Search

The effect of ultrasound, ozone, and their combination treatment on the removal of two common pesticides (trichlorfon and phoxim) in pak choi samples was studied in this work. The results showed that both ultrasound and ozone treatment alone can significantly remove trichlorfon and phoxim residues in pak choi (>90%), but they reduced the quality of pak choi (such as vitamin C and color). Ultrasound and ozone had a synergistic effect on the removal of pesticide residues in pak choi. The synergistic effect of combined treatment was evaluated from the perspective of pesticide removal speed, and found that their combination significantly accelerated the removal of pesticides. Compared with ultrasound or ozone alone, the removal rate constant of trichlorfon by the combined treatment increased by 121% and 347%, and that of phoxim increased by 159% and 367%, respectively. In addition, the combined treatment of ultrasound and ozone can well maintain the vitamin C and color of pak choi while removing pesticides. Therefore, the combined treatment of ultrasound and ozone can be used as an effective cleaning method to remove pesticide residues in vegetables. Practical applications: Reducing pesticide residues in vegetables is of great significance to human health, and how to maintain the quality of vegetables as much as possible while removing pesticides is a key issue. In this study, the combination of ultrasound and ozone significantly accelerated the removal of pesticides, and retained the vitamin C and color of pak choi well. Therefore, the combined application of ultrasound and ozone has the potential to be an industrial cleaning method for removing pesticide residues in fruits and vegetables without compromising quality. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ultrasound has the potential to increase microbial metabolic activity, so this study explored the stimulatory effect of ultrasound pre‐treatment on the degradation of four common pesticides (fenitrothion, chlorpyrifos, profenofos, and dimethoate) during milk fermentation by Lactobacillus plantarum and its effect on yogurt quality. RESULTS: Appropriate ultrasound pretreatment significantly enhanced the growth of L. plantarum. The degradation percentages of pesticides increased by 19–38% under ultrasound treatment. Ultrasonic intensity, pulse duty cycle, and duration time were key factors affecting microbial growth and pesticide degradation. Under optimal ultrasonic pre‐treatment conditions, the degradation rate constants of four pesticides were at least 3.4 times higher than those without sonication. In addition, such ultrasound pretreatment significantly shortened yogurt fermentation time, increased the water holding capacity, hardness and antioxidant activity of the yogurt, and improved the flavor quality of the yogurt. CONCLUSION: Ultrasonic pretreatment significantly accelerated the degradation of the four pesticides during yogurt fermentation. In addition, such ultrasound pretreatment increased the efficiency of yogurt making and improved the quality of yogurt in terms of water holding capacity, firmness, antioxidant activity, and flavor. These findings provide a basis for the application of ultrasound to the removal of pesticide residues and quality improvement of yogurt. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

There has been a growing concern for methicillin-resistant Staphylococcus aureus (MRSA) contamination in the food industry. In the present study, the highest inactivation effect (5.80 log CFU/mL) was observed in simultaneous treatment compared with sequential treatment of ultrasound (US)-assisted cinnamaldehyde (CA). The absence of sublethal bacteria indicated US-assisted CA did not induce the tolerance or adaptation to MRSA cells. The results of SEM analysis indicated that the application of US-assisted CA resulted in severe damage to the cell membrane, as demonstrated by the highest fluorescence intensity of propidium iodide dye, intracellular substance leakage, and molecular docking analysis, as well as ATPase activity. Furthermore, US-assisted CA significantly disrupted energy metabolism, as evidenced by a reduction in ATP concentration, succinate dehydrogenase, and malate dehydrogenase activities. The exacerbation of ROS-induced damage to MRSA cells was observed due to the reduction in catalase and peroxidase activities. Additionally, a significant decrease (p < 0.05) in extracellular carbohydrates and proteins within the MRSA biofilm was noted on both glass and stainless-steel surfaces exposed to US-assisted CA. Ultimately, US-assisted CA treatment resulted in a maximum reduction (p < 0.05) of MRSA cells in beef meat, while maintaining color, pH, and sensory properties during an 8-day storage period at 4 °C. These findings suggested that simultaneous US-assisted CA treatment may serve as an alternative method for ensuring microbiological safety. [Display omitted] • Ultrasound-assisted cinnamaldehyde did not cause tolerance of MRSA. • Ultrasound assisted rapid destruction of cell membrane by cinnamaldehyde. • Disordered energy metabolism aggravated the accumulation of ROS. • Negligible changes of quality attributes in beef meat subjected to simultaneous treatment was observed. [ABSTRACT FROM AUTHOR]

An ultrasound-induced albumin gelation method was utilized to prepare nanostructured hydroxyapatite (HAP). After ultrasound irradiation, hybrid colloids of bovine serum albumin (BSA) and amorphous calcium phosphate (ACaP) were formed, where the nanosized ACaP was homogenously distributed in the fibril-like BSA matrix. The freeze-dried BSA/ACaP sponge showed an oriented pore structure and the ACaP nanoparticles were transformed into nanostructured HAP after calcinations at 400–600 °C. With the aid of BSA/ACaP sponge, HAP nanocrystals were aggregated into rod-like nanostructures, which were merged into large rod-like HAP crystals at 700 °C. This study demonstrates that ultrasound-induced albumin gelation method can be successfully used to fabricate nanostructured HAP. [ABSTRACT FROM AUTHOR]

[Display omitted] • PAW pre-exposure and subsequent US treatment has energy-efficient in MRSA inactivation. • The enhanced inactivation was partly due to the in-situ generation of RONS. • Elevated arginine levels induced the formation of VBNC bacteria. • Regrowth potential of MRSA cells was negligible. Methicillin-resistant Staphylococcus aureus (MRSA) and antibiotic resistance gene (mecA) are considered emerging contaminants that have been extensively identified in aqueous environments due to their high resistance to disinfectants. Herein, we report for the first time the inactivation of MRSA through a sequential application of plasma-activated water and ultrasound (PAW-SU). While the impact of PAW alone on bacterial culturability and mecA integrity was negligible, the combined PAW-SU treatment outperformed the inactivation method involving PAW with direct US (PAW-DU). It exhibited a shorter lag phase and a higher maximum inactivation rate constant. We numerically demonstrated that sonolysis processes induced by external ultrasound sources considerably improved the intracellular and extracellular reactive oxygen and nitrogen species (RONS) of MRSA in PAW system, thereby increasing the PAW reactivity and applicability. The highest inactivation efficiency of PAW-SU can be attributed to the synergistic effect of enhanced intracellular RONS (i.e., peroxynitrite and singlet oxygen) and membrane disruption induced by US, resulting in irreparable oxidative damage to the Save our Soul response and energy metabolic system. In particular, the elevated arginine metabolites in MRSA cells were primarily responsible for the formation of the viable but nonculturable state (VBNC) bacteria associated with high resistance to PAW system. Surprisingly, a decrease in arginine synthesis capacity was observed to expedite the flow of the tricarboxylic acid cycle, accelerating the detrimental effects of PAW-SU on intracellular components in VBNC bacteria. Finally, the limited regrowth potential of injured MRSA caused by cyclic inactivation of PAW-SU process was further confirmed in wastewater from meat and dairy models and therefore, advocates the possible real-world applications. [ABSTRACT FROM AUTHOR]

Pyrazines is a group of volatile heterocyclic nitrogen-containing compounds contributing to baking, roasted, and nutty flavors in food products. Maillard reaction (MR) is an important mean of synthesizing pyrazines. As welcomed volatile compounds, the generation of pyrazines from the MR are expected to be promoted during food processing. On some occasions, the MR needs to be suppressed for minimizing the formation of harmful MR products (MRPs), undesirable color, and off-flavors, but in turn, inhibiting the formation of pyrazines simultaneously. Control strategies of pyrazines generation from the MR were emphasized in this review, including utilization of new reactants, modification of reaction conditions, and adoption of emerging techniques. Ammonia released from the pyrolysis of amino sources significantly promoted the generation of pyrazines. Peptides-involved MR systems generally synthesized more types and higher content of pyrazines, which depended on the structure of N -terminal amino acid in the peptide. The oil-in-water MR emulsions generated more pyrazines due to numerous lipid oxidation products imparted into the MR as intermediates. Emerging technologies, such as ultrasound promoted the pyrazines formation in MR model systems due to an extremely high temperature and pressure environment favored by the MR. Some other strategies suppressed the MR for minimizing the generation of harmful MRPs and meanwhile, inhibiting the formation of pyrazines, e.g. high-pressure processing, addition of phenolic compounds, and utilization of low reactive pentapeptide and ketohexoses. The strategies summarized in this review are applicable for achieving pyrazines control in the food industry. [Display omitted] • Control strategies of pyrazines generation from Maillard reaction (MR) are reviewed. • Utilization of new amino sources as reactants of MR promotes formation of pyrazines. • Ultrasound-assisted MR is a promising mean of synthesizing various pyrazines. • Substituted pyrazines are largely formed in oil-in-water MR emulsions. • Polyphenols as dicarbonyl compounds scavengers inhibit formation of pyrazines via MR. [ABSTRACT FROM AUTHOR]

The existence of chemical contaminants in food brings a serious threat to human health. Researchers have been making persistent efforts to eliminate contaminants from food to make it safe for human consumption. Traditional methods, such as washing with various agents, peeling, cooking and chemical oxidants, cannot achieve the desired results. In recent years, non-thermal technology, such as ultrasound, has attracted extensive attention as an emerging technology for removing food contaminants. This review analyzed the research status of ultrasound in the elimination of food contaminants, studied the transformation products and their potential toxicity during ultrasound treatment, discussed the effect of ultrasound on food quality, and summarized the advantages and disadvantages of ultrasound treatment. At the same time, the challenges of this technology, the problems to be studied, and future development prospects were discussed. Ultrasound is a green processing technology, which would not impart secondary pollution. It also has advantages of high efficiency and low energy consumption, compared with traditional decontamination technologies. The combination of ultrasound with other techniques such as ultraviolet, ozone and pulsed electric field shows better decontamination effect. However, ultrasound treatment may cause degradation of some phenolic compounds and vitamins, changes in color, loss of anthocyanin and other adverse effects on food characteristics. In addition, the appropriate ultrasound processing system in terms of probe design, geometry, and operating conditions, needs to be specially designed for different food materials. Thus, some challenges need to be addressed to improve its application. • Ultrasound was used as an emerging technology for removing food contaminants. • Combined ultrasound and other strategies showed better decontamination effect. • Free radicals induced by cavitation contribute to the degradation of contaminants. • Ultrasonic parameters (e.g. intensity) had great influence on decontamination. • Ultrasound had a dual effect on food quality depending on the processing conditions. [ABSTRACT FROM AUTHOR]

Pollution of foodborne microbial biofilms is a serious problem in the food industry. Microorganisms in the biofilms become insensitive to environmental stresses and increase tolerance to antimicrobial agents, therefore, making them extremely hard to be inactivated by conventional methods. Ultrasound-involved emerging strategies offer options for effectively controlling the biofilms formed on either food contact surfaces or real foods. This review emphasizes the significances of either ultrasonication alone or combined with other strategies for controlling foodborne microbial biofilms. Ultrasound as an emerging technology would effectively destroy biofilm structure and partially inactivate microorganisms in the biofilms; however, stimulated the growth of microbes may happen after treatment of low-frequency and low-intensity ultrasound. Combined ultrasound (especially low-frequency and high-intensity ultrasound) and chemical disinfectants shows a synergistic effect with a relatively high proportion of inactivated microbes in the biofilms compared with that adopted one strategy alone. Ozone and electrolyzed water are also developed for inactivating microbes and removing the biofilms after combining with the ultrasound. Combined treatment of ultrasonication and chelating agents or enzymes is proved to effectively remove the biofilms instead of achieving a strong bactericidal effect. Mechanical oscillation, localized high temperature and pressure, as well as free radicals generated by cavitation during the ultrasonication can partially destroy the basic structure of biofilms, and furthermore, increase the penetration and diffusion of chemicals into the deeper layer of biofilms for achieving a synergistic effect on the biofilm control. • Ultrasound is used for controlling biofilms formed on foods and food contact surfaces. • Combined ultrasound and other strategies show a synergistic effect on biofilm control. • Mechanical oscillation and cavitation contribute to destruction of biofilm structure. • Bactericidal effect in biofilms depends on intensity and frequency of ultrasound. • Future studies are recommended regarding ultrasound-involved emerging strategies. [ABSTRACT FROM AUTHOR]

• Ultrasound and ultraviolet had synergistic effect on the degradation of chlorpyrifos. • The degradation mechanism mainly involves oxidation, hydrolysis and de-chlorination. • The toxicities of degradation products were lower than that of chlorpyrifos. • The combined treatment had little effect on the quality of the treated milk. The aim of this study was to compare the degradation kinetics of chlorpyrifos by treatment with ultrasound (US), ultraviolet radiation (UV) and a combination of both (US/UV), to evaluate the toxicity of the degradation products and the effect of the treatments on milk quality. US/UV markedly accelerated the degradation of chlorpyrifos. The half-life of chlorpyrifos by US/UV was 6.4 min, which was greatly shortened compared to the treatment with US or UV alone. Five degradation products were identified by GC–MS, and a degradation pathway for chlorpyrifos was proposed, based on density functional theory calculations. According to the luminescent bacteria test and predictions from a structure/activity relationship model, the toxicity of the degradation products was lower than that of chlorpyrifos. In addition, US/UV treatment had little effect on the quality of the treated milk. Therefore, US/UV can be used as a potential non-thermal processing method to degrade pesticide residues in milk. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combined ultrasonic and thermal treatment against Pseudomonas fluorescens was studied. • P. fluorescens biofilm was efficiently removed by ultrasound with power > 80 W. • Ultrasound with a mild heat at 50 °C synergistically inactivate P. fluorescens cells. • Acoustic pressure and temperature distribution were simulated using COMSOL. • Potential "dead ends" were identified due to reflectivity of the sound waves. A combined ultrasonic and thermal (US-TM) treatment was developed in this study to achieve a high efficacy of P. fluorescens biofilm control. The present study demonstrated that combined a moderate ultrasound treatment (power ≥ 80 W) and a mild heat (up to 50 °C) largely destroyed biofilm structure in 15 min and removed>65.63% of biofilm from a glass slide where cultivated the P. fluorescens biofilm. Meanwhile, the viable cell count was decreased from 10.72 to 6.48 log 10 CUF/mL. Differences in biofilm removal and lethal modes of US-TM treatment were confirmed through microscopies analysis in vitro. The ultrasound first contributed to releasing the bacteria in the biofilm to the environment and simultaneously exposing inner bacteria at the deep layer of biofilm depending on shear force, shock waves, acoustic streaming, etc. When the biofilm structure was destroyed, US-TM treatment would synergistically inactivate P. fluorescens cells. In silico studies adopted COMSOL to simulate acoustic pressure and temperature distribution in the bioreactor; both of them were significantly influenced by various factors, such as input power, sonotrode position, materials and volume of container, etc. Facing the biofilm issue existing on the surface of container, boundary conditions were exported and thereby pointing out potential "dead ends" where the ultrasound may not be effectively transduced. Both in vitro and in silico results may inspire the food industry to adopt US-TM treatment to achieve biofilm control. [ABSTRACT FROM AUTHOR]

[Display omitted] • More pyrazines were generated in high-intensity ultrasound-Maillard reaction (HIU-MR). • Pyrazines generation pathways were elucidated by Carbohydrate module labeling method. • [M]+ proportion in pyrazines with long-length side chains was lower than thermal MR. • Aldol-type condensation as a high-pressure favored reaction was promoted by HIU. • Cleavage of glucose contributed to the promoted synthesis of pyrazines in HIU-MR. This study evaluated how the generation of pyrazines was promoted by high-intensity ultrasound (HIU) in a Maillard reaction (MR) model system of glucose-glycine. Carbohydrate module labeling (CAMOLA) technique was adopted using D-glucose-13C 6 to elucidate the carbon skeleton of both intermediate and final MR products (MRPs). In the D-glucose-13C 6 -glycine HIU-MR model system, the concentration of 11 types of pyrazines was significantly higher than their counterparts in the thermal MR. Results of CAMOLA analysis showed that a significantly lower proportion of [M]+ in pyrazines with long-length side chains was observed when compared with the pyrazines generated in thermal MR. This phenomenon may suggest the aldol-type condensation was promoted by the HIU, which is a conversion from pyrazines with short-length side chains to those with long-length side chains involving carbonyl compounds. Furthermore, the analysis of isotopomers distribution in 2,3-dimethyl-quinoxaline as the o-phenylenediamine-derivatized 2,3-butanedione indicated that the increased proportion of [M + 4]+ in 2,3-dimethyl-quinoxaline (15.74% ± 0.11%) was attributed to a cleavage of D-glucose-13C 6 promoted by the HIU. The above-mentioned findings elucidate that the aldol-type condensation and cleavage of D-glucose contribute to the promoted synthesis of pyrazines. The HIU would generate an extremely high temperature and pressure environment that is favored by the aldol-type condensation as a high-pressure favored reaction. The HIU, therefore, can be further developed as a promising technique to promote flavor generation through the MR. [ABSTRACT FROM AUTHOR]

• Ultrasound-assisted Maillard reaction (US-MR) is comprehensively reviewed. • Critical steps promoted/inhibited by US are determined in US-MR model systems. • US-MR is a promising mean of producing food flavors. • Glycation of food proteins through US-MR promotes their functional properties. • Enhanced organoleptic and functional properties in processed food contribute to US-MR. Maillard reaction (MR) is one of the most important chemical reactions in the food science domain with a long history of more than 100 years. As for ultrasound-assisted MR (US-MR), it has gradually drawn attention in a recent decade. Purpose of this paper is to provide a systematic review on recent advances of US-MR in model systems, glycation of protein, and food processing. Fundamental studies on simple MR model systems (i.e. reducing sugar and amino acid) have reported a promoted generation of colored and volatile MR products (MRPs). Critical steps influenced by US and possible mechanisms have been elucidated simultaneously. Other studies focused on modification of proteins which undergoes a glycation between proteins and saccharides as the initial stage of MR. Since the MR rate is extremely low in the presence of protein and saccharide, US becomes a promising mean of promoting the glycation. As a result, a number of functional properties of glycated protein obtained by US are significantly promoted, which extend their utilization in the food industry. The rest of studies reviewed in this article are concentrated on applying US to process real foods. Many attributes changed during US-assisted processing are induced by MR. Positive aspects brought by the promoted US-MR include enhanced antioxidant capacity and organoleptic properties (e.g. desirable color, low bitterness, enhanced flavor, etc.), as well as inhibited hazards (e.g. advanced glycation end-products, acrylamide, etc.) formed in the processed foods. Meanwhile, the promoted MR by US may also inevitably bring some negative aspects to the processed foods due to unfavored yellowish/browning colors, off-flavors and hazard components. [ABSTRACT FROM AUTHOR]