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This is the first time to investigate the synergistic inactivation effect and mechanism of multifrequency ultrasound (MTUS) on A. acidoterrestris (AAT) vegetative cells and spores, nutrients and enzymes of orange juice. The optimized results of MTUS (using Box Behnken design- surface responsemethodology) and further comparison with different mode of ultrasound (mono-and multi-frequency) revealed that 20/40 kHz, 24 min and 64 °C were the best optimum results. The AAT spores and vegetative cells were inactivated by 2 and 4 logs, respectively, without deteriorating orange juice contents. In addition, AAT inactivation indicated an inversely proportional relationship with ROS production. FT-IR and UV-Vis spectroscopy characterization confirmed the existence of ROS in treated orange juice and LF-NMR analysis confirmed the inactivation of AAT spores. The findings illustrated the successfully used dual-frequency ultrasound technology for fruit beverages, promoting beneficial changes in physical properties without any significant effects on the quality of ascorbic acid., (Copyright © 2021. Published by Elsevier Ltd.)

In this study, the effect of sonication on the fermentation process of a single-celled fungus was examined. During the experiment, Saccharomyces cerevisiae (S. cerevisiae) was used as the starting strain for ethanol fermentation (batch fermentation) in a 7.5 L automated fermentation tank. The fermentation tank connected with a six-frequency ultrasonic equipment. Non-sonication treatment was set up as the control. Sonication treatment with power density of 280 W/L and 48 h of treatment time were set up as trial groups for investigating the influence of different ultrasound frequency including 20, 23, 25, 28, 33 and 40 kHz on the changes in dry cell-weight, glucose consumption rate, and ethanol yield. The results showed that the dry cell-weight, glucose consumption rate, and ethanol content reached the best results under the ultrasonic condition of 28 kHz ultrasound frequency in comparison with other ultrasound frequency. The dry cell-weight and ethanol content of the 28 kHz ultrasonic treatment group increased by 17.30% and 30.79%, respectively in comparison with the control group The residual sugar content dropped to a lower level within 24 h, which was consistent with the change in ethanol production. Besides, the results found that the glucose consumption rate increased compared to the control. It indicated that ultrasound accelerated glucose consumption contributed to increase the rate of ethanol output. In order to explore the mechanism of sonication enhanced the content of ethanol output by S. cerevisiae, the morphology, permeability of S. cerevisiae and key enzyme activities of ethanol synthesis were investigated before and after sonication treatment. The results showed that after sonication treatment, the extracellular nucleic acid protein content and intracellular Ca 2+ concentration increased significantly. The morphology of S. cerevisiae was observed by SEM and found that the surface of the strain had wrinkles and depressions after ultrasonic treatment. furthermore after sonication treatment, the activities of three key enzymes which catalyze three irreversible reactions in glycolysis metabolism, namely, hexokinase, phosphofructokinase and pyruvate kinase increased by 59.02%, 109.05% and 87.27%, respectively. In a word, low-intensity ultrasound enhance the rate of ethanol output by S. cerevisiae might due to enhancing the growth and cell permeability of strains, and increasing the activities of three key enzymes of ethanol biosynthesis., (Copyright © 2021. Published by Elsevier B.V.)

Vacuum freeze-drying is a new and high technology on agricultural product dehydrating dry, but it faces the high cost problem caused by high energy consumption. This study investigated the effect of ultrasound (US), freeze-thawing (including the freeze-air thawing (AT), freeze-water thawing (WT), freeze-ultrasound thawing (UST), and freeze-air ultrasound thawing (AT + US)) pretreatments on the vacuum freeze-drying efficiency and the quality of dried okra. The results indicated that the application of ultrasound and different freeze-thawing pretreatments reduced the drying time by 25.0%-62.50% and the total energy consumption was 24.28%-62.35% less. The AT pretreatment reduced the time by of okra slices by 62.50% and the total energy consumption was 62.35% less. The significant decrease in drying time was due to a change in the microstructure caused by pretreatment. Besides, the okra pretreated with the US retained most of the quality characteristics (flavor, color, hardness, and frangibility) among all methods, while, AT + US had the most changeable characteristics in quality, which is deprecated in our study. The okra pretreated with the US and AT, separately, had the best dry matter content loss (9.008%, 5.602%), lower chlorophyll degradation (5.05%, 5.44% less), and higher contents of total phenolics, total flavonoids, and pectin, with strong antioxidant capacity, compared to other methods. The pretreatments did not have a large effect on the functional groups and the structure of pectin, but slightly affected the viscosity. It can be concluded that AT and US pretreatment methods are better than others., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The influence of multi-frequency combined ultrasound thawing on primary, secondary, and tertiary structures, electrophoresis pattern, particle size distribution, zeta potential values, thermal stability, rheological behavior, and microstructure of small yellow croaker myofibrillar proteins (MPs) were studied. Four treatments were used for thawing small yellow croakers: flow water thawing (FWT), mono-frequency ultrasonic thawing (MUT), dual-frequency ultrasonic thawing (DUT), and tri-frequency ultrasonic thawing (TUT). Compared with fresh samples (FS), the MPs of the sample pretreated by DUT had non-significant effect on protein primary (including free amino groups and surface hydrophobicity), secondary, tertiary structures, electrophoresis pattern, and microstructure. MPs pretreated by DUT had less aggregation and degradation. Besides, DUT treatment increased the thermal stability of MPs. The ultrasound had significant effects on the rheological properties of MPs. Overall, DUT effectively minimized the changes in MPs structure and protected the protein thermal stability and rheological behavior during the thawing process., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The effect of dual-frequency ultrasound treatment with different working modes on the lysinoalanine (LAL) formation and structural characterization of rice dreg protein isolates (RDPI) was studied during alkaline exaction processing. Ultrasonic notably decreased the LAL amount of RDPI and enhanced the protein dissolution rate. The LAL content of RDPI, especially sequential dual frequency 20/40 kHz, decreased by 12.02% (P < 0.05), compared to non-sonicated samples. Herein, the protein dissolution rate was higher. The changes in sulfhydryl groups was positively correlated with the LAL formation. The amino acids (AA) such as threonine (Thr), lysine (Lys), and arginine (Arg) were reduced, resulting in a decrease in LAL content following sonication. Besides, ultrasonication altered protein secondary structure by reducing random coil and β-sheet contents, while α-helix and β-turn contents increased. Alterations in the surface hydrophobicity, particle size, particle size distribution, and microstructure indicated more irregular fragment with microparticles of RDPI by sonochemical treatment. Thus, ultrasound treatment may be a new and efficacious process for controlling the LAL generation in prepared-protein food(s) during alkali extraction., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The influences of dual-frequency slit ultrasound (DFSU) pretreatment with various working parameters on the enzymolysis efficiency and conformational characteristics of corn gluten meal (CGM) were studied. Results indicated that under the conditions of ultrasonic power density of 80 W/L, time of 30 min, ultrasonic intermittent ratio of 5:2 s/s, temperature of 30 °C, and substrate concentration of 50 g/L, the relative enzymolysis efficiency (REE) of CGM reached a maximum of 21.05%, and the protein dissolution rate was 68.50%. In addition, ultrasonication had considerable impact on the conformation of CGM and consequently improved the susceptibility to alcalase proteolysis. Changes in free sulfhydryl (SH F ) and disulfide bonds (SS) groups indicated spatial conformation of CGM was altered following sonication (sonochemical) treatment. Fourier Transform Infrared Spectrum (FITR) analysis showed a reduction in α-helix and β-turn content; and an increase in β-sheet and random coil content of CGM. Alterations in the particle size, particle size distribution, microstructure and surface roughness (R a , R q ) indicated generation of smaller and more uniform protein fragments of CGM by sonochemical pretreatment. The proposed mechanism of sonicated CGM was elaborated. Our findings suggest that using DFSU in pretreating CGM may be an efficacious approach to enhance proteolysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The suitability of some non-linear kinetic models (Weibull {with or without tail}, Log-linear, Log-linear shoulder {with or without tail}, Biphasic linear, Logistic, Multi-target and Single-target models) were evaluated to determine the inactivation kinetics of inoculated E. coli, and natural microbiota (i.e. mesophilic aerobic bacteria, and mold and yeast) on cherry tomato treated with fixed multi-frequency ultrasound. Almost all the studied model fitted well (R 2  ≥ 0.9) for the inactivation kinetics; however, the Weibull, Log-linear shoulder, and Biphasic linear model showed the highest statistical parameters (0.9 ≤ adj. R 2  ≤ 0.99 and smallest RMSE and SSE values). All the three models could be used to compare the kinetic behavior of E. coli and the first two models for the kinetic behavior of mesophilic aerobic bacteria and mold and yeast during sonication treatment. Two distinctive inactivation curves were obtained for the mono-frequency and the multi-frequency (dual and tri-frequency) for all the microbial inactivation. The remarkable results obtained for dual and tri-frequency sonication shows to be an effective and promising alternative to the traditional microbial inactivation techniques and the common practice of using ultrasound with other sanitizing methods., Competing Interests: Conflict of interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The effects of moderate thermosonication (MTS) on the quality quartet: physico-chemical, microbial, nutritional and sensory qualities of orange juice (OJ) inoculated with Alicyclobacillus acidoterrestris (AAT) were studied during 24 days of storage at ambient and refrigerated temperatures. The bioactive compounds and antioxidant activity of OJ decreased with storage, while the pectin methyl esterase (PME) increased. Nonetheless, noticeable changes were observed from the 12th day of storage. There was no obvious (p > 0.05) variation in pH and total soluble solids. To determine the nutritional and microbial quality characteristics of OJ during storage, non-linear kinetic curves were successfully fitted with least square fitting polynomial and four-parameter log-logistic distribution models. The E-nose sensors succeeded in discriminating between the aroma of non-treated and treated OJ based on linear discriminant analysis (LDA). Furthermore, terpenes, alcohol and partially aromatic compounds were the main spoilage indicators of OJ during storage based on E-nose analysis and confirmed by HS-SPME-GC/MS analysis. Thus, MTS significantly extended the shelf life of the quality quartet of natural OJ at 4 °C. E-nose-GC/MS fusion offered odor fingerprints to AAT microorganisms that can be used as spoilage index without using traditional food analysis techniques. The proposed approach can be used as an alternative tool for rapid detection of spoilage microorganisms in OJ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This study investigated effects of ultrasound on the contents of peptide and soluble protein, antioxidant activity, functionalities and structural characteristics of fermented soybean meal (FSBM) with Bacillus subtilis systematically. The results showed that there were significant effects of ultrasound treatments (frequency, treatment time and power density) on the contents of peptide and soluble protein (p < 0.05). Under the optimum ultrasound conditions (power density of 0.08 W/mL, frequency of 33 kHz and treatment time of 1 h) by single factor experiment, the contents of peptide and soluble protein increased by 31.27% and 18.79% compared to those of the control, respectively. Additionally, the in vitro antioxidant activity (•OH scavenging rate, Fe 2+ chelating capacity and DPPH radical scavenging rate) and functional properties (emulsifying activity and emulsifying stability) of FSBM were found to be noticeably improved by ultrasound (p < 0.05). The fourier transform infrared (FTIR) spectroscopy revealed that ultrasound caused protein molecules to unfold with a decrease content of α-helix and β-turn and an increase in the proportion of β-sheet and random coil. Besides, atomic force microscope (AFM) results indicated that ultrasonication generally increased the surface roughness of protein and the protein sonicated with higher frequency (≥33 kHz) exhibited a greater height compared to lower frequency ultrasonication. Structure-activity relationship analysis illustrated that there was a good linear relationship between •OH scavenging rate and β-sheet/β-turn with Pearson's correlation coefficient r of -0.86/0.90. Collectively, the selection of ultrasonic parameters is essential for the preparation of functional protein and bioactive peptide by enhancing fermentation of agroindustrial by-products., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A scheme for preparing milk ACE inhibitory peptides by in vitro proteolysis and simulated gastrointestinal digestion was constructed. The ultrasonic assisted pretreatment was used to improve the enzymolysis of milk protein. The in-situ real-time infrared was used to establish monitoring model of enzymatic process. Results showed that under the conditions of single frequency 28 kHz, ultrasound time 40 min, ultrasound power density 20 W/L, milk protein concentration 34 g/L, batch ratio 2:4 and initial temperature 30 °C, the ACE inhibition rate of gastric digestion of enzymatic hydrolysate reached 67.20%, which was 22.87% higher than that of non-ultrasound samples. The results of secondary structure studies of proteins showed that after the ultrasonic treatment, the content of α-helix and β-corner reduced, and the content of β-folding and random coil increased. Compared with the control group, the ultrasonic treatment increased surface hydrophobicity and the content of SH while reduced the content of SS in milk protein, thus improving the ACE inhibitory activity of enzymatic hydrolysates. Furthermore, three quantitative prediction models of PLS, iPLS and Si-PLS for ACE inhibition rate of milk protease hydrolysates were established. And all these three different in-situ real-time prediction models had good predictive effect on the ACE inhibition rate of milk proteolysis products and gastrointestinal simulated digestion products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Sonication can significantly enhance amino acids (AAs) release to accelerate maturation during short-term and low-salt soy sauce fermentation. Here, sonication was applied at 68 kHz (60 W/L/10 min/8 circles) to determine its effects on the taste during long-term and high-salt soy sauce fermentation. The possible mechanisms were explored by analyzing differences in enzymes profile, proximate indices, molecular weight distribution of peptides, AAs composition and microstructures of sonicated moromis and their controls. Sonication greatly elevated levels of organic taste compounds ranging from 8.4% to 22.2%, but lowered levels of NaCl (6.0%), peptides ≤ 1 kDa (5.2%), histidine (20.5%) and glutamic acid (3.4%). Compared to its controls, sonicated raw soy sauces also had a more harmonious and palatable taste. Increased enzymes' activities and formation of more surface area and reaction sites in sonicated moromis might be the possible mechanisms for sonication to elevate levels of taste compounds and sensory quality of soy sauce., (Copyright © 2019. Published by Elsevier Ltd.)

Functionalities, conformational characteristics and antioxidative capacities of sunflower meal protein isolate (SMPI) and its hydrolysates (SMPIH) at various degree of hydrolysis (DH) (6, 12, 18, 24%) were investigated following sonication. Enzymolysis notably enhanced the solubility, foaming properties and emulsion stability index (ESI) of untreated and sonicated SMPI at most examined pH. Nonetheless, emulsion activity index (EAI) of SMPI were more than SMPIH at all pH values, especially at pH 4.0-10.0 (P < 0.05). Compared with control, sonication improved solubility, foaming capacity and emulsification properties, but decreased foaming stability and had significant influence on the SMPI and SMPIH structure. Furthermore, sonication efficaciously enhanced reducing power and superoxide, and ABTS radical scavenging capacity of all preparations (P < 0.05) over control, confirmed by the analyses of hydrophobicities and content of amino acid compositions. Finally, our investigation suggests that sonicated SMPIH can create new opportunities for developing natural additives for different cosmetic, food and pharmacological preparations., (Copyright © 2019 Elsevier B.V. All rights reserved.)

We investigated the impact of sonochemical action and the reaction of Hermetia illucens larvae meal protein (HILMP) as regards enzymolysis under varied enzyme concentration and temperature to explain the mechanism and effect of sonication on molecular conformation, limits of kinetics, free-Gibbs energy, and antioxidative capacity. Control treatment was used for comparison. The results showed sonochemical treatment enhanced HILMP-enzymolysis efficiency at various enzyme volume, and temperature. Enzymolysis-kinetics revealed sonochemical treatment increased the rate constant (p < .05) by 17.21%, 25.06%, 26.91%, and 41.38% at 323, 313, 303, and 293 K, respectively. On free-Gibbs, sonochemical treatment reduced the reactants-reactivity energy, enthalpy, and entropy by 30.53%, 35.05%, and 10.71%, respectively (p < .05). Changes in spectra of UV and fluorescence, and micrographic imaging indicated alterations of HILMP by sonochemical treatment. Antioxidative activity of sonochemically-treated HILMP increased, compared to control. Thus, sonochemical treatment may be beneficial in the production of edible insect proteins with smaller molecular weights for different food and/or pharmaceutical applications. PRACTICAL APPLICATIONS: Sonochemical pretreatment of HILMP positively impacted it enzymolysis rate-reaction, stability of reaction products, structure, and bioactivity. Thus, the technique may be beneficial to industry in the processing/development of new (bioactive/pharmaceutical) products involving enzymolysis of edible insects (e.g., Hermetia illucens) protein; particularly at such a time where edible insects are projected to be a source of protein for human nutrition and livestock in the next few years., (© 2019 Wiley Periodicals, Inc.)

In recent years, there has been increasing interest in renewable and sustainable protein resource of plant origin. The reasons for this are summarized as follows: (1) green, low-cost, environmental friendly and sustainable concepts are deeply rooted in people's minds; (2) long-term use of animal protein can lead to high blood pressure, obesity, negative environmental impacts; (3) more and more vegetarians are emerged; (4) many consumers still do not accept food grade insect. Based on this situation, this paper links eco-innovative ultrasound technology to plant-derived sustainable proteins resource, and magnifies the advantages of both at the same time. Ultrasound is a novel, green and rapid developing environmental friendly technology, which is suitable for up scaling and improving the physicochemical properties of protein. This review summarizes the mechanisms, cavitation properties of ultrasonic field, consumption of energy, applications of spectroscopic techniques for evaluating plant-derived proteins conformation changes, effects of ultrasound on the structure and physicochemical properties of plant-derived renewable proteins, and application of ultrasound treatment proteins in food industry. Furthermore, future research to better utilize this green technology is suggested. In this way, it not only conforms to the concept of sustainable, high-efficiency, and environmental protection of the food protein industry, but also clarifies the relationship between protein structure and properties, which are conducive to the application of ultrasound in protein industrialization., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The effects of ultrasound and acid on the aggregation, structures and emulsifying properties of soybean protein isolate (SPI) were investigated. Results of solubility showed that ultrasonic treatments at 0.001 M HCl increased the content of soluble SPI. The particle size of soluble aggregates subjected to ultrasonication and acid was initially decreased and then increased with increasing ultrasonic time. Secondary structure analysis, by circular dichroism, indicated lower a-helix and higher random coil amounts in SPI treated with short ultrasonic time, in contrast to the higher a-helix and lower random coil in SPI treated with longer time (more than 20 min). Emulsions prepared with SPI by 10 min of ultrasonication demonstrated significantly (P < 0.05) small droplet sizes and long term stability in comparison with their untreated counterparts. These results highlight that the emulsifying properties of SPI can be significantly improved by the synergistic effect of ultrasound and acid., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of this study was to establish a new model to reflect the real ultrasound pretreatment process on rice protein (RP). In this study, ultrasound treatment affected the yield of soluble protein of RP significantly and also improved the enzymatic hydrolysis efficiently. However, the aggregation of soluble protein occurred when ultrasonic power density and temperature reached a high level. The traditional model cannot reflect the real pretreatment process on RP due to the aggregation of protein. In this paper, a modified kinetic model was thus established by introducing a parameter of aggregation coefficient based on the Fick's second law, suggesting the two coefficients were highly dependent on the ultrasonic power density and temperature. Besides, the results of scanning electron microscope (SEM) both the untreated and samples pretreated by ultrasound indicated that the enzymatic hydrolysis efficiency was influenced by changing the structure of RP. Thereto, ultrasound treatment at proper conditions can shorten the enzymolysis time of RP and improve the efficiency of hydrolysis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Effects of low-intensity ultrasound (at different frequency, treatment time and power) on Saccharomyces cerevisiae in different growth phase were evaluated by the biomass in the paper. In addition, the cell membrane permeability and ethanol tolerance of sonicated Saccharomyces cerevisiae were also researched. The results revealed that the biomass of Saccharomyces cerevisiae increased by 127.03% under the optimum ultrasonic conditions such as frequency 28kHz, power 140W/L and ultrasonic time 1h when Saccharomyces cerevisiae cultured to the latent anaphase. And the membrane permeability of Saccharomyces cerevisiae in latent anaphase enhanced by ultrasound, resulting in the augment of extracellular protein, nucleic acid and fructose-1,6-diphosphate (FDP) contents. In addition, sonication could accelerate the damage of high concentration alcohol to Saccharomyces cerevisiae although the ethanol tolerance of Saccharomyces cerevisiae was not affected significantly by ultrasound., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Biodiesel production from soybean oil deodorizer distillate enhanced by counter-current pulsed ultrasound was studied. Effect of static probe ultrasonic enhanced transesterification (SPUE) and counter-current probe ultrasonic enhanced transesterification (CCPUE) on the biodiesel conversion were compared. The results indicated that CCPUE was a better method for enhancing transesterification. The working conditions of CCPUE were studied by single-factor experiment design and the results showed that the optimal conditions were: initial temperature 25 °C, methanol to triglyceride molar ratio 10:1, flow rate 200 mL/min, catalyst content 1.8%, ultrasound working on-time 4 s, off-time 2 s, total working time 50 min. Under these conditions, the average biodiesel conversion of three experiments was 96.1%., (Copyright © 2014 Elsevier B.V. All rights reserved.)

There is a great demand for developing efficient extraction methods in order to reduce extraction time and increase the yield and activity of functional antioxidants. The yields, activities, and extraction kinetics of antioxidants from dry peel of pomegranate marc were studied using ultrasound-assisted extraction in continuous and pulsed modes and the results were compared with conventional extraction (CE) at a temperature of 25±2°C and water/peel ratio of 50/1, w/w. The studied factors were intensity level and treatment time for continuous ultrasound-assisted extraction (CUAE), and intensity level, number of pulse repetition, and pulse duration and interval for pulsed ultrasound-assisted extraction (PUAE). The results showed that all factors significantly affected the antioxidant yield, but only treatment time had a significant effect on the antioxidant activity. Compared to CE, PUAE at intensity level of 59.2 W/cm(2), and the 5 and 5s of pulse duration and interval increased the antioxidant yield by 22% and reduced the extraction time by 87%. Similarly, CUAE at the same intensity level increased the antioxidant yield by 24% and reduced the extraction time by 90%. Since PUAE had 50% energy saving compared to CUAE, we recommend using PUAE for the extraction with antioxidant yield of 14.5% and DPPH scavenging activity of 5.8 g/g. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound-assisted extractions under PUAE and CUAE. This research clearly demonstrated the superiority of PUAE for producing antioxidants from peel of pomegranate marc., (Published by Elsevier B.V.)

Background: It would be impossible to imagine a country where cereals and their byproducts were not at the peak of foodstuff systems as a source of food, fertilizer, or for fiber and fuel production. Moreover, the production of cereal proteins (CPs) has recently attracted the scientific community's interest due to the increasing demands for physical wellbeing and animal health. However, the nutritional and technological enhancements of CPs are needed to ameliorate their functional and structural properties. Ultrasonic technology is an emerging nonthermal method to change the functionality and conformational characteristics of CPs. Scope and approach: This article briefly discusses the effects of ultrasonication on the characteristics of CPs. The effects of ultrasonication on the solubility, emulsibility, foamability, surface-hydrophobicity, particle-size, conformational-structure, microstructural, enzymatic-hydrolysis, and digestive properties are summarized. Conclusions: The results demonstrate that ultrasonication could be used to enhance the characteristics of CPs. Proper ultrasonic treatment could improve functionalities such as solubility, emulsibility, and foamability, and is a good method for altering protein structures (including surface hydrophobicity, sulfhydryl and disulfide bonds, particle size, secondary and tertiary structures, and microstructure). In addition, ultrasonic treatment could effectively promote the enzymolytic efficiency of CPs. Furthermore, the in vitro digestibility was enhanced after suitable sonication treatment. Therefore, ultrasonication technology is a useful method to modify cereal protein functionality and structure for the food industry. [ABSTRACT FROM AUTHOR]

In this study, the accumulation of γ‐aminobutyric acid (GABA) in coffee leaves under ultrasonication and the impacts on total phenolic content (TPC), the activities of glutamate decarboxylase (GAD) and GABA transaminase (GABA‐T), and angiotensin‐converting enzyme (ACE) were investigated. The pH, incubation time, and ultrasonic power were the three most important factors that affected the accumulation of GABA. Coffee leaves treated with 20/40 kHz ultrasound have the highest GABA and the greatest GAD and ACE inhibitory activity. After optimization with a Box–Behnken design, GABA content was increased by 1.6 times under the optimal conditions of pH 5.9, incubation time 6.6 hr, and ultrasonic power 150 W. Our study indicated that ultrasonication activated GAD while inhibited GABA‐T, thereby leading to an increase in GABA and ACE inhibitory activity. Ultrasonication also enhanced TPC; however, long time incubation caused the oxidation of phenolic compounds, and thus, affected the ACE inhibitory activity. Novelty impact statement: This is the first research that studied the enrichment of Gamma‐aminobutyric acid (GABA) in coffee leaves using ultrasound stress. GABA‐enriched coffee leaves can be used to prepare tea‐like beverage or natural health products to prevent hypertension, anxiety, and sleeplessness. [ABSTRACT FROM AUTHOR]

The use of ultrasound has the potential of improving the production of valuable substances in Ganoderma lucidum (G. lucidum)—a well‐known fungus rich in bioactive compounds. The effect of different ultrasonic parameters on the fermentation of G. lucidum was studied. The results showed that under optimal ultrasonic conditions, the mycelium biomass and triterpenoids production increased by 26.99 and 33.62%, respectively (p <.05). Compared with the control, ultrasonication notably increased (p <.05) the content of intracellular and extracellular polysaccharides (by 18.48 and 35.90%) and flavonoids (by 30.27 and 12.00%) in mycelium. Ultrasonic treatment promoted growth, and increased metabolism of G. lucidum. Scanning electron microscopy images showed that ultrasonic treatment caused moderate breakages in mycelium leading to leaked content at recovery time of 0.5 hr. When the recovery time lasted for 3 hr, the mycelium was recovered with increased branches and tighter winding. The findings of Fluo‐4/AM suggested that the intracellular calcium ion concentration of the mycelium improved after ultrasound treatment, demonstrating the altering‐influence of sonication on the cell membrane permeability of mycelium. These results suggest that ultrasound is an efficacious approach to produce more biomass and metabolites of G. lucidum in liquid fermentation. Practical Applications: Ultrasonic technology has been widely used in the field of food fermentation. By changing the ultrasonic time, power density or frequency or other conditions, the ultrasonic energy entering the cell suspension can be changed, thereby controlling the effect of ultrasound on microbial activity. The outcome of this work indicated that the use of ultrasonication in fermentation process of G. lucidum promoted its growth and metabolism. This study provides a theoretical basis for the application of ultrasonication technology in the microbial fermentation industry. [ABSTRACT FROM AUTHOR]

The purpose of this study was to come up with a method to screen ultrasonication parameters that mainly predict ultrasound extraction process efficiency, using multiple regression analysis and response surface method (RSM). The relevance of this study is the fact that combining RSM with multiple regression modeling gives a conclusive report on the actual effects of individual treatment parameters. Although all predictors [time (A), frequency (B), power (C) and ratio (D)] showed significance in RSM models, multiple regression models further indicated that only D significantly influenced the variability observed in total phenol content and antioxidant activity of buckwheat extracts. [ABSTRACT FROM AUTHOR]

In this study, an in situ 7.5 L ultrasonic fermentation tank was used to culture Saccharomyces cerevisiae at 30°C for 36 hr to explore the effects of low intensity ultrasound on the production of glutathione (GSH). Ultrasonic conditions of 28 kHz frequency, 28 W/L power density for fermentation time of 0–12 hr, 280 W/L power density for fermentation time of 12–36 hr, 3 s of interval and fixed frequency mode were used for the set‐up and a nonsonicated set‐up served as the control for the experiment. Results showed that ultrasound treatment increased total GSH production by 15.60% from a maximum value of 45.52 mg/L in the control to a maximum value of 52.62 mg/L in the sonicated sample. Also, intracellular and extracellular GSH productions in the sonicated sample increased by 5.60% and 42.92% respectively. Regular detection of the changes of biomass yield, residual sugar, dissolved oxygen and pH showed that sonication resulted in biomass increased by 7.25%, glucose consumption rate increased by 53.08% and dissolved oxygen content decreased by 41.67%. The biomass models of sonication and nonsonication treatments were established according to growth of S. cerevisiae showed that the model fitted well with Logistic regression in which the strain specific growth rate increased by 60.95% after sonication. GSH production model agreed with Luedeking‐Piret regression in which GSH synthesis parameters of sonication, α and β increased by 1.96% and 19.64% in comparison to the nonsonicated sample. This study clearly demonstrated that ultrasonic stimulation could improve the biosynthesis of GSH during fermentation. Practical Applications: In this study, the GSH was producted by microbial fermentation in in situ 7.5 L ultrasonic fermentation tank. During the fermentation, sonication was applied to increasing yield of GSH. The results show that the study provides a theoretical basis for manufacture GSH combined with sonication industrialization. The fermentation kinetic model was established, which provided experimental basis for continous fermentation. [ABSTRACT FROM AUTHOR]

Impacts of dual‐frequency ultrasonic (DFU) with various operating modes (simultaneous and sequential modes) on degree of hydrolysis (DH) and conversion rate (CR) of sunflower meal protein (SMP) and activity of ACE‐inhibition of SMP hydrolysates were examined. Results revealed that sequential and simultaneous modes enhanced DH by 7.73% and 11.22%, and CR by 26.23% and 26.98% of SMP (p <.05). Additionally, the maximal ACE‐inhibition activity obtained at 75 min of enzymolysis was 64.46% for sonicated SMP hydrolysate (simultaneous mode), which was 32.52% higher than the control. Alterations in surface hydrophobicity, UV‐Vis spectra, and intrinsic fluorescence indicated unfolding of SMP. AFM showed that sonication decreased the particles size and altered the structure of SMP. Amino acids composition demonstrated that both DFU modes pretreatments could improve the hydrophobic amino acids. Consequently, sonication enhanced DH, CR of SMP, and the activity of ACE‐inhibition of hydrolysates confirmed by changes in SMP structure. Practical applications: Sunflower protein, an extract from sunflower meal, is a potential source for preparing the bioactive compounds such as ACE‐ inhibition peptides. These peptides are safe, easy to absorb and stable, and have certain benefits for patients. Sonication with different operating frequency modes were applied to enhance enzymolysis of sunflower protein and ACE‐inhibition activity of its hydrolysates. Sonication was displayed to be an operative technique to yield hydrolysates with good ACE‐inhibition activity confirmed by monitoring the alterations in sunflower protein structure. Thus, sonication pretreatment of sunflower protein maybe practicable in the enzymolysis and the activity of ACE‐inhibition in industry. [ABSTRACT FROM AUTHOR]

Antioxidant activity, total phenolic content (TPC), total flavonoids, carotenoids, pH, and total titratable acidity of red and black date's vinegar were analyzed. The extraction method was designed and optimized for this purpose with respect to the variety and solvent concentrations along with the time of ultrasonication. The results showed that red dates' vinegar has significantly (p < 0.05) higher total phenols (3.38 ± 0.13 mg GAE/ml) and antioxidant activity as compared to black dates' vinegar, which had a higher amount of carotenoids (3.43 ± 0.11 mg/100 ml). Similarly, red dates' vinegar has more flavonoids as compared to commercially available Zhenjiang vinegar. In terms of physiochemical properties, both red and black date's vinegar were not significantly different (p > 0.05). Use of 50% and 80% methanol with 25 min of ultrasonication for extraction seemed more effective. The total phenols, flavonoids, antioxidant activity, carotenoids, and physiochemical analysis of the red and black date's vinegar indicated that vinegar from dates (red or black dates) is a competitive product in the marketplace. [ABSTRACT FROM AUTHOR]

Highlights: [•] The ACE-inhibitory activity increased by horn and bath sonication. [•] Combinations of fixed frequency (bath) produced more ACE-inhibitory peptides. [•] Changes in structural properties of DWGP after sonication were found. [•] Horn sonication was efficient in preparation of ACE-inhibitory peptides. [Copyright &y& Elsevier]

Cherry tomato fruits were treated with three dual‐frequency ultrasound (US) at different temperature and time. The three treatment variables, that is, dual‐frequency US, temperature, and time were optimized with the aid of response surface methodology (RSM). About 20/40 kHz, 52°C, and 6 min were the optimum condition obtained for total bacteria count (TBC, 1.08 log cfu/g), firmness (15.90 N), and total phenolic content (TPC, 34.34 mg GAE/100 g). All the linear relations of the treatment variables showed a significantly negative and positive effect on the TBC and TPC, respectively, while positive significant effects were obtained for some of the relations of the firmness. Hence dual‐frequency sonication is effective for microbial safety and maintaining the quality of cherry tomato. Also, RSM was found to be a useful tool in setting and optimizing the variables responsible for sonication treatment. Practical applications: Thermosonication (ultrasonication and heat) has been applied toward improving the microbial safety and nutritional quality of vegetables and fruit. However, factors such as power, frequency, time, temperature, etc. determine the efficiency of its operation. Controlling these factors is difficult and therefore requires a robust and efficient optimization tool in determining their effects (individual and interactions) on food during treatment. In this study, response surface methodology provides the solution in settling and optimizing the variables for the sonication treatment. Besides, the remarkable result obtained in this work offers an alternative to the combined use of ultrasound and chemical in food industries. [ABSTRACT FROM AUTHOR]

The study investigated the effect of sonication conditions on antioxidant activity of Hermetia illucens larvae meal protein hydrolysates. Three‐factor three‐level: pH (7–9), time (10–30 min), and temperature (25–55°C) were optimized. Box–Behnken's design was applied to optimize sonication treatment. Ferrous ion chelating activity (ICA), DPPH‐radical scavenging activity (DPPHRSA), Hydroxyl radical scavenging activity (HRSA), and cupric ion chelating activity (CCA) were considered as responses. Findings demonstrated that sonication preceding enzymolysis significantly impacted on ICA, DPPHRSA, HRSA, and CCA. ANOVA showed the determination coefficient (R2) were 0.98 (ICA), 0.99 (DPPHRSA), 0.98 (HRSA), and 0.88 (CCA); demonstrating that the models were reasonably fit with experimental results. Optimum sonication conditions were pH (9), time (29.84 min), and temperature (54.93°C). For these conditions, the experimental data obtained [ICA (37.84%), DPPHRSA (43.19%), HRSA (71.01%), and CCA (68.93%)] were consistent with predicted values, higher than control, and supported by protein subunits, fluorescence spectra and microstructure. Practical applications: With a rich nutrient profile, edible insects are potential ingredient for food applications. Hermetia illucens is one of the most encouraging edible insect species for incorporation in food products as it has several benefits to the environment, coupled with the already available knowhow for their rearing. With the prediction that in the next few decades insects will be reliable source of protein for humans and livestock, it is logical that the antioxidants activity of insect larvae meal proteins are investigated for new product development. Ultrasound is reported to enhance enzyme action in the preparation of bioactive hydrolysates/peptides. The present study showed that the use of ultrasonication pretreatment in the enzymatic hydrolysis of HILMP to generate hydrolysates with antioxidant constituents was efficient (likened to conventional approach). The study outcome could help the food and/or pharmaceutical industry to advance new bioactive products/ functional foods from HILMP hydrolysates. [ABSTRACT FROM AUTHOR]

Abstract: There is a great demand for developing efficient extraction methods in order to reduce extraction time and increase the yield and activity of functional antioxidants. The yields, activities, and extraction kinetics of antioxidants from the dry peel of pomegranate marc were studied using ultrasound-assisted extraction in continuous and pulsed modes and the results were compared with conventional extraction (CE) at a temperature of 25±2°C and water/peel ratio of 50/1, w/w. The studied factors were intensity level and treatment time for continuous ultrasound-assisted extraction (CUAE), and intensity level, number of pulse repetition, and pulse duration and interval for pulsed ultrasound-assisted extraction (PUAE). The results showed that all factors significantly affected the antioxidant yield, but only treatment time had a significant effect on the antioxidant activity. Compared to CE, PUAE at an intensity level of 59.2W/cm2, and a pulse duration of 5s and a resting interval of 5s increased the antioxidant yield by 22% and reduced the extraction time by 87%. Similarly, CUAE at the same intensity level increased the antioxidant yield by 24% and reduced the extraction time by 90%. Since PUAE had 50% energy saving compared to CUAE, we recommend using PUAE for the extraction with antioxidant yield of 14.5% and DPPH scavenging activity of 5.8g/g. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound-assisted extractions under PUAE and CUAE. This research clearly demonstrated the superiority of PUAE for producing antioxidants from peel of pomegranate marc. [Copyright &y& Elsevier]

The effect of pectin concentration on the structural and emulsifying properties of black soldier fly larvae albumin (BSFLA) modified by pH-shifting (pH 12) and ultrasound (US) was studied. The results (intrinsic fluorescence, surface hydrophobicity, Fourier transform infrared spectrum, and disulfide bonds) showed that modified BSFLA samples, especially pH 12 -US, were more likely to bind to pectin through hydrogen bonding, electrostatic interactions, and hydrophobic interactions due to the unfolding of BSFLA, the collapse of disulfide bonds and exposure of hydrophobic groups. Thus, a BSFLA-pectin complex with smaller particle size, more negative charges, and a relatively loose structure was formed. The emulsifying activity (EAI) and stability index (ESI) of pH 12 -US modified BSFLA were significantly enhanced by the addition of pectin, reaching the highest values (associated with 174.41 % and 643.22 % increase, respectively) at pectin concentration of 1.0 %. Furthermore, the interface modulus of the emulsion prepared by the modified BSFLA was mainly viscous, and had higher apparent viscosity, smaller particle size and droplet size, contributing to higher EAI and ESI. The study findings suggest the addition of pectin to pH 12 -US treated BSFLA could be used in industry to prepare BSFLA-pectin emulsion with exceptional/desirable properties. • Ultrasound and pH-shifting significantly improved the emulsibility of BFSLA. • BSFLA bond to pectin by hydrogen bonding, electrostatic and hydrophobic interactions. • Pectin had a high affinity for BSFLA subunits with molecular weights between 55 and 95 kDa. • Modified BSFLA was easier to bind to pectin due to its structural unfolding. • The emulsibility of modified BSFLA could be significantly improved by adding pectin. [ABSTRACT FROM AUTHOR]

• Sonication did not cause change in lightness of protein hydrolysates. • Zeta, dispersibility, and thiol value(s) increased following sonication. • Turbidity, and particle size (of samples) decreased after sonication. • SDS-PAGE profile showed similar bands for control and sonicated samples. • Ultrasonic-treated hydrolysates exhibited high fraction of small-sized peptides. The effect of conventional (control), and different ultrasonic treatment modes (fixed, and sweep frequency ultrasound) on structural, physical and functional traits of soldier fly (Hermetia illucens) larvae protein preparations and hydrolysates were examined. Ultrasonication significantly increased lightness (L*) of protein isolates by x ¯ 7.46 % compared to control. Sonic-treated (particularly sweep-type) isolates and hydrolysates showed significant increases in thiol value, reconstitutability function (pH 2–10), and surface charge; and significant decreases in turbidity, and particle size, relative to controls. Protein isolates were characterized by higher molecular weight (M W) using SDS-PAGE, whereas hydrolysates were lower (with no observable variances). By numerical estimation, hydrolysates (especially the sweep-treated) showed significantly lower M W (<1000 Da). Deconvoluted FTIR spectra (α-helix, β–sheet/turn, random coil fractions), and UV spectra analyses showed differences in samples. Treatment type (sweep/ fixed frequency ultrasound) could be used to alter protein structure, modify functionality, and thereby usage of H. illucens protein/hydrolysate preparations. [ABSTRACT FROM AUTHOR]

We added three different carbohydrates (Xylose/Xyl, Maltose/Mal, and Sodium alginate/Sal) to pH 12.5 -shifted silkworm pupa protein isolates (SPPI), and examined the influence of multi-frequency ultrasound (US) on them, with reference to lysinoalanine (LAL) formation, changes in conformational characteristics and functionality. Results showed that, the LAL content of the glycoconjugates - SPPI-Xyl, SPPI-Mal, and SPPI-Sal decreased by 1.47, 1.39, and 1.54 times, respectively, compared with the control. Notably, ultrasonication further reduced the LAL content by 45.85 % and brought SPPI-Xyl highest graft degree (57.14 %). SPPI-Xyl and SPPI-Mal were polymerized by different non-covalent bonds, and SPPI-Sal were polymerized through ionic, hydrogen, and disulfide (covalent/non-covalent) bonds. Significant increase in turbidity, Maillard reaction products and the formation of new hydroxyl groups was detected in grafted SPPI (p < 0.05). US and glycation altered the structure and surface topography of SPPI, in which sugars with high molecular weight were more likely to aggregate with SPPI into enormous nanoparticles with high steric hindrance. Compared to control, the solubility at pH 7.0, emulsifying capacity and stability, and foaming capacity of SPPI-US-Xyl were respectively increased by 244.33 %, 86.5 %, 414.67 %, and 31.58 %. Thus, combined US and xylose-glycation could be an effective approach for minimizing LAL content and optimizing functionality of SPPI. [Display omitted] • The LAL content in SPPI decreased by 1.39– 1.54 times using glycation treatment. • SPPI-sugar conjugates involved different covalent or non-covalent linkages. • US promoted the Maillard reaction while inhibiting the formation of end products. • The LAL content in SPPI-US-Xyl reduced by 45.85 % compared to pH 12.5 -shifted SPPI. • The solubility, emulsifying and foaming properties of SPPI-US-Xyl were prominent. [ABSTRACT FROM AUTHOR]

• Multi-mode S-type ultrasound device was used to extract protein from walnut dregs. • The extraction level of walnut protein was improved under the ultrasonic treatment. • Sonication could cause the structure changes of walnut protein. • The extraction level of protein was positively correlated with the -SH content. • In situ and real-time monitoring model with good prediction effect was established. This study aimed to investigate the impact of multi-mode S-type ultrasound treatment on the protein extraction level of walnut dregs. The structural properties of the walnut protein (WP) were characterized, and the correlation between protein structure and extraction level was analyzed. The in situ real-time monitoring model for the ultrasound-assisted WP extraction process was established by a miniature fiber near-infrared (NIR) spectrometer. Results showed that the protein yield, purity, and comprehensive extraction index (CEI) of extracted WP were 71.07 %, 72.69 %, and 71.72, respectively, under optimal conditions (dual-frequency 20/28 kHz, ultrasonic treatment duration 30 min, and ultrasound power density 120 W/L). The secondary structure of extracted WP displayed that the proportion of α -helix and β -sheet reduced, while the contents of β -turn and random coil increased after ultrasonic treatment. Besides, sonication decreased the disulfide bond content and increased free sulfhydryl (-SH) and surface hydrophobicity compared to the control. The microstructures of WP confirmed that appropriate sonication could unfold the protein aggregates and reduce the particle size. The extraction level of WP is positively correlated with the -SH content (p < 0.01). The quantitative prediction model of Si-PLS for -SH content in the ultrasound-assisted WP extraction process was established and performed a good correction and prediction performance (Rc = 0.9736; RMSECV = 0.446 μmol/L; Rp = 0.9342; RMSEP = 0.807 μmol/L). This study exploited a high-efficiency way for the WP extraction industry, and provided theoretical support for the development of the intelligent system in industrial protein extraction process. [ABSTRACT FROM AUTHOR]

• Ultrasound conditions affected alkaloids and phenolics differently in coffee leaves. • Triple-frequency (20/35/50 kHz) ultrasound inhibited phytochemicals and PPO activity. • Single frequency (35 kHz) ultrasound increased phenolics and inhibited POD. • PPO and POD were temporarily inactivated by ultrasound. • The activities of PPO and POD were recovered during the incubation period. In the present study, we investigated the impacts of ultrasonic conditions on the phytochemical profiles, antioxidant activity, and polyphenol oxidase (PPO) and peroxidase (POD) activities in coffee leaves. Ultrasonic frequency, power, and time, pH, and incubation time affected PPO and POD differently, thus resulting in different ABTS scavenging capacity and phenolic content in coffee leaves. Triple-frequency (20/35/50 kHz) ultrasound significantly (P < 0.05) inhibited trigonelline, caffeine, mangiferin, rutin, chlorogenic acids, antioxidant activity, and PPO activity, while the single frequency of 35 kHz increased the phenolics compounds, which was associated with the lowest POD activity. Increasing the incubation time after ultrasonication gradually decreased phenolic compounds and antioxidant activities, however, POD activity followed a temporal pattern of first increase and then decrease. Our results showed that PPO and POD were temporally inactivated after ultrasonication, which leading to the continuous decrease of phenolics in coffee leaves. [ABSTRACT FROM AUTHOR]

• Dual-frequency ultrasound thawing (DUT) was used to treated small yellow croaker. • The small yellow croaker treated by DUT exhibited satisfactory quality traits. • The quality of the fish was evaluated by TMT-labeled quantitative proteomics. • There were 40 proteins correlated closely with quality indicators of the fish meat. • Eleven proteins can be potential biomarkers for monitoring quality of the fish. The effect of dual-frequency sequential ultrasonic thawing (DUT) on the quality of quick-frozen small yellow croaker was studied by TMT-labeled quantitative proteomic method. A total number of 75 proteins were identified as differentially abundant proteins (DAPs) in fish meat treated by DUT, while 72 DAPs were in flow water thawing (FWT). The Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that the DAPs in the significant enrichment pathway of DUT group were enzymes. Compared with FWT, DUT had a significant effect on the enzyme content. The correlation analyses indicated that 40 DAPs were related with the quality traits. The 11 highly correlated DAPs are expected to be used as potential protein markers for texture profile analyses, color, thawing loss, water-holding capacity, and pH of thawed small yellow croaker quality. These results provide a further understanding of the quality stability of quick-frozen small yellow croaker treated by the DUT. [ABSTRACT FROM AUTHOR]

• Sonication further lowered bitterness of enzymatically hydrolyzed Ougan juice. • Sonication improved flavor of enzymatically hydrolyzed Ougan juice. • Sonication markedly enhanced glycosidic hydrolases activities from A. niger. • Sonication markedly weakened C O bonds of naringin in Ougan juice. • Improved enzyme activities and substrate structure facilitated bitter compounds degradation. The optimal sonication conditions (40 kHz, 80 W/L and 60 min) during Ougan juice debittering by Aspergillus niger koji extract were established. Enzymatic hydrolysis degrees of naringin and limonin were enhanced to 89.90% and 36.16%, and enzymatic hydrolysis time was shortened by 33%. Sonication significantly enhanced activities of α- l -rhamnosidases, β-glucosidases and limoninases from A. niger koji extract and facilitated break of C O bonds in naringin (p < 0.05). These accounted for the enhanced enzymatic hydrolysis degrees and velocities of bitter compounds. Meanwhile, sonication lowered 40%, 7% and 21%, 13%, 11%, 25% of bitter, sour tastes and green, citrus-like, floral, woody notes, but enhanced 18% and 15% of fruity and sweet notes, resulting in 38% and 33% increases in over-all taste and aroma scores. Lowered levels of bitter compounds, organic acids, green, citrus-like, floral, woody aroma compounds and enhanced levels of fruity, sweet aroma compounds caused by sonication accounted for the flavor improvements. [ABSTRACT FROM AUTHOR]

• Low-power density ultrasound pretreatment enhanced enzymolysis efficiency of CGM. • Sequential and simultaneous dual-frequency mode improved notably enzymatic efficacy. • A duple-frequency of 20/40 kHz was particularly effective on enzymatic efficiency. • Enzymolysis property may be affected by various ultrasonic frequency combinations. • SEM displayed that the microstructure of CGM changed by ultrasound-induced effect. The influence of varying frequency modes of a low-power density ultrasound (LPDU) on the enzymolysis efficacy and structural property of corn gluten meal (CGM) was investigated. Sonication pretreatment (of CGM) with sequential and simultaneous duple-frequency modes enhanced notably the relative enzymolysis efficiency, compared to other LPDU frequency modes. With a sequential duple-frequency of 20/40 kHz showing the most significant effect, the maximum value of enzymolysis efficiency and protein dissolution rate were 15.99% and 61.69%, respectively. Changes in the surface hydrophobicity, secondary structure and microstructure revealed alterations of conformation of CGM by ultrasound-induced effect. Furthermore, the molecular weight distribution CGM hydrolysates primarily distributed in 200–500 Da following ultrasonication. Sonication efficaciously enhanced the susceptibility of CGM to alcalase proteolysis. Thus, the use of various LPDU frequency modes in pretreating target proteins (CGM) may be considered as a practical approach to improve protein-enzyme reactions (proteolysis). [ABSTRACT FROM AUTHOR]

• Thermosonication (TS) on carrots was effective to inactivate peroxidase (POD). • A dual-frequency of 22/40 kHz was particularly effective on the POD inactivation. • TS treatment (22/40 kHz) down-regulated the related POD gene expression. • EPR spectra contribute to understanding the inactivation mechanism of TS on POD. • Ultrastructure verified the phytochemical changes of carrot slices after treatments. The effects of ultrasonication (US) and thermosonication (TS) blanching at varying frequencies on the carrot peroxidase (POD) inactivation and potential mechanisms were studied. The physicochemical properties were evaluated. Hot water (HW) blanching was used as control. Thermosonication decreased the POD activity to a greater extent, with a dual-frequency of 22/40 kHz showing the most significant effect. The POD-related gene expression was down-regulated by TS, which was contrary to the thermally treated samples. Electron paramagnetic resonance (EPR) spectra revealed that ultrasound-induced radicals from water sonolysis might involve in the POD inactivation. Thermosonication substantially increased the total carotenoid content (TCC). The color analysis showed that thermosonicated samples with a dual-frequency (22/40 kHz) exhibited the maximum values of C * and Δ E , and the minimum value of the whiteness index (WI). The micrographs verified the alterations in TCC and relative electrolyte leakage (REL) of carrot treated by HW, US, and TS. [ABSTRACT FROM AUTHOR]

• Sonication accelerated aroma formation of soy sauce and reduced fermentation time by 90 days. • Sonication facilitated soy sauce aroma formation by lowering activation energy of reaction. • Sonication enhanced microbial growth, which increased the rate of aroma formation. Sonication was applied to accelerate aroma formation and shorten fermentation time of soy sauce. Effects of sonication at 68 kHz on the aroma and aroma-producing Zygosaccharomyces rouxii and Tetragenococcus halophilus in moromis were investigated using sensory evaluation, SPME–GC–olfactometry/MS, viable cell counting and scanning electron microscopy. The sensory scores of caramel-like, fruity, alcoholic, floral, malty, smoky, sour and overall aroma in sonicated moromis were enhanced by 23.4%, 23.2%, 13.6%, 12.8%, 7.6%, 6.3%, 5.6% and 14.4%, respectively. Sensory scores of samples fermented for 90–180 days were higher than those of controls fermented for 180 days, suggesting that sonication could reduce fermentation time by 90 days. Thirty-four aroma-active compounds were detected from 85 volatile compounds in soy sauces. Sonication accelerated and elevated the formation of aroma compounds by chemical reactions. It also markedly increased the reproduction and cell permeability of both microorganisms in moromis, which favored the formation of aroma compounds by both strains. [ABSTRACT FROM AUTHOR]

Sequential delignification of watermelon rind using ultrasonication and deep eutectic solvent (DES) pretreatment methods was demonstrated in this study. The effects of pretreatment factors on delignification were investigated using parametric screening and subsequent optimization of significant factors. Plackett–Burman Design was used for the screening of pretreatment variables, while optimization was performed adopting Central Composite Rotatable Design. For the range of variables considered in the study, the screening experiments revealed that the effects of ultrasonication power, ultrasonication frequency, ultrasonication time, DES reaction temperature and DES reaction time on delignification were significant, while the effects of ultrasonication solid-liquid ratio, ultrasonication temperature, hydrogen bond acceptor/hydrogen bond donor molar ratio, and DES solid-to-liquid ratio were not significant. The significant factors were further investigated and maximum lignin removal of 43.56 % was achieved at ultrasonication power 180 W , ultrasonication frequency 60 k H z , ultrasonication time 40 m i n , reaction temperature 120° C and reaction time 180 m i n. Synergistic effect between the two pretreatment methods was observed and it correlated positively with the severity of the ultrasound pretreatment. The SEM and FTIR analyses further established the effectiveness of the sequential combinative pretreatment methods on watermelon rind delignification. • Novel two-pot approach ultrasound-assisted DES pretreatment was demonstrated. • Effect of pretreatment factors on watermelon rind delignification was investigated. • Synergistic effect between ultrasonication and DES pretreatments was observed. • Synergistic effect correlated positively with severity of ultrasound pretreatment. • SEM and FTIR established the effectiveness of the combinative pretreatment methods. [ABSTRACT FROM AUTHOR]

• Enzymolysis and sonication altered the physical attributes of sunflower protein (SMP). • Sunflower protein hydrolysate (SMPH) displayed higher dispersibility than SMP. • SMPH had more movable/flexible secondary structure than SMP. • SDS-PAGE profile exhibited significant reduction in MW of sonicated SMP. • MW analysis revealed that SMPH had high proportion of small-sized peptides. Impacts of localized enzymolysis and sonication on physical, techno-functional, and structure attributes of sunflower meal protein (SMP) and its hydrolysate (SMPH) were studied. SMP was subjected to enzymolysis (using alcalase) to prepare SMPH with various degrees of hydrolysis (6–24% DH). Enzymolysis decreased colour lightness, turbidity, and particle size of unsonicated and sonicated SMP, while it increased the absolute values of zeta potential (P < 0.05). Sonication improved oil absorption capacity and dispersibility over unsonicated samples. Contrarily, sonicated preparations showed a decrease in water holding capacity. Intrinsic fluorescence and FTIR spectral analyses suggested that SMPH had more movable/flexible secondary structures than SMP. Moreover, the changes in sulfhydryl clusters and disulfide linkages following sonication demonstrated limited unfolding of SMP and SMPH structure and decrease in intermolecular interactions. SDS-PAGE profile exhibited significant reduction in molecular weight (MW) of sonicated SMP, whereas did not display differences between unsonicated and sonicated SMPH. From further MW analysis, SMPH was categorized with high proportion of small-sized peptides ≤ 3 kDa fractions, which increased from 78.64 to 93.01% (control) and from 82.3 to 93.88% (sonication) with enzymolysis (6–24DH). Localized enzymolysis and sonication can be utilised to modify the physical and conformational attributes of SMP and SMPH, which could enhance their functionalities and broaden the utilisation area in food industry. [ABSTRACT FROM AUTHOR]

To elucidate the effects of sonication on the antioxidant activities of compounds in soy sauce, sonication at 68 kHz (60 W/L/10 min/8 circles) was employed during moromi fermentation. Sonication enhanced four antioxidant indices of soy sauce from 5.29% to 24.29%, which were attributed to the significantly higher levels of free amino acids (FAAs, 12.45%), total phenolics (26.71%) and 1–3 kDa peptides (12.28%) in sonicated moromi. Amongst them, FAAs contributed 65.88% and 53.45% to the enhanced metal ion chelating activity and DPPH radical scavenging activity (p < 0.05), respectively. However, Maillard reaction products and isoflavones contributed little to the enhanced antioxidant activities, because sonication slightly affected Maillard reaction products, isoflavones and β-glucosidase activities during moromi fermentation. It was concluded that cell wall of soybean was destroyed by sonication, facilitating the release of antioxidant compounds, which significantly enhanced the antioxidant activities in raw soy sauce. • Sonication significantly facilitated antioxidant compounds release. • Sonication remarkably improved antioxidant activities of soy sauce. • FAAs, phenolics, 1–3 kDa peptides increase led to antioxidant activities improvement. [ABSTRACT FROM AUTHOR]

• With rich nutrient profile, insects are would-be ingredient for food applications. • Sonication yields H. illucens protein/hydrolysate (HIPH) with improved solubility. • Sonochemical action generates HIPH with augmented antioxidant effect. • HIPH may be used in food products based on desired functionality/bioactivity. Hermetia illucens (edible insect) larvae protein, and hydrolysates were prepared using three pretreatment modes (conventional, fixed-frequency ultrasonic, and sweep-frequency). Protein subunit scores, microstructure, antioxidative activity, and techno-functional property of the respective isolates and hydrolysates were investigated. Alkaline protease hydrolysis significantly enhanced protein solubility, but impaired the emulsifying property and foaming stability. Isolates and hydrolysates treated by ultrasound exhibited highest antioxidative effect, and showed excellent solubility and foam expansion over wide (2–12) pH, likened the conventional. Ultrasonic, particularly sweep-frequency, treated hydrolysates overall showed superior solubility, foam, and antioxidative (ABTS, Superoxide scavenging, and Ferric-reducing) capacity than the remaining modes and isolates (p < 0.05). Treatment type influenced microstructure, functional attributes and antioxidative capacity of hydrolysates and isolates. Thus, functional/antioxidative property could be improved or modified for different food applications based on elected treatment. H. illucens isolate and hydrolysate preparations thereof could suitably be used in development of novel food formulations. [ABSTRACT FROM AUTHOR]