Effect Of Hydrothermal Treatment Research Articles

Effect of hydrothermal treatments on the nutritional, functional and storage stability characteristics of decorticated foxtail millet grains and flour

Rapid off-flavor development and bitterness is a major concern during storage of grains and cereal flours, especially millet flour due to the occurrence of rancidity. The pre-treatment of grains before milling ensures the better retention of quality of the grains and flour, thus enhancing their utility in various products. The flour obtained from untreated, soak-boil and soak-steam treated foxtail millet grains was stored at ambient and under refrigerated conditions for 90 days. The % FFA content of untreated, soak-boil and soak-steam was 0.49, 0.22 and 0.21 %, respectively which increased significantly to 0.68, 0.28 and 0.26 % oleic acid after 90 days at storage at ambient conditions. The last phase of storage depicted a significant increase in the peroxide value and FFA of untreated samples. Under refrigerated conditions the flour obtained from soak-steamed grain had a better storage stability, functional characteristics than soak-boiled grains, and those stored at ambient temperature. The moisture, carbohydrates, FFA, peroxide levels increased, whereas antioxidant activity, pasting properties, decreased significantly during 90 days of storage. The current investigation reveals that the hydrothermal treatments by soak-boil and soak-steam methods could be effectively used to prolong the storage period of millet grain and milling fractions for better utilization.

The effect of heat treatment and high‐pressure homogenization on the dispersibility and interfacial behavior of faba bean protein isolate and concentrate

AbstractThe effect of hydrothermal treatments, high‐pressure homogenization (HPH) and their combined effects on faba bean protein isolate (FBI) and concentrate (FBC) dispersions was investigated. With HPH, a significant reduction in particle size was observed for FBI but not for FBC. For FBI, dispersion stability under accelerated gravitation was significantly improved by both hydrothermal and HPH. For FBC, hydrothermal treatment had a negative effect on dispersion stability unless it was combined with HPH. The protein dispersibility of FBI increased, and FBC decreased with increasing temperature. Upon HPH, the protein dispersibility of FBI dramatically improved, making it almost completely soluble. All FBI dispersions had a higher surface charge compared to FBC. SDS PAGE profile showed strong protein crosslinking in the original FBI, leading to a loss of legumin and vicilin bands, which were visible in a more native state of FBC. Physical modifications did not significantly affect the viscosities except for a significant increase in FBC heated at 75°C due to starch gelatinization. The equilibrium interfacial tension of the modified FBI was significantly lower than the FBC. Analysis of dynamic interfacial adsorption showed that FBI had a much faster initial diffusion (beyond detection limit) towards the interface than FBC. Physical modifications improved the surface hydrophobicity of the proteins, leading to faster interfacial adsorption. Overall, FBI dispersions had improved functional properties compared to FBC, and HPH had a more significant effect than hydrothermal treatments. Physically modified FBI could be a promising emulsifier in various food applications.

Effect of hydrothermal treatment on the rheological properties of xanthan gum

In this study, the effect of hydrothermal treatment with different temperatures (120–180 °C) on the rheological properties of xanthan gum was evaluated. When the temperature of hydrothermal treatment was relatively low (120 °C), the rheological properties of the hydrothermally treated xanthan gum was similar to the untreated xanthan gum (pseudoplastic and solid-like/gel-like behavior). However, as the temperature of hydrothermal treatment was higher, the rheological properties of the hydrothermally treated xanthan gum changed greatly (e.g., a wider range of Newtonian plateaus in flow curves, existence of a critical frequency between the storage modulus (G') and the loss modulus (G") in the dynamic viscoelasticity measurement, variation of complex viscosity). Although the hydrothermal treatment showed little influence on the functional groups of xanthan gum, it altered the micromorphology of xanthan gum from uneven and rough lump-like to thinner and smoother flake-like. In addition, higher concentration (2 %) of hydrothermally treated xanthan gum made its viscosity close to that of the untreated xanthan gum (1 %). Besides, hydrothermal treatment also affected the effect of temperature and salt (CaCl2) adding on the rheological properties of xanthan gum. Overall, this study can provide some useful information on the rheological properties of xanthan gum after hydrothermal treatment.

Effect of Hydrothermal Treatment and Prolonged Extraction on the Generation of Hydrocarbons from High-Carbon Low-Permeability Rocks from Domanik Deposits

Effect of Hydrothermal Treatment and Prolonged Extraction on the Generation of Hydrocarbons from High-Carbon Low-Permeability Rocks from Domanik Deposits

Effect of hydrothermal treatment on physicochemical of arenga starch

Native arenga starch has several disadvantages such as easy retrogradation and syneresis and tends to be unstable to acid and heat conditions. Physical modification was carried out on arenga starch which has limitations in the application of food products. Hydrothermal treatment is a physical starch modification technique by combining moisture and heat. This study aimed to modified arenga starch with Heat Moisture Treatment (HMT) and Autoclaving-Cooling (AC) treatment and investigate the properties of modified arenga starch. This study was conducted experimentally using a completely randomized design (CRD) with 7 treatments and 3 replicates. The treatments in this study were native arenga starch (control), HMT heating time (3, 4, and 5 hours) and AC cycle (1, 2, and 3 cycles). The data obtained were statistically analyzed using Analysis of Variance (ANOVA) followed by Duncan’s multiple range test (DMRT) at the 5% level. The result shows that hydrothermal modification of starch can improve the physicochemical properties of arenga starch. Modification arenga starch by HMT and AC resulted moisture content ranging from 6.76%-10.24%; amylose content 41.55%-55.79%; amylopectin content 44.86%-58.45%; can increase the value of water holding capacity and oil holding capacity and decrease the swelling power and solubility values. The decrease in peak gelatinization of HMT and AC modified starch which was also followed by a decrease in breakdown showed that the modification was able to increase the stability of starch paste during heating, pressure, and freezing.

Optimization Studies of Mg/Al-NO3 Layered Double Hydroxide Nanoparticles by Hydrothermal Treatment

Layered Double Hydroxides based nanoparticles offer significant advantages in biological applications with high biocompatibility and low cytotoxicity. In this study, nanoparticles (nMg/Al-NO3-LDH) were synthesized by the co-precipitation method and synthesis optimization of the nanoparticles was carried out by hydrothermal treatment. The effect of hydrothermal treatment on Z-average and surface charge was evaluated. Experiments were performed at 80˚C and 100˚C during in the range of 2-48 h by using different stirring rates (250, 1000, and 1500 rpm) and without stirring. Dynamic Light Scattering (DLS) was used to assess the particle size (nm), polydispersity index (PDI), and zeta potential (mV) of the nanoparticles. The chemical structure of nanoparticles was characterized by Fourier Transform Infrared spectrometry (FTIR). As a result, nanoparticles with an optimum particle size of 86.87 nm, a PDI of 0.132 and a zeta potential (mV) of 44.4±8.74 were obtained at 80˚C, 48h and 250 rpm. The data showed that Mg/Al-NO3-LDH nanoparticles have suitable physical properties for biological applications.

Effect of hydrothermal treatment on the corrosion resistance of CO2 gas-assisted MAO coatings

1Micro-arc oxidation (MAO) is an effective method for preparing highly corrosion-resistant coatings on metal surfaces, but the presence of a porous structure on the surface tends to limit further improvements in corrosion resistance. In this paper, we report a CO2 gas-assisted MAO method to prepare a ceramic coating on the surface of magnesium alloys and seal the pores using a hydrothermal reaction. By comparing the corrosion resistance of the coatings of the specimens in different electrolytes, the study reveals the mechanism of the influence of CO2 gas and hydrothermal post-treatment method on the initial structure of the coating, as well as the influence law of the corrosion resistance of different coatings. The results show that the coating prepared in NaOH + Na2SiO3 solution has the largest thickness and exhibits the most excellent corrosion resistance, which is at least one order of magnitude higher than that of several other groups of specimens.

The effect of controlled catalyst hydrothermal deactivation on morphology, structural and activity of K-decorated ZnO/ZnAl2O4 catalysts for HT-WGS

The effect of hydrothermal treatment on activity of Fe-based and Zn-Al-based HT-WGS catalysts has been studied. The catalysts were investigated by XRF, XRD, low-temperature N2 sorption, Hg‑porosimetry, CO2- and NH3-TPD, FT-IR, SEM, STEM-EDS, HR-TEM with FFT and HT-WGS rates in the range of 330–400 °C were measured. The temperature of thermal treatment which causes processes corresponding to the textural changes resulted from long-term performance in an industrial reactor was estimated and a methodology for the simulation of deactivation in hydrothermal process conditions for both conventional and novel K-ZnO-ZnAl2O4 catalysts was proposed. It has been shown that the promotion by potassium is both structural, electronc and inhibits the growth of ZnAl2O4 crystallites.The K-decorated ZnO-ZnAl2O4 catalyst for HT-WGS shows significantly lower tendency to sintering than Fe-based catalysts, which results in higher resistance to hydrothermal deactivation under typical conditions of the HT-WGS process and also under lower steam/gas ratios. Finally, it was concluded that non-stoichiometric Zn-Al catalyst promoted with K can be regarded as an attractive next generation catalyst for more efficient and cheaper technologies of generating hydrogen for industry.

The Effect of Hydrothermal Treatment on the Biological Properties of Anting-Anting (Acalypha indica Linn.) Plant Extract Containing Carbon Dots

Anting-anting plant (Acalypha indica Linn.) is shrubs that grow as a weed in most parts of tropical countries. The plant has a record of ethno-pharmacological uses by native Asians, the plant has especially been used widely in the therapeutically practice in India. Owing to its rich biological active compounds content, Acalypha indica is rendered as a wild-plants with excellent antioxidant activities. In this work, hydrothermal extraction was performed to obtained liquid products containing high biological active compounds and carbon dots from Acalypha indica plant powder. The effect of hydrothermal temperature of 100, 110, 120, 130, and 140°C was evaluated on the optical properties and biological activity of the resultant liquid products from A. indica. The results imply that the liquid products obtained at highest investigated hydrothermal temperature of 140°C had the highest total phenolic and total flavonoid content, specifically the calculated total phenolic content is 5.50 mg GAE/g and total flavonoid content is 0.53 mg QE/g; that is higher than the non-hydrothermally treated extract. Owing to the high biological active compounds, the liquid products also show high radical scavenging activity, that is 78.5% against DPPH and 47.2% against superoxide radicals. The antibacterial assays show that the liquid product obtained from hydrothermal treatment at 140°C has better activity than the extract, with inhibition rate of 61.1 and 97.2% against Escherichia coli and Staphylococcus aureus, respectively.

Низкотемпературное старение композитов системы Al2O3–[ZrYb]O2, включающих гексаалюминат стронция

The paper considers the effect of hydrothermal treatment, simulating a long stay in a biological environment, on the phase composition and bending strength of Al2O3 – [ZrYb]O2 composites containing a variable amount of Al2O3 and including strontium hexaaluminate. It has been shown that composites retain bending strength after hydrothermal action. This fact indicates the preservation of the phase composition in the volume of materials. It is determined that a monoclinic phase of zirconia is formed in the near-surface layer of the samples, the amount of which ranges from 11 to 9 %, correlating with the increase in the content of alumina in the composite. The formation of the monoclinic phase of zirconia in such an amount is well below the limit of 25 % specified in ISO 13356 2015 Implants for surgery — Ceramic materials based on yttria-stabilized tetragonal zirconia (Y-TZP). The results obtained make it possible to recommend Al2O3 – [ZrYb]O2 composites containing strontium hexaaluminate for medical applications.

Effects of Hydrothermal Treatment on Mesopore Structure and Connectivity in Doped Ceria-Zirconia Mixed Oxides.

Pore size and pore connectivity control diffusion-based transport in mesopores, a crucial property governing the performance of heterogeneous catalysts. In many cases, transition-metal oxide catalyst materials are prepared from molecular precursors involving hydrothermal treatment followed by heat treatment. Here, we investigate the effects of such a hydrothermal aftertreatment step, using an aqueous ammonia solution, on the disordered mesopore network of CexZr1-x-y-zYyLazO2-δ mixed oxides. This procedure is a common synthesis step in the preparation of such ceria-based oxygen storage materials applied in three-way catalysis, employed to improve the materials' thermal stability. We perform state-of-the-art Ar-physisorption analysis, especially advanced hysteresis scanning, to paint a detailed picture of the alterations in mesopore space caused by the hydrothermal aftertreatment and subsequent aging at 1050 °C. Furthermore, we investigate the network characteristics by electron tomography in combination with suitable statistical analysis, enabling a consistent interpretation of the desorption scans (physisorption). The results indicate that the hydrothermal aftertreatment enhances the mesopore connectivity of the continuous 3D network by widening pores and especially necks, hence facilitating accessibility to the particles' internal surface area and the ability to better withstand high temperatures.

Valorization of orange peel waste to tunable heteroatom-doped hydrochar-derived microporous carbons for selective CO2 adsorption and separation

Constrained by the extortionately expensive carbon sources, low carbon yields, inadequate adsorption capacities, and corrosive chemical activating agents, the commercialization of carbonaceous CO2 adsorbents remains a challenging task. Herein, potassium oxalate (K2C2O4), an activating agent with less corrosive properties, was used for the synthesis of activated carbons from inexhaustibly available “orange peel biowaste.” For the first time, a comprehensive report is presented on the effect of hydrothermal treatment, hydrochar/K2C2O4 ratio, activation temperature, and melamine modification in tailoring the porosity and surface functionalization of activated carbons. The optimized sample, OPMK-900, exhibited large specific surface area ~2130 m2/g; micropore volume ~1.1166 cm3/g, and a high pyrrolic nitrogen content (~ 46.1 %). Notably, melamine played the dual role as a promoter to K2C2O4 porosity generation and a nitrogen dopant, which synergistically led to an efficient CO2 uptake of ~6.67 mmol/g at 273 K/ 1 bar via micropore-filling mechanism and Lewis acid–base interactions. Moreover, remarkably high IAST CO2/N2 selectivity (105 at 273 K and 96 at 298 K) surpasses most of the biomass-derived carbons. Furthermore, the moderately high isosteric heat of adsorption (∆Hads ~ 38.9 kJ/mol) revealed the physisorption mechanism of adsorption with a limited energy requirement for the regeneration of the spent adsorbents.

Effects of hydrothermal treatment on organic compositions, structural properties, dewatering and biogas production of raw and digested sludge

The effects of hydrothermal treatment (HTT) under different temperatures and time (120 °C to 250 °C, 10 min to 60 min) on organic matter solubilization and structure changes of secondary sludge (SS) and digested sludge (DS), as well as downstream dewatering and anaerobic digestion were investigated. The results showed that organic matter solubilization increased significantly at 120 °C to 170 °C, then decreased at 200 °C to 250 °C. The organic matter solubilization during HTT showed no obvious difference for two sludge, but for the different organic components. The polysaccharides are easier to be dissolved than protein, which was manifested by the higher dissolution rate at low temperature. The protein was the main soluble component for both of hydrothermal SS and DS, which accounted for 44 % to 64 % of soluble chemical oxygen demand (SCOD). The decrease of residual extracellular polymeric substances (EPS) content and increase of N-acetylglucosamine and DNA concentrations indicated that sludge EPS and cell wall structure were damaged at 170 °C, which contributed to the high organic matter solubilization. Nitrogen balance and molecular weight distribution indicated the concentrations of soluble organic components were the combined result of dissolution and hydrolysis reaction. The hydrolysis and polymerization reaction were intensified at 170 °C to 250 °C, which was verified by the COD balance and molecular weight transformation. The hydrothermal time could further facilitate the organics dissolution and hydrolysis based on the effect of hydrothermal temperature. The EPS structure damage also contributed to the high percentage of free moisture, resulting in enhanced dewaterability. The highest methane production was 298.1 mL CH4/g VSadd for DS hydrothermally treated at 170 °C, which were 125 % and 9.8 % higher than SS and SS-HTT, respectively. This study provided an insight into the general mechanism of HTT and the application of different HTT and AD configurations.

Effect of hydrothermal treatment and LaMnO3 loading on the oxygen reduction activity of chitosan-derived carbon-based gas diffusion electrodes

Effect of hydrothermal treatment and LaMnO3 loading on the oxygen reduction activity of chitosan-derived carbon-based gas diffusion electrodes

A hierarchically combined reduced graphene oxide/Nickel oxide hybrid supercapacitor device demonstrating compliable flexibility and high energy density

This work demonstrates a hierarchical structure design with mixed holey graphene oxide (HGO) and Ni(OH)2 active material layer made by one-pot hydrothermal reaction clinging to Nickel foam as backbone and ice-template oriented graphene oxide (GO) aerogel as filling, aiming to create an asymmetric solid supercapacitor (ASC) device with compliable flexibility and high electrochemical performance. The effects of hydrothermal treatment and ice-template freezing parameters on electrochemical stability under repeated exterior deformation are discussed, the optimal parameters result in a high areal capacitance of 479.8 mF/cm2 in asymmetric supercapacitor device setup. The use of porous HGO and oriented GO aerogel synergistically contribute to the high energy and power density up to 1.69 Wh/m2 and 9 W/m2 as well as excellent electrochemical performance retention under repeated curving deformation which reaches 102% thanks to a novel activation process. The electrode assembly including metal foam and the buffering GO aerogel should be instructive for future supercapacitor design.

Activated Carbon Preparation from Sugarcane Leaf via a Low Temperature Hydrothermal Process for Aquaponic Treatment.

The effects of hydrothermal treatment, 0–5% KMnO4 content, and 300–400 °C pyrolysis temperature, were studied for activated carbon preparation from sugar cane leaves in comparison with non-hydrothermal treatment. The percent yield of activated carbon prepared by the hydrothermal method (20.33–36.23%) was higher than that prepared by the non-hydrothermal method (16.40–36.50%) and was higher with conditions employing the same content of KMnO4 (22.08–42.14%). The hydrothermal and pyrolysis temperatures have the effect of increasing the carbon content and aromatic nature of the synthesized activated carbons. In addition, KMnO4 utilization increased the O/C ratio and the content of C-O, Mn-OH, O-Mn-O, and Mn-O surface functional groups. KMnO4 also decreases zeta potential values throughout the pH range of 3 to 11 and the surface area and porosity of the pre-hydrothermal activated carbons. The use of the pre-hydrothermal activated carbon prepared with 3% KMnO4 and pyrolyzed at 350 °C as a filter in an aquaponic system could improve the quality of water with pH of 7.2–7.4, DO of 9.6–13.3 mg/L, and the turbidity of 2.35–2.90 NTU. It could also reduce the content of ammonia, nitrite, and phosphate with relative removal rates of 86.84%, 73.17%, and 53.33%, respectively. These results promoted a good growth of catfish and red oak lettuce.

Effect of hydrothermal treatment on organic matter degradation, phytotoxicity, and microbial communities in model food waste composting

Hydrothermal treatment (HTT) as a pretreatment method for compost raw material has multiple benefits such as enhanced solubility of organic material, improved bioaugmentation, and reduced biohazard by killing harmful microorganisms. In this study, we pretreated food waste via HTT at 180°C for 30min to investigate its effect on food waste composting. HTT generated 8.98 mg/g-dry solid (g-ds) of 5-hydroxymethylfurfural and 4.32 mg/g-ds furfural. These furan compounds were completely decomposed in the early stage of composting, subsequently the organic matter in the food waste started to be degraded. The HTT-pretreated experiment demonstrated less organic matter degradation during composting as well as lower compost phytotoxicity compared to the non-HTT-pretreated experiment, where the conversion of carbon was 25.2% and the germination index value was 55%. HTT probably denatured part of the organic matter and making it more difficult to decompose, thereby preventing the rapid release of high concentrations of phytotoxic compounds such as organic acids and ammonium ions during composting. High-throughput microbial community analysis revealed that only Firmicutes appeared in the HTT-pretreated experiment, however, other bacterial groups also appeared in the non-HTT-pretreated experiment. This was possibly influenced by furan compounds and the changes of easily degradable organic matter to hardly degradable. Bacillus and Lysinibacillus were dominant in both composting experiments during vigorous organic matter degradation, suggesting that these bacterial groups were the main contributors to food waste composting. This study suggests that HTT is advantageous for the pretreatment of easily degradable food waste, as compost with less phytotoxicity was produced.

Influence of Culinary Treatment on Soriz Mineral Elements (Sorghum Oryzoidum)

Soriz (Sorghum oryzoidum) is a relatively new cereal of hybrid origin obtained at the Research Institute for Maize and Sorghum of Moldova. This paper presents and analyzes the results of the study of essential minerals content (K, Na, Ca, P, Mg, Fe) in native and hulled sorghum grains and their changes under the effect of hydrothermal treatment. The results show that the sorghum grains are a good source of essential minerals, especially of K, P and Mg and are less rich in Ca, Na and Fe. The experimental data have demonstrated that the technological process applied to obtain hulled sorghum leads to a considerable decrease in minerals content. Culinary treatment had a greater impact on the K content and lower on P and Mg content. The results will be used to optimize the parameters of raw material processing and culinary treatment with the aim of minimizing the mineral loss as well as for the nutritional value balance of soriz sorghum dishes.

Effects of Hydrothermal Treatment on Organic Compositions, Structural Properties, Dewatering and Biogas Production of Raw and Digested Sludge

Effects of Hydrothermal Treatment on Organic Compositions, Structural Properties, Dewatering and Biogas Production of Raw and Digested Sludge

Effects of Hydrothermal Treatment on the Phase Transformation, Surface Roughness, and Mechanical Properties of Monolithic Translucent Zirconia.

This study aimed to investigate the effects of hydrothermal treatment on four types of monolithic, translucent, yttria-stabilized, tetragonal zirconia polycrystals (Y-TZPs). Two commercially available Y-TZP brands-SuperfectZir High Translucency (Aidite Technology Co, China) and Katana HT (Kuraray Noritake Dental, Japan) were assessed. For each brand of Y-TZP, materials of four coloring types, including noncolored (NC), colored by staining (CS), precolored (PC), and multilayered (ML) specimens were investigated after hydrothermal aging in an autoclave at 134°C/0.2 MPa for 0 (control group), 5, 10, and 20 hours. The tetragonal-to-monoclinic phase transformation, surface roughness, flexural strength, and structural reliability (Weibull analysis) were measured and statistically analyzed (α=0.05). The subsurface microstructure was analyzed with scanning electron microscopy. The group ML exhibited the lowest flexural strength and Weibull characteristic strength among the four coloring types (p<0.05). Slight increases in the monoclinic phase volume, flexural strength, and Weibull characteristic strength were observed after hydrothermal aging (pall<0.05). Regardless of coloring type, no significant effects of aging on the Weibull modulus or surface roughness were found for the tested materials. Compared with the Katana HT cross-sections, the SuperfectZir High Translucency cross-sections exhibited a similar but thicker transformation zone. The coloring procedure and material type were found to affect the mechanical properties and aging resistance of translucent monolithic Y-TZP ceramics. Regardless of the aging time, the surface roughness of the tested Y-TZP ceramics remained unchanged.