticles prepared via ultra-high pressure homogenization

Abstract

Native rice starches were treated with five periods of ultra-high pressure homogenization (UHPH) under each of 60, 80, 100, 120, 140 and 160 MPa, respectively. The morphological, structural and physicochemical properties of starches treated with UHPH were examined. The mean particle diameter of starch nanoparticles ranged between 154.20 and 260.40 nm. SEM revealed that the granular amorphous region of starch granules was damaged under pressures between 60 and 80 MPa, and the crystalline region was further destroyed under pressures as high as 100–160 MPa. DSC demonstrated that the gelatinization temperatures and enthalpies of nanoparticles reduced. The relative crystallinity reduced from 22.90 to 13.61% as the pressure increased. FTIR showed that the absorbance ratio at 1047/1022 cm−1 decreased, and increased at 1022/995 cm−1. RVA results indicated that the viscosity of starch samples increased between 60 and 120 MPa, and the reverse effect was observed under 140 and 160 MPa.

Structural characterization and in vitro digestibility of rice starch processed with the combination of ultra‐high pressure homogenization, debranching, and temperature‐cycled crystallization

“…The samples of UDT‐60, UDT‐80, UDT‐100, UDT‐120, UDT‐140, and UDT‐160 contained the atactic lumps with an uneven and tiny pore structure. Our previous study suggested that the shear, cavitation, and turbulence effects produced by UHPH can destroy starch granules, causing the damage of amorphous regions under 60–100 MPa and the destruction of crystalline regions under 120–160 MPa (Sun et al, 2021). More importantly, UHPH disrupted the hydrogen bonds and glycosidic bonds between starch molecules, which resulted in the degradation of amylopectin molecules.…”

“…The starch was dispersed in water to form a suspension (3%, w/v) that was homogenized for 5 cycles under pressures of 0, 60, 80, 100, 120, 140, and 160 MPa using an ultra-high pressure homogenizer (APV-2000, Beijing Udare Technology Co., Ltd., China) equipped with a water circulation temperature control system (Sun et al, 2021). The temperature of the entire process was maintained below 30 C. After freeze-drying, the samples were pulverized, passed through a 100-mesh sieve and stored in a desiccator.…”