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Fresh meat has a limited shelf life and is prone to spoilage. Drying serves as a common method for food preservation. Non-thermal techniques such as ultrasound treatment (US) can positively affect the drying processes and alter the final product. The study aimed to evaluate the impact of US pre-treatment on the hot air (HA) and freeze-drying (FD) of chicken breast meat and the quality of the dried products. US pre-treatment had a varied impact depending on the drying method used. The contact US method extended the HA drying time (about 50%) but improved water removal during FD (about 30%) compared to the untreated samples. Both methods resulted in low water content (<8.3%) and low water activity (<0.44). While rehydration properties (RR) and hygroscopicity (H) were not significantly affected by US pre-treatment in HA drying (about 1.35% and about 1.1, respectively), FD noticed differences due to shrinkage and porosity variations (RR: 2.4–3.2%, H: 1.19–1.25). The HA-dried samples exhibited notably greater tissue shrinkage and a darker surface color than the FD meat. Ultrasonic processing holds substantial potential in creating dried meat products with tailored characteristics. Hence, meticulous consideration of processing methods and parameters is of utmost importance. [ABSTRACT FROM AUTHOR]

Fresh meat has a limited shelf life and is prone to spoilage. Drying serves as a common method for food preservation. Non-thermal techniques such as ultrasound treatment (US) can positively affect the drying processes and alter the final product. The study aimed to evaluate the impact of US pre-treatment on the hot air (HA) and freeze-drying (FD) of chicken breast meat and the quality of the dried products. US pre-treatment had a varied impact depending on the drying method used. The contact US method extended the HA drying time (about 50%) but improved water removal during FD (about 30%) compared to the untreated samples. Both methods resulted in low water content (

The study of organic molecules in meteorite and return samples allows for the understanding of the chemistry that undergoes in our Solar System. The present work aims at studying ultrasound assisted extraction technique as effective extraction method for these molecules in extraterrestrial samples and analogs. Optimal conditions were selected from the investigation of ultrasonic frequency, irradiation duration and solvent effects on amino acids, nucleobases and dipeptides extraction yields from a model clay-rich mineral matrix. Optimal ultrasound-assisted extraction parameters were frequency of 20 kHz within 20 min irradiation time and methanol/water solvent ratio of 1. We then validated this protocol on Mukundpura and Tarda meteorite fragments and compared it to the reference extraction protocol used in astrobiology and based on 24 h extraction time at 100 °C in water We obtained similar quantitative results without any racemization with both methodologies.

Exploitation of polar resources and scientific research require efficient ice drilling technology. Thermal drilling is a common method for polar ice drilling, and is similar to the principle of ultrasonic assisted drilling; both are drilled by melting ice layers, but improving energy utilization has always been a challenge. In order to improve energy utilization and drilling efficiency, this paper proposes a method for ice drilling with ultrasonic frequency vibration. The mechanism of ultrasonic vibration drilling into ice was analyzed, the solid theoretical foundation for the application of ice melting efficiency under ultrasonic frequency vibration was determined and a series of indoor experiments were conducted. According to experimental data obtained, two conclusions were provided. First, different frequencies have distinct influence on power density, drilling speed and melting rate, and the optimum range excitation frequency for ultrasonic ice drilling is at least 30~32 kHz, under which the ice melting efficiency and drilling speed reached the peak value. Second, ultrasonic assisted drilling was verified to have the ability of improving the efficiency of ice breaking by comparing to thermal drilling under the same power density under 30 kHz. As an environmentally friendly and efficient drilling method, ultrasonic assisted ice drilling has great application prospects in the field of polar exploration. By using Ultrasonic assisted drilling, we demonstrate a strategy for a faster and more efficient drilling method, which is important for humankind.

The application of ultrasonic assisted extraction to extract seed oils for multifaceted food applications is discussed in this study. Seed oils, which are notable sources of health‐promoting characteristics and reservoirs of fatty acids and phytochemicals, are being targeted for effective extraction. Conventional techniques of oil extraction, including mechanical pressing and rendering, have limitations such as low extraction rate, high energy consumption, and low yield. In this context, ultrasonic assisted extraction is green and fast oil extraction technology with a greater extraction rate and low energy consumption. Ultrasound assisted oil extraction is mostly used technique since it is environmentally friendly and can be easily integrated with other extraction processes. Ultrasound‐aided extraction uses less solvent than traditional extraction methods. In this process, cavitation bubbles form in the solvent and burst, causing changes in pressure and temperature that expedite the mass transfer of solutes into solvent. The miscella, including the solvent and oil mixture, is then desolventized using evaporators, followed by steam‐stripping to remove the extracted oil. The current review paper discusses the characteristics of ultrasonic extractions for efficient oil extraction (extraction duration, ultrasound frequency, temperature, solvent employed, and ultrasound type). The conventional and non‐conventional oil extraction methods from sources have been examined in this article, in addition to the ultrasound assisted extraction. Along with traditional and advanced oil extraction techniques, the use of ultrasonication in conjunction with other cutting‐edge techniques is covered in this article. Practical applications: Ultrasound assisted oil extraction extracts oil from vegetables, oilseeds, and nuts by using a suitable carrier. The key parameters influencing ultrasound aided extraction of oilseed include particle shape and size, moisture content of seed, amount of solvent, and extraction time/temperature. The ultimate extraction yield is influenced by the extraction time, operating frequency, operational temperature, solvent type, and proportion, and ultrasonicator design. This technique consumes less energy and requires less maintenance. It is quite efficient and reliable. On this basis, ultrasound aided extraction may be utilized commercially to increase oil extraction rate from oil seeds. [ABSTRACT FROM AUTHOR]

In sonochemistry, acoustic bubbles are a population of microreactors where hydrogen and oxidants are produced. Optimizing the effectiveness of sonochemical processes and, as a result, designing ultrasonic reactors for diverse uses, including hydrogen generation, requires determining the number density of acoustic microreactors. The number density of micro-bubbles during water sonolysis was determined in this study using a novel semi-empirical method developed (for the first time) using hydrogen sono-production. The technique is based on relying on the overall molar production rate of hydrogen (i.e. resulted from the sonicated solution) to the amount of hydrogen produced per a single collapsing bubble, either from its internal gas phase reaction (pyrolysis) or from both the bubble inside and its liquid shell (via H•+H•→H 2). The retrieved number density of bubbles varied between ∼108 to ∼1013 L−1 s−1 (depending on empirical conditions), showing an excellent order with that reported in the literature. As the frequency increased, the number of active bubbles increased, regardless of whether the number density is calculated through the amount of hydrogen formed inside the bubble or the total single-bubble yield (gas phase + liquid shell). However, a reduced number density was obtained as it was calculated via the total single-bubble yield, where this decrease goes up with the rise of ultrasound frequency (from 210 to 724 kHz) and the decrease of the liquid temperature. It has been deduced that hydrogen is mainly formed at the bubble's liquid shell (via H•+H•→H 2), particularly at higher frequency and cold liquid. [Display omitted] • Hydrogen sonoproduction was quantified and used for determining the bubbles number. • A full cavitation-based model was applied for predicting the H 2 's single bubble yield. • The H 2 -based technique relies the overall and the single bubble yield during sonication. • The bubbles' number density was ∼108 to ∼1013 L−1 s−1, depending on circumstances. • The number density increased with frequency increase and liquid temperature decrease. [ABSTRACT FROM AUTHOR]

The effects of power ultrasound (US) pretreatment on the preparation of soy protein isolate hydrolysate (SPIH) prepared at the same degree of hydrolysis (DH) of 12 % were measured. Cylindrical power ultrasound was modified into mono-frequency (20, 28, 35, 40, 50 kHz) ultrasonic cup coupled with an agitator to make it applicable for high density SPI (soy protein isolate) solutions (14 %, w/v). A comparative study of the alterations of the hydrolysates molecular weight, hydrophobics, antioxidants and functional properties change as well as their relation were explored. The results showed that under the same DH, ultrasound pretreatment decelerated the degradation of protein molecular mass and the decrease rate of the degradation lessened with the increase of ultrasonic frequency. Meanwhile, the pretreatments improved the hydrophobics and antioxidants properties of SPIH. Both surface hydrophobicity (H0) and relative hydrophobicity (RH) of the pretreated groups increased with the decrease of ultrasonic frequency. Lowest frequency (20 kHz) ultrasound pretreatment had the most improved emulsifying properties and water holding capacities, although decrease in the viscosity and solubility were found. Most of these alterations were correspondence toward the change in hydrophobics properties and molecular mass. In conclusion, the frequency selection of ultrasound pretreatment is essential for the alteration of SPIH functional qualities prepared at the same DH.

Sonodynamic antimicrobial chemotherapy (SACT), as a novel anti-infective program, has received tremendous attention due to its good tissue penetration depth and low invasion. Ultrasound (US) frequency was one of the important parameters for SACT. To investigate the influence of different US frequencies on sonodynamic antimicrobial activity of ciprofloxacin-capped gold nanoparticles (CIP:GNPs). C. albicans and E. coli were chosen as the action objects. The bacterial survival rate was used in the assessment index and measured by plate colony-counting methods. The reactive oxygen species (ROS) produced under US irradiation were detected by ROS fluorescence probe and used to analyze the sonodynamic antibacterial mechanism of CIP:GNPs following different US frequencies. High-frequency US combined with CIP:GNPs had a good synergistic antimicrobial impact on C. albicans , while medium-frequency US showed a strong effect on E. coli. Moreover, the mechanism research experiment proved that intracellular ROS levels were closely related to changes in US frequency, and significantly affected the synergistic activity of CIP:GNPs. The injury of E. coli appearance showed more sensitivity to the change of US frequency than that of C. albicans , but its action laws were relatively complicated and needed to be further studied. • High-frequency US combined with CIP:GNPs had a better synergistic antimicrobial activity on C. albicans than on E. coli a nd medium-frequency US combined with CIP:GNPs got a stronger antibacterial effect on E.coli than on C.albicans. • The influence of US frequency on the synergistic antimicrobial activity of CIP:GNPs were relatively complicated, but it largely related to the yields of intracellular ROS and the cellular structural damage caused by the acoustic cavitation. [ABSTRACT FROM AUTHOR]

An ultrasonic microreactor with rough microchannels is presented in this study for oil-in-water (O/W) emulsion generation. Previous accounts have shown that surface pits or imperfections localize and enhance cavitation activity. In this study cavitation bubbles are localized on the rough microchannels of a borosilicate glass microreactor. The cavitation bubbles in the microchannel are primarily responsible for emulsification in the ultrasonic microreactor. We investigate the emulsification mechanism in the rough microchannels employing high-speed imaging to reveal the different emulsification modes influenced by the size and oscillation intensity of the cavitation bubbles. The effect of emulsification modes on the O/W emulsion droplet size distribution for different surface roughness and frequency is demonstrated. The positive effect of the frequency on minimizing the droplet size utilizing a reactor with large pits is presented. We also demonstrate microreactor systems for a successful generation of miniemulsions with high dispersed phase volume fractions up to 20%. The observed emulsification mechanism in the rough microchannel offers new insights into the utility and scale-up of ultrasonic microreactors for emulsification.

Numerous experimental studies have shown that the interaction of ultrasound with different cell membranes can result in a wide range of non-thermal effects on different cells or their membrane, including increased membrane permeability, ultrasonic cavitation in cells, and increased gene and drug delivery. However, the molecular mechanism for the interaction between ultrasound and cell membrane remains unclear. In this study, we model ultrasonic waves as cycles of alternating positive and negative pressure, and then use atomic molecular dynamics simulation to investigate how the applied ultrasound affects the structure of cell membranes and the corresponding molecular distribution of dissolved gas. We find that ultrasound energy is concentrated more effectively on the hydrophobic core of the membrane because it causes a strong oscillation of membrane thickness while producing a much weaker response in the surrounding water. In addition, our simulations reveal a substantial effect of the ultrasonic frequency on redistribution of dissolved gas molecules, and only an ultrasound with a long period can result in a significant gas redistribution. [ABSTRACT FROM AUTHOR]

[Display omitted] • This paper constitutes a step forward in ultrasonic extraction of biomolecules from clays rich sample and meteorites. • It presents a fast and efficient ultrasonic extraction compared to highly energy and time-consuming hot water extraction. • The proof of concept has been made extracting amino acids and nucleobases from meteorites. The study of organic molecules in meteorite and return samples allows for the understanding of the chemistry that undergoes in our Solar System. The present work aims at studying ultrasound assisted extraction technique as effective extraction method for these molecules in extraterrestrial samples and analogs. Optimal conditions were selected from the investigation of ultrasonic frequency, irradiation duration and solvent effects on amino acids, nucleobases and dipeptides extraction yields from a model clay-rich mineral matrix. Optimal ultrasound-assisted extraction parameters were frequency of 20 kHz within 20 min irradiation time and methanol/water solvent ratio of 1. We then validated this protocol on Mukundpura and Tarda meteorite fragments and compared it to the reference extraction protocol used in astrobiology and based on 24 h extraction time at 100 °C in water We obtained similar quantitative results without any racemization with both methodologies. [ABSTRACT FROM AUTHOR]

• Emulsification mechanism in a microreactor with rough microchannels is reported. • Influence of cavitation bubble size on emulsification and droplet breakup is visually confirmed. • Influence of frequency on the emulsion droplet size is highlighted. • Optimal setup for miniemulsion generation is demonstrated. An ultrasonic microreactor with rough microchannels is presented in this study for oil-in-water (O/W) emulsion generation. Previous accounts have shown that surface pits or imperfections localize and enhance cavitation activity. In this study cavitation bubbles are localized on the rough microchannels of a borosilicate glass microreactor. The cavitation bubbles in the microchannel are primarily responsible for emulsification in the ultrasonic microreactor. We investigate the emulsification mechanism in the rough microchannels employing high-speed imaging to reveal the different emulsification modes influenced by the size and oscillation intensity of the cavitation bubbles. The effect of emulsification modes on the O/W emulsion droplet size distribution for different surface roughness and frequency is demonstrated. The positive effect of the frequency on minimizing the droplet size utilizing a reactor with large pits is presented. We also demonstrate microreactor systems for a successful generation of miniemulsions with high dispersed phase volume fractions up to 20%. The observed emulsification mechanism in the rough microchannel offers new insights into the utility and scale-up of ultrasonic microreactors for emulsification. [ABSTRACT FROM AUTHOR]

• Hydrogen production by methanol sono-pyrolysis was computationally analyzed. • An accurate model was developed for H 2 production from methanol sono-conversion. • Hydrogen yields were substantially increased with methanol addition at low dosage. • Hydrogen yielding and CH 3 OH conversion decreased with frequency increase. • The H 2 yield is ideal at an acoustic intensity of 1 W/cm2 and liquid temp. of 20-30 °C. A comprehensive numerical investigation was conducted to analyze the effect of ultrasound frequency (213-1000 kHz), ultrasonic intensity (0.7-1.5 W/cm²) and medium temperature (293.15-333.15 K) on the production of hydrogen from methanol decomposition inside acoustic bubbles (methanol sono-conversion). The adopted model was firstly compared with some reference data. It was found that in the absence of methanol (in the presence of methanol), the bubble temperature, hydrogen production (and methanol conversion) are decreased monotonously with an increase in frequency. The maximal bubble temperature is slightly impacted by the presence of methanol under ultrasonic frequencies that are equal to or greater than 515 kHz. In addition, the yield of H 2 is larger in the presence of methanol, regardless of the utilized frequency. Between 213 to 355 kHz, methanol conversion and hydrogen production are most efficient. Both H 2 production and CH 3 OH degradation are accelerated under an ideal acoustic intensity of 1 W/cm2. At a liquid temperature of 303.15 K, a turning point in bubble temperature may be noticed in the absence of methanol, and at a liquid temperature of 323.15 K, the highest hydrogen production can be achieved. Hydrogen production and methanol conversion are most efficient at liquid temperatures between 293.15 and 303.15 K. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

Fixed frequency ultrasound (FFU), cyclic-sweeping frequency ultrasound (CSFU), and random-sweeping frequency ultrasound (RSFU) with the identical central frequency were constructed, and their effects on enzymatic hydrolysis and structural characteristics of rice protein (RP) were studied. FFU and RSFU enhanced the degree of hydrolysis (DH) and the angiotensin-I converting enzyme (ACE) inhibitory activity of RP hydrolysate significantly. CSFU increased the ACE inhibitory activity but had no significant effect on DH. The molecular weight distribution results showed that FFU and RSFU promoted the conversion of the hydrolysate to low molecular weight peptides (1000–2000 and 200–1000 Da). Meanwhile, FFU, CSFU, and RSFU pretreatment improved the surface hydrophobicity index H 0 from 397.53 to 464.23, 436.37, and 477.6, respectively. Circular dichroism spectra indicated that the three ultrasonic frequency modes decreased α-helix but increased random coil content. Ultraviolet–visible spectra and atomic force microscopy showed that the three ultrasound frequency modes caused the exposure of hydrophobic groups and reduced the particle size, respectively. Therefore, the innovative ultrasonic frequency modes modified the structural characteristics of RP and enhanced the ACE inhibitory activity of its hydrolysate. • Three frequency modes of one ultrasonic generator were constructed. • FFU, CSFU, and RSFU enhanced the DH and ACE inhibitory activity of RP hydrolysate. • Random-sweeping frequency ultrasound increased the ACE inhibitory activity most. • The enzymolysis effect of RP could be associated with the protein structure changes. [ABSTRACT FROM AUTHOR]