Compound Powders Research Articles

Process optimization of polyphenol‐rich milk powder using bee pollen based on physicochemical and functional properties

AbstractThe present study aims to optimize and explore the bee pollen as a functional component in milk powder using response surface methodology. The experimental design comprised of process variables: bee pollen (5–15%), temperature (20–30°C), and pressure (15–25 inHg) to investigate their effect on physical properties and total phenolic content of developed product. Results indicated an increase in powder recovery (41.53–52.96%) with pollen, temperature, and pressure whereas total phenolic content (12.35–22.65%) raised with pollen and pressure. The solubility (74.86–83.73%) and bulk density (0.37–0.63 g cm−3) decreased with pollen and temperature while hygroscopicity (13.10–18.29%) increased with pollen. The optimum conditions for polyphenol‐rich milk powder were 13.72% pollen, 26.84°C temperature, and 23.37 inHg pressure. Further, the morphological and FTIR analysis also strengthens the presence of polyphenols in optimized product. This investigation, thus, would open door for utilization of polyphenol‐rich milk powder in formulating several value‐added food products.Practical applicationsBee pollen—a potent source of essential amino acids, fatty acids, dietary fiber, and polyphenols is an underutilized but nourishing food. This study aims at developing the vacuum‐dried bee pollen—rich milk powder based on process variable: bee pollen concentration, temperature, and pressure. Results showed the significant amount of total phenolic compounds in developed milk powder that is even higher compared to fresh bee pollen. The powder manufacturing process discussed here is quite simple and can be easily adapted by small and medium scale industries to achieve drying at a lower cost which may be beneficial for beekeepers to raise their economic status in developing countries. Further, the developed polyphenol‐rich milk powder can be employed in cereals, bakery, confectionery, and frozen dessert industry to make healthier processed food products.

Combined equipment for synthesis of ultrafine metals and metal compounds powders via Flow-Levitation and crucible methods.

Laboratory automated equipment for synthesis of ultrafine particles of metals, alloys and metal compounds via evaporation-condensation Flow-Levitation Guen-Miller method combined with crucible method using high-frequency (440 kHz) electromagnetic field for heating is described. The equipment synthesizes the said particles and multilayer core-shell structures with mean size ranging from tens to hundreds of nanometers with output from grams to tens of grams per hour. Synthesized particles may be collected into container with inert gas, or into non-volatile liquid, or in situ passivated with air for further handling. Examples of synthesized particles are presented.

Plastometric Simulation of the Hot Rolling Process of Al/B4C Powder Composite

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Development of a headspace solid-phase microextraction gas chromatography mass spectrometry method for the quantification of volatiles associated with lipid oxidation in whole milk powder using response surface methodology

Lipid oxidation is a major contributor to the deterioration of the sensory quality of fat-containing dairy powders. Hydroperoxides are the primary oxidation products from unsaturated fatty-acids that readily yield a complex mixture of volatile organic compounds that can adversely impact product quality and shelf life. Headspace solid-phase microextraction gas-chromatography mass-spectrometry was chosen to quantify thirteen lipid oxidation compounds in whole milk powder encompassing a range of volatilities and chemical classes. A central composite rotatable design (CCD, α = 1.1) based on a 23 factorial table was used with response surface methodology to optimize the HS-SPME parameters; determined at; 45 min extraction time and 43 °C extraction temperature. The significant model terms were found to be extraction temperature (p < 0.05) and the interaction between time and temperature (p < 0.05). Precision, accuracy, LOD and LOQ were determined and the method was validated for whole milk powder.

Automated method for the determination of the band gap energy of pure and mixed powder samples using diffuse reflectance spectroscopy

An automated method to determine the band gap energy (Eg) of pure and mixed powder compounds using diffuse reflectance spectroscopy is presented. This method is based on a five-step algorithm that mimics the judgment made by an expert analyst in identifying the linear segments in Tauc plots and subsequent estimation of the Eg value. It is demonstrated that the method to estimate Eg by intersecting the straight-line fit of the Tauc segment with the photon energy axis is not appropriate for those samples containing more than one optical absorbing phase because systematic underestimation of the Eg value results. The automated method accounts for such cases by introducing a base line function. The robustness of the implemented algorithm was tested using three model systems, ZnO-Al2O3, ZnO-CoO and ZnO-CdO. The estimated Eg's using the automated method differ in less than 1% than those obtained by its manual counterpart.

Characterization and quantification of tannins, flavonols, anthocyanins and matrix-bound polyphenols from jaboticaba fruit peel: A comparison between Myrciaria trunciflora and M. jaboticaba

Jaboticaba, a polyphenol-rich fruit, has numerous nutraceutical properties. Studies on jaboticaba composition have focused on solvent-extractable polyphenol compounds, whereas the matrix-bound polyphenols that can be delivered during digestion have been neglected. This study aimed to characterize the polyphenol profiling of matrix-bound and free phenolic compounds in Jaboticaba peel powder (JPP) using two fruit species, Myrciaria jaboticaba (JPP-MJ) and M. trunciflora (JPP-MT). An HPLC-DAD-MS/MS method was developed and validated to analyze JPP polyphenols. The total content of free phenolic compounds was 2.4 times higher in JPP-MT than in JPP-MJ and the profile of free polyphenols differed between the two species. JPP-MT had 60.3% tannins and 33% anthocyanins, whereas JPP-MJ had 34.7% and 50.7%, respectively. The content of matrix-bound phenolic compounds was higher in JPP-MJ than in JPP-MT (15.3% vs. 4.3% of total phenolic compounds). Besides cyanidin 3-glucoside, three other compounds were identified as major: a tetragalloylglucose isomer for both species, trigalloylglucose for JPP-MT, and delphinidin-3-glucoside for JPP-MT. Phenolic profiling of JPP revealed new compounds that may contribute to health benefits after JPP consumption. Despite differences in the phenolic profile between the jaboticaba species, both JPPs are rich sources of polyphenols and could be used for promoting health benefits.

Application of gum Arabic, β-cyclodextrin, and hydroxypropyl-β-cyclodextrin to microencapsulation by molecular inclusion of grape skin extract (Vitis labrusca var. Isabel)

Gum Arabic (GA), β-cyclodextrin (β-CD), and hydroxypropyl-β-cyclodextrin were used in different proportions to microencapsulate polyphenols obtained by aqueous extraction from a grape skin. Phenol contents of the microcapsules were evaluated for anthocyanins, flavonoids and total flavanols, antioxidant activity, color, moisture, water activity (Aw), solubility, hygroscopicity, and glass transition temperature (Tg). The microcapsules prepared with either 5% GA or a mixture of 3% GA and 2% β-CD had the highest retention of phenolic (78.9 and 67.5%, respectively), anthocyanins (35.3 and 29%, respectively) and antioxidant activity greater than 50% measured by the DPPH and CUPRAC methods. Treatment with 3% GA and 2% β-CD showed the highest retention of flavonoids (67.2%) and total flavanols (51.1%), as well as physical properties suitable for this type of product, such as Aw of 0.175, solubility greater than 90%, hygroscopicity of 17.3%, and Tg of 32.8°C, which may contribute to a greater stability of the powder. Practical applications Grape processing by-products have a great feasible commercial, and this is due at high concentrations of phenolic compounds in grape skin. It was possible to obtain inclusion complexes powder of phenolic compounds from grape skin, using cyclodextrin and its derivates in mixture with Arabic gum as carriers. This way, the stability of bioactive compounds may be improved during food processing, storage and pass through the gastrointestinal tract. In addition, it is possible to enhance solubility of phenolics compounds in aqueous dispersions. Powders obtained have antioxidant properties and potential prebiotic activity.

Determination of 50 antibiotic residues in drone pupa powder by liquid chromatography-tandem mass spectrometry

A method was established for the determination of 50 kinds of antibiotic residues (macrolides, quinolones, sulfonamides, tetracyclines, nitroimidazoles, lincomycin and chloramphenicol) in drone pupa powder by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with perchloric acid and lead acetate solution, and the protein was precipitated. The extraction solution was adjusted to pH 8 using dipotassium hydrogen phosphate, then the solution was purified by solid phase extraction (SPE) and analyzed by LC-MS/MS. The target compounds in the drone pupa powder were determined quantitatively and quantitatively by using multiple reaction monitoring and positive ion or negative ion modes. The recoveries of the 50 antibiotics were in the range of 70.2%-118.3%, and the relative standard deviations (RSDs) were 1.8%-13.6%. The method is simple, selective, and can be suitable for the analysis and confirmation of veterinary drug residues in drone pupa powder.

Synthesis, characterization and sintering of fluorite and pyrochlore-type compounds: Pr2Zr2O7, Sm2Zr2O7 and PrSmZr2O7

Fluorite and pyrochlore-type compounds (Pr2Zr2O7, Sm2Zr2O7 and PrSmZr2O7) powders were prepared by glycine nitrate process (GNP) starting from metal (Sm, Pr) nitrate, zirconium chloride and glycine as a fuel. The GNP process at room temperature initially yielded amorphous powders, which crystallized after subsequent calcination to form crystalline ceramics. The formation of well crystalline compounds took place at temperature as low as 950°C. The phase evolution with thermal treatment as well as powder properties such as crystallite size, lattice strain and lattice parameter were studied by X-ray powder diffraction (XRPD) at room temperature. High-density ceramic pellets free of any additives were obtained after compaction of the obtained powders and subsequent sintering at 1600°C for 4 h in air. Sintering behaviour of the synthesized pyrochlore phases was followed with a scanning electron microscope. Hardness of the sintered samples was found to be in range of 8.9 to 9.9 GPa depending of chemical composition.

Закономерности формирования структуры частиц порошковых композиций на основе алюминия, получаемых механическим реакционным легированием

Закономерности формирования структуры частиц порошковых композиций на основе алюминия, получаемых механическим реакционным легированием

Recovery of rare earths from waste cathode ray tube (CRT) phosphor powder by selective sulfation roasting and water leaching

Until recently, most displays, such as television and computer screens, were based on cathode ray tubes (CRTs). With the introduction of new types of displays including liquid crystal displays, CRTs have been widely replaced, leading to a gradual build-up of hazardous CRT powder waste. In this paper, a new approach is introduced where the valuable rare-earth elements (REEs) (i.e. yttrium and europium) in the powder are selectively recovered, leaving behind a zinc-rich residue and glass for further recycling. The main rare-earth compound in the waste powder is Y2O2S:Eu3+ (YOS). The fine-grained CRT powder was mixed with zinc sulfate monohydrate (ZnSO4·H2O) and roasted at 600–900 °C for short periods of time. In this way, Y2O2S:Eu3+ was transformed into water-soluble rare-earth sulfates. Meanwhile, ZnS underwent a two-stage reaction with ZnSO4·H2O, where first a partially water-soluble intermediate (ZnO·2ZnSO4) and then the water-insoluble ZnO was formed. Addition of a sufficient amount of ZnSO4·H2O ensured the recovery of ≥95% of the rare earths in a subsequent water leaching step, but there was also co-dissolution of about 5% of the total amount of zinc present. Several purification methods were tested and compared to separate the REEs from the zinc impurity in the solutions. In addition to the conventional precipitation methods with sulfides and oxalic acid, a novel liquid-liquid exchange reaction between REE-containing leachate and zinc-loaded Versatic Acid 10 was tested. Finally, a complete flow sheet is proposed for the (almost complete) valorization of REEs as well as the total zinc present.

Fabricating a Novel Intragranular Microstructure for Al₂O₃/GdAlO₃ Ceramic Composites.

In order to make the embryonic form of intragranular structure, the Al2O3/GdAlO3 system was selected due to its excellent mechanical properties. Gd2O3 and Al(NO3)3·9H2O were used as the starting materials. A co-precipitation method was used for the preparation of fine ceramics and applied to synthesize the nano-powder of GdAlO3 firstly. Then, the nano-powder of GdAlO3 was mixed with the precipitates by the second co-precipitation method. After drying and calcination, the compound powder with eutectic composition (77 mol % Al3+—23 mol % Gd3+) was fast sintered by using the spark plasma sintering technique. The results revealed that the phases of the sintered samples were Al2O3 and GdAlO3. The phases showed a homogeneous and interlaced distribution. All the matrix grains were submicron. The sizes of the intragranular structures were between 50 nm and 150 nm. Therefore, the intragranular structure displayed a novel mixture of nanometer–submicron and submicron–submicron types. The different intragranular structures all changed the fracture modes of Al2O3 grains from intergranular fracture to transgranular fracture.

Microstructural evolution and mechanical properties of Nb-Si-Cr ternary alloys with a tri-phase Nb/Nb5Si3/Cr2Nb microstructure fabricated by spark plasma sintering

In this work, pure Nb, Nb5Si3 and Laves Cr2Nb compound powders were used as raw materials to prepare Nb-Si-Cr ternary alloys by spark plasma sintering (SPS). A comprehensive estimation of the microstructure and properties, including room temperature fracture toughness, high temperature strength and oxidation resistance, of the Nb-Si-Cr ternary alloys as a function of the Nb/Nb5Si3/Cr2Nb phase volume fraction combinations was conducted. The results showed that Nb-Si-Cr ternary samples with the relative density larger than 98.42% were obtained by SPS processing, and the samples all consisted of Nb, Nb5Si3 and Cr2Nb phases that were distributed homogeneously. The fracture toughness KQ of the Nb/Nb5Si3/Cr2Nb microstructure, which was dominated by the Nb phase, naturally increased with the Nb fraction. As expected, the room-temperature Vickers hardness and the high-temperature strength of the bulk alloys increased monotonically with the increasing of the stiffening Nb5Si3 fraction. Interestingly, the binary Cr2Nb phase played a positive role in the high temperature strength and oxidation resistance. Finally, the fracture modes of the typical Nb/Nb5Si3/Cr2Nb microstructures under bending and compression conditions at room and high temperatures as well as the oxidation mechanism are described and discussed.

Effect of spray drying on bioactive and volatile compounds in soursop (Annona muricata) fruit pulp.

Soursop is seasonal and highly perishable fruit, which limits its commercialization. Thus it is necessary to conserve its pulp so that it is available throughout the year. One of the most common forms of fruit preservation is by dehydration. This work had an objective to dehydrate soursop pulp by spray drying at optimum conditions and to analyze the retention of bioactive and volatile compounds in soursop powder, besides analyzing its antioxidant capacity. The total phenolics, carotenoids and flavonoids contents were determined, while volatile compounds were analyzed by Stir Bar Sorptive Extraction (SBSE) coupled with GC-MS system. The total content of the phenolic compounds and flavonoids in the fresh pulp were 160.28 mg of GAE/100 g and 87.17 mg of quercetin/100 g, respectively while for rehydrated dried powder their values were 158.95 mg of GAE/100 g and 85.17 mg of quercetin/100 g, respectively. The total phenolic compounds, flavonoids and antioxidant capacity did not show any significant difference (p < .05) between the fresh fruit pulp and dehydrated powder. A total of 85 volatile compounds were identified, of which 33 were esters, representing the major class of organic compounds, 15 were terpenes, 10 aldehydes, 7 acids, 5 alcohols, 5 lactones, 3 ketones, and 6 other compounds. Of the total 85 compounds, identified in soursop pulp, 58 compounds were identified in the rehydrated dried powder. The principal compounds for both samples were methyl (E)-2-hexenoate, methyl hexanoate and methyl (E)-2-butanoate, which contribute to soursop aroma according to their Odor Active Values (OAV). Considering that there was no significant difference (p < .05) between fresh pulp and the rehydrated dried powder in concentrations of bioactive compounds and even with the reduction in the concentration of the main volatile compounds while the OAVs of these compounds were relatively high, it is concluded that spray dried powder of soursop pulp retains its nutritional and aroma quality, besides maintaining the antioxidant capacity.

A thermochemical and experimental study for the conversion of ilmenite sand into fine powders of titanium compounds

The adiabatic temperatures and equilibrium phases in the FeTiO3-αMg-C(B, Si)-kNaCl system (where α = 0.2–15, k = 0–3) were analyzed to predict the formation of fine powders of titanium compounds from natural ilmenite sand. From the parametric study, the critical variables were identified and optimized for the synthesis of FeTi, TiC, TiB2, and TiFeSi2 under a combustion regime. The experimentally measured temperatures were in good agreement with those predicted from thermochemical calculations in the 900–1800 °C range. The purified products were characterized using X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The fine powders of titanium compounds were mainly single phase with a purity of at least 95 wt%. Considering the various stages of the synthetic process, a mechanism is proposed to explain how the process of ilmenite recovery occurred.

On the usage of a neutron source to determine the density distribution in compacted cemented carbide powder compounds

ABSTRACTDensity variations in pressed powder materials are of substantial importance and will affect shrinkage and geometry after sintering. It is therefore important to accurately measure this quantity in green bodies. This is emphasised by the fact that the density variation can be used for determining material properties in constitutive mechanical models of compaction. An obvious method to determine the density variation is X-ray tomography. For cemented carbides this is not a possible alternative due to the very high X-ray absorption of tungsten making the samples impossible to penetrate. Neutron radiation has a much higher penetration and this suggests that a neutron source could be used for density distribution determination in such materials. This was investigated currently showing promising results when compared with finite element predictions. It is clear that this approach must be improved to be able to use neutron radiation as a tool for density determination. Improvements are suggested.

Fabrication of Mo-Si-B Intermetallic Compound Powders Under Different Heat Treatment Conditions

Fabrication of Mo-Si-B Intermetallic Compound Powders Under Different Heat Treatment Conditions

Different Spectrophotometric Methods Manipulating Ratio Spectra Applied for the Analysis of Aclidinium in Duaklir® Genuair® Inhalation Powder

Two simple, accurate, and selective spectrophotometric methods were developed to determine aclidinium in the presence of formoterol as interferent compound in Duaklir Genuair inhalation powder. The methods under study are ratio derivative and ratio subtraction spectrophotometric methods. These methods are based on different mathematical processing of the obtained ratio spectra. The methods are linear over the concentration range of 5–50 µg/mL for aclidinium and validated according to the ICH guidelines. The accuracy and precision are found to be within the acceptable limits and assessed by applying the standard addition technique. The specificity of the proposed methods was tested using laboratory-prepared mixtures. Furthermore, the methods were statistically compared to the reported RP-HPLC method, and good results were obtained.

Comparative Analysis of Boron Powders Obtained by Various Methods. I. Microstructure and Oxidation Parameters during Heating

This paper describes a study of boron powders and powder compounds, obtained by various methods, including metallothermal, electrolytic, and borane cracking methods. The crystal state, particle size and microstructure, presence and composition of impurities, and chemical composition of the oxide layer of boron particles are profoundly investigated. The effects of the above-mentioned characteristics on the particle oxidation parameters during heating with a constant rate are analyzed. The determining influence of chemical composition of the particle surface layer on the initial temperature of their intense oxidation is established. It is shown that the maximum increase in the mass and heat release value during oxidation of the boron powders is almost independent of microstructural features, crystal state, and chemical composition of and oxide layer thickness of the particles, and cannot serve as indicators of completeness of boron oxidation during heating.

Synthesis, characterization and sintering of Gd2Hf2O7 powders synthesized by solid state displacement reaction at low temperature

Pyrochlore compound (Gd2Hf2O7) powder was prepared by reacting gadolinium nitrate and hafnium chloride with NaOH during solid state displacement reaction at low temperature (SSDR). The SSDR process at room temperature initially yielded amorphous powders, which crystallized after subsequent calcination to form crystalline ceramics. The formation of crystalline Gd2Hf2O7 took place at temperature as low as 600 °C. The phase evolution with thermal treatment as well as powder properties such as crystallite size, lattice strain and lattice parameter were studied by X-ray powder diffraction (XRPD) at room temperature. High-density ceramic pellets free of any additives were obtained after compaction of the obtained powders and subsequent sintering at 1600 °C for 4 h in air. Rietveld analysis of X-ray diffraction (XRD) pattern of sintered sample showed that the unit cell parameter of the obtained Gd2Hf2O7 is 10.5501 (2) Å with x value = 0.345(2) in Wyckoff positions, indicating small distortion of octahedra. Hardness of the sintered samples was found to be 7.1 GPa. The thermal conductivity measurements performed in temperature range from room temperature to 1000 °C showed that thermal diffusivity of sintered samples was between 0.5 and 1 mm2/s whereas thermal conductivity was between 4 and 7 W/(m K).