Chemical Modification Process Research Articles

Bioinformatics for Inosine: Tools and Approaches to Trace This Elusive RNA Modification.

Inosine is a nucleotide resulting from the deamination of adenosine in RNA. This chemical modification process, known as RNA editing, is typically mediated by a family of double-stranded RNA binding proteins named Adenosine Deaminase Acting on dsRNA (ADAR). While the presence of ADAR orthologs has been traced throughout the evolution of metazoans, the existence and extension of RNA editing have been characterized in a more limited number of animals so far. Undoubtedly, ADAR-mediated RNA editing plays a vital role in physiology, organismal development and disease, making the understanding of the evolutionary conservation of this phenomenon pivotal to a deep characterization of relevant biological processes. However, the lack of direct high-throughput methods to reveal RNA modifications at single nucleotide resolution limited an extended investigation of RNA editing. Nowadays, these methods have been developed, and appropriate bioinformatic pipelines are required to fully exploit this data, which can complement existing approaches to detect ADAR editing. Here, we review the current literature on the "bioinformatics for inosine" subject and we discuss future research avenues in the field.

Advanced ion-selective wood membranes: Leveraging aligned cellulose nanofibers for enhanced osmotic energy conversion

Nanofluidic reverse electrodialysis (RED) is widely recognized as an exceptionally effective method for harvesting osmotic energy. Nevertheless, its progress has been impeded by the high costs and intricate fabrication processes associated with the required ion exchange membranes. The ion-selective wood membranes (ISWM) are derived directly from natural wood through a meticulously designed two-step chemical modification and densification process. The obtained ISWM with a highly charged surface effectively preserves the alignment of nanochannels from the cellulose fibers sourced in natural wood. Moreover, the laminated structure consisting of oriented nanofibers enhances ion conductivity by a factor of 4 compared to natural wood birch under low KCl concentrations. The charged and aligned nanochannels serve as nanofluidic conduits, facilitating selective ion transport. This, in turn, engenders efficient charge separation and the generation of an electrochemical potential difference. In energy harvesting systems such as ISWM-RED, the synergistic interplay between the electrochemical potential difference and ionic flux manifests in a remarkable output power density, reaching up to 658 mW m−2 to a salinity gradient of KCl at a magnitude of 50-fold. ISWM is an outstanding nanofluidic material that provides a cost-effective and easy-to-prepare solution for producing natural nanofluidic materials. Our investigation delineates a promising trajectory for developing high-performance nanofluidic RED devices tailored for efficient osmotic energy harvesting from renewable and abundant natural resources.

Surface-engineered in-situ fibrillated thermoplastic polyurethane as toughening reinforcement for geopolymer-based mortar

Geopolymer composites often exhibit severe brittle failure when subjected to tensile and flexural loads, mainly owing to their inherently ceramic-like structure. Therefore, this study aims to overcome the previously mentioned weaknesses by introducing 2 wt% of surface-modified, in-situ fibrillated Co-PP (copolymer of polyethylene (PE) and polypropylene (PP))/thermoplastic polyurethane (TPU) blend to produce fiber-reinforced geopolymer mortars. The fiber-in-fiber Co-PP/TPU was first fabricated using spunbond, then functionalized using a mild, two-step, one-pot chemical surface modification process. A comprehensive and detailed study of the fibers' chemical structure, morphology, and mechanical properties has been conducted. As well as their impact on the geopolymer mortars' mechanical performances. Moreover, incorporating the modified fibers dramatically increased the flexural toughness and strength at failure of the composite, reaching up to 1600 % and 280 % compared to the control sample, respectively. Furthermore, the flexural modulus was improved by 2 folds. Additionally, the split tensile and compressive strength were improved by 84 % and 17 %, respectively. These findings and the SEM images of the fractured samples indicate the presence of several toughening mechanisms, associated with an improved matrix-fiber interface and an enhanced growth of geopolymer products around the fiber's surface.

Modificación química de almidón procedente de semillas de frutos: Métodos, propiedades y aplicaciones

The fruit seeds, commonly regarded as waste after consuming the fresh pulp, emerge as a source of unconventional starch with innovative potential. This study focuses on highlighting the significance of these seeds by exploring chemical modification methods in this starch source that add value by transforming their properties. The review emphasizes the influence of key factors such as the type of chemical reagent, its concentration, reaction parameters (pH, temperature, time), and the botanical source of the seed on the degree of modification and the resulting morphological and functional properties of the starch. The importance of specific conditioning during the chemical modification process is underscored, as it significantly contributes to enhancing the properties of the modified starch derived from fruit seed. In this regard, new perspectives are opened to efficiently harness fruit seeds, turning them into a valuable source of starch with diverse applications in both the food and non-food industries.

Properties of biopolymer blends based on Rugulopteryx okamurae and hydrophobic polycaprolactone (PCL) and hydrophilic acylated soy protein isolated (SPIa)

The present study explored the utilization of Rugulopteryx okamurae (RO), an invasive brown seaweed, as a renewable raw material for plastic materials based on biopolymer blends. The goal of this study was to improve the previously observed poor mechanical properties of materials based on single biopolymer RO. To enhance these properties, two polymers with distinct hydrophobicities were incorporated into the formulation of different blends: hydrophobic polycaprolactone (PCL) and hydrophilic acylated soy protein isolate (SPIa). SPIa was derived from soy protein through a chemical modification process, introducing hydrophilic carboxyl groups. The addition of PCL significantly strengthened the blend, increasing the storage modulus (E′1 Hz) from ~ 110 to ~ 250 MPa. Conversely, SPIa incorporation resulted in softening, with E′ values around 40 MPa. Both additives enhanced deformability proportionally to their concentrations, with SPIa exhibiting notably higher deformability, reaching a maximum deformation of ~ 23% for a RO/SPIa ratio of 25/75. In summary, the study demonstrates the feasibility of producing environmentally friendly blend materials based on RO, tailored for specific applications by incorporating suitable additives into the formulation. Therefore, PCL is recommended for applications susceptible to moisture effects, such as packaging, while SPIa is suggested for highly absorbent applications such as personal care or horticulture.

CHEMICAL MODIFICATION OF ROAD PETROLEUM BITUMEN WITH MALEIC ANHYDRIDE AND POLYETHYLENE GLYCOLS

A number of problems arise in the production and application of road bitumen. One of them is unsatisfactory operational characteristics, mainly heat resistance, elasticity and adhesion between the binder and aggregate. With an increase in the intensity of traffic, an increase in the volume of heavy goods transportation, the mass of cars, together with the influence of weather and climate factors on the structure, this leads to the destruction of the road surface. The work describes the results of the study of the process of chemical modification of road petroleum bitumen with maleic anhydride and polyethylene glycols (PEG) to obtain bitumen-polymer mixtures, which, in addition to good heat resistance, also have high elasticity. When modifying road bitumen with maleic anhydride, the latter acts as a certain narrowing link, which contains on the one hand a double bond that interacts with bitumen, and on the other hand an anhydride group that can interact with various polymers containing functional groups (hydroxyl, epoxy and other). Further, by adding a polymer to maleinized bitumen (bitumen modified with maleic anhydride), the resulting bitumen-polymer mixtures can be given various properties (heat resistance, elasticity, adhesion, and others). Polyethylene glycol is a cheap polymer capable of interacting with the anhydride group of maleic anhydride in bitumen on the hydroxyl group. It was established that the effect of maleic anhydride and maleic anhydride together with PEG on the heat-resistant characteristics of bitumen is the same regardless of the modification conditions. Compared to the original bitumen, the obtained BPS is characterized by a higher softening temperature, lower penetration and ductility. The temperature of brittleness is not rapid, but it is increasing. The influence of the used modifiers on bitumen elasticity is significant and depends on the modification conditions. It was established that PEG 2000 is the optimal PEG for modifying maleinized bitumen, from the point of view of ensuring good bitumen elasticity.

Tribological behaviour of surface modified carbon-fibre-reinforced polyphenylene sulphide under dry condition

This study presents a direct electrochemical modification technique for incorporating two specific small molecules, phenol, and aniline into carbon fibre (CF) surface. These molecules have a strong hydrogen bonding for polyphenylene sulphide (PPS) and are intended to improve the friction and wear properties of PPS/CF composites. The tribological properties of PPS/CF composites were evaluated using a pin-on-disc. To get a more thorough comprehension of the working conditions of PPS/CF composites, a comparative examination of the composites' tribological characteristics was carried out by modifying the nature of the opposing surface while keeping the sliding speed of the applied force consistent. The results showed that the addition of 10 mM phenol to carbon fibre results in a significant reduction in the coefficient of friction (COF) compared to carbon fibre treated with 50 mM phenol and 6 mM aniline when in contact with a steel counter-face. When sliding against a polymer counter-face, the composites experienced a reduction in the COF due to the formation of a transfer film rich in PPS. Introducing aniline groups to the fibre surface reduced the wear rate by 57.5% to 46% with applied forces of 25 N compared to PPS and unmodified PPS/CF when sliding against the polymer counter-face. This study thoroughly discusses the synergistic process of chemical modification on the tribological performance of PPS/CF. It also analyses the surface microstructures of the worn surfaces of the composites. This study has the potential to provide new insights into the design and development of CF/polymer composites with enhanced friction and wear properties.

Effect of single step oxidation-esterification process on the physicochemical properties of modified cassava starch

The oxidation and esterification are examples of starch modification processes which is often carried out. The conventional combination of the oxidation-esterification process has many defects due to its wasting of time, energy-consuming and quality-damping. This research focuses on combining chemical modification processes to produce modified cassava starch by developing a single-step process of oxidation-esterification and a drying process using a rotary UV dryer. The oxidized-esterified cassava starch is characterized by Fourier-transformed insfrared (FTIR) spectroscopy, X-ray diffraction, scanning electron microscope (SEM) and physicochemical properties. The results revealed that the oxidizedesterified cassava starch (COAEC 14) meets the SNI requirements for several parameters such as water content of 13.10±0.141%, ash content of 0.0042±0.0002%, and crude fiber content of 0.6677±0.0424%. In addition, the single-step oxidation-esterification process also improved the quality of swelling power and starch amylose content. Meanwhile, in SEM analysis, the single-step oxidation-esterification process did not change the surface morphology but changed the crystal system and size of starch using XRD analysis.

Sulfonated Molecules and Their Latest Applications in the Field of Biomaterials: A Review

This review provides an overview of the latest applications of sulfonated molecules in biomaterials. Sulfonation, a chemical modification process introducing sulfonic acid groups, enhances biomaterial properties. This review explores the effect of sulfonation and recent innovations in biomaterial applications. It covers hydrogels, scaffolds, and nanoparticles, emphasizing sulfonation’s unique advantages. The impact on cellular responses, including adhesion, proliferation, and differentiation, is discussed. This review also addresses sulfonated biomaterials’ role in regenerative medicine, drug delivery, and tissue engineering challenges. It also provides a small overview of the sources and features of marine-derived sulfonated molecules, emphasizing their potential roles in advancing scientific research. As a novel aspect, an unconventional complex, “traditional Chinese medicine” and its sulfonation method have come to the forefront after a thousand years of history. This article concludes with a reflection on current research and future avenues, highlighting sulfonation’s transformative potential in biomedicine.

Unraveling the permeation-enhancing effect of didecyl dimethyl ammonium chloride (DDAC) on poplar wood (Populus cathayana Rehd.)

ABSTRACT Wood is a sustainable, porous material with a diverse range of applications. However, the low permeability of liquids within wood poses significant challenges for the widespread application of advanced wood-based materials such as oil–water separation, as well as traditional chemical modification processes of wood. Surfactants exhibit potential to improve permeability of liquids within wood by effectively enhancing liquid wettability on solid surfaces. In this study, the effects of didecyl dimethyl ammonium chloride (DDAC) on liquid absorption of water and copper ethanolamine (CE) by wood were explored under atmospheric temperature and pressure. With an increase in concentration of DDAC, its promotion effect on liquid absorption of wood became more pronounced. The most notable enhancement was observed in wicking test where 0.10% DDAC increased liquid absorption of wood to water by 156.7% and to CE by 65.5%. The enhancement of liquid wettability on wood surface cannot be solely attributed to reduction of liquid surface tension, the adsorption of DDAC onto wood surface also plays a crucial role in this process. This study investigated the intrinsic mechanisms by which DDAC enhanced the permeability of liquids within wood, contributing to increased productivity and reduced energy consumption.

Conventional properties, rheological characteristics, and thermal performance of waste polyurethane modified asphalt with butyl rubber

To enhance the low-temperature performance of waste polyurethane (WPU) modified asphalt, a composite modifier incorporating butyl rubber (BR) was investigated. In this study, recycled waste polyurethane for industrial filling is selected, which is belonging to the Polyether polyols. Various concentrations of BR were introduced to WPU modified binder, with and without stabilizer. The blends underwent conventional asphalt performance tests, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests. Thermal performance and morphology were analyzed using differential scanning calorimeter (DSC) and fluorescence microscopy (FM). Fourier transform infrared spectroscopy (FTIR) experiments revealed the mechanism of WPU/BR modified asphalt. Results indicated that adding 3% BR to 15% WPU increased ductility at 5 ℃ by over 5 times, elevating the performance grade from PG-22 to PG-28. BR addition lowered the glass transition temperature, enhancing stability at higher temperatures. Besides improving low-temperature performance, BR also enhanced high-temperature performance and deformation resistance. Functional group analysis suggested a chemical modification process. Considering overall performance and modification effects, the optimal composite modifier was found to be 15% WPU and 3% BR.

Electrospun PAN/PEG Nanofibrous Membrane Embedded with a MgO/gC3N4 Nanocomposite for Effective Bone Regeneration.

Developing biomaterial scaffolds using tissue engineering with physical and chemical surface modification processes can improve the bioactivity and biocompatibility of the materials. The appropriate substrate and site for cell attachment are crucial in cell behavior and biological activities. Therefore, the study aims to develop a conventional electrospun nanofibrous biomaterial using reproducible surface topography, which offers beneficial effects on the cell activities of bone cells. The bioactive MgO/gC3N4 was incorporated on PAN/PEG and fabricated into a nanofibrous membrane using electrospinning. The nanocomposite uniformly distributed on the PAN/PEG nanofiber helps to increase the number of induced pores and reduce the hydrophobicity of PAN. The physiochemical characterization of prepared nanoparticles and nanofibers was carried out using FTIR, X-ray diffraction (XRD), thermogravimetry analysis (TGA), X-ray photoelectron spectroscopy (XPS), and water contact angle measurements. SEM and TEM analyses examined the nanofibrous morphology and the structure of MgO/gC3N4. In vitro studies such as on ALP activity demonstrated the membrane's ability to regenerate new bone and healing capacity. Furthermore, alizarin red staining showed the increasing ability of the cell-cell interaction and calcium content for tissue regeneration. The cytotoxicity of the prepared membrane was about 97.09% of live THP-1 cells on the surface of the MgO/gC3N4@PAN/PEG membrane evaluated using MTT dye staining. The soil burial degradation analysis exhibited that the maximum degradation occurs on the 45th day because of microbial activity. In vitro PBS degradation was observed on the 15th day after the bulk hydrolysis mechanism. Hence, on the basis of the study outcomes, we affirm that the MgO/gC3N4@PAN/PEG nanofibrous membrane can act as a potential bone regenerative substrate.

Ultrasensitive detection and photocatalytic degradation of polyketide drug tetracycline in environment and food samples using dual-functional Ag doped zinc ferrite embedded functionalized carbon nanofibers

The efficient degradation and accurate quantification of tetracycline in environment and food samples is pivotal for ensuring public health and safety by monitoring potential contamination and maintaining regulatory standards. Hence, in this study, photocatalytic degradation of tetracycline and its electrochemical detection in environment and food samples based on dual-functional silver-doped zinc ferrite nanoparticles embedded chitosan-functionalized carbon nanofibers fabricated on a screen-printed carbon electrode (AgZFO/CHIT-CNF/SPCE) is presented. A hydrothermal method was used in the synthesis of Ag-doped ZFO, and chitosan was functionalized on the CNF surface using a swift and cost-effective chemical modification process of carboxyl groups. Various techniques, such as XRD, HRTEM, elemental mapping, EIS, XPS, FTIR, VSM, BET, UV–Vis DRS, and Raman spectroscopy were used to analyze the characteristics of the prepared nanocomposite. Cyclic voltammetry and differential pulse voltammetry were used to evaluate the surface-controlled electrocatalytic properties of AgZFO/CHIT-CNF towards tetracycline. Electrochemical tests revealed that the proposed electrode exhibited excellent sensitivity for detecting tetracycline. The fabricated electrode had a low detection limit of 1 nM and a wide linear range (0.2–53.2 μM). The sensor also demonstrated exceptional selectivity, stability, and reusability. The practical feasibility evaluated with real samples, including chicken feed, shrimp, milk, soil, and wastewater, resulted in high recovery values.

Nanosilver Embedded in a Magnetosome Nanoflower to Enhance Antibacterial Activity for Wound Dressing Applications.

The natural biofilm on magnetosomes obtained from the biomineralization of magnetotactic bacteria, which replaced a complex chemical modification process on the surface of Fe3O4, can be used as the organic component and copper(II) ions as the inorganic component to form organic-inorganic nanoflowers in phosphate systems. Characterization by scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating-sample magnetometry proved that magnetic nanoflowers loaded with silver ions (Ag/MN-Cu×NFs) were successfully fabricated. In vitro antibacterial experiments demonstrated that Ag/MN-Cu×NFs displayed strong antibacterial effects against Escherichia coli and Staphylococcus aureus, with minimum inhibitory concentrations of 10 and 80 μg/mL, respectively. Ag/MN-Cu×NFs, which possessed good biocompatibility as confirmed by cytotoxicity and hemolysis tests, were able to promote wound healing in the face of bacterial infection in vivo without causing toxicity to major organs. Therefore, magnetosomes as a natural carrier have great application potential in the synthesis of multifunctional magnetosomes by direct hybridization with a target substance.

Development of bio lubricant from castor oil via chemical softening: An ease towards sustainable substitute

In the 21st century, Environment sustainability is considered to be the superficial,coherent vision in the development of a societal goal. At the moment, the prices of crude oil have been skyrocketing which results into the depletion of petroleum reservoirs contributing to environmental pollution cum hazards. This has inspired researchers globally in the development of non-toxic, renewable, and sustainable. ecologically sound alternative i.e., Bio-lubricant which will aim to replace conventional petroleum-based lubricants towards a green and clean society deliberately. The proposed work introduces the design and development of biodegradable bio-lubricant from commercially available, non-edible castor oil via chemical softening by the virtue of two successive transesterification stages. The presented study, explores the chemical modification process of vegetable oil to intensify the yield, grade, and physicochemical vis-a-vis tribological properties of the produced lubricant. The proposed method of production of castor oil-based bio-lubricant via chemical softening is made to achieve a high yield i.e., exceeding 97.4 % with a kinetic investigation for optimized parameters including catalyst concentration, alcohol/oil ratio, temperature, additives calibrated to be 1% w/w NaOH, 6:1, 65 °C and 15% SLS (Sodium lauryl sulfate) respectively for the maximum conversion with minimum costs associated with the production of ecologically viable castor oil-based bio-lubricant. The peaks observed at 1730 cm−1 and 3025 cm−1 are associated with the stretching vibration of the carbonyl group (C = O) in the ester bond and the stretching of the C–H bond vibration in the fatty acid chains, respectively. This has been confirmed through Fourier-transform infrared spectroscopy (FTIR) and evaluated through ASTM analyses.

The Influence of Short-Term Tillage, Compost, and Beneficial Microbes on Soil Properties and the Productivity of Wheat and Cowpea Crops

Tillage systems comprise physical, chemical, and biological modification processes that influence soil properties. Soil cultivation aims to create favorable conditions for the development and growth of crops, as evident in their yields. Three growing seasons (winter 2019/2020 (wheat), summer 2020 (cowpea), and winter 2020/2021 (wheat)) were studied in field experiments in Sidi Salem, Kafr El-Sheikh, Egypt, to investigate the effects of soil tillage and the application of organic and beneficial microbes on various biological, chemical, and physical properties of soil and its productivity. Three replicates of the experimental treatments were set up in a split-plot design, in which there were four main plots: conventional soil tillage (ST) treatment for all three seasons (ST1); tillage in the first and second seasons (ST2); tillage only in the first season (ST3); and no tillage for all three seasons (ST4). However, the subplots (soil additives) were conditioned as follows: without treatment (control, T1); compost (C, T2); beneficial microorganisms (BM, T3); and combination (C + BM, T4). The biological property results showed that ST4T4 treatment produced high levels of microbial communities (bacteria, fungi, and actinomycetes), as well as high levels of soil enzyme activity (dehydrogenase, urease, and phosphatase), during the three growing seasons. However, the second season produced high numbers and dry weights of cowpea plants’ nodules. Additionally, changes in the chemical and physical properties showed that the application of various soil tillage treatments during the examined seasons led to significant increases in electrical conductivity (ECe, dSm−1), bulk density (BD, kg m−3), and soil infiltration rate (IR, cm h−1), following the trend of ST4 > ST3 > ST2 > ST1. In contrast, the results revealed decreases in the exchangeable sodium percentage (ESP, %), porosity (PO, %), soil aggregates (stable aggregates and optimal-sized aggregates, %), and soil penetration resistance (SPRa, Mpa). The combination treatment (ST4T4) provided the best yields, with grain yields of 4.991 and 5.325 tons ha−1 and straw yields of 5.214 and 5.338 tons ha−1 in the first and third seasons (wheat), respectively. Cowpea plants showed the same pattern in the second season. Therefore, improvements in soil properties and enhancements in biological activity help maintain its productivity and fertility through simplified tillage processes that reduce interference with the soil surface layer.

Toward the Improvement of Maleic Anhydride Functionalization in Polyhydroxybutyrate (PHB): Effect of Styrene Monomer and Sn(Oct)2 Catalyst.

In this work, polyhydroxybutyrate (PHB) was maleic anhydride (MA)-grafted in the molten state, using dicumyl peroxide (DCP) as a reaction initiator. Tin(II) 2-ethylhexanoate (Sn(Oct)2) and styrene monomer (St.) were used to maximize the maleic anhydride grafting degree. When PHB was modified with MA/DCP and MA/DCP/Sn(Oct)2, viscosity was reduced, suggesting chain scission in relation to pure PHB. However, when the styrene monomer was added, the viscosity increased due to multiple grafts of MA and styrene into the PHB chain. In addition, the FTIR showed the formation of a new band at 1780 cm-1 and 704 cm-1, suggesting a multiphase copolymer PHB-g-(St-co-MA). The PHB (MA/DCP) system showed a grafting degree of 0.23%; however, the value increased to 0.39% with incorporating Sn(Oct)2. The highest grafting efficiency was for the PHB (MA/DCP/St.) system with a value of 0.91%, while the PHB (MA/DCP/St./Sn(Oct)2) hybrid mixture was reduced to 0.73%. The chemical modification process of PHB with maleic anhydride increased the thermal stability by about 20 °C compared with pure PHB. The incorporation of 0.5 phr of the Sn(Oct)2 catalyst increased the efficiency of the grafting degree in the PHB. However, the St./Sn(Oct)2 hybrid mixture caused a deleterious effect on the maleic anhydride grafting degree.

Methacrylated gellan gum hydrogel: a smart tool to face complex problems in the cleaning of paper materials

One of the main challenges in the preservation of paper materials is the development of compatible and eco-friendly cleaning systems suitable for the wet removal of hydrophobic, aged compounds, such as greasy materials or synthetic adhesives, whose presence enhances paper degradation and worsens its optical features. To avoid the use of organic solvents that can be potentially harmful to operators, in this work we propose a new water-based gel obtained by chemical modification of gellan gum gel, a well-known paper cleaning hydrogel. With the aim of obtaining a cleaning system that is able to interact and adsorb not only hydrophilic cellulose degradation byproducts, but also greasy materials and synthetic adhesives, methacrylation has been applied on gellan gum. First, the chemical modification process of gellan gum has been monitored by means of NMR and ATR-FTIR spectroscopy. Then, the mechanical and physical–chemical properties of the resulting gel have been evaluated by using rheological, AFM, and wettability measurements. Finally, the compatibility and cleaning efficiency of the newly synthetized gel have been tested on paper with different age (from eighteenth and twentieth centuries) and composition by means of a multi-technique framework consisting of spectroscopic, chromatographic, SEM, colorimetric and pH measurements. This work shows a first interesting step towards the development of single component paper cleaning system, easy to use, for the removal of both cellulose hydrophilic degradation products and hydrophobic compounds from different paper typologies.

Chemical synthesis of reduced graphene oxide: a review

Due to its exceptional and distinct features, graphene has become a prominent two-dimensional material. According to the raw materials and synthetic procedures, there are two categories of graphene synthesis techniques: “bottom-up” and “top-down” methods. Reduction of graphene oxide (GO) is one of the “top-down” techniques that use graphite as the starting material. This approach is now regarded as the most potential way to produce graphene on a large scale and is particularly well-suited for chemical modification and subsequent processing. This review summarizes the synthesis procedure of reduced GO (RGO) and presents the preparation methods of it and its precursors, such as graphite oxide and GO. In addition, the possible approaches for reducing the defects in RGO have been discussed.

Improvement of Prebiotic Properties and Resistant Starch Content of Corn Flour (Zea mays L.) Momala Gorontalo Using Physical, Chemical and Enzymatic Modification.

Probiotics are a non-digestible food ingredient that promotes the growth of beneficial microorganisms in the intestines. One of the functional food ingredients, Momala corn flour, is a source of prebiotics with a resistant starch content of 4.42%. Thi s study aimed to improve the prebiotic properties and resistant starch content of modified corn flour (MCF) Momala Gorontalo by using physical, chemical, and enzymatic modification processes. The research methods include physical modification (heat moisture treatment, annealing, autoclaving-cooling cycling, microwave), chemical modification (acid hydrolysis), and enzymatic modification (debranching pullulanase). The results showed that the modified by heat moisture treatment (HMT) increased RS levels 1-fold, annealing modification (ANN) 8.9-fold, autoclaving-cooling one cycle modification (AC-1C) 2.9-fold, autoclaving-cooling two cycles modification (AC-2C) 2.0-fold, microwave modification (MW) 1.3-fold, acid hydrolysis (HA) modification 5.0-fold, and debranching pullulanase (DP) modification 3.8-fold compared with corn flour control without modification. The value of the prebiotic activity of MCF hydrolysed acid (HA) is 0.03, and debranching pullulanase (DP) is 0.02 against Enteropathogenic Escherichia coli (EPEC). The prebiotic effect value of MCF HA and DP were 0.76 and 0.60, respectively. The prebiotic index value of MCF HA and DP were 0.60 and 0.48, respectively. This study confirms that MCF HA and DP are good prebiotic candidates because they have resistant starch content, low starch digestibility, and resistance to simulated gastric fluid hydrolysis than unmodified corn flour.