Powder Bulk Density Research Articles

Optimization of ultrasonic-assisted debittering of Ganoderma lucidum using response surface methodology, characterization, and evaluation of antioxidant activity.

Ganoderma lucidum (G. lucidum) has gained increasing attention as a potential health care product and food source. However, the bitter taste of G. lucidum has limited its development and utilization for the food industry. The response surface methodology was employed to optimize the inclusion conditions for the debittering of G. lucidum. The effects of 2-hydroxypropyl-β-cyclodextrin concentration (12-14 g/mL), ultrasound temperature (20-40°C and host-guest ratio (1:1-2:1) on response variables were studied. The physical characteristics of inclusion complexes prepared through spray drying and freeze drying were analyzed. The antioxidant activity of the different treated samples was subsequently investigated. Study results showed that, in comparison to the control group, the inclusion solution displayed a significantly enhanced taste profile under optimal processing conditions, exhibiting an 80.74% reduction in bitterness value. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (NMR) studies indicated the successful formation of inclusion compounds. The moisture content and bulk density of spray-dried powder were found to be significantly superior to those of freeze-dried powder (p<0.05). In comparison to the diluted solution, the inclusion liquid demonstrated a 20.27%, 30.01% and 36.55% increase in ferric ion reducing antioxidant power (FRAP), hydroxyl radical scavenging and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging respectively. Further, the DPPH clearance of microencapsulated powder was not significantly different from that of tocopherol at a concentration of 25 mg/mL. In summary, the study provides theoretical basis and methodological guidance to eliminate the bitterness of G. lucidum, and therefore provide potential options to the use of G. lucidum as a food source.

Characterization of Robusta Coffee Powder with Addition of Palm Sugar and Vanilla Powder to Improve The Quality of Robusta Coffee (Coffea canephora Pierre)

Bondowoso Robusta Coffee is a type of Robusta coffee that has a distinctive taste and high quality. The distinctive taste and high quality are obtained from the results of harvest management and post-harvest processing in accordance with Standard Operating Procedures (SOP). This research will be carried out by testing the characteristics of Robusta ground coffee with a mixture of palm sugar and vanilla flavoring to improve the quality of Robusta ground coffee. This was done by knowing the physicochemical and organoleptic properties of the mixed Robusta ground coffee. The aim of this research is to determine the interaction between roasting level and the composition of palm sugar and vanilla powder on the physiochemical and organoleptic properties of 3 in 1 Robusta Coffee. This research uses an experimental plan arranged factorially with the basic pattern of a Completely Randomized Design (CRD) with 4 replications. This design has two factors, the first factor is the roasting level and the second is the mixture composition. The results of this research show (1) The interaction of Roasting Level and Mixture (palm sugar and vanilla powder) has no significant effect on all observed variables such as water content, Brix content, pH value, and powder bulk density. (2) The effect of the main level of roasting has a very significant effect on the observed variables of rainfall density and an insignificant effect on the variables of air content, Brix content and pH value. (3) The effect of the main mixture has a very significant effect on the observed variables of air content, Brix content and powder bulk density and has no significant effect on the variable pH value.

Effect of Different Drying Techniques on Quality Attributes of Ready to Reconstitute (RTR) Coffee Mix

Coffee is one of the most ubiquitous and culturally significant beverages worldwide, transcending borders and influencing societies in myriad ways. Ready-to-reconstitute (RTR) coffee, often referred to as instant coffee, occupies a unique and significant niche in the global coffee market. In the present study, A mixture of Arabica to Robusta coffee beans in the ratio of 70:30 was found most suitable for manufacture of ready to reconstitute coffee mix. The concentrated coffee decoction prepared using this mixture is to be blended with concentrated milk (30%TS) in the ratio of 1:5 and dried using vacuum tray dryer, tray dryer and freeze dryer. The coffee mix is vacuum-dried at 30 to 45 degrees Celsius with a vacuum of 600 to 650 mm of Hg, gives better quality of dried product. The optimized final product has better rheological and physico chemical characteristics. In present study found that ready to reconstitute coffee mix has solubility in hot water 26.4 seconds and 2.74 minutes in cold water at 16◦C. The freeze-dried coffee mix powder exhibited reduced flowability 42.08 seconds compare to vacuum try dried and tray-dried coffee mix power that was 47.41 and 46.27 seconds respectively. Same as bulk density of freeze-dried powder (0.64 g/cm3) found lowest compare to vacuum tray dried (0.78 g/cm3) and tray dried (0.82 g/cm3) coffee mix powder.

Mechanical Properties and Corrosion Resistance of Hot-Pressed Dysprosium Molybdate Samples

The purpose of this work was to study the consolidation features using hot pressing method of dysprosium molybdate billets and to study their mechanical properties and corrosion resistance.Methods. The technological and physical properties of the mechanosynthesised dysprosium molybdate powder were investigated. Properties and structure of the obtained dysprosium molybdate powder were studied by methods of chemical and X-ray phase analyses and scanning electron microscopy. Bulk density of dysprosium molybdate powder was studied according to GOST 19440-94. Flowability of dysprosium molybdate powder was determined according to GOST 20899-75. The specific surface of dysprosium molybdate was determined using a specific surface analyser NOVA 1200e (USA) by the method of low-temperature nitrogen adsorption (BET). X-ray phase analysis of mechanosynthesised dysprosium molybdate powder was carried out on a diffractometerResults. The bending strength of hot-pressed dysprosium molybdate specimens was determined, it was found that the highest value of the bending strength was recorded for these specimens at a pressing pressure of 35 MPa and is 314 MPa. The corrosion resistance of hot-pressed dysprosium molybdate samples in aqueous coolant at a temperature of 100 °C was studied. It was recorded that the mass of the mechanosynthesised dysprosium molybdate specimens remained practically unchanged throughout the corrosion resistance test in aqueous coolant.Conclusion. Tests on corrosion resistance have shown absence of change of mass of samples from dysprosium molybdate during 60 hours. The bending strength of samples from dysprosium molybdate obtained by hot pressing at pressure 35 Pa, temperature 1400 oÑ and time of holding under pressure 5 min is 314 MPa.

Pulse Spray Drying for Bovine Skimmed Milk Powder Production.

Pulse Spray Drying (PSD) has potential as a sustainable means of skimmed milk powder (SMP) production. In this study, powders were obtained from PSD using different drying outlet temperatures (70, 80, 90 and 100 °C), and their characteristics were compared to those of traditional Spray Drying (SD). Native whey proteins were well preserved and Solubility Indexes were over 98% in all cases, despite powders obtained by PSD displaying lower solubility than the SD ones. No visual difference was observable in the powders (ΔE < 2); however, PSD powders were found to be yellower with a higher Browning Index. The drying technology did not have a significant effect on powder moisture content and bulk density. Particle size distribution and scanning electron microscopy images confirmed the presence of fine particles (<10 μm) in all samples that might have provided poor flowability and wetting behavior (overall Carr Index and Hausner ratio were 33.86 ± 3.25% and 1.52 ± 0.07, respectively). Higher amounts of agglomerated particles were found at low temperatures in the products processed with both technologies, but PSD samples showed a narrower particle size distribution and hollow particles with more wrinkles on the surface (probably due to the fast evaporation rate in PSD). Overall, PSD provided SMP with comparable physicochemical characteristics to SD and, once optimized at the industrial level, could offer significant advantages in terms of thermal efficiency without significant modification of the final product quality.

Influence of Spray Drying Inlet Temperature on the Physical Properties and Antioxidant Activity of Black Garlic Extract Powder

Black garlic is a fermented product from garlic (Allium sativum L.) that is processed by heating fresh garlic at a certain temperature and humidity for several days. Black garlic has higher antioxidant activity and is rich in organosulfur compounds. Therefore, black garlic has an unpleasant taste and odor. Spray drying of black garlic extract is important for wider application, preservation and prolongation of its shelf-life. Black garlic powders were produced using SD-18A mini spray dryer. The purpose of this research was to evaluate the effect of inlet temperatures on the physical properties and antioxidant activity of aqueous black garlic powder. The inlet temperatures ranged from 165 to 225 °C, whereas other conditions were kept constant such as maltodextrin concentration (8 %) and feed flow rate (4.5 mL/min). The black garlic powders were examined for powder yield, moisture content, hygroscopicity, bulk density, wettability, antioxidant activity and total phenolic and flavonoid content. The optimal conditions for the drying process were achieved with an inlet temperature of 225 °C. An increase in the inlet temperature of the spray dryer has increased the powder yield, hygroscopicity, antioxidant activity and total phenolic and flavonoid content of the black garlic powder, but reduced the water content, bulk density and wettability of the spray-dried product. HIGHLIGHTS The best properties of black garlic powder were obtained at an inlet temperature of 225 °C The bioactive compounds of black garlic were stable at high temperatures The higher inlet temperatures increased antioxidant activity in black garlic powders GRAPHICAL ABSTRACT

Improving the physical and wettability properties of skim milk powders through agglomeration and lecithination

This study aimed to reduce the bulk density of skim milk powders (SMP) and improve subsequent wettability and dissolution by a combination of agglomeration and lecithination. Agglomeration significantly increased powder particle size from a D90 of 120–201 μm, and decreased tapped bulk density (0.73–0.65 g/cm3), although it led to increased friability (32.7%) compared to regular SMP (22.9%). Spraying lecithin on to SMP in the fluid bed improved wettability (8.94 s) compared to regular SMP (>300 s). Agglomeration without lectithination had no effect on powder wettability, similarly, adding lecithin in to liquid skim milk concentrate prior to drying did not improve subsequent powder wettability. Overall, improving the functionality of skim milk is quite complex, and while powder bulk density can be reduced, the particles remain susceptible to breakdown, and the wettability is relatively poor, but can be improved by spraying lecithin directly on to the powder particles.

Effect of different processing methods on functional and physiochemical properties of turmeric (Curcuma longa Linn.) rhizome Var. Kapurkot Haledo-1

This study was conducted to evaluate the impact of different processing methods on the functional and phytochemical properties of turmeric rhizomes. The experiment consisted of four treatments: Treatment 1 involved oven-drying the turmeric powder, Treatment 2 involved blanching followed by oven-drying, Treatment 3 involved cooking followed by oven-drying, and Treatment 4 involved sun-drying. Each treatment was replicated four times. The major findings of the study revealed that sun-drying (68.50%) and blanching/oven-drying (66.50%) positively influenced the dispersibility of turmeric powder. Blanching/oven-drying (0.32 g/ml) and cooking/oven-drying (0.30 g/ml) significantly improved the bulk density of turmeric powder (p&lt;0.001), with no significant difference observed between these two treatments. The water absorption capacity of the turmeric powders ranged from 3.35 to 5.35 g/ml, with the sun-dried sample displaying the lowest capacity and the cooked/oven-dried sample demonstrating the highest capacity. Similarly, sun-dried powder exhibited the lowest swelling power and solubility, while heat treatment resulted in a substantial increase in both of these parameters. Additionally, the curcumin content was found to be highest in the cooked/oven-dried (3.11%) and sun-dried (2.99%) turmeric powder. In conclusion, this study suggests that blanching and cooking methods have wide applicability in the food industry to enhance the bulkiness of turmeric powder for appropriate packaging and handling. Moreover, these methods contribute to the characteristic flavor and aroma of turmeric. The findings emphasize the importance of considering different processing techniques for optimizing the functional and phytochemical properties of turmeric, thus enabling its effective utilization in various food applications.

Structural, thermal, techno‐functional and chemical characterization using Fourier Transform Infrared Spectroscopy, Gas‐Chromatography‐Mass Spectrophotometry, Thermogravimetric Analyser, Field Emission Scanning Electron Microscopy and Energy‐Dispersive X‐Ray Spectrometer of Moringa Oleifera flower powder

SummaryThe aim of this research is to characterise the physicochemical and techno‐functional properties of the Moringa oleifera flower powder, and various techniques were used in this regard, such as FTIR, GC–MS, TGA, FESEM, and EDS. The bulk and tapped density of the Moringa oleifera flower powder were found to be 0.44 ± 0.03 (g/cm3) and 0.51 ± 0.01 (g/cm3), respectively. The water absorption index and water solubility index were 10.60 ± 0.10 (g/g) and 8.70 ± 0.20 (%), respectively. The foaming capacity was found to be 15.20 ± 0.20 (%), and the foaming stability was 56.34 ± 0.10 (%). The total phenolic content of the Moringa oleifera flower extract was 15.97 ± 0.223 mg GAE/g, whereas the flavonoid content was 12.38 ± 0.321 mg QE/g. The antioxidant activity of the flower extract was measured by DPPH assay and was found to be 59.65%. The flower extract showed 11 mm and 8 mm of the zone of inhibition against Escherichia coli and Staphylococcus aureus, respectively, whereas, with antibiotic streptomycin, the zones of inhibition were found to be 20 and 18 mm, respectively. Based on the research findings, Moringa oleifera flower powder and extract can be used as food fortification, antioxidant, and antibacterial agents.

Utilization of Out-of-specification Unripe Cavendish Banana [Musa acuminata (AAA)] as Banana Powder

Around 5–20% of the total banana crop in the Philippines is rejected because it does not meet the specifications for export as fresh fruit. This study aimed to utilize the out-of-specification unripe Cavendish banana of local exporters into banana powder. The effects of different pre-drying treatments such as blanching time and concentrations of citric acid and ascorbic acid on the properties of the resulting Cavendish banana powder in terms of moisture content, water activity, color, solubility, water absorption capacity, bulk density, water holding capacity, and % yield were determined using a central composite face-centered response surface methodology design. Significant mathematical models were generated that predicted the effects of individual and combined influences of pre-drying treatments. Results showed that ascorbic acid was the main factor that influence the lightness, water activity, swelling power, bulk density, and water absorption capacity of banana powder. Results of the optimization process suggested that the desirable pre-drying treatments for banana powder were a blanching time of 0–5 min, as well as soaking in ascorbic acid ranging from 0.01–0.10% and in citric acid ranging from 0.07–0.10%. The identified optimal treatment ranges for blanching time, ascorbic acid concentration, and citric acid concentration provide valuable insights for producing acceptable, safe, and high-quality banana powder. By utilizing out-of-specification bananas and transforming them into value-added intermediate products like powder, the banana industry can reduce waste, maximize resource utilization, and create a more environmentally friendly and economically viable approach to banana production.

Microstructural Characterization of High-Protein Dairy Powders

Dairy proteins are potential and multipurpose ingredients used to prepare various food products. It exhibits many beneficial functionalities and bioactivities in the processing of food products. All the functionalities of different dairy proteins depend on their peculiar structural characteristics. So, the present study aimed to characterize high-protein powders with different matrices (milk protein concentrate (MPC), rennet casein (RCN), micellar casein concentrate (MCC), whey protein isolate (WPI), and native whey concentrate (NWC)) for their composition, handling, and reconstitution properties, and microstructure and compared them with whole milk powder (WMP) and skim milk powder (SMP). The bulk density of the high-protein powders was significantly (p &lt; 0.05) lower than WMP and NFDM. Due to the low bulk density of the high-protein powders, the wettability of these powders in the water was very high. Microstructural analysis of powders by scanning electron microscopy reveals that the high-protein powder had tetrahedron-to-polyhedron-shaped particles depending on the protein level. The idea regarding the powder’s morphology might be helpful for further improvement in the production processes to modify the functional properties of high-protein milk powders.

Influence of Carrier Agents Concentrations and Inlet Temperature on the Physical Quality of Tomato Powder Produced by Spray Drying

The study aims to obtain spray-dried tomato powders with a high and effective product yield and enhanced powder quality. The experiment for this investigation entailed the use of several carrier agents, which were maltodextrin (MD) of 4-7 dextrose equivalents (DE), MD of 10-12 DE, and gum Arabic (GA), each in varied concentrations of 5% and 10% with spray drying inlet temperatures of 140°C, 150°C, and 160°C. Powder yield, bulk density, hygroscopicity, moisture content, water solubility, water absorption, color properties, particle size, and powder morphology were all evaluated in spray-dried tomato powders. The results revealed that the stability of the tomato powder is considerably better at high temperatures and concentrations (at 10%, 160oC), with MD 4-7 DE being the best carrier agent among the three tested carrier agents. According to the powder analysis, the product has a moisture content of 3.17 ± 0.29%, the highest yield percentage of 32.1%, a low bulk density of 0.2943 ± 0.01 g/cm3, the lowest hygroscopicity at 5.67± 0.58 %, a high water solubility index (WSI) at 89.98 ± 1.25%, a low water absorption index (WAI) at 6.22 ± 0.22%, an intermediate particle size of 24.73 µm, and color L*, a*,b* values at 31.59 ± 0.03, 11.62 ± 0.08 and 13.32 ± 0.12. The result showed that at higher temperatures and higher concentrations, the powder characteristics are more likely to have a higher yield, WSI, and larger particle size, as well as lower bulk density, hygroscopicity, moisture content, WAI, and color index.

Preparation and properties of a new core–shell-modified gel dry-water powder

To improve the spray fire extinguishing performance of magnesium-hydroxide gel dry-water powder, this paper studied the preparation speed, material mass ratio, fluidity, bulk density, pressure resistance, and fire extinguishing performances of modified dry-water powders. A pure-water dry-water powder was modified by applying an effective extinguishing component, magnesium hydroxide, and a coagulant, Gellan gum. The preparation process parameters of the pure-water dry-water powder system were optimized. The results showed that the optimal process parameters for the preparation of dry-water powder were a rotation speed of 4000 rpm, an SiO2:H2O ratio of 9:100, and a stirring time of 3 min. The resting angle of magnesium-hydroxide gel dry-water powder was below 28°, with good fluidity. The bulk density of the dry-water powder was lower than that of the BC-class dry powder extinguishing agent, and the bulk density of the magnesium-hydroxide gel dry-water powder was 0.467 g·mL−1. With the increase in pressure, the damage rate of the dry-water powder increased. The addition of magnesium hydroxide and Gellan gum significantly improved the pressure resistance of the dry-water powder. At a pressure of 1.4 MPa, the magnesium-hydroxide gel dry-water powder was only 11% damaged. The performance of the magnesium-hydroxide gel dry-water powder was improved by 37.21% compared with the average cooling rate of the BC-class dry powder extinguishing agent used as a control fire extinguishing group. The dry-water powders produced by modifying the dry-water powders with magnesium hydroxide and Gellan gum could withstand higher driving pressures, and they had improved powder diffusion, reduced powder charge volume, and increased fire extinguishing properties compared with those of the other dry-water powders.

Сравнительный анализ фармакотехнологических характеристик твердых дисперсий албендазола, полученных механохимическим твердофазным синтезом

Introduction. Albendazole is a broad-spectrum antiprotozoal and antihelminthic drug which also has an anti-opisthorchiasis effect. Currently, the problem of increasing the bioavailability of albendazole for the treatment of systemic helminthiasis and parasitosis is becoming urgent. One way to improve the absorption of albendazole is to increase its water solubility due to the formation of intermolecular complexes with arabinogalactan, a plant polysaccharide during mechanical treatment of their mixtures under intense mechanical treatment. The solid dispersion of albendazole with arabinogalactan, obtained by the mechanochemical method, has higher water solubility, and also increased antihelminthic, including against Opisthorchis spp. infection, pharmacological activity, without toxic effect on liver cells, compared with the officinal preparations of albendazole. Aim. The study of physicochemical and technological characteristics of solid dispersions of albendazole with arabinogalactan obtained by the mechanochemical method. Materials and methods. A mixture of albendazole and arabinogalactan substances was ball milled to obtained solid dispersions, in a ratio of 1:5, 1:10, 1:20; the duration of mechanical treatment was 2, 8 and 24 hours. The shape and particle size of the parent substances and the obtained solid dispersions were determined by light and scanning electron microscopy. The particle size distribution of coarse fractions of solid dispersions was determined by sieve analysis, fine fractions – by dynamic image analysis of bulk materials. The determination of technological characteristics was performed using conventional pharmacopoeial methods. Results. During the study, experimental data were collected on the physical (shape and size of particles, particle size distribution) and pharmacotechnological properties (powder flowability, bulk density and tapped density of powders, Hausner’s ratio and Carr’s index) of albendazole and arabinogalactan, as well as their solid dispersions obtained by mechanochemical solid-phase synthesis. Conclusion. According to the results of the study, a sample of solid dispersion of albendazole and arabinogalactan (ratio 1:5, mechanical treatment time 2 hours) with appropriate physicochemical and technological properties was determined for use in the technology of further oral dosage form obtaining. The revealed rather low technological parameters of the rest solid dispersions of albendazole with arabinogalactan determine the need to select the optimal composition of excipients during further pharmaceutical development.

Preparation and Investigation of Spherical Powder Made from Corrosion-Resistant 316L Steel with the Addition of 0.2% and 0.5% Ag.

The paper describes the production and study of spherical powder made from corrosion-resistant 316L steel with the addition of 0.2% and 0.5% Ag. The study of granulometric composition, morphology, fluidity and bulk density, phase composition, microhardness and impurity composition of the spherical powders was carried out. The study showed compliance of the spherical powders with the requirements for powders used for additive manufacturing. The fluidity of the powders was 17.9 s, and the bulk density was 3.76 g/cm3. The particles have a spherical shape with a minimum number of defects and an austenitic-ferritic structure. The study of the phase composition of ingots, wires and powders showed that the ingot structure of all samples consists of austenite. According to the results of studies of the phase composition of the wire, there is a decrease in γ-Fe and an increase in α-Fe and σ-NiCr in going from wire No. 1 to wire No. 3. According to the results of studies of the phase composition of the powder particles, there are three phases, γ-Fe, α-Fe, and Fe3O4. The study of microhardness showed a decrease in HV depending on the increase in silver. The hardness of the powder is lower than that of the ingot by 16-24% due to the presence of a ferritic phase in the powder. As a result of plasma spraying, an increase in residual oxygen is observed, which is associated with the oxidation of the melt during plasma dispersion. The amount of nitrogen and sulfur does not change, while the amount of carbon and hydrogen decreases, and the impurities content corresponds to the standards for corrosion-resistant steel. Qualitative and quantitative analysis of the silver content in the samples indicates that it was not affected by the stages involved in obtaining the spherical powder.

Impact of hydrocolloid and foaming agent on the physicochemical, microstructural and bioactive characteristics of foam-mat freeze-dried tapai (fermented black glutinous rice) powder.

The aim of this study was to obtain fermented black glutinous rice (FBGR) powder using the foam-mat freeze-drying method and to evaluate the physicochemical, microstructural, and bioactive characteristics of FBGR powder. To obtain FBGR foams, maltodextrin (MD; 0%-40% w/w) and whey protein isolate (WPI; 7.5% w/w) were used. The results showed that MD concentration had a significant effect (p ≤ .05) on powder recovery and bulk density which increased from 68.9% to 80.5% and 0.46% to 0.63 g/ml, respectively. The lowest moisture content (2.17%) and water activity (0.48) were found in powders produced with 20% MD. The solubility of FBGR powders ranged from 74% to 75% and increasing MD concentration gave higher lightness (L*) and yellowness (b*) readings in color properties of powders. Although the addition of the carrier agent caused reductions in total phenolic content and anthocyanins, the retention of these bioactive compounds rose with increasing MD content from 67% to 76% and 78% to 84%, respectively. FBGR produced with 40% MD had the most superior physical and technological properties, and foam-mat freeze-drying is a promising technology for retaining the bioactive compounds in FBGR.

Flow behaviour of zeolite powders at high process temperatures

Zeolite powders are an active ingredient for various applications and processing condition could affect powder flow behaviour. One of the important process conditions that changes during the manufacturing process is temperature. Temperature can change the particle properties affecting the powder flow properties and, therefore, the latter need to be tested at the process conditions. The flow properties of two types of zeolite powders, Z302 and T804, were evaluated at temperatures of 150, 300, and 500 °C in the range of 1–8 KPa of normal consolidation stresses by an Anton Paar shear cell. The two materials show a very different flowability behaviour, even at the lowest temperature tested. The temperature appears much more significant effect on the T804 zeolite at 500 °C and the flow function falls into the cohesive range while the Z302 zeolite flow function changes only for large values of consolidation stresses, by showing a flow function falling entirely within the very cohesive range. To find an explanation for understanding such a different behaviour of these two materials at changing temperature and consolidation stress, a theoretical framework was developed to take into account the different particle size distributions of the two powders. The resulting analysis, which is specific to the system taken into account, supports the goodness of the general approach that an adequate estimate of the average material fabric provides averaged estimates of contact forces that are able to explain the different behaviours of temperature and consolidation changes shown by powders. An original analysis of flowability based on the calculation of a structural length is also introduced to account for different powder bulk densities. • The higher temperatures decrease the flowability of Zeolite powders. • A theoretical framework was developed for the effect of particle size distribution. • A characteristic structural length was calculated on the changing density.

Cracking behavior of AISI 316L stainless steel powder by gas nitriding and its influence on spark plasma sintering

In this study, the effect of nitriding temperature on the deformation behavior of spherical AISI 316L powders was investigated. The results showed that the nitrogen content in powders was significantly increased by increasing the nitriding temperature under ammonia atmosphere. However, the resulted residual stress led to the deformation or even cracking in powders, the cause of drastic changes in the bulk density and fluidity of powders. Furthermore, the microstructure and properties of alloys synthesized by spark plasma sintering were also analyzed. The obtained results also indicate that the powder deformation has no influence on the consistency of sintered samples, but the nitriding temperature of AISI 316L powder obviously affects the morphology and performance of sintered samples. Nitrogen initially exists as interstitial atom in the steels till the nitriding temperature rises to 500 °C where nitrides begin to precipitate in the sample. Such morphological transition of nitrogen atoms has a significant impact on the mechanical properties of the alloys. The better corrosion resistance of the alloy prepared over 500 °C in 3.5 wt.% NaCl solution shows that the nitriding temperature also matters for corrosion performance.

Nutritional Content, Phytochemical Profiling, and Physical Properties of Buckwheat (Fagopyrum esculentum) Seeds for Promotion of Dietary and Food Ingredient Biodiversity

The adoption of food crops as a source of dietary macro- and micro-nutrients is a sustainable way to promote diet biodiversity and health while being respectful to the environment. The aim of this work was to comprehensively characterize the nutrient and phytochemical content of buckwheat seeds (Fagopyrum esculentum) and assess their physical properties for the evaluation of their suitability as food ingredients. The buckwheat samples were found to be complete sources of amino acids (UPLC-TUV analysis), with a protein content between 11.71 ± 0.40% and 14.13 ± 0.50% (Vario Max CN analysis), and a source of insoluble fiber with 11.05 ± 0.25 %, in the UK hulled samples (GC analysis). The buckwheat samples were rich in phosphorus, manganese, molybdenum, zinc, magnesium, and selenium (ICP-MS analysis). A total of 196 plant metabolites were detected using HPLC and LCMS analysis, with anthocyanidins (pelargonidin and cyanidin) being the most abundant phenolic molecules that were measured in all the buckwheat samples. Removing the hull was beneficial for increasing the powder bulk density, whereas the hulled buckwheat samples were more easily rehydrated. The implementation of buckwheat as a staple food crop has enormous potential for the food industry, human nutrition, and diet diversification and could contribute towards meeting the daily recommendation for dietary fiber, essential amino acids, and minerals in Western-style diet countries such as the UK.

Hydrothermal preparation of lightweight calcium silicate powder from alumina-leaching residue of low-calcium sintering red mud

In order to realize the complete and high-value utilization of red mud, a hydrothermal process was proposed to prepare the lightweight calcium silicate powder from a sodium calcium silicate residue after alumina extraction. The synthesized products were characterized by XRD, XRF, SEM, EDS, and PSD, and the corresponding transition mechanism and physical properties were also studied. The main silicon- and aluminum-bearing phases in the clinker after the low-calcium sintering are Na2CaSiO4 and NaAlO2, and the former silicate keeps stable during the alumina leaching process under atmospheric pressure. In the hydrothermal process, Na2CaSiO4 in the alumina-leaching residue is converted into NaOH and Ca5Si6O16(OH)2·4H2O in the alkali solution, and the residual alumina is converted into Ca3Al2SiO8·4H2O which promotes the generation of Ca5Si6O16(OH)2·4H2O. Increasing the reaction temperature, duration and liquid-solid ratio of the hydrothermal process can facilitate the alkali removal efficiency in calcium silicate powder and decrease its bulk density, while the excessive hydrothermal temperature and duration reduce the alkali removal efficiency. The Na2O residue and bulk density of the calcium silicate powder are 0.42% and 0.30 g·cm−3 obtained at the optimal hydrothermal conditions. The flaky particles of Ca5Si6O16(OH)2·4H2O are aggregated into a porous cauliflower structure, which improves the absorption and insulation properties of calcium silicate powder.