Acid-treated Samples Research Articles

Influence of the elicitors on the accumulation of secondary metabolites and antioxidant activities in the <em>Polyscias fruticosa </em>(L.) Harms <em>in vitro</em> roots

Polyscias fruticosa (L.) Harms, belonging to the Ginseng family (Araliaceae), is a valuable medicinal plant in Vietnam. Recognized in the Vietnamese Pharmacopoeia, it is esteemed for its antioxidant, anti-inflammatory, and antipyretic properties, making it a significant contributor to traditional medicine. This research contributes to the understanding of elicitor-induced changes in antioxidant activity, and secondary metabolite content of in vitro root extract of P. fruticosa. The results showed that the antioxidant activity of the root extract tested by DPPH radical scavenging assay with an IC50 value of 1.28 mg/mL in the baseline and the lowest IC50 value of 0.89 mg/mL in the medium treated with yeast extract (YE). The highest total phenolic and flavonoid content were displayed in jasmonic acid-treated samples at 24.31 ± 2.86 mg gallic acid/g extract and 29.25 ± 0.26 mg quercetin/g extract, respectively. The highest saponin was also produced in roots elicited by jasmonic acid, where it reached about 167.19 ± 3.29 mg aescin/g extract. Furthermore, investigation with antioxidant enzyme activities showed another superiority when using elicitors YE (64.4 ± 3,14 U/mg protein) and mannitol (Man) (65.39 ± 3.85 U/mg protein) in peroxidase (POD) activity and using jasmonic acid (8.87 ± 0.74 U/mg) in catalase (CAT) activity. Lastly, TPC and TFC exhibited a positive correlation of r = 0.53 while the TPC and DPPH scavenging activity and TFC and POD showed a remarkably negative correlation of r around -0.8. In conclusion, this study highlights the advancements in eliciting root cultures to enhance specific phytochemicals and antioxidant activity. The information provided holds significant value and will be of interest to scientists engaged in plant biotechnology, particularly in the elicitation of medicinal plant roots.

Controlled chemical transformation of lignin by nitric acid treatment and carbonization

This study focuses on understanding the chemical reactions and results of Kraft lignin transformation through nitric acid treatment and subsequent carbonization. With its rich carbon content, lignin stands out as a promising candidate for the manufacturing of high-value carbon materials. The lignin underwent effective nitration, depolymerization, and oxidation under ambient conditions and at 40 °C, while a slight increase in reaction temperature significantly reduced the reaction time. The molecular weight Mw was effectively reduced from 4371 g/mol to 767 g/mol. The acid-treated lignin samples with incorporated nitro groups were further carbonized to create nitrogen-doped carbon structures. The resulting materials show stable nitrogen content (about at 5 wt%) even after carbonization due to the transformation of nitro groups into thermally stable pyridinic moieties, thereby exhibiting enhanced electrocatalytic properties compared to nitrogen-free carbon materials derived from Kraft lignin. The nitric acid-assisted treatment of lignin obviates the need for catalysts, and additional extraction or purification steps for preparing bio-derived carbon precursors, rendering it facile, fast, and cost-efficient.

Modification of crystalline graphitic carbon nitride for improve efficiency in photocatalytic destruction of volatile organic compounds (VOCs) under visible light irradiation

In this study, we show that the use of a mixture of melamine and oxalic acid during the synthesis of acid-treated crystalline graphitic carbon nitride samples significantly enhances its photocatalytic activity in VOCs destruction processes. The rate of photocatalytic ethanol destruction with the participation of modified crystalline graphitic carbon nitride obtained under optimal conditions is 67.1 μmol h−1, which is almost twice higher than sample synthesized in the absence of oxalic acid, and is two orders of magnitude higher than the activity of bulk g–C3N4. The synthesized materials were characterized using XRD, FT-IR, UV–Vis, PL, SEM, and EDXA methods. The high activity of the modified carbon nitride samples is attributed to increased light absorption in the visible region of the spectrum and better crystallinity, which can lead to more efficient separation and transport of photogenerated charges. To our knowledge, the effect of the simultaneous use of melamine and oxalic acid for obtaining acid-treated crystalline graphitic carbon nitride is, shown for the first time.

Preparation and properties of hydrogen storage materials of porous carbon composite diatom skeleton

Using a diatom treated with acid as the base skeleton, and introduced furfuryl alcohol into diatom skeleton was in-situ polymerized, followed by carbonizing, alkali activation, and a series novel hydrogen storage materials of porous carbon composite diatom skeleton (A-PCDS) were prepared. The effect of composites prepared with different concentrations of acid treatment diatomaceous earth on the hydrogen storage properties was investigated. The results showed that the use of suitable concentrations of acid treatment was beneficial to the hydrogen storage properties of the final synthesized materials. The 4 M acid-treated final samples showed stronger hydrogen storage performance relative to the 0.5 M acid-treated final samples, and the hydrogen storage capacity was increased from 3.25 wt% (77K, 5 MPa) to 4.21 wt% (77K, 5 MPa). This results will be of great value for the application and development of high-performance and low-cost hydrogen storage materials, which can be prepared in large quantities.

Modification of natural clinoptilolite zeolite to enhance its hydrogen adsorption capacity

In this study, natural clinoptilolite was treated with HCl, HNO3, and C2H2O4 at various concentrations (0.1, 0.5, and 1.0 M) at different temperatures (60, 70, and 80 °C) and treatment times (2, 3, and 4 h). The hydrogen adsorption capacity of natural clinoptilolite increased from 0.446 to 3.255 mmol/g after treating with 0.5 M HNO3 at 80 °C for 2 h. The correlation of the newly produced textural and structural properties with hydrogen adsorption ability is explained by characterizing the modified clinoptilolites using X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and temperature programmed desorption of ammonia (NH3-TPD) measurements. The results show that the hydrogen adsorption capacity of modified clinoptilolites is associated with both the quantity and strength of the strong acid sites, in addition to the enhanced surface area and micropore volume. The hydrogen adsorption data for natural and acid-treated clinoptilolite samples at 77 K obeyed the Freundlich isotherm model.

Comprehensive cannabinoid profiling of acid-treated CBD samples and Δ8-THC-infused edibles

Δ8-Tetrahydrocannabinol (Δ8-THC) is increasingly popular as a controversial substitute for Δ9-tetrahydrocannabinol (Δ9-THC) in cannabinoid-infused edibles. Δ8-THC is prepared from cannabidiol (CBD) by treatment with acids. Side products including Δ9-THC and other isomers that might end up in Δ8-THC edibles are less studied. In this paper, three orthogonal methods, namely reversed-phase (RP)-UHPLC-DAD/HRMS, normal-phase/argentation (silica-Ag(I))-HPLC-DAD/MS, and GC-FID/MS were developed for analysis of cannabinoid isomers, namely Δ8-THC, Δ9-THC, CBD, Δ8-iso-THC, Δ(4)8-iso-THC, and hydrated THC isomers. Eight acid-treated CBD mixtures contained various amounts of Δ8-THC (0–89%, w/w%), high levels of Δ9-THC (up to 49%), Δ8-isoTHC (up to 55%), Δ(4)8-iso-THC (up to 17%), and three hydrated THC isomers. Commercial Δ8-THC gummies were also analyzed, and issues like overclaimed Δ8-THC, excessive Δ9-THC, undeclared Δ8-iso-THC, and Δ(4)8-iso-THC were found. These findings highlight the urgency of improving regulations towards converting CBD to Δ8-THC for use as food ingredients.

Formation of resistant starch and cracker products from leftover rice in Saudi Arabia

Food leftovers are a worldwide concern and the Food and Agriculture Organization reported about 400 billion USD worth of food is wasted yearly. In the Kingdom of Saudi Arabia, food waste is increasing; the loss is about 33.6% of the rice commodity only. To achieve sustainable development goals including zero hunger and sustainable consumption, the current investigation aimed to study the recycling possibilities of rice leftovers through the production of resistant starch (a nutraceutical active component). Proximate analysis, in vitro digestibility (rapidly, slowly, and resistant starches), and conformational techniques (SEM, FTIR, and DSC) were accomplished before and after treating heated or not samples with acetic, citric, and tartaric acids. Also, crackers were produced from rice starch and its sensory evaluations were completed. Results reported variations in starch content between the controls and acid treatments, but interestingly, amounts of protein, and fiber were not different. The highest production of resistant starch (more than 35%) was when treated with tartaric acid and heat treatment, followed by citric acid and heat treatment (32.5%), then acetic acid and heat treatment (28%). The FTIR pictograms revealed the acetylation of heat and acid-treated rice samples. The gelatinization enthalpy (ΔH) decreased from 10.51 to 7.81 J/g for control and treated rice by acetic acid without heat. Surprisingly, the panelists reported no differences in the sensory evaluations of crackers produced from treated rice with a high content of resistant starch, which considered as functional food. These findings help achieve food sustainability through commercial-scale functional food production.

Development of Non-Spherical Platinum Nanoparticles on Carbon Supports for Oxygen Reduction Reaction

Proton exchange membrane fuel cells are anticipated to play an important role in decarbonizing the global energy system, but the performance of platinum (Pt) catalysts must be improved to make this technology more economical. Studies have identified non-spherical Pt nanoparticles on carbon supports as promising approaches to address this challenge. However, to realize the full benefits of these strategies, the catalyst synthesis procedures must be successfully simplified and scaled up, and the catalyst must perform well in half and full-cell tests. In this study, a surfactant-free one-pot method is developed to synthesize non-spherical Pt nanoparticles on Ketjen Black carbon, which is either non-treated (Pt/KB), acid-treated (Pt/KB-O), or nitrogen-doped (Pt/KB-N). The catalysts are synthesized in both small and large batches to determine the effect of scaling up the synthesis procedure. The nitrogen-doped carbon support shows a nearly identical morphological structure with uniform distribution of non-spherical Pt nanoparticles for both small and large batches’ synthesis compared with non-treated and acid-treated carbon samples. The comparative oxygen reduction reaction (ORR) activity shows that the Pt/KB-N prepared in small and large batches has better ORR activity, which is likely caused by uniformly distributed non-spherical Pt nanoparticles on the nitrogen-doped carbon support. All three catalysts show similar ORR durability, testing from 0.5–1.0 V, while Pt/KB-O displays slightly better durability from 1.0–1.5 V for carbon corrosion. These results will help inform the implementation of shape-controlled Pt catalysts on modified carbon supports in large scale.

Acid-modified CNT/Zinc Oxide nanowires based high performance broadband photodetector

In this study, the authors have reported the impact of post-treatment via exposure to acid on single walled carbon nanotubes (SWNTs) thin film (TF) based SWNT/ZnO Nanowire (NW) broad band photodetector. The ZnO NWs were deposited on SWNT (with and without acid-treated) using a simple catalytic free process called glancing angle deposition (GLAD) technique. Acid-treated SWNT samples warranted the growth of high quality ZnO NWs over them. On fabricating photodetectors with the acid-treated ZnO NW/SWNT TF heterostructure (HS) gave better device performance as compared to the as-deposited ZnO NW/SWNT TF HS (without acid-treatment) sample. The acid-treated device showed a large responsivity (85.45 A/W), specific detectivity (0.859 × 1012 Jones) and with a low noise equivalent power of 3.9101 pW values. Moreover, the oxygen adsorption–desorption mechanism in SWNTs impacted the electrical resistance of the nanotubes which affected nanotube conductivity. The acid-treatment favoured relatively faster charge separation at the ZnO NW/SWNT heterojunction thus providing a fast device response (trise = 0.11 s, tfall = 0.39 s at + 5 V). The fabricated acid-treated device showed good broad band detection (250 nm-750 nm) which was explained with respect to the optical absorption profile of the sample.

Effects of kojic acid on changes in the microstructure and myofibrillar protein of duck meat during superchilled storage.

This study investigated the effect of 0.8% (m/v) kojic acid treatment on changes in the microstructure and myofibrillar protein of duck meat covered with oxygen-permeable polyvinylchloride (PVC) film (9±0.5µM) during superchilled storage (-1.65±0.5°C). The superchilled samples exhibited wider gaps between muscle fibers at 5 weeks storage compared with kojic acid-treated groups. Based on the variation of water status, the water-holding capacity decreased significantly (p<0.05), and bound water and immobilized water were gradually converted into free water during superchilled storage. For kojic acid-treated samples, however, no major changes were observed with respect to muscle structure, water status, and protein degradation at 6 weeks. The 0.8% (m/v) kojic acid treatment increased the water-holding capacity, reduced carbonyl content and protein degradation, and decreased the α-helix contents loss of myofibrillar proteins. Kojic acid treatment effectively protected myofibrillar protein structure from being destroyed during superchilled storage, suggesting that this method was a good way to reduce protein oxidation and prolonged its shelf life.

Effects of microwave dryers on the properties of Jerusalem artichoke: physico-chemical, thermo-physical, energy consumption

Effects of pretreatments and drying methods on physico-chemical, thermo-physical, energy values were investigated. The longest drying duration was seen in control samples dried in hybrid microwave dryer at 350 W + 50 °C and the shortest in citric acid-treated samples dried in temperature-controlled microwave dryer. Citric acid-treated samples dried in temperature-controlled microwave dryer at 70 °C had the closest color values to fresh ones. Effective diffusion values of dried Jerusalem artichoke samples varied between 4.66 x 10−8 − 1.33 x 10−7 m2 s−1 and activation energy values varied between 14.53 − 41.74 kJ mol−1. Drying date was estimated with the Midilli-Küçük model. The highest specific heat, thermal conductivity and thermal diffusivity values were observed in control samples dried in temperature-controlled microwave oven at 60 °C and the highest density values were seen in citric acid-treated samples dried in hybrid microwave oven at 70 °C. The highest SMER value was observed in control samples dried in temperature-controlled microwave dryer at 60 °C. The lowest SEC value was seen in control samples dried in temperature-controlled microwave dryer at 60 °C. The lowest total energy consumption was encountered in citric acid-treated samples dried in temperature-controlled microwave dryer at 70 °C.

Continuous low pH viral inactivation: Operation and scaling strategy informs viral clearance study.

A continuous viral inactivation (CVI) tubular reactor was designed for low pH viral inactivation within a continuous downstream system across multiple scales of operation. The reactors were designed to provide a minimum residence time of >60 min. The efficacy of this tubular reactor was tested with xenotropic murine leukemia virus (X-MuLV)through pulse injection experiments. It was determined that the minimum residence time of the small-scale reactor design, when operated at the target process flow rate, occurred between 63 and 67 min. Inactivation kinetics were compared between continuous operation and standard batch practices using three monoclonal antibodies. The quantification of the virus log reduction values (LRV) wassimilar between the two modes of operation and most of the acid-treated samples had virus concentrations below the limit of detection. However, residual infectivity was still present in the endpoint batch samples of two experiments while the continuous samples always remained below the limit of detection. This provides the foundation for leveraging a standard batch-based model to quantify the LRV for a CVI unit operation.

Enhanced catalytic degradation of organic pollutant by AgBiO3 with metastable lattice

In this study, a series of AgBiO3 with metastable lattice were prepared via a facile chemical method. It was found that the acid treatment induced the reduction of Bi5+ ions and led to the formation of metastable Bi(III)O6 in AgBiO3, which greatly facilitated the release of active lattice oxygen. As a result, all the acid-treated AgBiO3 samples (ABO-x) exhibited enhanced catalytic performance toward the degradation of methyl orange (MO), phenol and Tetracycline (TC). Among them, ABO-0.7 provided the highest catalytic activity, which could remove 98.9% of MO and 98.4% of TC within 40 min and 91% of phenol within 90 min under dark condition. the EPR and trapping experiments revealed that 1O2 and ·O2− played a key role in the catalytic degradation reaction. This work indicated that acid treated-AgBiO3 could be a promising catalyst in the remediation of wastewater.

Establishing a MALDI-TOF-TOF-MS method for rapid identification of three common Gram-positive bacteria (Bacillus cereus, Listeria monocytogenes, and Micrococcus luteus) associated with foodborne diseases

We aimed to establish a method for the rapid identification of three common Gram-positive bacteria (Bacillus cereus, Listeria monocytogenes, and Micrococcus luteus) associated with foodborne diseases. MALDI-TOF-MS was used to determine the effects of sample pretreatment, culture medium, and culture time on the identification results. Then, MALDI-TOF-TOF-MS was used to establish an optimized method and further explore the effects of culture time on secondary proteins. Among the three sample pretreatment methods, formic acid extraction outperformed direct transfer and extended direct transfer, resulting in more protein peaks and higher peak intensity in B. cereus culture samples. However, with different culture times (1–7 d), ion peaks of all bacterial proteins were relatively stable according to MALDI-TOF-TOF-MS data. The protein peaks of B. cereus (1430 m/z), L. monocytogenes (2100 m/z), and M. luteus (2140 m/z) were split into small ion peaks at 1162, 1465, and 1625 m/z, respectively. After 7 d of culture, the secondary spectra, peak intensities, and peak values of formic acid-treated samples were relatively stable, indicating that secondary protein peaks were less affected by culture time. It provides a new approach for the routine identification and market supervision of food safety in China.

Peracetic Acid: A Practical Alternative to Formalin for Disinfection of Extracted Human Teeth.

Extracted human teeth provide the closest approximation to teeth in situ and play important roles in dental education and materials research. Since extracted teeth are potentially infectious, the Centers for Disease Control recommend their sterilization by autoclaving or disinfection by formalin immersion to ensure safe handling. However, autoclaving is not recommended for teeth with amalgam fillings and formalin is hazardous. The goal of the present study was to investigate the potential of peracetic acid (PA) as an alternative method to achieve reliable disinfection of freshly extracted teeth. A total of 80 extracted teeth were collected for this study. Whole teeth were incubated in one of four solutions for defined periods of time: sterile water (2 weeks), formalin (2 weeks), PA 1000 ppm (2 weeks), and PA 2000 ppm (1 week). After sectioning, the crown and root fragments were transferred into separate tubes containing brain–heart infusion broth and incubated at 37 °C under anaerobic conditions for 72 h. Absence of broth turbidity was used to assess effectiveness of disinfection. No turbidity was observed in any of the formalin-treated or peracetic acid-treated samples, signifying complete disinfection. Our results indicate that PA can effectively disinfect extracted human teeth, providing a reliable alternative to formalin and autoclaving.

Effect of Acid Treatment on the Properties of Zeolite Catalyst for Straight-Run Gasoline Upgrading

The objective of this research was to analyze the effect of different concentrations of nitric and hydrochloric acids on the structural, acidic, and catalytic properties of a post-synthetic treated ZSM-5 type zeolite at various temperatures. The properties of zeolite catalysts were determined using different methods, such as the Brunauer-Emmett-Teller (BET) method for specific surface area, temperature-programmed desorption (TPD) of ammonia method for acidic properties, and a flow-through unit with fixed bed catalyst (with upgrading straight-run gasoline fraction of oil) for catalytic activities of initial zeolite and acid-treated samples. The structural and acidic properties of both untreated and treated zeolites were investigated, and the effect of acid treatment on the catalytic properties of the samples in the course of upgrading the straight-run gasoline fraction of oil was determined. The post-synthetic treatment with aqueous nitric acid increased the specific surface area and volume of micropores of ZSM-5 zeolite, while the treatment with aqueous hydrochloric acid led to the formation of mesopores. Acid treatments of zeolite decreased the number of acid sites, mainly due to diminished concentration of low-temperature sites. The yield of liquid products in the conversion of straight-run gasoline fraction of oil, i.e., generation of high-octane gasolines with improved environmental features, was increased using acid-treated zeolites, which was due to the decrease in arene content.

Effects of Hydroxyl and Carboxyl Functional Groups on Calcite Surface Wettability Using Atomic Force Microscopy and Density Functional Theory

Surface-active compounds, primarily in asphaltene fractions of crude oil, are responsible for binding the nonpolar oil components to mineral surfaces and, therefore, control wettability changes on reservoir rock/mineral surfaces. Surface wettability changes occur mainly through polar functional groups in these compounds, such as hydroxyl, carboxyl, or carbonyl. By using crude oil with its asphaltene fraction removed, so-called maltenes, we investigate the effect of hydroxyl and carboxyl functional groups on wettability changes of calcite surfaces. Atomic force microscopy (AFM) images show significantly increased adsorption of maltenes on calcite samples treated with two asphaltene surrogates (phenol with a hydroxyl group and benzoic acid with a carboxyl one) than that on water-treated samples. However, the adsorbate patterns are different between those two asphaltene surrogates, suggesting different aggregation mechanisms. In addition, we observed the formation of larger surface-adsorbed droplets on the phenol or benzoic acid-treated calcite samples even for relatively short exposure times (<30 min) to maltenes. Quantum-mechanical calculations show more favorable adsorption for benzoic acid onto the calcite surface both on terraces and step edges. However, when a model oil molecule adsorbs onto those two preadsorbed asphaltene surrogates, nonpolar oil molecules preferentially adsorb onto phenol on terrace sites and benzoic acid on step edges. Overall, benzoic acid changes the calcite surface wettability more significantly than phenol.

Effects of isolation conditions on structural and functional properties of the seed gum from Chinese quince (Chaenomeles sinensis)

Chinese quince seed gum (CQSG) extracted under water-, alkali- and acid- conditions at 25, 50, and 80 °C, were evaluated in terms of yield, monosaccharide composition, molecular distribution, thermal gravimetry, emulsifying stability, rheological properties, and free radical scavenging ability. The results showed that the yield of CQSG increased to 3.9% after water extraction at 80 °C. Alkali and acid treatments promoted the conversion of neutral sugars to the uronic acid branch. Regardless of the extraction temperature, the xylose chain was the main component (35%–40%); however, a reduction was observed as the extraction temperature increased to 80 °C. All CQSG solutions extracted under these isolation conditions exhibited non-Newtonian rheological behavior. Compared to water-extracted samples, the alkali-extracted samples showed the worst thermal stability, while the acid-treated samples showed the worst emulsifying stability. This study provides theoretical support for the potential application of CQSG polysaccharides in the food and pharmaceutical industries.

How Does Cultivar, Maturation, and Pre-Treatment Affect Nutritional, Physicochemical, and Pasting Properties of Plantain Flours?

The effect of cultivar, ripening stage, and pre-treatment method were investigated on the nutritional, physicochemical, and pasting properties of plantain flours from two plantains and two plantain hybrids. There were significant variations (p < 0.05) in chemical composition and physical properties influenced by the interaction of cultivars, ripening stages, and pre-treatment methods. The highest levels of amylose, water-holding capacity (WHC), and oil-holding capacity (OHC) were observed in unripe flours and acid-treated flour recorded the highest content of resistant starch (RS). Flour after pre-blanching contained the highest level of total phenolic (TP), carotenoid contents, and browning index (BI) value. In contrast, acid-treated flours had the lowest BI value. As ripening progressed, peak viscosity and breakdown values increased but final viscosity, setback, and pasting temperature values were reduced. Untreated flour samples showed the highest peak viscosity. Higher breakdown values were found in acid-treated samples and higher setback values in pre-blanched samples.

Experimental investigation for effect of multicomponent inorganic-organic acid solution on pore structure of lignite

To study the effect of multicomponent inorganic-organic acid solutions on the pore structure of lignite, acid-treated coal samples were analyzed by the liquid nitrogen adsorption method, scanning electron microscopy, energy dispersive spectrometry and molecular dynamics simulation. First, SEM analysis shows that different multicomponent acid solutions promote the formation of different types of corrosion pores. Second, EDS analysis shows that organic acids can be used as auxiliary acids to reduce the activation energy required for the reaction and promote the dissolution of minerals. In addition, liquid nitrogen adsorption analysis shows that multicomponent acid can significantly improve the connectivity of coal samples, and the hole expansion effect is obvious, which can expand the original micropores in the coal into mesopores and macropores. Finally, molecular dynamics simulation shows that acid molecules can promote more water molecules to act on the coal surface, enhancing the penetration of water and the coal surface.