Ultrasonics Sonochemistry最新文献

Tiger nuts are rich in both oil and starch. In this paper, an immiscible binary solvent consisted of water and hexane was used to separate oil and starch from tiger nut with the assistance of ultrasound. The effects of various factors including ultrasonic power, ultrasonic time, extraction temperature, water-hexane ratio and solid-liquid ratio on the oil yield were examined. The oil and starch obtained were characterized and compared with those obtained through conventional methods, such as mechanical pressing (MP) and solvent extraction (SE). The results indicated that all examined factors, especially water-hexane ratio significantly affected the oil yield. Under the optimum conditions, ultrasound-assisted immiscible binary solvent extraction (UASE) yielded more oil than SE and MP. The quality analysis revealed that the acid value and iodine value of UASE oil were comparable to those extracted using the MP and SE methods, but the peroxide value was lower, and the vitamin E content was higher. In addition, the starch from tiger nut after UASE exhibited lower viscosity, greater solubility and swelling power, and better thermal and freeze-thaw stability. This study demonstrated that the UASE method is an efficient and environmentally friendly technique for simultaneously extracting oil and starch from tiger nuts.

This study aims to assess free radical (FR) generation potential of ultrasound in water and sour cherry juice (SCJ) model systems using an indirect method with specific indicators including glutathione (GSH), a well-known antioxidant, and terephthalic acid (TPA), which fluoresces upon oxidation. Initially, aqueous GSH solutions were subjected to ultrasound at varying amplitudes (60 % and 80 %) for up to 30 min using probes of different diameters (13 mm and 19 mm) to identify maximal oxidation conditions. FR formation was monitored using UPLC equipped with diode array detector and fluorescence spectrophotometer for GSH and TPA oxidation, respectively. Increasing sonication time decreased GSH and increased oxidized glutathione (GSSG) in water for both probes; however, the 19 mm probe generated five times more GSSG than the 13 mm, implying a substantially higher rate of FR formation. Subsequently, ultrasound was applied to aqueous TPA solution using the 19 mm probe-representing the more challenging conditions-at a previously optimized amplitude (67 %) during 30 min. Time-course water samples showed a steady increase in TPA fluorescence intensity with longer sonication durations, suggesting that oxidation reactions driven by FRs were progressing over time in water. Following sonication of GSH- and TPA-added SCJ under the same conditions, analysis by LC-QTOF-MS and fluorescence spectrophotometry revealed no GSSG or fluorescence formation, confirming the absence of notable oxidation of both indicators, likely due to the juice's complex composition (e.g., presence of antioxidant compounds). This study offers key insights into how ultrasound conditions affect FR formation in water and SCJ media by stabilizing them in detectable forms.

Biofilms can persist in food industry environments leading to repeated cross-contamination, thus threatening human health. Slightly acid electrolyzed water (SAEW) and ultrasound have emerged as environmentally-friendly antimicrobial agents. However, their bactericidal efficacy is not high when used alone. In the present study, the effect of ultrasound combined with SAEW on removing Listeria monocytogenes biofilms from a glass surface was evaluated. Listeria monocytogenes biofilms were treated by immersion in sterilized deionized water (control treatment), immersion in sterilized deionized water combined with ultrasound (US treatment), immersion in SAEW (SAEW treatment), immersion in SAEW combined with ultrasound treatment (SAEW + US treatment), immersion in SAEW followed by immersion in sterilized deionized water combined with ultrasound (SAEW - US treatment), and immersion in sterilized deionized water combined with ultrasound followed by immersion in SAEW (US - SAEW treatment). The results showed that treating biofilms by US - SAEW treatment led to the lowest number of Listeria monocytogenes, the lowest amount of biofilm remaining on the glass slide were visualized by crystal violet staining and scanning electron microscope, and a minimal content of extracellular polymeric substances. Overall, the highest biofilm removal efficacy was observed for the US - SAEW treatment.

In this study, the effects of ultrasound-assisted enzymatic hydrolysis on the production of antioxidant and antiosteoporotic peptides derived from oysters were investigated. Results showed that ultrasound-assisted enzymatic hydrolysis significantly enhanced the peptide content, free radical scavenging ability, and ferric reducing antioxidant power of total oyster protein hydrolysate (TOPH), with optimal results achieved at 200 W (TOPH-200). Correspondingly, ultrasound treatment at 200 W increased the exposure of hydrophobic regions, reduced α-helix content, and facilitated the generation of small molecular weight peptides in TOPH. In an H₂O₂-induced oxidative damage model of osteoblastic MC3T3-E1 cells, TOPH-200 significantly attenuated intracellular reactive oxygen species and improved mitochondrial membrane potential. Importantly, TOPH-200 effectively enhanced osteogenic cell proliferation, differentiation, and mineralization in H₂O₂-treated MC3T3-E1 cells. Additionally, two novel peptides, DSQLAPFRF and HFNPRL, were screened from the TOPH-200 using PeptideRanker and molecular docking. Further cell experiments indicated that both peptides exhibited potent antioxidant and antiosteoporotic activities in oxidatively damaged MC3T3-E1 cells. In summary, mild ultrasound-assisted enzymatic hydrolysis proved effective in producing bioactive peptides from oysters, and these newly identified peptides exhibit potential for osteoporosis prevention.

Sweet potatoes are a rich source of nutrients and bioactive compounds, but their quality can be impacted by the drying process. This study investigates the impact of slot jet reattachment (SJR) nozzle and ultrasound (US) combined drying (SJR + US) on sweet potato quality, compared to freeze-drying (FD), SJR drying, and hot air drying (HAD). SJR + US drying at 50 °C closely resembled FD in enhancing quality attributes and outperformed HAD and SJR in key areas such as rehydration, shrinkage ratios, and nutritional composition. Notably, SJR + US at 50 °C produced the highest total starch (36.84 g/100 g), total dietary fiber (8.48 g/100 g), total phenolic content (158.19 mg GAE/100 g), total flavonoid content (119.08 mg QE/g), DPPH antioxidant activity (6.44 μmol TE/g), β-carotene (31.98 mg/100 g), and vitamin C (5.27 mg/100 g). It also exhibited higher glass transition temperatures (Tg: 14.49 °C), indicating better stability at room temperature. The hardness values for SJR + US samples were similar to FD, while HAD samples had the highest hardness. SJR + US at 50 °C resulted in the lowest total color changes (ΔE), indicating minimal impact on appearance. Additionally, FTIR analysis revealed that peaks in specific spectral regions indicated superior preservation of bioactive compounds in SJR + US samples compared to other methods, which was also confirmed by principal component analysis (PCA) and heatmap visualization. Overall, these findings suggest that SJR + US is an effective alternative to conventional drying techniques, significantly improving the quality of dried sweet potatoes.

This study focused on the adverse sonochemical effect of ultrasound on biofilm extracellular polysaccharide and the adaptive biofilm responses for ultrasound resistance. Results showed ultrasound triggered phase transition of polysaccharides within biofilm from solation to gelation, which induced following biofilm viscoelasticity enhancement, consequential failure of biofilm removal and bacteria killing. Introducing additional cationic polysaccharide, 1.25 % chitosan, inhibited the ultrasound responsive polysaccharides gelation and biofilm viscoelasticity enhancement, exerted synergistic antibacterial (97.40 %) and antibiofilm (96.38 %) effects with 120 W ultrasound combined on S. aureus biofilm, prolonged the preservation time of milk 2.45 times longer compared with ultrasound alone. These findings indicated the possible mechanism and solution to improve ultrasound efficacy on biofilm control and bacteria suppression, exhibit the promising prospect of ultrasound combined strategy in hygiene issues of food and medical industry.

Formation of unilamellae of fully hydrated dipalmitoylphosphatidylcholine (DPPC) was induced by a horn sonicator from multilamellar vesicles and followed by time-resolved synchrotron small angle X-ray scattering and direct visual morphological investigations by the means of transmission electron-microscopy combined with freeze-fracture. Without incubation the ultrasonication causes continuous increasing in temperature and transformation from the gel to rippled gel structures, then reaching the main transition, the formfactor of unilamellar structure appeared. The ultrasonication resulted in different layer formations at the characteristic temperatures of the gel (20 °C), rippled gel (38 °C), and liquid crystalline (45 °C) phases of the system. At 20 °C irregular stacks of multi and oligolamellar lamellae were shaped even after three hours of ultrasonication. At 38 and 45 °C the ultrasound induced dominantly unilamellar vesicles (ULVs) in a short time (10 and 3 - 5 min, respectively, under typical ultrasound treatments in the general laboratory practice). After the end of the ultrasonication, irregular layer formations with defects structures increased when the temperature of sonication was above the chain melting temperature of the hydrated DPPC system, underlining the importance of optimized sonication processes.

Owing to the long duration of cooking legumes, which limits their consumption and utilization, soaking has been used to reduce cooking time, save energy consumption, and diminish their hardness. However, limited studies have reported the influence of cooking and soaking treatment along with ultrasonication on hydration, hardness, and cooking time reduction of legumes. Therefore, this study investigated the impact of cooking and soaking treatments on Dr. Saunder cowpea's water absorption, hardness, and cooking time reduction with and without ultrasonication. Samples of Dr. Saunder's cowpea were first soaked at 30 °C and 50 °C for 15 - 90 min (with and without ultrasonication), after which they were cooked at 100 °C and 121 °C for 15 - 120 min. The absorbed water and hardness of the tested samples under these treatments were measured. Hydration and softening behaviors were modeled from the obtained data using Ibarz-Augusto and first-order equations, respectively. Arrhenius equation was used to describe the kinetics of the hydration and softening process. Results showed that ultrasonic treatments accelerated water absorption and reduced the hardness of the samples; consequently, in a shorter time, using less energy will receive the desired hardness as the final product. The Ibartz-Augusto and first-order equations perfectively fit the sigmoidal and decaying exponential behavior of the absorbed water and hardness data with high prediction performance (R² ≈ 1) marked by minimal error values. The deployment of ultrasonication and increased cooking temperature were observed to reduce the kinetic parameter (water absorption) and elevate the softening rates and activation energy (for hydration and softening). A synergy of the trio treatments reduced the total cooking duration from 120 min to 90 min (25 %), thus promoting the benefit of deploying ultrasonication to soften cowpeas and other seeds rapidly.

Although there have been many studies on the efficacy of ultrasonic inactivation, the stress resistance mechanism of bacteria is still a challenge for complete ultrasonic inactivation. In this study, the dominant spoilage bacteria in crayfish, Shewanella baltica (S. baltica) and Aeromonas veronii (A. veronii), were subjected to high-intensity ultrasonic treatment. The results showed compromised cell membrane, decreased membrane fluidity, hyperpolarized membrane potential, and disrupted succinate-coenzyme Q reductase. Transmission electron microscopy revealed significant fragmentation of S. baltica, whereas A. veronii, with its thick cell wall and outer capsule membrane, demonstrated enhanced resistance to ultrasound. Real-time quantitative PCR indicated that in response to ultrasonic stress, bacteria initiated a stress response mechanism by increasing the expression of mechanosensitive channels; meanwhile, the outer capsule of A. veronii delayed the transformation of ultrasonic external forces into cell membrane stress. The study found that in response to ultrasonic stress, bacteria initiated a stress response mechanism by increasing the expression of mechanosensitive channels as "emergency valve" in short time but could not prevent the process of membrane destruction with prolonged exposure. This finding provided a basis for addressing bacterial stress tolerance in ultrasonic inactivation.

Biomass-derived porous carbon (PC) has emerged as a promising candidate for electrode materials in energy storage applications, effective pretreatment of the precursor is a key strategy for enhancing the electrochemical performance of PC. However, challenges remain in achieving this goal through environmentally friendly, simple, and efficient methods. In this paper, a dual-frequency ultrasonic-assisted enzymolysis strategy combined with carbonization-activation method was proposed to prepare high-performance garlic peel-derived PC (DUGPC) for supercapacitors. Gentle and effective sonobiocatalysis facilitates microstructural regulation and composition management of the precursor, granting DUGPC an impressive specific surface area (SSA, 3006 m²/g), improved pore distribution, low metal impurity content (less than 100 ppm) and high wettability. As anticipated, DUGPC demonstrates excellent specific capacitance (408.77 F/g at 1 A/g) and rate performance (retention is 81.8 % at 50 A/g) surpassing most recently reported biomass-based PCs. In addition, the assembled aqueous symmetric supercapacitor achieves an excellent energy density of 15.78 Wh kg^-1 at a power density of 50.04 W kg^-1 with a remarkable cycle stability of 95.5 % after 10,000 cycles at 5 A/g, and the assembled 2.8 V high-voltage organic supercapacitor even exhibits an ultra-high energy density of 58.96 Wh kg^-1 at a power density of 139.86 W kg^-1. Significantly, this dual-frequency ultrasonic-assisted enzymolysis strategy is expected to be applicable to various biomass wastes and promotes the high-value utilization of biomass in the field of energy storage.