Structural Modifications Research Articles

Impact of Ex Vivo Bisphenol A Exposure on Gut Microbiota Dysbiosis and Its Association with Childhood Obesity

Dietary exposure to the plasticiser bisphenol A (BPA), an obesogenic and endocrine disruptor from plastic and epoxy resin industries, remains prevalent despite regulatory restriction and food safety efforts. BPA can be accumulated in humans and animals, potentially exerting differential health effects based on individual metabolic capacity. This pilot study examines the impact of direct ex vivo BPA exposure on the gut microbiota of obese and normal-weight children, using 16S rRNA amplicon sequencing and anaerobic culturing combined methods. Results showed that direct xenobiotic exposure induced modifications in microbial taxa relative abundance, community structure, and diversity. Specifically, BPA reduced the abundance of bacteria belonging to the phylum Bacteroidota, while taxa from the phylum Actinomycetota were promoted. Consistently, Bacteroides species were classified as sensitive to BPA, whereas bacteria belonging to the class Clostridia were identified as resistant to BPA in our culturomics analysis. Some of the altered bacterial abundance patterns were common for both the BPA-exposed groups and the obese non-exposed group in our pilot study. These findings were also corroborated in a larger cohort of children. Future research will be essential to evaluate these microbial taxa as potential biomarkers for biomonitoring the effect of BPA and its role as an obesogenic substance in children.

Protein-Based 2D Nanoarchitectures Constructed by Heterochiral π-Stacking Dimerization of Helical Foldamers.

In this study, we focus on the designability and controllability of the interaction interface between secondary structures, and discover an important interface interaction between helical secondary structures by non-covalent synthesis along the helical axis. The formation of discrete heterochiral dimers consisting of left-handed helix and right-handed helix not only helps to discover nonclassical supramolecular chirality phenomena, but also enables controllable protein assembly. Highly ordered nanostructures were thus constructed using π-stacking dimerization of helical foldamers to control tetrameric avidin proteins. The designable and modifiable primitives of artificial folded molecules enable the modification of secondary structure interfaces through non-covalent interactions, leading to the generation of unique structures and functions. These findings are of fundamental importance to the understanding of the precise assembly process of helical foldamers and can provide insights to facilitate the rational design of abiotic protein-like tertiary structures and further functionalization.

Enhancing Osteogenesis and Mechanical Properties through Scaffold Design in 3D Printed Bone Substitutes.

In the context of regenerative medicine, the design of scaffolds to possess excellent osteogenesis and appropriate mechanical properties has gained significant attention in bone tissue engineering. In this review, we categorized materials into metallic, inorganic, nonmetallic, organic polymer, and composite materials. This review provides a more integrated and multidimensional analysis of scaffold design for bone tissue engineering. Unlike previous works that often focus on single aspects, such as material type or fabrication technique, our review takes a broader approach. It analyzes the interaction between scaffold materials, 3D printing techniques, scaffold structural designs, modification methods, porosities, and pore sizes, and the composition of materials (particularly composite materials). Meanwhile, it focuses on their impacts on scaffolds' osteogenic potential and mechanical performance. This review also provides suggested ranges for porosity and pore size for different materials and outlines recommended surface modification methods. This approach not only consolidates current knowledge but also highlights the interdependencies among various factors affecting scaffold efficacy, offering deeper insights into optimization strategies tailored for specific clinical conditions. Furthermore, we introduce recent advancements in innovative 3D printing techniques and novel composite materials, which are rarely addressed in previous reviews, thereby providing a forward-looking perspective that informs future research directions and clinical applications.

Dual-protein system composed of soy protein and β-lactoglobulin: effect of transglutaminase-mediated crosslinking on its allergenicity and conformation.

The escalating global prevalence of food allergies has intensified the need for hypoallergenic food products. Transglutaminase (TGase)-mediated crosslinking has garnered significant attention for its potential to reduce the allergenicity of food proteins. This study aimed to investigate the effects of TGase crosslinking on the potential allergenicity and conformational changes in a dual-protein system composed of β-lactoglobulin (β-LG) and soy protein isolate (SPI) at varying mass ratios (10:0, 7:3, 5:5, 3:7 and 0:10 (w/w)). TGase preferentially crosslinked the 7S and 11S subunits of soy protein, rather than β-LG. Crosslinking treatment reduced the allergenic potential of both soy protein and β-LG, with the degree of reduction depending on the protein ratio. The β-LG5:SPI5 and β-LG7:SPI3 mixtures showed the most significant reduction in antibody reactivity towards soy protein and β-LG, respectively. Additionally, TGase-mediated crosslinking significantly reduced the binding capacity of all dual-protein samples to serum immunoglobulin E from allergic patients, compared to the control group (P < 0.05). The allergenicity reduction was accompanied by structural modifications, including a decrease in β-sheet content, an increase in β-turn and random coil structures, enhanced ultraviolet absorption and intrinsic fluorescence, reduced free sulfhydryl levels and altered intermolecular forces. These changes suggest that TGase-induced crosslinking may disrupt or mask allergenic epitopes, thus lowering allergenicity. TGase crosslinking effectively reduced the allergenic potential of the dual-protein system by inducing structural changes. These findings underscore the potential of TGase in developing hypoallergenic dual-protein food products and provide a scientific foundation for future research and application in the food industry. © 2025 Society of Chemical Industry.

Optical assessment of lignin-containing nanocellulose films under extended sunlight exposure

Abstract This study investigates the stability and UV-blocking properties of cellulose nanofibril (CNF) and TEMPO-oxidized cellulose nanofibril (TOCNF) films, with and without lignin, under 1000 h of artificial sunlight. The literature to date provides no quantitative analysis of such films’ stability, however such insight is critical for optoelectronic applications for instance solar cells. This contribution examines the films from practical perspectives, considering aging with respect to their optical performance and retention of UV protective qualities. Films containing residual lignin (LignoCNF and LignoTOCNF), and lignin nanoparticles (CNF-LNP and TOCNF-LNP) demonstrated remarkable UV-blocking stability; even after the aging transmittance of LignoCNF and CNF-LNP films remained lower than 1% below 390 nm. Most lignin-containing films exhibited increased transmittance between 400 and 600 nm after aging, except for LignoTOCNF, which showed a decrease in transmittance that was comparable to that displayed by non-lignin films. Nevertheless, long-term light exposure induced a decrease in their mechanical properties. Tensile tests revealed increased brittleness in CNF and LignoCNF, while LNP-containing films showed reduced strain at the break. The observed changes were linked to the potential oxidation of COO- groups and structural modifications in both cellulose and lignin. Overall, the incorporation of lignin into nanocellulose films enhances their durability, UV protection, and mechanical stability, making them promising candidates for sustainable optoelectronic applications.

Novel Co-Polyamides Containing Pendant Phenyl/Pyridinyl Groups with Potential Application in Water Desalination Processes

This study explores the development and evaluation of a novel series of aromatic co-polyamides featuring diverse pendant groups, including phenyl and pyridinyl derivatives, designed for water desalination membrane applications. These co-polyamides, synthesized with a combination of hexafluoroisopropyl, oxyether, phenyl, and amide groups, exhibited excellent solubility in polar aprotic solvents, thermal stability exceeding 350 °C, and the ability to form robust, flexible films. Membranes prepared via phase inversion demonstrated variable water permeability and NaCl rejection rates, significantly influenced by the pendant group chemistry. Notably, pyridinyl-substituted membranes achieved water fluxes up to 17.7 L m−2 h−1 and a NaCl rejection of 37.3%, while phenyl-substituted variants provided insights into the interplay of hydrophobicity and porosity. These findings highlight the critical role of pendant group functionality in tailoring membrane performance, offering a foundation for further structural modifications to enhance efficiency in water treatment technologies.

Study on the effect of acid fracturing fluid on pore structure of middle to high rank coal

Acid fracturing fluids can effectively improve the microporous structure of coal, thereby enhancing the permeability of coal seam and the efficiency of gas drainage. To explore the effects of acid fracturing fluids on the pore structure modification of coal samples from different coal ranks, hydrochloric acid-based acid fracturing fluids were prepared and used to soak four types of medium to high-rank coal in an experiment. High-pressure mercury intrusion and liquid nitrogen adsorption techniques results demonstrated that the acid fracturing fluid can effectively alter the pore structure of coal. However, the modification effect does not exhibit a linear relationship with coal rank. The porosity of fat coal and coking coal increased by approximately 30%, while the surface area of gas coal and fat coal increased by about 20%. The new micropores produced by the acid fracturing fluid will increase the roughness of the fracture surface, but the widening of the original fracture will reduce the tortuosity of the fracture. Only the fractal dimension of lean coal has a significant change, about 6%. Overall, acid fracturing fluid has the best effect on gas coal and coking coal. The research results provide a reference for the selection and application of acid fracturing fluid in coal seam hydraulic fracturing.

Excited-State Rotational Dynamics of Amine-Functionalized Terephthalic Acid Derivatives as Linker Models for Metal-Organic Frameworks.

Understanding how structural modifications affect the photophysics of organic linkers is crucial for their integration into metal-organic frameworks (MOFs) for light-driven applications. This study explores the impact of varying the amine functional group position on two terephthalic acid derivatives─linker 1 and linker 2─by investigating their photophysics through a combination of steady-state and ultrafast laser spectroscopy and time-dependent density functional theory (TD-DFT) calculations. With tetrahydrofuran as the solvent, time-correlated single-photon counting revealed a 2-fold increase in the S1 excited-state lifetime of the molecule with the amine group at the meta position compared with that of the molecule with the amine group at the ortho position. This phenomenon can be attributed to restricted intramolecular twisting for the molecule with the amine group in the meta position. In this regime, an interplay of high-energy steric and conjugation barriers was revealed for the molecule with the amine group at the meta position by TD-DFT calculations. Moreover, femtosecond/nanosecond transient absorption spectroscopy revealed a reversible excited-state conformational change for the ortho isomer via intramolecular rotation that occurred within ∼110 ps, unlocking a triplet state manifold. This study underscores the importance of modifying organic emitters, either as free linkers or within MOFs, to increase their performance in sensing and light-emitting applications.

Kifunensine-sensitive ADP-ribosylation factor A1EG69R mutant revealed coordination of protein glycosylation and vesicle transport pathways.

Complex N-glycans are asparagine (N)-linked branched sugar chains attached to secretory proteins in eukaryotes. They are produced by modification of N-linked oligosaccharide structures in the endoplasmic reticulum (ER) and Golgi apparatus. Complex N-glycans formed in the Golgi apparatus are often assigned specific roles unique to the host organism, with their roles in plants remaining largely unknown. Using inhibitor (kifunensine, KIF)-hypersensitivity as read-out, we identified Arabidopsis mutants that require complex N-glycan modification. Among over 100 KIF-sensitive mutants, one showing abnormal secretory organelles and a salt-sensitive phenotype contained a point mutation leading to amino-acid replacement (G69R) in ARFA1E, a small Arf1-GTPase family protein presumably involved in vesicular transport. In-vitro assays showed that the G69R exchange interferes with protein activation. In vivo, ARFA1EG69R caused dominant-negative effects, altering the morphology of the ER, Golgi apparatus, and trans-Golgi network (TGN). Post-Golgi transports (endocytosis/endocytic recycling) of essential glycoprotein KORRIGAN1, one of KIF-sensitivity targets, is slowed down constitutively as well as under salt stress in ARFA1EG69R mutant. Because regulated cycling of plasma membrane proteins is required for stress tolerance of the host plants, ARFA1EG69R mutant established a link between KIF-targeted luminal glycoprotein functions/dynamics and cytosolic regulators of vesicle transport in endosome-/cell wall-associated tolerance mechanisms.

Carbonized Polymer Dots‐Based Spectrally Adaptable Photonic Microbarcodes

AbstractCarbonized polymer dots (CPDs) are versatile nanomaterials with remarkable optical properties that enable their use in a wide range of photonics applications. CPDs exhibit excitation‐wavelength‐dependent tunable emissions that span the visible to near‐infrared (NIR) spectrum. In this study, whispering‐gallery‐mode (WGM) emission achieved using CPDs‐coated monodisperse polystyrene (PS) microbeads (CPDs@PS) are used to develop wavelength‐adaptable photonic barcodes by leveraging the excitation‐dependent photoluminescence of CPDs. Each resonant emission peak acts as a unique fingerprint of photonics barcodes related to the corresponding microresonator caused by WGM emission. These photonic barcodes can be easily disguised and then authenticated by varying the excitation wavelength. WGM‐based barcodes can exhibit a large number of encoding capacities by adjusting the resonator diameter. Monodisperse CPDs@PS microbeads (3, 4.5, and 6 µm) are used to demonstrate adaptable photonic barcodes, which can improve the readability and reproducibility of spectral patterns for the reliable tagging and identification of commodities. Unlike traditional semiconductor quantum dots or dye‐doped microresonators, this adaptive resonant emission does not require structural or chemical modifications, making it an ideal candidate for multiplexed assays, cell tagging and tracking, anti‐counterfeiting, and for ensuring the integrity and authenticity of products in various high‐value sectors.

Light-Driven Adaptive Molecular Crystals Activated by [2+2] and [4+4] Cycloadditions.

Photomechanical crystals act as light-driven material-machines that can convert the energy carried by photons into kinetic energy via shape deformation or displacement, and this capability holds a paramount significance for the development of photoactuated devices. This transformation is usually attributed to anisotropic expansion or contraction of the unit cell engendered by light-induced structural modifications that lead to accumulation and release of stress that generates a momentum, resulting in readily observable mechanical effects. Among the available photochemical processes, the photoinduced [2+2] and [4+4] reactions are known for their robustness, predictability, amenability to control with molecular and supramolecular engineering approaches, and efficiency that has already been elevated to a proof-of-concept smart devices based on organic crystals. This review article presents a summary of the recent research progress on photomechanical properties of organic and metal-organic crystals where the mechanical effects are based on [2+2] and [4+4] cycloaddition reactions. It consolidates the current understating of the chemical strategies and structure-property correlations, and highlights the advantages and drawbacks of this class of adaptive crystals within the broader field of crystal adaptronics.

Recent Total Syntheses of Cephalotaxine‐Type Alkaloids and Their Structural Diversification (2021–2024): An Update

AbstractCephalotaxine‐type alkaloids present a challenging yet rewarding target for synthetic chemists due to their intricate polycyclic structures and significant biological activity. This review consolidates recent reports (2021–2024) on the total synthesis of cephalotaxine‐type alkaloids, emphasizing innovative catalytic approaches and key transformations that enable efficient construction of the core tetracyclic framework. Advances in techniques such as asymmetric polycyclization, dual catalysis, and rearrangement strategies have streamlined synthetic routes, reducing the number of steps and enhancing stereocontrol. Additionally, structural diversification on the cephalotaxine scaffold during this period has offered valuable insights into structural modifications in medicinal chemistry and potential biosynthetic pathways. This review proposes a new structural classification of cephalotaxine‐type alkaloids. It covers ten recent total syntheses, providing detailed descriptions of the synthetic methodologies employed and comparative analyses with previous syntheses. Four reports on the structural diversification of cephalotaxines are also included.

Cytotoxic Activity of Bisphosphonic Derivatives Obtained by the Michaelis–Arbuzov or the Pudovik Reaction

Background: Methylenebisphosphonic derivatives including hydroxy-methylenebisphosphonic species may be of potential biological activity, and a part of them is used in the treatment of bone diseases. Methods: Methylenebisphosphonates may be obtained by the Michaelis–Arbuzov reaction of suitably α-substituted methylphosphonates and trialkyl phosphites or phosphinous esters, while the hydroxy-methylene variations are prepared by the Pudovik reaction of α-oxophosphonates and different &gt;P(O)H reagents, such as diethyl phosphite and diarylphosphine oxides. Results: After converting α-hydroxy-benzylphosphonates and -phosphine oxides to the α-halogeno- and α-sulfonyloxy derivatives, they were utilized in the Michaelis–Arbuzov reaction with trialkyl phosphites and ethyl diphenylphosphinite to afford the corresponding bisphosphonate, bis(phosphine oxide) and phosphonate–phosphine oxide derivatives. The Pudovik approach led to α-hydroxy-methylenebisphosphonic species and to their rearranged products. A part of the derivatives revealed a significant cytotoxic effect on pancreatic adenocarcinoma or multiple myeloma cells. Conclusions: The new families of compounds synthesized by our novel approaches may be of practical importance due to the significant cytotoxic activity on the cell cultures investigated. Compounds lacking hydroxy groups showed anti-myeloma activity or limited effect on pancreatic cancer (PANC-1) cells unless substituted with para-trifluoromethyl group. Hydroxy-containing bisphosphonates and their rearranged derivatives demonstrated varying effects depending on structural modifications. While myeloma (U266) cells indicated greater sensitivity overall, the most significant reductions in cell viability were observed in PANC-1 cancer cells, raising potential therapeutic applications of bisphosphonates beyond myeloma-associated bone disease, particularly for malignancies like pancreatic ductal adenocarcinoma.

DNA vaccines as promising immuno-therapeutics against cancer: a new insight

Cancer is one of the leading causes of mortality around the world and most of our conventional treatments are not efficient enough to combat this deadly disease. Harnessing the power of the immune system to target cancer cells is one of the most appealing methods for cancer therapy. Nucleotide-based cancer vaccines, especially deoxyribonucleic acid (DNA) cancer vaccines are viable novel cancer treatments that have recently garnered significant attention. DNA cancer vaccines are made of plasmid molecules that encode tumor-associated or tumor-specific antigens (TAAs or TSAs), and possibly some other immunomodulatory adjuvants such as pro-inflammatory interleukins. Following the internalization of plasmids into cells, their genes are expressed and the tumor antigens are loaded on major histocompatibility molecules to be presented to T-cells. After the T-cells have been activated, they will look for tumor antigens and destroy the tumor cells upon encountering them. As with any other treatment, there are pros and cons associated with using these vaccines. They are relatively safe, usually well-tolerated, stable, easily mass-produced, cost-effective, and easily stored and transported. They can induce a systemic immune response effective on both the primary tumor and metastases. The main disadvantage of DNA vaccines is their poor immunogenicity. Several approaches including structural modification, combination therapy with conventional and novel cancer treatments (such as chemotherapy, radiotherapy, and immune checkpoint blockade (ICB)), and the incorporation of adjuvants into the plasmid structure have been studied to enhance the vaccine’s immunogenicity and improve the clinical outcome of cancer patients. In this review, we will discuss some of the most promising optimization strategies and examine some of the important trials regarding these vaccines.

Unbinding of Alpha Chain of Hemoglobin in Sickle and Normal Structures

Abstract Sickle cell disease, a genetic disorder, is caused by a mutation of glutamic acid into valine in the β chain of hemoglobin at the sixth residue, resulting in structural change of the entire hemoglobin molecule into a sickle shape. We investigated the atomic level interaction between the α chain (chain A) and the remaining three chains to identify the structural modification in sickle hemoglobin using the molecular dynamics simulations. H-bond, solvent accessible surface area (SASA), hydrophobic interactions, salt bridges of sickle and normal hemoglobin have been estimated. The estimated parameters from sickle hemoglobin are compared to normal hemoglobin structure. Steered molecular dynamics (SMD) is utilized to estimate the force required in breaking hydrogen bonds in given chains. The SMD simulations at different pulling velocities show that the decoupling forces depend on values of pulling force. This relation is linear, 6780 pN to 12345 pN with pulling velocities of 0.00020 nm/ps to 0.00040 nm/ps in sickle hemoglobin. Much higher force of 8738 pN to 16557 pN in normal is required in normal hemoglobin with same spring constants values from k = 500 to 1100 kcal mol-1 nm-2 and same pulling velocities.

Structural modification of defective WO3 by g-C3N4 for photocatalytic gold recovery from non-cyanide-based plating effluent

A set of nCN/WO3 − x composites was synthesized through a simple thermal treatment for gold recovery from the simulated effluent of a non-cyanide-based plating bath. The obtained results exhibited that all nCN/WO3 − x composites demonstrated a higher photocatalytic activity for gold recovery than their pristine components due to the formation of nanocomposites which paved a convenient pathway for charge transfer. Among all synthesized composites, the 5.0CN/WO3 − x composite exhibited the highest photocatalytic activity, recovering around 69.4% of gold within 120 min under UV-vis light irradiation at an intensity of 3.45 mW/cm² and a catalyst loading of 1.0 g/L, in the absence of hole scavenger. This result can be ascribed to the presence of an optimal number of defects, which can act as electron trapping sites and thereby reduce the recombination rate of charge carriers. Gold recovery increased with repeated reuse, attributed to the decorated gold, which enhances light absorption and decreases the recombination rate of charge carriers. The feasible application of used CN/WO3 − x were also explored for H2 production, dye degradation and gold recovery. The obtained results provide a new insight about the photocatalytic recovery of gold from industrial wastewater and also shed light on the application of gold-decorated CN/WO3 − x as a catalyst for other photocatalytic applications.

A novel small-molecule fluorescent probe caused by minimal structural modifications for specific staining of the cell nuclear membrane.

The nuclear membrane is a double-layered structure that physically protects the cell's DNA from the chemical reactions occurring in other parts of the cell. In this study, we present the first brand-new small-molecule fluorescent probe that selectively stains the nuclear membrane, allowing for the visualization of nuclear morphology without interfering with the DNA's activity.

Research Progress on Gene Regulation of Plant Floral Organogenesis

Flowers, serving as the reproductive structures of angiosperms, perform an integral role in plant biology and are fundamental to understanding plant evolution and taxonomy. The growth and organogenesis of flowers are driven by numerous factors, such as external environmental conditions and internal physiological processes, resulting in diverse traits across species or even within the same species. Among these factors, genes play a central role, governing the entire developmental process. The regulation of floral genesis by these genes has become a significant focus of research. In the AE model of floral development, the five structural whorls (calyx, corolla, stamens, pistils, and ovules) are controlled by five groups of genes: A, B, C, D, and E. These genes interact to give rise to a complex control system that governs the floral organsgenesis. The activation or suppression of specific gene categories results in structural modifications to floral organs, with variations observed across different species. The present article examines the regulatory roles of key genes, including genes within the MADS-box and AP2/ERF gene clusters, such as AP1, AP2, AP3, AG, STK, SHP, SEP, PI, and AGL6, as well as other genes, like NAP, SPL, TGA, PAN, and WOX, in shaping floral organ genesis. In addition, it analyzes the molecular-level effects of these genes on floral organ formation. The findings offer a deeper understanding of the genetic governance of floral organ genesis across plant species.

Antistaphylococcal Triazole-Based Molecular Hybrids: Design, Synthesis and Activity

Background: In the era of resistance, the design and search for new “small” molecules with a narrow spectrum of activity that target a protein or enzyme specific to a certain bacterium with high selectivity and minimal side effects remains an urgent problem of medicinal chemistry. In this regard, we developed and successfully implemented a strategy for the search for new hybrid molecules, namely, the not broadly known [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines. They can act as “building blocks” and allow for the introduction of certain structural motifs into the desired final products in order to enhance the antistaphylococcal effect. Methods: The “one-pot” synthesis of the latter is based on the conversion of substituted 4-hydrazinoquinazolines or substituted 2-aminobenzonitriles and carboxylic acid derivatives to the target products. The possible molecular mechanism of the synthesized compounds (DNA gyrase inhibitors) was investigated and discussed using molecular docking, and their further study for antistaphylococcal activity was substantiated. Results: A significant part of the obtained compounds showed high antibacterial activity against Staphylococcus aureus (MIC: 10.1–62.4 µM) and 5-bromo-2-(3-(furan-3-yl)-1H-1,2,4-triazol-5-yl)aniline and 5-fluoro-2-(3-(thiophen-3-yl)-1H-1,2,4-triazol-5-yl)aniline, with MICs of 5.2 and 6.1 µM, respectively, approaching the strength of the effect of the reference drug, “Ciprofloxacin” (MIC: 4.7 µM). The conducted SAR and ADME analyses confirm the prospects of the further structural modification of these compounds. The obtained [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines reveal significant antimicrobial activity and deserve further structural modification and detailed study as effective antistaphylococcal agents. The SAR analysis revealed that the presence of a cycloalkyl or electron-rich heterocyclic fragment in the third position of the triazole ring was essential for the antibacterial activity of the obtained compounds. At the same time, the introduction of a methyl group into the aniline moiety led to an enhancement of activity. The introduction of halogen into the aniline fragment has an ambiguous effect on the level of antistaphylococcal activity and depends on the nature of the substituent in the third position. Conclusions: Obtained [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines reveal significant antistaphylococcal activity and deserve for further detailed study as effective antibacterial agents.

Unveiling lotus root processing under vacuum microwave: starch-malic acid interactions based on moisture, structure, and in vitro digestibility.

This study evaluated the effects of malic acid vacuum microwave preconditioning (MVMP) on lotus root (LR) by examining its moisture content, dielectric properties, microstructure, and starch characteristics, including modifications in starch structure and composition. Dielectric properties and LF-NMR indicated that the dielectric constant (ε') was closely associated to moisture content and state, while changes in water migration depended on microwave power and the dielectric loss factor (ε″). Increased microwave power and malic acid concentration resulted in microstructural damage (indentation and breakage of starch granules) and starch hydrolysis into smaller particles. MVMP preserved higher levels of phenolic and flavonoid compounds. FT-IR analysis revealed an additional absorption peak at 1740cm-1. The maximum degree of substitution was 0.131. Starch from MVMP-treated LR exhibited higher crystallinity, with a maximum resistant starch (RS) content of 68.3%. In addition, microwave power considerably influenced amylose content, solubility, swelling power, and thermal enthalpy.