High-intensity Ultrasonic Treatment Research Articles

EFFECT OF HIGH-INTENSITY ULTRASONIC TREATMENT ON REFINEMENT OF Al-5Cu ALLOY INGOTS

The effect of high-intensity ultrasonic treatment combined with bottom cooling treatment on the refinement of Al-5Cu alloy ingots was studied. The results show that ultrasonic treatment combined with forced cooling at the bottom of ingots has a good refining effect, and the best refining effect can be obtained at 2000 W and after 120 s. The cross-section of an ingot exhibits almost 100 % refined equiaxed grains and no porosity. The method of combining ultrasonic treatment and forced cooling at the bottom of ingots not only influences the ingot refinement, but also decreases the porosity of the ingots with an increase in the ultrasonic duration. The ultrasonic degassing effect is due to the release of hydrogen in biofilms, which expand and grow gradually; finally, they burst on the melt surface, achieving the effect of degassing.

Emulsifying properties of wheat germ protein: Effect of different ultrasonic treatment

The effect of ultrasonic treatment on emulsifying properties of wheat germ protein (WGP) was studied in this paper. WGP was subjected to low frequency (20 kHz), high intensity ultrasonic treatment at different power (200, 400, 600, 800 W) for 10 min, or different time (2, 4, 6, 8, 10, 15, 20 min) at 400 W. The emulsifying activity index and emulsion stability index of WGP were significantly improved, and the emulsion droplet was smaller and more uniform after ultrasound treatment. Ultrasound increased the adsorbed WGP concentration at the oil-water interface and reduced the interfacial tension, which explained the improved emulsifying properties of WGP. The investigation on molecular properties and protein conformation showed that ultrasound processing increased solubility, but decreased particle size and surface charge of WGP. Ultrasound processing resulted in the unfolding of the protein molecular structure indicated by the increase of surface hydrophobicity and surface free sulfhydryl group levels, and the decrease of intrinsic fluorescence intensity. Correlation analysis showed that the changes in WGP solubility, particle size, and surface hydrophobicity were the main driven factors for the improved emulsifying properties of WGP.

The microstructure and mechanical properties of 2219 alloy during ultrasonic treatment

High-intensity ultrasonic melt treatment technique plays a key role in improving the performance of large-scale 2219 alloy ingot (Φ630 mm × 4500 mm). In this current paper, ultrasonic treatment-assisted casting techniques were developed and applied to manufacture large-scale 2219 aluminium (Al) alloy ingot in direct chill casting (DC). The industry-level experiments revealed that the α-Al grains of the ingot with ultrasonic (USDC) were refined, the area fraction of the coarse Al2Cu eutectic phase showed a decreasing trend, and the mechanical properties were lightly improved than without ultrasonic ingot (DC). Based on the present results and previous proposed hypotheses, the synergistic effects of cavitation and acoustic streaming were considered as the dominant mechanisms of USDC.

Effect of high intensity ultrasonic treatment on structural, rheological, and gelling properties of potato protein isolate and its co-gelation properties with egg white protein.

The study aimed to investigate the effect of high intensity ultrasonic(HIU) treatment at different times (0, 10, 20, and30 min) on the structure and gel properties of water-soluble potato protein isolate (WPPI) and to further investigate the improvement of gel properties of ultrasonicated WPPI (UWPPI) by the addition of egg white protein (EWP). HIU reduced theparticle size of WPPI, whose structure became loose and disordered, which improved gelling properties of UWPPI. Fourier transform infrared results indicated that α-helix content decreased, whereas the proportion of irregular curl increased with the increase in ultrasonication time (0-20 min), indicating that the initially ordered structure of UWPPI became disordered. AfterHIUtreatment, thefree sulfhydryl groups of UWPPI and surface hydrophobicity decreased and fluorescence intensity increased. Theseresultsdemonstrated that the HIUloosenedthestructure of UWPPI, exposing more chromogenic groups while embedding more hydrophilic groups. After thermal induction, UWPPI gel hardness increased and exhibited excellent water holding capacity. After the addition of EWP, rheological properties stabilized, and thehardness of UWPPI-EWP gels increased significantly, forming internally structured protein gels with a tightly ordered structure and increased brightness. Thus, HIU changed the structure and gelling properties of WPPI, and the addition of EWP further enhanced the performance of hybrid protein gels. PRACTICAL APPLICATION: High intensity ultrasonic changed the structure of water-soluble potato protein isolate (WPPI) and improved the properties of WPPI gels. The addition of egg white protein significantly improved the quality of mixed protein gels which showed great potential industrial value.

Optimization of the ultrasonic treatment for Tara gum using response surface methodology

High-intensity ultrasound irradiation proved to be an effective method for modifying tara gum by generating low molecular weight products and better water solubility. The objectives of this research were to optimize the parameters for the high-intensity ultrasonic treatment with response surface methodology and improve the tara gum solubility. The results demonstrated that after the ultrasound treatment, the solubility of the tara gum had increased (17.7%) as a result of the reduced intrinsic viscosity (70%). The molecular weight of the untreated tara gum was 1.89 x 106 Da, and after ultrasound treatment, it was reduced to 0.47 x 106 Da. Rheological analyses confirmed the reduction in molecular weight for the modified and optimized tara gum and the resulting increase in solubility. This knowledge provides a better understanding of ultrasound treatment technology and increases the scope for use of tara gum in the food industry.

Improving the Functional Performance of Date Seed Protein Concentrate by High-Intensity Ultrasonic Treatment.

Date kernel is a plant-derived byproduct that has the potential to be converted into a high-value-added food ingredient, such as protein concentrate, in the food industry. Ultrasound, which is an alternative method for improving the functional properties of food proteins, is an effective physical treatment for modifying protein functionality. Solubility is the main criterion that primarily affects other functional properties of protein concentrates, such as emulsification, foaming, and water and oil binding. The aim of this study is to enhance the techno-functional performance of date seed protein concentrate (DSPC) by maximizing the solubility via a high-intensity ultrasound (HIUS) treatment at a fixed frequency of 20 kHz. The effect of ultrasonic homogenization under varying amplitudes and times (amplitude of 40, 60, and 80% for 5, 10, and 15 min, respectively) on the functional properties of the DSPC was investigated by using the response surface methodology (RSM). A face-centered central composite design (FC-CCD) revealed that the optimal process conditions of HIUS were at an amplitude of 80% for 15 min. The physicochemical and functional properties of the ultrasound-applied concentrate (DSPC-US) were determined under the optimum HIUS conditions, and then these properties of DSPC-US were compared to the native DSPC. The results showed that the solubility of all DSPC samples treated by HIUS was significantly (p < 0.05) higher than that of the native DSPC. In addition, emulsion activity/stability, foaming activity/stability, and oil-binding capacity increased after HIUS homogenization treatments, whereas the water-binding capacity decreased. These changes in the techno-functional properties of the DSPC-US were explained by the modification to the physicochemical structure of the DSPC (particle size, zeta potential, SDS-PAGE, SEM, FTIR, DSC, free SH content, surface hydrophobicity, and intrinsic emission). This work revealed that HIUS could be an effective treatment for enhancing the functional properties of date seed protein concentrate.

Ultrasonic-assisted spray drying as a tool for improving the instant properties of egg white powder

The mechanism by which high-intensity (20 kHz) ultrasonic treatment affected the rehydration performance and microstructure of egg white powder (EWP) was explored in this study. The wettability and dispersibility of EWP prepared from high-intensity ultrasound treated egg white liquid were observed to have an exciting enhancement. Furthermore, the most excellent dispersibility (65.67 s), solubility (90.33 g/100 g) and stability (98 %) of EWP were detected when ultrasonic treatment (120 W, 20 kHz, 10 mm ultrasonic horn) was performed for 10 min. SDS-PAGE results showed that ultrasonic treatment promoted the depolymerization of the original protein macromolecular aggregates. The particle size and scanning electron microscopy results also indicated that the particle size of EWP tended to decrease. Additionally, the zeta potential and surface hydrophobicity analyses suggested a tendency to first increase and then decrease over time. Overall, the instant properties of EWP were improved due to the changes of protein microstructure and conformation caused by ultrasonic treatment. These results revealed the mechanism of high intensity ultrasound affecting the instant properties and microstructure of EWP, which provided a theoretical basis for improving the rehydration of other food protein powder. • Ultrasound treatment improved the instant solubility of egg white powder. • The contact angle of egg white powder decreased and the wettability increased. • The dry and wet methods showed the particle size of egg white powder decreased. • SEM revealed that the microstructure of ultrasound-treated EWP was altered.

Cellulose Hollow Annular Nanoparticles Prepared from High-Intensity Ultrasonic Treatment.

Cellulose nanomaterials, such as cellulose nanocrystals (CNCs), have received enormous attention in various material research fields due to their unique properties and green/sustainable nature, among other qualities. Herein, we report hollow-type annular cellulose nanocrystals (HTA-CNCs), which are generated by following a high-intensity ultrasonic treatment. The advanced aberration-corrected transmission electron microscopy results reveal that HTA-CNCs exhibit ring structures with a typical diameter of 10.0-30.0 nm, a width of 3.0-4.0 nm, and a thickness of 2.0-5.0 nm, similar to those of elementary crystallites. The X-ray diffraction measurements show that the as-prepared HTA-CNCs maintain the cellulose I structure. The changes in structure and hydrogen-bonding characteristics of HTA-CNCs are further determined based on the FT-IR results after deconvolution fitting, showing that three types of hydrogen bonds decrease and the content of free OH increases in HTA-CNCs compared with those in the original CNCs. Furthermore, molecular dynamics simulation is carried out to support the experimental study. The formation of HTA-CNCs might be attributed to the structural change and entropy increase. The hollow-type annular CNCs may have broad value-added applications as cellulose nanomaterials in different fields.

Effect of high-intensity ultrasonic treatment on the emulsion of hemp seed oil stabilized with hemp seed protein

In this study, hemp seed oil (HSO) emulsions stabilized with hemp seed protein (HPI) were prepared and treated with high intensity ultrasonic (HIU). The effects of different treatment powers (0, 150, 300, 450, 600 W) on the properties, microstructure and stability of emulsions were investigated. HIU-treated emulsions showed improved emulsifying activity index and emulsifying stability index, reduced particle size, and increased absolute values of ζ-potential, with the extreme points of these indices occurring at a treatment power of 450 W. Here, the emulsion showed the best dispersion and the smallest particle size in fluorescence microscopy observation, with the highest adsorbed protein content (30.12%), and the highest tetrahydrocannabinol (THC) retention rate (87.64%). The best thermal and oxidative stability of the emulsions were obtained under HIU treatment with a power of 450 W. The D43 and the peroxide values (POV) values after 30 d storage were the smallest at 985.74 ± 64.89 nm and 4.6 μmol/L, respectively. Therefore, 450 W was optimal HIU power to effectively improve the properties of HPI-stabilized HSO emulsion and promote the application of HSO and its derivatives in food processing production.

Joint effects of enzymatic and high-intensity ultrasonic on the emulsifying propertiesof egg yolk

This study investigated the joint effect of the enzymatic and high-intensity ultrasonic (HIU) treatments on the emulsifying and structural properties of egg yolk (EY). The evaluation was performed under different HIU powers (i.e., 0, 240, and 480 W) and for different durations (10, 20, and 30 min). Results reveal that the emulsification activity and emulsification capacity at 240 W for 10 min significantly increase than that of the samples without HIU treatment (P < 0.05). The thermal stability reached a maximum of 90.33% in 480 W + 30 min. The HIU treatment under low power and for a short time (240 W + 10 min) reduced the average particle size of the EY to 224.77 nm. The combined treatment produced high zeta potential and total sulfhydryl contents. The highest hydrophobicity was 111.49 μg at 240 W for 20 min. The joint treatment enhanced the hardness and cohesiveness of the EY. Moreover, the α-helix content significantly decreased from 37.13% to 25.02% after the enzymatic treatment, while the β-sheet content increased with time in the 240 W treatment. The G' and G″ curves show an increasing tendency, and the highest G' and G″ were obtained in the 240 W + 30 min group, which is consistent with the dense microstructure. These results reveal that the combined treatment can improve the emulsifying characteristics, which could influence the structural properties of EY, expanding its application in the food industry.

Pea protein isolate-inulin conjugates prepared by pH-shift treatment and ultrasonic-enhanced glycosylation: Structural and functional properties

The application of pea proteins in the food industry is often limited by their poor functional properties, such as solubility, emulsification, and gelation. To address this problem, a novel method of constructing pea protein-inulin conjugates with improved functional attributes was developed, which consisted of combining a high-intensity ultrasonic treatment with a pH-shift wet heating method. This combined method promoted the Maillard reaction, leading to a grafting degree that was 2.3-times higher than that of the traditional wet heating method. SDS-PAGE confirmed the formation of pea protein-inulin conjugates. The pea protein-inulin conjugates had higher solubility than pea proteins alone, especially around the isoelectric point of the protein. Furthermore, the thermal stability, antioxidant activity, foaming and emulsifying properties of the conjugates were better than those of the protein. This study shows that the combined ultrasound/pH-shift wet heating method is highly effective at improving the functional properties of pea proteins.

Effects of low-frequency and high-intensity ultrasonic treatment combined with curdlan gels on the thermal gelling properties and structural properties of soy protein isolate

The effects of low-frequency and high-intensity ultrasonic treatments and curdlan gels on the thermal gelling and structural properties of soy protein isolate (SPI) were investigated. Low-frequency (20 kHz), high-intensity ultrasonic treatment improved the solubility and rheological properties of the SPI and promoted gelling, especially with 400 W treatment for 10 min. The addition of thermo-reversible curdlan gel (TRC) or thermo-irreversible curdlan gel (TIRC) further improved gel strength and reduced cooking loss from SPI gels pretreated with ultrasound. Fourier transform infrared spectroscopy (FTIR) of the SPI composite gel showed that the peak at 3268 cm−1 for the O–H vibration exhibited a blue shift compared to the control SPI and a red shift compared to pure TRC or TIRC, which indicated formation of hydrogen bonding interactions between SPI and TRC or TIRC. Circular dichroism spectroscopy (CD) showed that the addition of TRC or TIRC significantly decreased the α-helix content but increased the β-sheet contents of SPI gels due to denaturation and unfolding of SPI. Scanning electron microscopy (SEM) showed that the addition of TRC or TIRC led SPI gel to form a more regular and homogeneous network. These results revealed that the ultrasonic treatment and curdlan gels had obvious synergistic effects that improved the quality of SPI gels. Moreover, compared with TIRC, TRC addition promoted expansion and interactions of SPI molecules and formed a more stable network. Therefore, ultrasonic treatment combined with curdlan addition significantly improved the thermal gelation and structural properties of SPI.

Effect of high-intensity ultrasonic treatment on the physicochemical, structural, rheological, behavioral, and foaming properties of pumpkin (Cucurbita moschata Duch.)-seed protein isolates

Pumpkin-seed protein isolates were treated with high-intensity ultrasound (HIU). The effects of different ultrasound powers at the same treating time on the physicochemical, structure and foaming properties of pumpkin-seed protein isolates (PSPIs) were investigated. The results showed that the ultrasound treatment transformed the PSPI aggregates into smaller aggregates with a more uniform distribution. When the pH value increased, the solubility and foaming ability of the protein also increased significantly. Increasing the ultrasound power also increased the surface hydrophobicity of the PSPIs and the total sulfhydryl contents, while the active sulfhydryl content decreased. The most significant effect on the total sulfhydryl content occurred when 500 W ultrasonic power was used. The ultrasound treatment also had a significant effect on the chromaticity and turbidity of the pumpkin-seed protein isolates. With an increase in ultrasonic power, scanning electron microscopy (SEM) showed that the sizes of particles decreased as their distribution increased. Moreover, ultrasound treatment was found to be beneficial for enhancing and improving foaming performance. Ultrasound modification affected the protein's physicochemical properties and structure, which contributed greatly to the corresponding functional and nutritional properties of the protein. It would be, therefore, useful to develop and utilize plant protein and to improve its added-value.

Bacteriostatic effects of high-intensity ultrasonic treatment on Bacillus subtilis vegetative cells

The bacteriostatic effects of high-intensity ultrasonic treatment (HIU) on Bacillus subtilis vegetative cells were evaluated, and the related mechanisms were explored using quantitative proteomics. The bacteriostatic effect of HIU on B. subtilis was proportional to the ultrasound treatment time and power, and the number of cultivable B. subtilis cells was decreased by approximately one log (at 270 W for 15 min) or half log (at 90 W for 25 min or 360 W for 5 min). Scanning electron microscopy images and gel electrophoresis results showed that HIU caused the destruction of the cell structure and intracellular protein leakage. In addition, HIU treatment at 270 W for 15 min resulted in the greatest decrease (84.22%) in intracellular adenosine triphosphate (ATP) content. The quantitative proteomic analysis showed that B. subtilis resisted the stress of HIU treatment by regulating the key proteins in physiological activities related to membrane transport (ATP-binding cassette [ABC] transporter), signal transduction (the two-component system), and energy metabolism (the tricarboxylic acid [TCA] cycle). HIU-induced physical damage, stress, and metabolic disorders were the main causes of the bacteriostatic effects on B. subtilis. These findings provide a foundation for the subsequent optimization and potential applications of HIU inactivation of B. subtilis.

Modification of functional properties of perilla protein isolate by high-intensity ultrasonic treatment and the stability of o/w emulsion

This study investigated the effects of ultrasonic treatment on the structural characteristics and functional properties of perilla protein isolate (PPI). Besides, the performance of the emulsions stabilized by ultrasonic-treated PPI was analyzed, aiming at exploring the potential mechanism of ultrasonic technology to improve emulsion stability. Results showed that ultrasonic treatment reduced the particle size, induced the exposure of hydrophobic groups and changes in the secondary structure and tertiary conformation of PPI. However, the molecular weight and the crystalline regions were remained unchanged. Apart from this, ultrasonic treatment improved the solubility, water/oil holding capacity, foaming and emulsifying capacity of PPI. Furthermore, the emulsions prepared by ultrasonic-treated PPI possessed the highest stability, which might be due to the smaller droplets size and reduced droplets attraction by higher proportion of interfacial adsorbed protein. This findings will provide a new insight into the application of ultrasonic to improve the stability of PPI-stabilized emulsions.

Synthesis of biodiesel from waste cooking oil using a pulsed high-intensity ultrasound method

ABSTRACT Biodiesel is widely recognized as an environmentally friendly biofuel. The key to the industrial production of biodiesel is the cost of components, especially that of the feedstock. In this study, a green pulsed ultrasound-assisted synthesis method for biodiesel production is reported. The biodiesel was prepared from waste cooking oil by transesterification in the presence of KOH, a homogeneous catalyst, under pulsed high-intensity ultrasonic treatment. The effects of various experimental parameters such as catalyst type, catalyst dosage, molar ratio of oil to methanol, temperature, ultrasonic power, and ultrasonic pulse mode were investigated. The results demonstrated that KOH had high catalytic performance compared to a heterogeneous K3PO4 catalyst for the transesterification of waste cooking oil. The yield of biodiesel reached up to 91.5% in 120 min of reaction time under the most optimal reaction conditions. The reaction conditions included a catalyst dose of 3% KOH, oil to methanol molar ratio of 1:6, temperature of 55°C, ultrasonic intensity of 260 W, and pulse mode of 9 s on/1 s off. Kinetic studies were conducted to obtain the rate constants at various reaction temperatures. The kinetic rate constant was observed to increase with increasing temperatures, and the activation energy for the ultrasonic method was calculated to be 35.9 kJ/mol. Hence, this green method shows great potential for applications in biodiesel production.

Modification of functional, rheological and structural characteristics of myofibrillar proteins by high-intensity ultrasonic and papain treatment

The effects of sonication duration (15 and 30 min) and papain enzyme treatments on the conformational, physicochemical and functional traits of myofibrillar proteins (MPs) were addressed in this study. As the ultrasound duration was increased, the water holding capacity (WHC), solubility, foaming and emulsifying properties were improved as a result of the changes in the particles size distribution and zeta potential. Our results indicated that the turbulence force caused increments in the surface hydrophobicity and significant changes in the secondary structure. Also, the rheological properties were influenced by both cavitation force and papain treatment. According to the observations, the samples treated with sonication (for 15 and 30 min) and enzyme were more elastic with higher viscosity, as compared to the control. Compared with the control, enzymolyzed samples indicated better functionality. Moreover, papain treatment led to the increase of the hydrophobicity groups on the surface of proteins and the decrease of the amount of α-helix and β-sheet structures. It was noteworthy that the most changes in the structure and techno-functionality of myofibrillar proteins were observed for the sample affected by the simultaneous application of papain treatment and 15 min sonication. The highest values in the surface hydrophobicity, specific surface area, net charge, storage modulus, solubility and WHC belonged to this sample. However, enzyme-modified samples exposed to the longer sonication time (30 min) demonstrated reductions in solubility, WHC and surface hydrophobicity, as well as increases in the particle size distribution and protein turbidity.

Complexation of maltodextrin-based inulin and green tea polyphenols via different ultrasonic pretreatment

Ultrasound has been applied in food processing for various purpose, showing potential to advance the physical and chemical modification of natural compounds. In order to explore the effect of ultrasonic pretreatment on the complexation of inulin and tea polyphenols (TPP), different frequencies (25, 40, 80 kHz) and output power (40, 80, 120 W) were carried out. According to the comparison in particle size distribution and phenolic content of different inulin-TPP complexes, it was indicated that high-intensity ultrasonic (HIU) treatment (25 kHz, 40 W, 10 min) could accelerate the interaction of polysaccharides and polyphenols. Moreover, a series of spectral analysis including UV–Vis, FT-IR and NMR jointly evidenced the formation of hydrogen bond between saccharides and phenols. However, the primary structure of inulin and the polysaccharide skeleton were not altered by the combination. Referring to field emission scanning electron microscopy (FESEM), the morphology of ultrasound treated-complex presented a slight agglomeration in the form of bent sheets, compared to non-treated sample. The inulin-TPP complex also revealed better stability based on thermogravimetric analysis (TGA). Thus, it can be speculated from the identifications that proper ultrasonic treatment is promising to promote the complexation of some food components during processing.

Investigation on secondary deformation of ultrafine SiC particles reinforced LM25 metal matrix composites

In the past few years, aluminum alloys have been widely used in the field of automation, aeronautical, and heavy industries due to their light weight, high specific strength, high corrosion resistance, and excellent formability. However, the properties related to microstructure and dispersed medium are constant throughout the past research. The present research work is focused on the tensile tests of LM25 (reinforced with 10% SiC) metal matrix composites (MMCs) for its applications in aerospace industry through ultrasonic treatment (UST) of the liquid melt by varying the ultrasonic sonotrode (US) power and ultrasonic frequency. The high intensity UST is carried out on the LM25 MMCs reinforced with 10% SiC (proportion by weight) in a temperature range between 850 and 750 °C. The preheated mold at 250 °C temperature is used to cast the liquid melt after the UST. The castings are produced by varying time intervals and temperature ranges at distinct US power levels such as (a) 65% and (b) 75%. The casting process samples are prepared as per ASTM standard for tensile tests to reveal the effects of the UST. In the present investigation, the effects of UST on melt temperature, processing time, US power, and ultrasonic frequency (kHz) are studied in detail.

CFD Simulation Based Investigation of Cavitation Dynamics during High Intensity Ultrasonic Treatment of A356

Ultrasonic treatment (UST) and its effects, primarily cavitation and acoustic streaming, are useful for a high range of industrial applications, e.g., welding, filtering, cleaning or emulsification. In the metallurgy and foundry industry, UST can be used to modify a material’s microstructure by treating metal in the liquid or semi-solid state. Cavitation (formation, pulsating growth and implosion of tiny bubbles) and its shock waves, released during the implosion of the cavitation bubbles, are able to break forming structures and thus refine them. In this context, especially aluminium alloys are in the focus of the investigations. Aluminium alloys, e.g., A356, have a significantly wide range of industrial applications in automotive, aerospace and machine engineering, and UST is an effective and comparatively clean technology for its treatment. In recent years, the efforts for simulating the complex mechanisms of UST are increasing, and approaches for computing the complex cavitation dynamics below the radiator during high intensity ultrasonic treatment have come up. In this study, the capabilities of the established CFD simulation tool FLOW-3D to simulate the formation and dynamics of acoustic cavitation in aluminium A356 are investigated. The achieved results demonstrate the basic capability of the software to calculate the above-mentioned effects. Thus, the investigated software provides a solid basis for further development and integration of numerical models into an established software environment and could promote the integration of the simulation of UST in industry.