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This study aimed to explore the effect of induced electric field (IEF) treatment on acid hydrolysis of corn starch by altering the connection modes of sample coils of a 4-reactor IEF system. Results suggested that IEF treatment could enhance the hydrolysis of corn starch and series connection (1. RRRR, η = 16 E Si 2 P in 4 Z Si + Z load ) exhibited higher energy efficiency than parallel (9. (RRRR), η = 4 E Si 2 P in Z Si + 4 Z load ), thus contributing to more extensive hydrolysis. Although no new functional group was formed, the starch granules were partially cracked into pieces and the crystallinity was slightly increased after IEF-assisted hydrolysis. Differential scanning calorimetry results indicated that IEF-assisted hydrolysis increased the gelatinization temperatures but decreased the enthalpy of starch, with a greatest variation was observed by series connection. Rapid visco-analysis showed that IEF-assisted hydrolysis greatly decreased the pasting viscosity of corn starch and also series connection showed the strongest reduction. The obtained results could provide a theoretical guide for the applications of IEF technology in biomaterial processing. [Display omitted] • Induced electric field (IEF) could enhance the acid hydrolysis of corn starch. • IEF-assisted hydrolysis highly depends on the energy efficiency of IEF system. • Series connection of IEF reactors showed the highest energy efficiency. • IEF-assisted hydrolysis largely decreased the pasting viscosity of corn starch. • IEF-assisted hydrolysis increased gelatinization temperatures but decreased enthalpy. [ABSTRACT FROM AUTHOR]

Compared to traditional heating methods by static immersion or stirring, induced electric field (IEF) treatment can significantly increase hydrolysis rate of potato starch. The aim of this study was to examine the characterization of acid hydrolysis of granular potato starch under IEF. Potato starch was hydrolyzed using 0.15 mol/L HCl combined with IEF (IEF-HCl) at an excitation voltage of 75 V from 4 h to 120 h. The changes in granular, crystal, and molecular structure of starch granules during IEF-HCl hydrolysis were investigated. Scanning electron microscope analysis showed the outer surface of potato starch was firstly attacked by free ions and then the inner structures was completely disrupted and broken into pieces. X-ray diffraction studies indicated that the crystallinity decreased from 38.92% to 34.9% after 4-h hydrolysis, and then gradually increased to 41.88% as hydrolysis time increased to 96 h, but decreased thereafter. The weight-average molecular weight dramatically decreased from 104.7 × 10 6 Da to 9.291 × 10 6 Da in the first 24 h and then decreased gradually. These results suggested that there were three steps in the catalytic process of IEF-HCl hydrolysis. Initially, hydrogen ions destroyed the external crystalline shell of granules. Next, hydrogen ions attacked the loose amorphous region and dense crystalline part within starch granules simultaneously. Finally, the remaining crystalline region was hydrolyzed slowly. [ABSTRACT FROM AUTHOR]

The induced electric field assisted hydrochloric acid (IEF-HCl) hydrolysis of potato starch was investigated in a fluidic system. The impact of various reaction parameters on the hydrolysis rate, including reactor number (1–4), salt type (KCl, MgCl 2 , FeCl 3 ), salt concentration (3–12%), temperature (40–55 °C), and hydrolysis time (0–60 h), were comprehensively assessed. Under optimal conditions, the maximum reducing sugar content in the hydrolysates was 10.59 g/L. X-ray diffraction suggested that the crystallinity of IEF-HCl-modified starches increased with the intensification of hydrolysis but was lower than that of native starch. Scanning electron microscopy indicated that the surface and interior regions of starch granules were disrupted by the hydrolysis. The solubility of IEF-HCl-modified starches increased compared to native starch while their swelling power decreased, contributing to a decline in paste viscosity. These results suggest that IEF is a notable potential electrotechnology to conventional hydrolysis under mild conditions without any electrode touching the subject. [ABSTRACT FROM AUTHOR]

This study aimed to improve induced electric field (IEF)-assisted hydrolysis of polysaccharide by controlling electrical conductivity. As the conductivity of reaction medium was increased, the energy efficiency of IEF was increased because of deceased impedance, as well as enhanced output voltage and temperature, thus the hydrolysis of guar gum (GG) was accelerated under IEF. Changes in weight-average molecular weight (Mw) suggested that IEF-assisted hydrolysis of GG could be described by the first-order kinetics 1/Mw ∝  k t, with the rate constant ( k ), varying directly with the medium conductivity. Although IEF-assisted hydrolysis largely disrupted the morphological structure of GG, it had no impact on the chemical structure. In comparison to native GG, the steady shear viscosity of hydrolyzed GG dramatically declined while the thermal stability slightly decreased. This study extended the knowledge of electrical conductivity upon IEF-assisted acid hydrolysis of GG and might contribute to a better utilization of IEF for polysaccharide modification. [ABSTRACT FROM AUTHOR]

• IEF-assisted hydrolysis enhanced with increasing DD of chitosan. • Electrical properties of chitosan showed no significant effect on the hydrolysis. • Structural compactness determined the hydrolysis behavior of different-DD chitosan. This study explored the impact of re-acetylation on induced electric field (IEF)-assisted hydrolysis of chitosan. Chitosan with different degree of deacetylation (DD) exhibited different charge content but similar electrical conductivity and output voltage of the electrolyte system, thus theoretically resulting in equivalent electro-processing efficiency. However, molecular and rheological measurements suggested that the hydrolysis rate decreased with an increase of DD. Re-acetylation had no significant effect on the molecular weight and viscosity of chitosan but damaged its granular and crystal structure, making chitosan chains more susceptible to the acid. The IEF-assisted hydrolysis of dissolved chitosan confirmed that the structural compactness of chitosan played a more important role on the hydrolysis than the charge content. This study extended current knowledge regarding the effect of charge content and structural compactness on IEF-assisted hydrolysis process, which contributed to the applications of IEF in biopolymer modification. [ABSTRACT FROM AUTHOR]