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Ultra-low ash coal is an essential clean energy and material. The preparation of ultra-low ash coal by flotation is facing challenges due to the inherent drawbacks. This work aims to enhance the flotation efficiency of ultra-low ash coal by ultrasonic pretreatment. Timed-release flotation experiments were conducted with ultrasonic pretreatment before and after collector addition. The results showed that the recovery and combustible recovery and flotation perfect index of clean coal increased after ultrasonic pretreatment. Additionally, the flotation circuits can reduce from three to two times to obtain clean coal with ash content around 5%. The particle size distribution of coal varied from unimodal to bimodal after ultrasonic pretreatment no matter whether collector was added, indicating that ultrasonic had both dispersing and flocculation effects. Scanning electron microscope (SEM) analysis illustrated that the surface of coal was cleaned due to the ultra-fine gangue particles coated on coal surface was dispersed, and the flocculation of low-ash coal particles was promoted after ultrasonic pretreatment. Consequently, the ultra-low ash coal with higher recovery and quality could be obtained with simplified circuits. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the impact of different ultrasonic power and time pretreatments on the structures and gel properties of the flaxseed gum and soybean protein isolate composite gel induced by TG enzyme. Methods: The structural characteristics, molecular conformation, and micro-network structures of the composite gel under varying ultrasonic conditions were analyzed using a texture analyzer, laser particle size meter, circular dichroism (CD), fluorescence spectrum, and scanning electron microscope (SEM). Results: The 50% power ultrasound pretreatment for 10 min could significantly improve the hardness, adhesiveness, chewiness, cohesiveness and water-holding property of the composite gel, and reduce its adhesiveness. After 50% power ultrasound pretreatment for 10 min, the α-helix and β-turn content of composite gel proteins decreased, and the content of β-folding and irregular curls increased, and the fluorescence intensity increased, which was conducive to the improvement of the functional properties of the gel. The microstructure of the composite gel became ordered from disorder, the network density increased, the pore diameter became smaller, and the pore wall was thickened. While after increasing the ultrasound power to 80%, the gel properties fluctuated only slightly and the microstructure was destroyed. Conclusion: 50% power ultrasound pretreatment for 10 min can significantly improve the gel properties and network structure of TG enzyme cross-linked flaxseed gum-soybean protein isolate composite. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: This study aimed to investigate the impact of different ultrasonic power and time pretreatments on the structures and gel properties of the flaxseed gum and soybean protein isolate composite gel induced by TG enzyme. Methods: The structural characteristics, molecular conformation, and micro-network structures of the composite gel under varying ultrasonic conditions were analyzed using a texture analyzer, laser particle size meter, circular dichroism (CD), fluorescence spectrum, and scanning electron microscope (SEM). Results: The 50% power ultrasound pretreatment for 10 min could significantly improve the hardness, adhesiveness, chewiness, cohesiveness and water-holding property of the composite gel, and reduce its adhesiveness. After 50% power ultrasound pretreatment for 10 min, the α-helix and β-turn content of composite gel proteins decreased, and the content of β-folding and irregular curls increased, and the fluorescence intensity increased, which was conducive to the improvement of the functional properties of the gel. The microstructure of the composite gel became ordered from disorder, the network density increased, the pore diameter became smaller, and the pore wall was thickened. While after increasing the ultrasound power to 80%, the gel properties fluctuated only slightly and the microstructure was destroyed. Conclusion: 50% power ultrasound pretreatment for 10 min can significantly improve the gel properties and network structure of TG enzyme cross-linked flaxseed gum-soybean protein isolate composite.

Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag (CGFS). The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and high collector dosage. In order to address these issues, CGFS sample taken from Shaanxi, China was used as the study object in this paper. A new process of size classification − fine grain ultrasonic pretreatment flotation (SC-FGUF) was proposed and its separation effect was compared with that of whole-grain flotation (WGF) as well as size classification − fine grain flotation (SC-FGF). The mechanism of its enhanced separation effect was revealed through flotation kinetic fitting, flotation flow foam layer stability, particle size composition, surface morphology, pore structure, and surface chemical property analysis. The results showed that compared with WGF, pre-classification could reduce the collector dosage by 84.09% and the combination of pre-classification and ultrasonic pretreatment could increase the combustible recovery by 17.29% and up to 93.46%. The SC-FGUF process allows the ineffective adsorption of coarse residual carbon to collector during flotation stage to be reduced by pre-classification, and the tightly embedded state of fine CGFS particles is disrupted and surface oxidizing functional group occupancy was reduced by ultrasonic pretreatment, thus carbon and ash is easier to be separated in the flotation process. In addition, some of the residual carbon particles were broken down to smaller sizes in the ultrasonic pretreatment, which led to an increase in the stability of flotation flow foam layer and a decrease in the probability of detachment of residual carbon particles from the bubbles. Therefore, SC-FGUF could increase the residual carbon recovery and reduce the flotation collector dosage, which is an innovative method for carbon-ash separation of CGFS with good application prospect.

This is an article in the field of mineral processing engineering. In order to explore the influence of ultrasonic pretreatment on the graphite flotation process of different stages, tests on the effects of different ultrasonic time on the roughing and cleaning of graphite were carried out. The research results show that when the ore contains muddy minerals, ultrasonic pretreatment can’t improve the effect of graphite roughing. Compared with the conventional flotation, the flotation effect of ultrasonic pretreatment for ultrasonic treatment cleaning stage 2, 4 and 6 is gradually improved with the increase of the ultrasonic pretreatment time. When the ultrasonic pretreatment time is 2.5 min, the graphite selection effect is the best. In the test of stage by stage ultrasonic cleaning, the effect of ultrasonic pretreatment for 0.5 min on 1～4 stages is not obvious, but it has a certain effect on 5 and 6 stages. When the ultrasonic pretreatment time is 2.5 min, the effect of each fine section is obvious. The order of the cleaning effect of ultrasonic pretreatment is ultrasonic treatment cleaning stage 5>stage 6>stage 4>stage 3>stage 2>stage 1. The research shows that the flotation effect of ultrasonic pretreatment in the rear section of graphite cleaning is better than that in the front one.

Due to stringent emission regulations, vehicle manufacturers must control diesel engine emissions. To address these regulations, this study introduces a novel approach for generating methane-enriched biogas through ultrasonic pretreatment and using it in dual fuel-mode diesel engines with a Hiptage biodiesel blend and biohydrogen. The study employs an RSM-based central composite design (CCD) approach to develop the L 54 orthogonal array for five factors and five levels of parameters. Additionally, seven different machine learning algorithms (DTR, RFR, ETR, GBR, LR, CBR, and XGBR) are used to develop a prognostic model based on the acquired experimental data. These models are used to estimate key performance indicators such as brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxides (NO x). Based on the evaluation of performance indicators, including R2 values (0.9021–0.97344), RMSE (0.00203–26.5539), MAE (0.00114–23.5944), and MAPE (0.0215–0.04438), the GBR model establishes the most accurate predictions. Furthermore, the RSM-based desirability approach is used to evaluate the trade-off between performance and emissions, thereby identifying the optimal engine operating condition. This condition includes an engine load of 83%, a compression ratio of 18:1, a fuel injection pressure (FIP) of 243 bar, a fuel injection timing (FIT) of 26° crank angle advance, and a biogas flow rate of 1.2 kg/h. Experimental investigation validates the RSM analysis findings, revealing an error margin of 7%. Overall, the introduction of methane-enriched biogas into a dual-fuel diesel engine improves combustion, resulting in increased engine performance and reduced emissions. [Display omitted] • Examine the effect of ultrasound on methane yield in the co-digestion of waste. • Study the behavior of a dual-fuel diesel engine with biodiesel, biogas, and biohydrogen. • Apply ML-RSM for prediction and optimization of engine characteristics. • The GB Regressor model demonstrated the most accurate predictions for key performance. • Experimental validation shows a maximum error of 7%. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT: Ultrasound-induced egg white fluidic gels (UEFG) were prepared through ultrasonic pretreatment followed by subsequent heating. The optimal preparation parameters for UEFG were: ultrasonic power density between 0.2 to 0.8 W/mL, ultrasonic treatment time surpassing 150 s, heating temperature within 70 to 76°C, and heating time under 16 min. The prepared UEFG is a milky white solution with a viscosity lower than that of fresh egg white, and displayed a particle size distribution primarily between 100 and 1,200 nm. Stability assessments conducted over 28 d at 4°C revealed that UEFG remained stable at pH 6-10, with exceptional stability from pH 8 to 10, while it is less stable in highly acidic (pH 2-4) or basic environments (pH 12). The UEFG also showed commendable stability in the presence of salt and sucrose solutions. We report a simple and novel method for preparing UEFG with good flowability after heating treatment. The UEFG has broad applications in the food industry, such as precooked egg white powder, high protein beverages, composite dairy products, etc.

This study aimed to investigate the effects of ultrasonic pre-treatment and low-temperature brining two-stage processing on the quality and flavor of chicken meat. The chicken breast meat was chosen as the research subject. Single-factor and orthogonal experiments were conducted to examine the influence of pre-cooking time, brining time, pre-cooking temperature, and brining temperature on the quality of low-temperature brined chicken meat. Shear force and sensory evaluation were used as target values to obtain optimized process parameters for low-temperature brining of chicken breast meat. Furthermore, using a high-temperature brining group (HT) and without-ultrasonic pretreatment group (WUP) as controls, measurements were taken for texture profile analysis (TPA), moisture content, color, lipid oxidation (thiobarbituric acid reactive substances, TBARS), myofibril fragmentation index (MFI), protein solubility, and volatile flavor substance levels in the ultrasonic pretreatment and low-temperature brine group (UP) based on the optimal process. The results showed that the optimal process for the UP group was a pre-cooking time of 10 minutes, a brining time of 3 hours, a pre-cooking temperature of 45 ℃, and a brining temperature of 69 ℃. Compared to the HT group, the UP group exhibited significantly reduced texture parameters (hardness, cohesiveness, springiness and resilience) (P

Cow dung contains high concentrations of organic matter, which can be used for methane production by anaerobic digestion. However, the refractory lignocellulose in cow dung often hiders methane production through anaerobic digestion. Ultrasonic pretreatment is an efficient method to enhance lignocellulose degradation and methane production, but the mechanism is not well studied. In this work, the influence of ultrasonic pretreatment on the anaerobic digestion of cow dung was studied. The impact of ultrasonic pretreatment on the dissolution rate of organic matter (including soluble chemical oxygen demand (sCOD) and carbohydrates) was investigated by modifying the ultrasonic power, length, and impulse time. The dissolution rate of sCOD increased by 96% with an ultrasonic power of 325 W by comparing the treatment without ultrasonic pretreatment. The optimized dissolution rates of sCOD (10,915 ± 112 mg/L) and carbohydrate (942 ± 12 mg/L) were achieved at 325 W ultrasonic power, 30 min ultrasonic time with impulse time of 2 s close and 1 s open. Under the above condition, after 26 days of anaerobic digestion, the cumulative methane production in the treatment with ultrasonic pretreatment was 851 mL, which was 1.36 times higher than that of the control without ultrasonic pretreatment (360 mL). In comparison with the treatment without ultrasonic pretreatment, the bacteria of Actinaobacteria phyla, which could degrade unselective organic substances, was significantly increased (by 44%) in the treatment with ultrasonic pretreatment. We conclude that ultrasonic pretreatment has a high potential to enhance methane production by anaerobic digestion of cow dung. [ABSTRACT FROM AUTHOR]

This study investigated the effect of ultrasonic (US) pretreatment at three different contact times (30, 45, and 60 min) with a power of 240 W and frequency of 40 kHz on the fate of antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and enteric pathogens during anaerobic digestion (AD) of sludge. By using real time-qPCR, three MGEs (int1, int2, and tnpA) and seven ARGs (sul1, sul2, tetW, tetA, tetO, ermF, and aac(6')-lb) were quantified that have serious human health impacts and represent the most widely used antibiotics (tetracycline, sulfonamide, macrolide, and aminoglycoside). Results indicated that US pretreatment under different contact times improved the removal of ARGs and MGEs. Compared to 30 and 45 min of US pretreatment, 60 min of US pretreatment resulted in a higher reduction of ARGs with total ARG reduction of 41.70 ± 1.13%. Furthermore, the relative abundance of ARGs and MGEs after US pretreatment was reduced more effectively in anaerobic reactors than in a control AD without US pretreatment. The total ARGs and MGEs removal efficiency of control AD was 44.07 ± 0.72% and 63.69 ± 1.43%, and if US pretreatment at different times were applied, the total ARGs and MGEs removal efficiency of the whole pretreatment AD process improved to 59.71 ± 2.76–68.54 ± 1.58% and 69.82 ± 2.15–76.84 ± 0.22%. The highest removal of total ARGs (68.54 ± 1.58%) and MGEs (76.84 ± 0.22%) was achieved after AD with US pretreatment at 45 min. However, US pretreatment and AD with US pretreatment were not effective in inactivation of enteric pathogens (total coliforms and E. coli), suggesting that posttreatment is needed prior to land application of sludge to reduce the level of enteric pathogens. There was no detection of the studied ARGs and MGEs in the enteric pathogens after US pretreatment in subsequent AD. According to this study, long contact times of US pretreatment can mitigate ARGs and MGEs in AD processes, offering valuable insight into improving environmental safety and sustainable waste management. Additionally, the study highlights the need to investigate posttreatment techniques for reducing enteric pathogens in AD effluent, a crucial consideration for agricultural use and environmental protection. [ABSTRACT FROM AUTHOR]

This is an essay in the field of mineral processing engineering. In China, fluorite mainly exists in the form of concomitant deposits. In the flotation process, other useful minerals are usually preferentially floated, and a large amount of fluorite exists in tailings. In this paper, the restrained fluorite and calcite in the floating tungsten tailings are taken as objects, and ultrasonic wave is added to change the floatability of the two, so as to explore a method to optimize the comprehensive utilization level of fluorite in the floating tungsten tailings. After ultrasonic pretreatment of pulp inhibited by sodium humate for 39 min, the flotation recovery of fluorite reached 84.74%, while the flotation recovery of calcite was only 11.47%, with a difference of 73.27%. Exploring the mechanism of ultrasonic pretreatment, it is found that the absorption intensity of sodium humate on the surface of fluorite is lower than that of calcite in the infrared spectrum detection. Ultrasonic pretreatment can desorb the sodium humate on the surface of fluorite, increase the absorption amount of sodium oleate on the surface, and make the zeta potential move forward; In addition, ultrasonic pretreatment mainly affects the content of sodium humate on the mineral surface, but does not affect the content of sodium oleate on the mineral surface. If only sodium humate exists in the slurry system during ultrasonic pretreatment, the sodium humate desorption speed is faster, which is more conducive to adsorbing the sodium oleate added subsequently.

In order to separate fluorite and calcite inhibited in tungsten tailings, the effect and mechanism of using ultrasonic external field activation to separate fluorite and calcite inhibited by sodium hexametaphosphate in a sodium oleate system were investigated. After pretreatment with an ultrasonic external field with a frequency of 40 kHz and sound intensity of 0.56, 0.50 and 0.40 W/cm2, the flotation recovery of calcite could be increased from 16.08% to about 80%, while the flotation recovery of fluorite was only increased from 7.5% to about 20%, with a difference of 60% between the two flotation recoveries, and the larger the sound intensity, the shorter the pretreatment time and the smaller the ultrasonic input energy. The contact angle of the calcite surface increased, sodium oleate adsorption increased, and zeta potential decreased after ultrasonic pretreatment, while the contact angle, sodium oleate adsorption, and zeta potential of fluorite surface were less changed. The results of heat of adsorption and XPS measurements showed that more heat was released from the interaction between sodium hexametaphosphate and fluorite, and the Ca2p peaks on the surface of fluorite were shifted to a greater extent after the interaction, which inferred that the adsorption of fluorite and sodium hexametaphosphate was relatively easier and stronger. It is presumed that the ultrasonic pretreatment can bring the mineral surface to different degrees of desorption according to the adsorption strength of sodium hexametaphosphate, exposing Ca2+ active sites for sodium oleate adsorption, while expanding the floatability difference between fluorite and calcite. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research investigates the effect of cooking methods prior to puffing on the quality of puffed germinated brown rice (GBR). The cooking methods include parboiling and steaming (PS), electric rice cooking (EC), ultrasonic pretreatment and parboiling and steaming (UPS), and ultrasonic pretreatment and electric rice cooking (UEC). The quality metrics are the physical, chemical, textural and microstructural properties of the puffed GBR. The hot salt puffing process was used to expand GBR. The results showed that EC and UEC significantly reduced the bulk density (0.30 g/mL compared with 0.36 g/mL for PS and 0.35 g/mL for UPS) and length/breadth ratio (2.55 compared with 3.21 for PS and 2.89 for UPS) of puffed GBR (p

Iron slag, a byproduct of the wet zinc refining process, contains a substantial amount of valuable metals such as iron and zinc, making it highly valuable for comprehensive recovery and reuse. However, before recovery, the iron slag requires dehydration pretreatment. The water content in iron slag remains relatively high and difficult to remove even after pressure filtration, leading to extended drying times, reduced drying efficiency, and increased energy consumption. This study explores a novel ultrasonic pretreatment process for iron slag. Using the response surface methodology, we investigated the effects of ultrasonic power, ultrasonic time, liquid-to-solid ratio, and their interactions on the water content, capillary suction time (CST), and filtration resistance of the slag. Regression equations were established to predict the relationships between the water content, CST, filtration resistance, and the various factors. The optimal process parameters were determined as an ultrasonic power of 60 W, ultrasonic time of 22 s, and a liquid-to-solid ratio of 4:1. Under these conditions, the dehydration performance of the iron slag was optimal. The measured values closely matched the predicted values, demonstrating the reliability of the model and the feasibility of the optimized process. Our study of the mechanism of ultrasonic action on iron slag found that under the influence of ultrasonic waves, the particle size of the slag significantly decreased, and the particle morphology changed. Compared to conventional drying, the drying rate of the iron slag after ultrasonic pretreatment was accelerated, and the drying time was reduced.

Abstract To investigate the protein–starch interactions in myofibrillar protein gels under the ultrasonic pretreatment, the effect of cassava starch content and ultrasonic pretreatment on gelling properties of myofibrillar protein from Lateolabrax japonicus was studied. For the myofibrillar protein–starch (MPS) solutions, the turbidity and elastic modulus increased when the starch content increased from 0% to 8%. For the MPS gels, the hardness, chewiness, gumminess, and water holding capacity increased with the starch content, whereas the cooking loss and whiteness decreased. Starch incorporation promoted the conversion of free water to immobilized water and bound water. The active sulfhydryl content decreased with the starch content, whereas the hydrogen bond and hydrophobic interaction content increased. Fine network structure containing pores at uniform size was formed in the MPS gel at an increased starch content, as shown in the scanning electron microscope images. When the ultrasonic pretreatment was introduced, the elastic modulus of MPS solutions and hardness, chewiness, gumminess, hydrophobic interaction, β‐sheet content, and microstructural compactness of the MPS gels increased, whereas the turbidity of the MPS solutions and cooking loss, whiteness, free water content, active sulfhydryl content, and random coil content of the MPS gels decreased. The MPS gel containing 8% of starch and subjected to ultrasonic pretreatment showed the highest hardness, chewiness, and gumminess of 220, 150, and 160 g, while the lowest cooking loss of 2.5% among all samples. Therefore, the gelling properties of myofibrillar protein from L. japonicus could be enhanced by the starch incorporation, ultrasonic pretreatment, and their synergistic effect.

Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface. The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment.

The aim of this study was to examine the impacts of microwave pretreatment (MWP) and ultrasonic pretreatment (USP) on drying time (DT), mass transfer kinetics, effective water diffusivity (Deff), rehydration rate, color index (L*, a*, b*), and the surface shrinkage of carrot slices when dried in a hot air dryer (70 °C). The microwave process was performed for 0, 15, 30, 45, and 60 s before drying of carrot slices. In addition, the ultrasound process was performed in an ultrasonic bath (40 kHz and 150 W) for 0, 5, 10, 15, and 20 min. The results confirmed that the MWP and USP decreased the DT (higher water loss) of carrot slices. Deff values for microwave-pretreated slices were considerably higher than those for nontreated carrot slices (p

It has been proven that the biocenosis of microalgae and bacteria improves the chemical properties of biomass for its use in anaerobic digestion. However, this anaerobic digestion can be limited by the strong, compact, and complex structure of granulated biomass. Therefore, there is a need to search for an effective method for microalgal–bacterial granular sludge pretreatment, which has not been undertaken in previous scientific works. In this study, ultrasonic pretreatment was used to determine the effects of sonication on anaerobic digestion efficiency. Anaerobic digestion was performed in batch respirometric reactors. It was found that the ultrasonic pretreatment enhanced the biomass solubility; thus, the organic matter concentration increased more than six times compared to the variant without pretreatment. The study showed a positive effect of sonication on the kinetics of the anaerobic process and methane production. The highest methane yield was found in the variants in which the ultrasonication lasted from 150 s to 200 s, and this yield was from 534 ± 16 mL CH4/g VS to 561 ± 17 mL CH4/g VS. The data analysis confirmed strong correlations between the pretreatment time, the amount of biogas and methane production, and the gross energy gain. The highest net energy output and net energy gain were obtained for 150 s of sonication, and, respectively, were 4.21 ± 0.17 Wh/g VS and 1.19 ± 0.18 Wh/g VS. [ABSTRACT FROM AUTHOR]

Our previous study has found that ultrasonic application on raw meat could improve the flavor of unsmoked bacon. For comprehensively evaluating the impacts of ultrasonic pretreatment (0, 250, 500 or 750 W, 20 kHz) on the overall quality of unsmoked bacon during processing, the following indicators were determined including salt and water content, pH, shear force, color, water distribution, texture and myofibril microstructure. Results manifest that ultrasonic pretreatment could significantly improve the salt and water content, pH and redness of unsmoked bacon. The water retention capacity was obviously enhanced by ultrasonic pretreatment proved by increased immobile water and decreased free water. Meanwhile, the shear force, the hardness and the chewiness were notably ameliorated after ultrasonic pretreatment, suggesting a better tenderness verified by the observation results of transmission electron microscope. However, no significant differences were found on the brightness, yellowness, springiness, cohesiveness and resilience of unsmoked bacon after ultrasonic pretreatment. Consequently, ultrasound could be considered as a potential tool for the overall-quality improvement of unsmoked bacon.

In this paper, the effects of different ultrasonic pretreatment processes on the far-infrared drying characteristics, quality indexes, and microstructure of licorice are evaluated. The results showed that ultrasonic pretreatment, combined with far-infrared drying, significantly reduced the drying time and moisture content of licorice compared with those of the control group. The highest total flavonoid content was obtained at an ultrasound power of 80 W. The total phenolic content (0.686 mg gallic acid equivalent/g) was higher than that in the control group, the increase was 19.4%, and its content was the highest at the sonication frequency of 20 kHz. The antioxidant capacity tended to increase and then decrease with the increase in sonication time, sonication power, and sonication frequency, and was the highest at 30 min of sonication. The soluble sugar content (31.490 mg glucose equivalent/g) was the highest at 30 kHz and 30 min. Observation of the microstructure revealed that the surface structure of the ultrasonic pretreated licorice slices changed significantly, forming more micropore channels, which facilitated the mass heat transfer during the drying process. In conclusion, ultrasonic pretreatment can significantly improve the quality of licorice tablets and significantly reduce the time required for subsequent drying. The combination of pretreatment parameters of 60 W ultrasonic power and 40 kHz ultrasonic frequency for 30 min was found to be an optimal combination of pretreatment parameters; therefore, this study may provide a technical reference for the industrialization of licorice drying. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine the content of phenolics, flavonoids and tannins, as well as the biological functions of propolis extracts from the stingless bee (Heterotrigona itama). The raw propolis was extracted via maceration with ultrasonic pretreatment in 100% water and 20% ethanol. The yield of ethanolic propolis extracts was about 1% higher than its aqueous counterpart. The colorimetric assays showed that the ethanolic propolis extract had about two times higher phenolics (17.043 mg GAE/g) and tannins (5.411 mg GAE/g), and four times higher flavonoids (0.83 mg QE/g). The higher phenolic content had enhanced the antiradical and antibacterial capacities of the ethanolic extract. The propolis extracts significantly exhibited higher antibacterial activity against gram-positive bacteria (Staphylococcus aureus) than gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). However, aqueous extract was found to have a higher anticancer property based on the viability of lung cancer cells. No cytotoxic effect was observed on normal lung cells as the cell viability was maintained >50%, even the concentration of propolis extracts were increased up to 800 µg/mL. Different chemical compositions of propolis extract would show different bioactivities depending upon the individual applications. The high content of phenolics suggests that the propolis extract could be a natural source of bioactive ingredients for the development of innovative and functional foods. [ABSTRACT FROM AUTHOR]

This study investigated the effects of ultrasonic pretreatment time, ultrasonic power, and ultrasonic frequency on the drying characteristics and physicochemical quality of Angelica sinensis, and the physicochemical quality content was selected as the evaluation index, the entropy weight‐coefficient of variation method was used to calculate the coupling weight and comprehensive score, and the weighted Technique for Order Preference by Similarity to Ideal Solution method was used to verify the evaluation model. The results showed that the drying rate of materials after ultrasonic treatment was increased by 22.48% to 93.26%, and the effective moisture diffusivity was in the range between 4.6831 × 10−9 and 7.0722 × 10−9 m2/s, and the drying activation energy was 31.90 kJ/mol. The energy consumption decreased by 5.75% to 25.88%. Compared with the samples without the ultrasonic pretreatment, the chlorogenic acid, ferulic acid, senkyunolide H, senkyunolide I, 3‐butenylphthalide, ligustilide, polysaccharides, total phenolic content, total flavonoid content, and antioxidant capacity of A. sinensis were increased after ultrasonic treatment, and the color, rehydration ratio, shrinkage ratio, and microstructure of dried products were improved significantly (p < 0.05). However, the quality of the dried products decreased after ultrasonic treatment for 40 min with an ultrasonic frequency of 60 kHz, and the internal tissue structure was destroyed. In summary, ultrasonic pretreatment at low frequency and high power can significantly increase the drying rate and improve the physicochemical quality of dried products. [ABSTRACT FROM AUTHOR]

The paper considers various biochar activation processes in bioprocesses, particularly in anaerobic digestion, to intensify the production of biogas and biofertilizer. Based on the literature research study, the applied aspects of biochar activation processes in the agricultural and bioenergy sectors were analyzed, with small-scale laboratory experiments to verify theoretical hypotheses. Ultrasonic pretreatment was performed with a power of 200 W and a frequency of 30 kHz. The biochar was also subjected to microscopy. After ultrasound treatment, changes in the structure of biochars of different genesis were detected, which is also consistent with changes in the ORP values of activated biochars. A comparative thermogravimetric analysis of biochar samples was carried out. [ABSTRACT FROM AUTHOR]

The ultrasound‐assisted hot air drying characteristics of Phyllanthus emblica was investigated in this paper. The effects of hot air temperature (60°C, 65°C, 70°C, and 75°C), ultrasonic pretreatment time (2, 4, 6, and 8 min), and ultrasonic power (200, 250, 300, and 350 W) on the drying rate, energy consumption, color change, and rehydration rate were evaluated and compared. It was found that the drying rate of Phyllanthus emblica increased with the hot air temperature. The drying time of Phyllanthus emblica with ultrasonic pretreatment was reduced by 10.0%, 25.0%, 21.4%, and 9.0% at 60°C, 65°C, 70°C, and 75°C, respectively. However, the hot air drying was not proportionally promoted by the increase of ultrasonic power or the extension of pretreatment time. Only an appropriate ultrasonic power or pretreatment time can not only improve the drying rate and rehydration rate, but also reduce the energy consumption and the total color change of the dried samples. A new drying model that considered the influences of hot air temperature, pretreatment time, and ultrasonic power was developed to fit the drying process. The results showed that the new model can accurately predict the hot air drying process of Phyllanthus emblica with and without ultrasonic pretreatment. Practical applications: Phyllanthus emblica contains a variety of nutrients and has various biological activities. However, the harvest period and shelf life of Phyllanthus emblica is very short, and the fruit is prone to mildrew and browning after picking, which in turn leads to the loss of its nutritional and economical value. Thus, for the long‐term preservation of Phyllanthus emblica, drying techniques are needed. In the food industry, hot air drying is widely used due to its low cost and easy operation; however, it also has some disadvantages such as long drying time, the oxygen‐rich drying environment. These shortcomings lead to a low quality of dried materials. Ultrasonic pretreatment before hot air drying can improve drying efficiency without adversely affecting the drying quality of the material. In recent years, ultrasonic pretreatment before food drying has become a research hotspot. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of ultrasonic pretreatment of flaxseeds for 0–10 min on the biosynthesis of tocopherols, tocotrienols, and carotenoids in flax sprouts. The results showed that tocopherol, tocotrienol and carotenoid contents were significantly increased (up to 130%) after 8-min ultrasonic pretreatment in LT001 flax sprouts as compared with control group. The similar increasing trend of tocopherols and tocotrienols was occurred in fiber flax sprouts after ultrasonic pretreatment, while carotenoid contents showed a decreasing trend. The expression levels of genes involved in the biosynthesis of tocopherols, tocotrienols, and carotenoids were analyzed and the results could partly explain the changing trends of tocopherols, tocotrienols and carotenoids in two different varieties of flax sprouts responding to ultrasonic pretreatments. Present study could be useful guidance for ultrasonic pretreatment to enhance micronutrients and biofortify nutritional values in flax sprouts.

Angiotensin-converting enzyme (ACE) plays an important role in blood pressure regulation, and inhibition of its activity is beneficial to maintain blood pressure balance. Food-derived ACE inhibitory peptides have attracted wide attention due to their safety and easy absorption. This study aimed to obtain a new peptide of high ACE inhibitory activity from tea residue protein. With the ACE inhibitory rate of ACE inhibitory peptides as the index, ultrasonic pre-treatment of tea residue protein was the best method through comparison of three ultrasonic methods. Response surface optimization was used to determine the optimal ultrasonic pretreatment parameters based on the single-factor tests. The enzymatic solution was separated and purified by ultrafiltration, and the stability of components with molecular weight less than 3 kDa was analyzed. The results showed that the optimum ultrasonic pretreatment conditions were ultrasonic power 300 W, ultrasonic temperature 45 °C, ultrasonic time 25 min. Under the optimal conditions, the ACE inhibitory activity was 64.8%, which was 10.7% higher than 54.1% in the control group (without ultrasonic). When the molecular weight cut-off was less than 3 kDa, the inhibition rate of ACE inhibitory peptide was 82.3%, which was 17.5% higher than that of the original hydrolysate. When the temperature rose from 30 to 90 oC, the inhibition rate of ACE inhibitory peptide decreased from 82.3% to 78.3%. The peptide showed stable ACE inhibition rate in pH and salt solution. The inhibition rate of ACE inhibitory peptide decreased from 82.3% to 62.3% after 8 h in simulated digestion environment.

Food waste (FW) generation has become one of the largest environmental concerns for human society. Thanks to its chemical features and its high biodegradability, FW can be used as starting platform to produce biocommodities. Lactic acid (LA) is one of those chemicals that is gaining the attention of industry and research for its important role in polylactic acids production. To exploit better the organic content of FW, several FW pretreatments have been proposed in the literature, though none of them were aimed at influencing LA fermentation. Thermal and ultrasonic pretreatment effects on solubilization rates and LA production yields have been investigated in this batch study. The highest solubilization rate was achieved with 30 minutes ultrasonic pretreated FW resulting in a 15% increment in soluble COD (sCOD). The highest LA yield was obtained after 90-minute thermal pretreatment at 80 and 100°C at a yield of 0.49 g LA•g COD−1. This study shows that ultrasonic pretreatment generally performed better than thermal pretreatment when considering the increase in sCOD but caused a reduction in LA concentrations and yields after fermentation with high production of ethanol. The opposite trend was recorded in the thermal pretreated incubations, in which LA was present for 50% of the sCOD with higher LA concentrations of 2.90 g COD•L−1. [ABSTRACT FROM AUTHOR]

In this paper, the effects of ultrasonic pretreatment on the drying kinetics, bioactive components (polysaccharides, total phenols, total flavonoids and antioxidant), qualitative characteristics (color index, lobetyolin and syringin) and microstructure of Codonopsis pilosula during radio frequency vacuum drying (RFVD) were studied. The average drying rate curve showed that the whole drying process could be divided into three stages: accelerating period, constant drying rate period and falling drying rate period. Deff values ranged from 6.61425 to 9.46745 × 10−8. Analysis of the drying rate constants revealed that different conditions of pretreatment were effective in increasing the drying rate. Ultrasonic pretreatment has a positive effect on the retention of polysaccharide content; low frequency favors retention of total phenols, flavonoids and syringin; and with the increase in ultrasonic time and ultrasonic power, the antioxidant capacity was higher than that without ultrasonic treatment. Ultrasonic pretreatment significantly improved color and microstructure. In summary, the pretreatment condition of ultrasonic frequency 20 kHz and power 60 W for 30 min is suitable, which provides a certain reference for the application of ultrasonic pretreatment technology in RFVD of Codonopsis pilosula slices. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the effect of ultrasonic pretreatment on the transesterification of lard with glycerol monolaurate (GML) using Lipozyme TL IM to synthesize diacylglycerol (DAG), and the physicochemical properties of lard, GML, ultrasonic-treated diacylglycerol (named U-DAG), purified ultrasonic-treated diacylglycerol obtained by molecular distillation (named P-U-DAG), and without ultrasonic-treated diacylglycerol (named N-U-DAG) were analyzed. The optimized ultrasonic pretreatment conditions were: lard to GML mole ratio 3:1, enzyme dosage 6 %, ultrasonic temperature 80 °C, time 9 min, power 315 W. After ultrasonic pretreatment, the mixtures reacted for 4 h in a water bath at 60 °C, the content of DAG reached 40.59 %. No significant variations were observed between U-DAG and N-U-DAG in fatty acids compositions and iodine value, while P-U-DAG had lower unsaturated fatty acids than U-DAG. Differential scanning calorimetry analysis showed that the melting and crystallization properties of DAGs prepared by ultrasonic pretreatment significantly differed from lard. FTIR spectra noted transesterification reaction from lard and GML with and without ultrasonic pretreatment would not change the structure of lard. However, thermogravimetric analysis proved that N-U-DAG, U-DAG, and P-U-DAG had lower oxidation stability than lard. The higher the content of DAG, the faster the oxidation speed.

In order to separate fluorite and calcite inhibited in tungsten tailings, the effect and mechanism of using ultrasonic external field activation to separate fluorite and calcite inhibited by sodium hexametaphosphate in a sodium oleate system were investigated. After pretreatment with an ultrasonic external field with a frequency of 40 kHz and sound intensity of 0.56, 0.50 and 0.40 W/cm2, the flotation recovery of calcite could be increased from 16.08% to about 80%, while the flotation recovery of fluorite was only increased from 7.5% to about 20%, with a difference of 60% between the two flotation recoveries, and the larger the sound intensity, the shorter the pretreatment time and the smaller the ultrasonic input energy. The contact angle of the calcite surface increased, sodium oleate adsorption increased, and zeta potential decreased after ultrasonic pretreatment, while the contact angle, sodium oleate adsorption, and zeta potential of fluorite surface were less changed. The results of heat of adsorption and XPS measurements showed that more heat was released from the interaction between sodium hexametaphosphate and fluorite, and the Ca2p peaks on the surface of fluorite were shifted to a greater extent after the interaction, which inferred that the adsorption of fluorite and sodium hexametaphosphate was relatively easier and stronger. It is presumed that the ultrasonic pretreatment can bring the mineral surface to different degrees of desorption according to the adsorption strength of sodium hexametaphosphate, exposing Ca2+ active sites for sodium oleate adsorption, while expanding the floatability difference between fluorite and calcite.

Hydrochar is a promising adsorbent for the removal of heavy metals, but the low surface area limits the removal efficiency and practical application. Therefore, improving the surface area of the hydrochar is critical to increasing the adsorbent removal. In this study, the ultrasonic pretreatment of biomass (10‒30 min) and CaO addition (5‒15%) were adopted to assist the hydrothermal carbonization (HTC) of granatum at 220°C. The properties of the modified hydrochar and the removal efficiency for Pb2+ in the aqueous solution were investigated. Results showed that the porosity of hydrochar was obviously improved by the CaO addition, and the largest surface area of 21.86 m2·g−1 was obtained during HTC with 15% CaO addition. Meanwhile, the functional groups of ‒OH and C═O increased and the pH of the hydrochar increased from weakly acidic to alkaline by CaO addition. The Pb2+ adsorption capacity of raw hydrochar was 10.03 mg·g−1, and it was enhanced by 80.76‒171.58% after CaO addition. The ultrasonic pretreatment of granatum had little effect on the characteristics of hydrochar except to improve the surface area from 8.27 to 9.06 m2·g−1, resulting in a 1.30‒6.78% increase in the adsorption capacity.

Three drying methods, including far infrared drying, infrared convection drying, and ultrasonic pretreatment assisted far infrared drying, were adopted in the drying of ginger slices. The effects of main parameters (ultrasonic pretreatment power and time, far infrared temperature and power, sample thickness, infrared convection temperature) on the drying kinetics, energy consumption, and color change were investigated and discussed in detail. The results showed that the drying process of ginger slices was controlled by falling rate period. For far infrared drying, the drying rate increased with the increase of infrared temperature and decrease of sample thickness, while the infrared power had no obvious effect on the drying process. The infrared convection drying showed the fastest drying rate and the smallest color change, however, the energy consumption was the highest. For ultrasonic pretreatment assisted far infrared drying, an appropriate ultrasonic pretreatment time and power would promote the far infrared drying process and the energy consumption was only slightly increased. However, the color change was relatively large. The ultrasound technology showed its greatest potential to enhance the drying rate at the early stage of drying and increasing ultrasonic power was more effective than prolonging the pretreatment time in promoting far infrared drying.

This study evaluated the effect of ultrasonic pretreatment of flaxseeds for 0–10 min on the biosynthesis of tocopherols, tocotrienols, and carotenoids in flax sprouts. The results showed that tocopherol, tocotrienol and carotenoid contents were significantly increased (up to 130%) after 8-min ultrasonic pretreatment in LT001 flax sprouts as compared with control group. The similar increasing trend of tocopherols and tocotrienols was occurred in fiber flax sprouts after ultrasonic pretreatment, while carotenoid contents showed a decreasing trend. The expression levels of genes involved in the biosynthesis of tocopherols, tocotrienols, and carotenoids were analyzed and the results could partly explain the changing trends of tocopherols, tocotrienols and carotenoids in two different varieties of flax sprouts responding to ultrasonic pretreatments. Present study could be useful guidance for ultrasonic pretreatment to enhance micronutrients and biofortify nutritional values in flax sprouts. [ABSTRACT FROM AUTHOR]

The impact of ultrasonic pretreatment on water loss, water mobility, microstructure, texture, volatile compounds, nutritional, and functional composition of French fries, and their intrinsic relationship, compared to commonly used blanching pretreatment, was investigated. Application of ultrasonic resulted in enhancement of water loss (27–56%), which also reflected in the NMR results. Ultrasonic (17–20%) and blanching (7–12%) pretreatments decreased the oil content in the French fries compared to untreated samples. Ultrasonic (250 W, 10 min) preserved nutritional and functional composition and antioxidant activity in comparison with blanching treatments while increasing the power (500 W, 10 min) triggered the loss of these nutritional ingredients. The hardness of ultrasonic pretreated French fries increased, probably related to the crispness of French fries. Volatile compounds were enhanced with ultrasonic and both pretreatments showed changes in the microstructure. In conclusion, non-thermal ultrasonic pretreatment can be an alternative to maintain nutritional quality and produce French fries with low oil content and good sensory quality. [ABSTRACT FROM AUTHOR]

The efficient filtration of low-rank coal (LRC) slurry was significantly beneficial to the production process of wet coal beneficiation. However, relatively few studies have been reported on novel pretreatment methods for the efficient filtration of LRC slurry. In this paper, the mechanism of ultrasonic pretreatment to promote flocculation and filtration of slurry was studied. The hydrophobic variation of the slurry surface was measured by contact angle and XPS. The flocculation properties of slurry were characterized using zeta potential and FBRM. The effects of filter cake porosity and ultrasonic pretreatment on slurry filtration resistance were calculated by L-F NMR and Darcy's theory. The results showed that the ultrasonic pretreatment promoted the flocculation and filtration performance of LRC slurry, increased the filtration rate, and decreased the cake moisture content. Meanwhile, the contact angle of LRC increased significantly from 50.1° to 67.8° after ultrasonic pretreatment, and the surface tension of the filtrate decreased from 69.5 to 53.31 mN/m. Ultrasonic pretreatment reduced the absolute value of the zeta potential of coal slurry from 24.8 to 21.0 mV, and the average chord length of flocs increased from 5–10 μm to 25–30 μm, thus weakening the electrostatic repulsion between coals to promote floc formation. In addition, the pore tests and filtration theory calculations showed that the ultrasonic pretreatment significantly improved the permeability of the filter cake to water and reduced the resistance to slurry during filtration. In particular, the mesopore porosity increased by 9.18%, and the permeability increased by 2.937 × 108 m2. Therefore, this contributed to the reduction of slurry filtration resistance. This research provides an efficient method for promoting the efficient filtration of slurry. [ABSTRACT FROM AUTHOR]

In this study, the effects of thermal hysteresis activity, ice recrystallization inhibition, amino acid composition and surface hydrophobicity of different ultrasonic pretreatments on gluten antifreeze polypeptide was studied. The results of the thermal hysteresis activity showed that the collaborative (flat-panel combined probe) ultrasonic working mode was superior to the single-frequence ultrasound mode. In the optimal working mode (15 min, 100 W/L), the results of polarized light microscope and gel chromatography column showed that ultrasonic pretreatment could effectively inhibit the growth of ice crystals, reduced the size of ice crystals, and to a certain extent, transfer the molecular weight distribution of peptides to small molecular peptides. The molecular weight was mainly concentrated at about 200–1000 u. The contents of Valine, Methionine, Leucine, Proline and Glutamic acid residues in the gluten antifreeze polypeptide pretreated by ultrasonic wave were relatively high and more hydrophobic groups were exposed. The secondary structure results showed that the molecular conformation of the polypeptide was mainly α-helix and β-sheet conformations. This paper systematically revealed the intrinsic correlation mechanism between the changes of key domains of substrate proteins and the antifreeze activity of enzymatic hydrolysis products assisted by ultrasoud, providing a theoretical basis for the preparation of antifreeze polypeptide. • Ultrasonic pretreatment improved the thermal hysteresis activity of gluten antifreeze peptides. • Ultrasonic pretreatment exposed more hydrophobic groups of gluten antifreeze peptides. • The molecular conformation of gluten antifreeze polypeptide was mainly α-helix and β-sheet conformations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biogas yield of cattle manure and green algae was 176 mL/g VS. • RSM and ANN models have been used to study the anaerobic digestion of biochar dose. • Effects of ozonation and ultrasonic pretreatment on culture have been studied. • After adding 150 mg BC to the environment, the biogas yield was 717 mL/g VS. • According to performance indicators, ANN performed relatively better than RSM. This study aimed to optimise and model biogas yields using artificial neural networks (ANN) and response surface method (RSM) of biogas yields after adding different doses of ozonation and ultrasonic pretreated biochar (BC) doses to the co-digestion of cattle manure and green algae substrates, with and without S.Parkle culture in the environment. The results of the RSM-D optimal design indicated that, in the absence of S.Parkle culture in the environment, the optimum ultrasonic pretreated biochar (UPBC) doses were 29.23 mg (for 100 mL digestion volume) and the corresponding optimum biogas yield was 340.50 mL/g volatile solids (VS). In the case of S.Parkle culture in the environment, the optimum ozonation pretreated biochar (OPBC) dose was 55.96 mg and the corresponding optimum biogas yield was 660.40 mL/g VS. ANN and RSM model performances were analyzed using different statistical indicators and ANN result obtain showed absolute percentage error (MAPE) value of 2.1, mean average error (MAE) value of 0.347, standard error of prediction (SEP) value of 0.590, and root-mean-square error (RMSE) value of 0.55, mean squared error (MSE) value of 0.31, the sum of the squared estimate of errors (SSE) value of 4.9 and coefficient of determination (R2) value of 0.9999, and RSM result reveals MAPE of 0.0030, MAE value of 30.693, SEP value of 45.57, RMSE of 42.63, MSE value of 1817.6, SSE value of 29,081 and R2 of 0.9612. The model performance indicators and estimation results indicate that the ANN performs relatively better than the RSM in modelling the process. It is recommended that the optimum OPBC and UPBC doses be tested and verified on different substrates. [ABSTRACT FROM AUTHOR]

Ultrasound-induced egg white fluidic gels (UEFG) were prepared through ultrasonic pretreatment followed by subsequent heating. The optimal preparation parameters for UEFG were: ultrasonic power density between 0.2 to 0.8 W/mL, ultrasonic treatment time surpassing 150 s, heating temperature within 70 to 76°C, and heating time under 16 min. The prepared UEFG is a milky white solution with a viscosity lower than that of fresh egg white, and displayed a particle size distribution primarily between 100 and 1,200 nm. Stability assessments conducted over 28 d at 4°C revealed that UEFG remained stable at pH 6-10, with exceptional stability from pH 8 to 10, while it is less stable in highly acidic (pH 2-4) or basic environments (pH 12). The UEFG also showed commendable stability in the presence of salt and sucrose solutions. We report a simple and novel method for preparing UEFG with good flowability after heating treatment. The UEFG has broad applications in the food industry, such as precooked egg white powder, high protein beverages, composite dairy products, etc. [ABSTRACT FROM AUTHOR]

The enhancement of ultrasonic pretreatment on the flocculation filtration of coal slurry water has been reported. The structural characteristics of flocs are critical parameters in the flocculation and filtration process. In this paper, the effect of ultrasonic pretreatment on the flocs' characteristics during flocculation and filtration was investigated. The flocs size, number, strength, and fractal dimension in the microstate were characterized through a polarized light microscope, PVM, and FBRM. The changes in flocs characteristics on the filter cake's pore structure and moisture distribution were analyzed using L-F NMR. The results showed that the optimal condition was an ultrasonic frequency of 30 KHz, ultrasonic time of 3 min, and the dosage of cationic polyacrylamide (CPAM) with ionicity of 60 at 50 g/t, under which the filtration rate was 597.42 mL·(m2s)−1 and the moisture content of the filter cake was 27.03 %. Ultrasonic pretreatment increased the flocs' size, with a decrease in the proportion of small flocs and an increase in the proportion of medium and large flocs, mainly medium flocs. The increase in the fractal dimension and strength of the flocs structure made the filter cake deformed less under pressure, formed a porous skeleton structure, and increased the total porosity of the filter cake, with the most significant variation in mesopores. Moreover, ultrasonic pretreatment could decrease the proportion of adsorbed and bound water while increasing the proportion of free water and effectively reducing the filter cake's moisture content. This study revealed the essential relationship between floc characteristics and flocculation filtration efficiency, filter cake pore structure, and moisture distribution and provided a new perspective for exploring the application mechanism of ultrasonic technology in enhancing flocculation filtration performance. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The interactive effect of the sonic power, time, dosage, and SOM on the FW substrate was studied. • Maximum solubilization of 21.753% was achieved in the USCSP at optimal condition. • A maximum biomethane yield of 85 mL/gCOD was obtained in USCSP. • Pretreatment of FW effectively improves the biomethane yield by 3.5 fold. Food waste (FW) can be a suitable substrate for generating biofuels such as biomethane. The complex polymer structure in FW reduces its biodegradability during anaerobic digestion (AD). Therefore, pretreatment of FW prior to AD helps to disintegrate the complex structure and thus makes the organic matter readily available to AD's hydrolytic enzymes. The present work focused on the optimization of process parameters to improve the solubilization of organic matter (SOM) and thereby enhance the biomethane yield from food waste (FW) using Ultrasonic coupled non-ionic surfactant (Alkyl poly glycoside, APG) pretreatment (USCSP). Initially, the effect of ultrasonic pretreatment (USP) was optimized using response surface methodology (central composite design), and then, under optimized USP conditions, USCSP was performed and optimized. Optimal results showed that SOM of 16.4 % was achieved at 159.0 W, 15.0 mins under USP. Moreover, USCSP reduces the pretreatment time to 6.6 mins and increases the SOM by 21.7 %. In addition, a 46.8 % reduction in specific energy input (EI Sp) can be achieved in USCSP compared to USP. This increment in SOM and decrease in EI Sp were due to the synergetic effect of APG over USP. The high R2 values of 0.988 and 0.984 for USP and USCSP revealed that the models applied effectively for the SOM of FW. The maximum biomethane generation was found in USCSP of 85 mL/gCOD, higher than that of USP and untreated samples. [ABSTRACT FROM AUTHOR]

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Background. A research was conducted on the ultrasonic pretreatment of chicken droppings for biogas production. The hydrolysis step in anaerobic digestion is rate-limiting and time-consuming due to the presence of complex molecules in the organic wastes. Pretreatment encourages faster digestion and yields improvement by making the organic waste ready for microbial attack. Material and methods. To achieve the optimum sonication time and slurry ratio for maximum biogas production, Response Surface Methodology (RSM) was used in this study. 13 experimental runs were developed according to Central Composite Design with different setup conditions and five replicates at center points to observe the Response, i.e., volumes of biogas produced. This was achieved with the aid of a software package (Design Expert 12.0.1.0). A quadratic model was developed for the responses and a 3D response surface plot was obtained to analyze the effect of the variables and their interactions to determine their optimum levels. Results. The numerical optimization and point prediction result gave a sonication time of 18.6 minutes and a slurry ratio of 2.0 (i.e., 2.0 : 1.0). Under this condition, the predicted maximum volume of biogas production is 24.514 ml in 12 days. This prediction was tested and validated, and the volume of biogas produced under the same conditions was 22.282 ml. This confirmed the adequacy of the predicted model as only a 10.02% error was recorded. Conclusions. Henceforth, the optimum sonication time and slurry ratio were achieved for maximum biogas production from chicken droppings. [ABSTRACT FROM AUTHOR]

It has been proven that the biocenosis of microalgae and bacteria improves the chemical properties of biomass for its use in anaerobic digestion. However, this anaerobic digestion can be limited by the strong, compact, and complex structure of granulated biomass. Therefore, there is a need to search for an effective method for microalgal–bacterial granular sludge pretreatment, which has not been undertaken in previous scientific works. In this study, ultrasonic pretreatment was used to determine the effects of sonication on anaerobic digestion efficiency. Anaerobic digestion was performed in batch respirometric reactors. It was found that the ultrasonic pretreatment enhanced the biomass solubility; thus, the organic matter concentration increased more than six times compared to the variant without pretreatment. The study showed a positive effect of sonication on the kinetics of the anaerobic process and methane production. The highest methane yield was found in the variants in which the ultrasonication lasted from 150 s to 200 s, and this yield was from 534 ± 16 mL CH4/g VS to 561 ± 17 mL CH4/g VS. The data analysis confirmed strong correlations between the pretreatment time, the amount of biogas and methane production, and the gross energy gain. The highest net energy output and net energy gain were obtained for 150 s of sonication, and, respectively, were 4.21 ± 0.17 Wh/g VS and 1.19 ± 0.18 Wh/g VS.

The aim of the present study was to determine the content of phenolics, flavonoids and tannins, as well as the biological functions of propolis extracts from the stingless bee (Heterotrigona itama). The raw propolis was extracted via maceration with ultrasonic pretreatment in 100% water and 20% ethanol. The yield of ethanolic propolis extracts was about 1% higher than its aqueous counterpart. The colorimetric assays showed that the ethanolic propolis extract had about two times higher phenolics (17.043 mg GAE/g) and tannins (5.411 mg GAE/g), and four times higher flavonoids (0.83 mg QE/g). The higher phenolic content had enhanced the antiradical and antibacterial capacities of the ethanolic extract. The propolis extracts significantly exhibited higher antibacterial activity against gram-positive bacteria (Staphylococcus aureus) than gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). However, aqueous extract was found to have a higher anticancer property based on the viability of lung cancer cells. No cytotoxic effect was observed on normal lung cells as the cell viability was maintained >50%, even the concentration of propolis extracts were increased up to 800 µg/mL. Different chemical compositions of propolis extract would show different bioactivities depending upon the individual applications. The high content of phenolics suggests that the propolis extract could be a natural source of bioactive ingredients for the development of innovative and functional foods.

In this paper, the effects of different ultrasonic pretreatment processes on the far-infrared drying characteristics, quality indexes, and microstructure of licorice are evaluated. The results showed that ultrasonic pretreatment, combined with far-infrared drying, significantly reduced the drying time and moisture content of licorice compared with those of the control group. The highest total flavonoid content was obtained at an ultrasound power of 80 W. The total phenolic content (0.686 mg gallic acid equivalent/g) was higher than that in the control group, the increase was 19.4%, and its content was the highest at the sonication frequency of 20 kHz. The antioxidant capacity tended to increase and then decrease with the increase in sonication time, sonication power, and sonication frequency, and was the highest at 30 min of sonication. The soluble sugar content (31.490 mg glucose equivalent/g) was the highest at 30 kHz and 30 min. Observation of the microstructure revealed that the surface structure of the ultrasonic pretreated licorice slices changed significantly, forming more micropore channels, which facilitated the mass heat transfer during the drying process. In conclusion, ultrasonic pretreatment can significantly improve the quality of licorice tablets and significantly reduce the time required for subsequent drying. The combination of pretreatment parameters of 60 W ultrasonic power and 40 kHz ultrasonic frequency for 30 min was found to be an optimal combination of pretreatment parameters; therefore, this study may provide a technical reference for the industrialization of licorice drying.

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)