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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]

Creating a fluidic system with an induced electrical field is regarded as an innovative, eco-friendly practice for the hydrolysis of lignocellulosic biomass at mild conditions. A multi-series, reconfigurable fluidic reactor was developed based on the transformer concept for the efficient hydrolysis of sugarcane bagasse via the interconversion of magnetic and electrical energy. A secondary coil comprised of a mixture of sulfuric acid (or other metal electrolyte) and the sample in continuous flow was exposed to an induced electric field at 400–700 Hz to accelerate the hydrolysis. The results showed that using an induced electric field to assist hydrolysis is indeed beneficial in the production of reducing sugar (RS). The total reducing sugar (TRS) yield is positively impacted by the excitation voltage but is negatively impacted by voltage frequency and the sample solution impedance. The hydrolysis efficiency improves as the number of reactors increases in both series and parallel modes of the system. The mode of connection of the reactors has varying effect on the TRS yield owing to differences in the equivalent impedance, output power, and load power factor. Increased number of secondary coil turns also improves hydrolysis efficiency under the same input power and primary coil turns and thus increasing the TRS yield. Induced-electric-field-assisted hydrolysis (IEFAH) substantially enhances the yield (by 756% approximately, at 300 V, 400 Hz in a 4-series reactors for 24 h) compared to continuous flow heating hydrolysis (CFHH) at mild conditions (50 °C and 1% H 2 SO 4 ). The proposed fluidic system combined with an induced electric field shows remarkable potential as a green technology for the efficient hydrolysis of lignocellulosic biomasses without the use of metal electrodes. [ABSTRACT FROM AUTHOR]

The mechanism of induced electric field (IEF)-assisted acid hydrolysis was investigated by using guar gum, chitosan, and pectin as model polysaccharides. Roles of thermal and non-thermal effects were explored by temperature determination, HPSEC-MALLS-RI, SEM, FT-IR, XRD, and a rheometer. Results suggested that IEF affected the hydrolysis of polysaccharides by inducing thermal and non-thermal effects. Thermal effect contributed to the hydrolysis. As the excitation voltage increased, the thermal effect enhanced, with a temperature increased by about 25 °C after IEF (75 V) treatment for 4 h. Non-thermal effect, induced by the rapid and directional migration of charged species, varied with the electrical properties of the polysaccharides. It enhanced the hydrolysis of guar gum and pectin but negatively impacted the chitosan due to their different migration directions under IEF. IEF-assisted hydrolysis damaged the structural compactness of polysaccharides and significantly decreased the viscosity of their solutions. This study clarified the hydrolysis mechanism of polysaccharides under IEF, providing a theoretical guide for the application of IEF in the chemical modification of biopolymers. Image 1 • IEF affected the hydrolysis of polysaccharides by thermal and non-thermal effects. • Thermal effect enhanced with increasing excitation voltage. • Non-thermal effect varied with the electrical properties of polysaccharides. • IEF-assisted hydrolysis damaged the structural compactness of polysaccharides. • IEF-assisted hydrolysis significantly decreased the viscosity of polysaccharides. [ABSTRACT FROM AUTHOR]

Herein, a multistage induced electric field (IEF) combined with a continuous-flow reactor was utilized to assist the acid hydrolysis of corn, potato, and waxy corn starch for avoiding plate corrosion and heavy metal leakage. It was found that adding IEF stages was beneficial to improve the hydrolysis efficiency. Treating potato, corn, and waxy corn starch via continuous-flow IEF increased the reducing sugar contents up to 78.76 %, 57.86 %, and 66.18 %, respectively. The electrical conductivity of starch grew with the reaction stages, while starch yield demonstrated the opposite trend. Treated starch had higher solubility and gelatinization peak temperature than native starch, with the gelatinization enthalpy showing fluctuations. Meanwhile, the swelling power decreased as the number of IEF stages was increased. Observations of Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy indicated that the treated starch became more ordered, and crystalline regions were destroyed to various degrees with pores forming on particle surfaces. These variations could be attributed to acid hydrolysis and IEF. [ABSTRACT FROM AUTHOR]

This study aimed to efficiently and selectively hydrolyze maize starch via induced electric field (IEF). The role of electrical conductivity in regulating hydrolysis efficiency and selectivity was investigated, and the structural and physicochemical properties of hydrolyzed products were characterized. Compared with water-bath heating, IEF induced the rapid and ordered migration of charged species, thus increasing the hydrolysis rate and narrowing the molecular weight distribution of hydrolyzed starch. The addition of KCl enhanced IEF-assisted hydrolysis due to the absorption of additional electrical energy into the reaction system. After hydrolysis, the molecular chains of maize starch exhibited cleavage, the granular surface became rough, the crystallinity increased, the gelatinization enthalpy slightly increased, the viscosity of starch paste reduced, the hardness of starch gel declined, and the re-crystallization showed no significant improvement. Overall, this study extends the potential applications of electro-techniques in preparing hydrolyzed starch with narrow molecular weight distribution in food and material fields. [Display omitted] • Induced electric field (IEF) improved the hydrolysis efficiency of maize starch. • IEF increased the hydrolysis selectivity of maize starch. • The efficiency and selectivity enhanced with the increasing conductivity. • IEF-assisted hydrolysis roughened granular surface and increased crystallinity. • IEF-assisted hydrolysis decreased viscosity but showed no effect on re-crystallization. [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]