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The aim of this work was to investigate the effects of ultrasonic treatment during soaking of potatoes on the physicochemical properties of starches obtained after 16 weeks of germination. The ultrasonic treatment showed a direct correlation between sprout length and ultrasonic time. The protein content decreased from 0.63 to 0.38 % and the fat content decreased significantly from 0.31 to 0.01 % after germination. The amylose content changed depending on the ultrasonic treatment, and increased from 36.27 to 40.92 % after 16 weeks of germination, which was related to the amylopectin debranching and the duration of the ultrasonic treatment. X-ray diffraction showed that the nanocrystals with hexagonal structure were not affected by the germination and the duration of ultrasonic treatment. Scanning electron microscopy showed that the surface of the starch granules was not affected by the enzymatic treatment. The sprouted potato starch resulted in films with better tensile strength and lower water vapor permeability (WVP) compared to the native potato starch films. In addition, the films produced with ultrasound stimulated potato starch exhibited better properties (high strength and low permeability), which is desirable when it comes to controlling moisture exchange between a food product and the surrounding atmosphere. • Ultrasound stimulate the germination of potatoes. • Germination has no influence on the nanocrystals structure with hexagonalarrangement that occur in potato starch. • Ultrasonic stimulation prior to potato germination increased the viscosity of the starch pastes. • Germinated potato starch reduces the water vapor permeability in thin films. [ABSTRACT FROM AUTHOR]

In this study, double enzyme hydrolysis significantly enhanced the DPP-IV inhibition rate compared to single enzyme. The α + K enzymes exhibited the highest inhibition rate. Ultrasonic pretreatment for 30 min improved the hydrolysis efficiency and DPP-IV inhibition rate, potentially due to the structural changes in hydrolysates, such as the increased surface hydrophobicity, and reduced particle size, α-helix and β-turn. Six peptides were screened and verified in vitro. QPY, WPEYL, and YPPQVM displayed competitive inhibition, while LPAAP and IPAPSFPRL displayed mixed competitive/non-competitive inhibition. The interactions between these six peptides and DPP-IV primarily occurred through hydrogen bonds, electrostatic and hydrophobic interactions. Network pharmacological analysis indicated that LPAAP might inhibit DPP-IV activity trough interactions with diabetes-related targets such as CASP3, HSP90AA1, MMP9, and MMP9. These results uncover the potential mechanism of regulating blood glucose by camel milk hydrolysates, establishing camel milk peptide as a source of DPP-IV inhibitory peptide. • Combination of double enzymatic and ultrasonication improved DPP-IV inhibition. • Six peptides were screened based on the predicted results and in vitro test. • LPAAP exhibited highest active against DPP-IV, with IC 50 values 199.66 ± 6.77 μM. • Molecular docking and network pharmacology predicted DPP-IV inhibition mechanism. [ABSTRACT FROM AUTHOR]

In order to better utilize the proteins in squid viscera (Dosidicus gigas), the effects of different pretreatments on the degree of hydrolysis (DH) and volatile compounds of hydrolysates were studied. The DH was used as an indicator to select alkaline protease as the optimal protease from 8 types of proteases. The hydrolysis conditions of alkaline protease and the flavor of the hydrolysates were investigated through single-factor, response surface methodology, and pretreatment-assisted hydrolysis experiments. The results showed that alkaline protease had the highest DH (42.08 ± 0.58%), with enzyme dosage of 1.5%, hydrolysis temperature of 45 °C, hydrolysis time of 5 h, and liquid-solid ratio of 4:1. The DH of the ultrasound group was significantly higher than other groups, with the highest DH (45.67 ± 0.34%) after ultrasound for 40 min (U40). The proportion of molecular weight < 1 kDa and the content of free amino acids (1613.64 mg/100 g) were the highest at U40. The electronic nose results indicated that the composition of organic sulfur and aliphatic compounds in U40 showed significant differences compared to other products. The U40 sample had the highest type and content of volatile compounds (especially benzaldehyde), which was more conducive to the volatilization of flavor substances. In conclusion, U40 pretreatment can effectively improve the DH and flavor of hydrolysates. • Hydrolysis conditions of squid viscera were optimized. • Effects of heat and ultrasound pretreatments on hydrolysis were investigated. • Ultrasound pretreatment enhanced the hydrolysis efficiency. • Ultrasound pretreatment improved the flavor of squid viscera hydrolysates. [ABSTRACT FROM AUTHOR]

• US-OH method was proposed as the optimal plant bioactive extraction technique. • EY, TPC, and antioxidant activity of US-OH extract were higher than other methods. • US-OH and MW-OH methods showed an improvement in the extract quality compared to the HAE method. The present study was carried out to investigate and optimize the recovery of Burdock (Arctium lappa L.) root extract (BRE) using Ohmic-assisted (OH) extraction method with ultrasonic (US-OH) and microwave (MW-OH) pretreatments. Initially the optimized OH condition was obtained with the aim of maximizing the extraction efficiency and total phenol content. Then, the effect of pretreatment time (20, 40 and 60 min), ultrasonic amplitude (50 and 100 %) and temperatures (30, 40 and 50 °C) in US-OH, and powers (100, 300 and 450 W) in MW-OH were investigated. Finally, optimized OH, US-OH, and MW-OH extraction methods were compared with the heat assisted extraction method (HAE). The results showed that all the main and interaction effects were significant in OH, US-OH, and MW-OH extraction methods (p < 0.05) and only the interaction effects on total phenolic content (TPC) were not significant in the OH method (p > 0.05). The voltage gradient equal to 12.8 V/cm, extraction time equal to 20.72 min and extraction temperature equal to 50 °C were obtained as optimal conditions in the OH extraction of BRE. Ultrasonic amplitude, extraction temperature and ultrasonic time 100 %, 50 °C and 40 min respectively were obtained as the optimum US-OH extraction method. According to the results of chemical compounds, microbial and morphological assays, extraction using pretreatment methods of ultrasound, microwave in ohmic heating, respectively, showed an improvement in the quality of the extraction compared to the conventional (HAE) method. [Display omitted] [ABSTRACT FROM AUTHOR]

Enzymolysis kinetics, thermodynamics and molecular conformation of brewer’s spent grain protein (BSGP) pretreated with ultrasound were examined. Results showed that ultrasound pretreatment significantly reduced Michaelis constant (Km) and the thermodynamic parameters, including activation energy (Ea), enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) of BSGP during enzymolysis. Moreover, the initial reaction rate (Vi), association constant (Ka) and reaction rate constants (k) of BSGP pretreated with ultrasound were higher than those of native BSGP. The spectral analysis with Ultraviolet-visible (UV–vis) and Fourier transform infrared (FTIR) manifested that ultrasound pretreatment exposed hydrophobic groups and induced molecular unfolding of BSGP. Particle size analysis and scanning electron microscopy (SEM) showed that ultrasound pretreatment decreased particle size while increasing flexibility of BSGP. All these structural changes resulted in the improvement on enzymolysis efficiency of BSGP pretreated with ultrasound. Therefore, ultrasound pretreatment could be an efficient method to enhance the enzymolysis sensibility of BSGP. [ABSTRACT FROM AUTHOR]

The effect of ultrasound (US) pretreatment (0, 200, 400, 600, and 800 W) on the physicochemical, emulsification, and gelatinization characteristics of citric acid (CA)-treated whey protein isolate (WPI) was investigated. Size exclusion chromatography demonstrated that when compared with untreated WPI, US pretreatment promoted production of more molecular polymers in the CA-treated WPI. There was a reduction in particle size of CA-treated WPI with the increase of US power (0–800 W), whereas its free sulfhydryl content, surface hydrophobicity, and intrinsic fluorescence strength increased. Furthermore, compared with untreated WPI, emulsifying ability index and emulsifying stability index of CA-treated WPI were increased by 14.04% and 10.10%, respectively, at 800 W. Accordingly, US pretreatment promoted the gel formation of CA-treated WPI, and its gel hardness was increased by 28.0% with US power ranging from 0 to 800 W. Therefore, US and CA treatment can be considered as an effective way to improve the emulsifying and gelatinization characteristics of WPI. [Display omitted] [ABSTRACT FROM AUTHOR]

• Combined ZnCl 2 -ultrasound and thermal modification treatment of Moso bamboo was used. • Moso bamboo's dimensional stability and thermal degradation efficiency were improved. • This method increased the relative crystallinity of Moso bamboo cellulose. • This method reduced the onset temperature of thermal decomposition. To save energy and reduce emissions during the thermal modification of Moso bamboo, this study investigated the effect of the combined zinc chloride-ultrasound pretreatment and thermal modification on the physicochemical properties of Moso bamboo. Samples were pretreated using 5% (w/w) ZnCl 2 solution and 40 kHz ultrasonic waves, followed by heat treatment at 160 °C. The samples were characterized by moisture absorption measurements, X-ray diffraction, Fourier-transform infrared spectroscopy, surface wettability measurements, thermogravimetric analysis, and colorimetry. The results showed that the combined pretreatment method reduced the moisture absorption by 10.15% and increased the relative crystallinity of Moso bamboo cellulose by 4.4%. It also increased the surface contact angle by 25.2%, lowered the onset of thermal decomposition, reduced the temperature required for hemicellulose to reach its maximum thermal degradation rate by 49 °C, and increased the color change (∆E* ab) by 23.60. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Oyster hydrolysate with aroma and umami was efficiently prepared. • The fingerprints of oyster compounds were analyzed by GC–MS and GC-IMS. • 19 key aroma compounds were identified in oyster hydrolysates from UP-NF. • UP-NF could increase the release of umami substances. In the study, an efficient protease Neutrase®-Flavourzyme® (NF) was screened to prepare the umami-aroma flavor oyster hydrolysate. The effect of protease and ultrasonic pretreatment (UP) assisted by the optimal protease on the flavor substances was investigated. The results demonstrated that the optimal UP-NF (450 W) showed a higher amino acid nitrogen content of 0.34 g/100 mL compared to the NF, and 19 major aroma compounds including octanal, decanal, nonanal, benzaldehyde, 2-undecanone, and 1-octen-3-ol were obtained. Additionally, the free amino acid and fatty acid spectrum indicated that the formation of flavor compounds was primarily due to the oxidation of linoleic and linolenic acids and the degradation of amino acids. Furthermore, taste analysis proved that increased umami and saltiness resulted from the accelerated release of Glu, Asp and 5′-IMP. Overall, UP-NF proved to be an effective method for producing umami-aroma flavor, facilitating further processing of oyster products for the application. [ABSTRACT FROM AUTHOR]

• Combined ultrasound-assisted immersion pretreatments were used prior Taikor drying. • Page and Weibull distribution models fitted the best to explain drying kinetics. • Immersion pretreatment by 10% glucose solution retained the nutritional quality. • Products' quality gradually degraded as the drying temperature raised from 50 to 70 °C. • Higher treatment time and drying temperature showed better microbial load reduction. The present study aimed to analyze and establish an effective combination of ultrasound and immersion pretreatment processes for drying Taikor (Garcinia pendunculata Roxb.) fruits. Taikor slices were first immersed in 10 % sucrose, fructose, and glucose solution. Then, the immersed slices were treated in an ultrasonic bath at 30 °C for 10, 20, and 30 min. Drying operations were carried out at 50, 60, and 70 °C, with a fixed relative humidity of 30 %. The Page, Newton, Henderson and Pabis, and Weibull distribution models were fitted to the obtained drying data to determine the best kinetic model that effectively describes the drying properties of Taikor. After drying operations, changes in quality parameters, e.g., β-carotene, vitamin C, B vitamins, color, antioxidant activities, and microbial loads, were measured to obtain the best drying temperature and the most effective pretreatment combination with minimum loss of nutrients of the sample. Among different kinetic models, both Page and Weibull distribution models showed the best R2 values of 0.9867 and 0.9366, respectively. The chemical properties were preserved to the greatest extent possible by drying at 50 °C with glucose pretreatment. The color parameters were better preserved by fructose pretreatment. Sonication time also had profound effect on the quality parameters of dried Taikor slices. However, higher temperature drying required a shorter time for drying and exhibited better performance in microbial load reduction. This study's findings will help to establish an effective drying condition for Garcinia pedunculata fruits. [ABSTRACT FROM AUTHOR]

• The ultrasound pretreatment enhanced the enzymatic hydrolysis of defatted corn germ protein. • The enzymatic hydrolysis kinetics followed the First-order kinetic model. • The ultrasound pretreatments of defatted corn germ protein reduced the thermodynamic parameters. In this paper, the impact of ultrasound pretreatment on the kinetics and thermodynamics of defatted corn germ protein (DCGP) enzymatic hydrolysis was evaluated. The enzymatic hydrolysis kinetics and thermodynamics were studied for traditional method and ultrasonic pretreatments with a single-frequency counter-current S type (20 KHz) (SFU) and a multi-frequency counter-current S type (20, 28, 35 and 40 KHz) (MFU). The results showed that the traditional, SFU and MFU pretreated enzymatic hydrolysis of DCGP followed the First-order kinetic model. Again, the SFU and MFU pretreatments enhanced the enzymatic hydrolysis of DCGP. Compared to traditional enzymatic hydrolysis, the reaction rate constant values were increased by 50.0%, 54.7%, 47.8% and 52.3% for SFU pretreated enzymatic hydrolysis, and 58.0%, 58.5, 53.6% and 54.7% for MFU pretreated enzymatic hydrolysis at 20, 30, 40 and 50 ºC respectively. Also, the results showed that the SFU and MFU ultrasound pretreatments of DCGP reduced the thermodynamic parameters which included the activation energy (Ea), enthalpy (ΔH), entropies (ΔS) and Gibbs free energy (ΔG) in enzymatic hydrolysis reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soluble fraction of pea protein isolate (SUPPI) was prepared via ultrasound. • SUPPI had an increased degree of Maillard reaction (MR) with glucose (G) • Both conjugates had similar emulsifying and foaming capacities. • Structural change notably affected functional and interfacial properties of SUPPI-G. Wet-heating Maillard reaction (MR) has been applied to improve the function of proteins by conjugating with soluble carbohydrates. However, the impact of soluble solutes particularly in plant protein on the degree of MR and the properties of the corresponding conjugates has yet to be discussed. In this study, high-intensity ultrasound (HIUS) was utilized to pretreat commercial pea protein isolate in order to improve its solubility. Two different fractions including soluble fraction (SUPPI) and whole solution (UPPI) of HIUS treated PPI were conjugated with glucose (G) to prepare SUPPI-G and UPPI-G, respectively, over a course of 24 h wet-heating at 80 °C. Conjugation was confirmed by the degree of glycation, SDS-PAGE, FTIR, and intrinsic fluorescence analysis. Color change and glucose content analysis showed that the degree of MR was greater when using SUPPI rather than UPPI. The solubility of SUPPI-G was further improved by 24 h of MR while it remained unchanged for UPPI-G. The emulsifying activity index and foaming capability of SUPPI-G were similar to those of UPPI-G. Interfacial properties determined by dynamic adsorption and dilatational rheology at both oil–water and air–water interface suggested that insoluble fraction of UPPI is essential to make stable emulsions and foams. In conclusion, the proportion of soluble protein in PPI is critical to its wet-heating MR based conjugation with glucose and the solubility of the conjugates. [ABSTRACT FROM AUTHOR]

This study was aimed at comparing the differences in image textures of windfall apple samples dried using different non-thermal and thermal techniques without and with ultrasound pretreatment. Six classes of sliced windfall apple samples, such as freeze-dried (control), freeze-dried (ultrasound pretreatment), greenhouse-dried (control), greenhouse-dried (ultrasound pretreatment), open-sun-dried (control), and open-sun-dried (ultrasound pretreatment) were obtained. The models to distinguish apple samples were developed based on selected image textures using machine learning algorithms. In the first step of the analysis, all six classes were distinguished. Then, apple samples were classified in pairs without and with ultrasound pretreatment to determine the effect of pretreatment on apple structure. Additionally, models were built to distinguish three control samples from each other as well as separately to classify three samples with ultrasound pretreatment. In the case of the classification of all six apple samples, an overall accuracy reached 80.83% for a model built using a Logistic Model Tree algorithm from the group of Trees and there were no mixing cases between freeze-dried without and with ultrasound pretreatment and samples dried using other techniques. Samples freeze-dried without and with ultrasound pretreatment were distinguished from each other with an accuracy reaching 95% (Random Forest from Trees). Greenhouse-dried (control) and greenhouse-dried with ultrasound pretreatment apple samples were classified with an accuracy of up to 93.5% (Bayes Net from Bayes). Whereas an accuracy reached 95% (Bayes Net) for the classification of open-sun-dried (control) vs. open-sun-dried with ultrasound pretreatment apples. Apple samples dried using freeze drying, greenhouse drying and open-sun drying without pretreatment were distinguished with an overall accuracy of up to 83.67% (Random Forest), and samples dried by freeze drying, greenhouse drying and open-sun drying with ultrasound pretreatment – with an accuracy of up to 93.67% (Bayes Net). The developed models may be used in practice to distinguish apple samples dried using different techniques and samples dried with and without pretreatment. [ABSTRACT FROM AUTHOR]

Highlights • Effect of ultrasound and osmotic dehydration (US + OD) pretreatments to drying was investigated. • The US + OD increased the water loss, sugar gain, drying rates, and effective water diffusivity. • The US + OD prior to hot air-drying decreased the total required drying time. • The US + OD preserved the quality properties in comparison with untreated group. Abstract In this study, the effect of the ultrasound and osmotic dehydration pretreatments before the convective drying of the persimmon fruit was assessed via their drying behavior and quality properties. Ultrasound-assisted osmotic dehydration (30 °C, 45 °Brix) was performed at 35 kHz for 10, 20, and 30 min. Afterward, samples were placed first in 45 then in 70 °Brix sucrose solutions; the solutions were next shaken at 100 rpm. The control group without ultrasound treatment dehydrated osmotically. The samples were dried in a tray drier at a temperature of 60 °C and an air velocity of 1.5 m/s. Ultrasound-assisted osmotic drying treatments increased water loss and sugar gain; moreover, the osmotic dehydration time was shorter than in the untreated group. The ultrasound-assisted osmotic dehydration demonstrated a significantly decreased drying time, increased drying rates, and a 21% increase in effective water diffusivity by 30 min. The ultrasound pretreated osmotic dehydration prior to hot air-drying decreased the total required drying time. The ultrasound-assisted osmotic dehydration affected the rehydration rate and total phenolic content significantly and there was no significant difference between the color change (ΔE, ΔC, and Hue°) of the ultrasound treatment (30 min) group and the untreated group. [ABSTRACT FROM AUTHOR]

Graphical abstract Both ultrasound and alkali pretreatment could facilitate enzymolysis of yeast β-glucan by loosening aggregated structure and enlarging its surface area, and increased water-soluble yeast β-glucan yield to 32.3% and 36.2%, respectively. Highlights • Ultrasound and alkali treatments reduced YG size from 8.80 μm to 1.77 and 7.19 μm. • Ultrasound cavitation disrupted YG aggregates and exposed its internal structure. • Alkali penetrated into YG particles and broke them into flakes by cleaving linkages. • Both treatments facilitated YG enzymolysis by adding surface area and contact point. • Ultrasound- and alkali-assisted enzymolysis enhanced WSYG yield to 32.3% and 36.2% Abstract This study investigated the effects and related mechanisms of ultrasound- and alkali-assisted enzymolysis on production of water-soluble yeast β-glucan (WSYG). Results indicated that ultrasound and alkali pretreatments reduced the particle size of yeast β-glucan (YG) from 8.80 μm to 1.77 and 7.19 μm, respectively. Ultrasound-induced cavitation disrupted YG aggregates to a coarse appearance and exposed internal structure. Alkali penetrated into YG particles and broke the YG aggregates into a flake-like morphology by cleaving the linkages within YG chains. Both pretreatments facilitated enzymolysis by enlarging the YG surface area and increased the WSYG yield to 32.3% and 36.2%, respectively. Meanwhile, the purity of WSYG reached 98.8% after zymoprotein removal by DEAE-Sepharose fast flow column. This work not only provides a green method for producing high-purity and high-yield WSYG, but also reveals the mechanisms of ultrasound and alkali pretreatments for improving enzymolysis efficiency by loosening the YG structure and increasing the surface area. [ABSTRACT FROM AUTHOR]

Ultrasonication and glycation are widely used in the food industry. In this study, we evaluated the independent and combined effects of ultrasound pretreatment (UP) and glycation on the heat-induced amyloid-like aggregation of β-lactoglobulin (β-Lg) by investigating both the fibrillation kinetics and aggregate conformations. Both UP and glycation respectively were found to accelerate the fibrillation process by promoting the denaturation and unfolding behavior of β-Lg according to both the thioflavine-T binding assay. Glycation reduced the fibrillation capacity of β-Lg by reducing the content of β-sheet secondary structures in β-Lg on the basis on circular dichroism spectral measurements. Based on the results of transmission electron microscopy, glycation derived from glucose and lactose suppressed the elongation of fibrils, and β-Lg incubated with maltodextrin was shown to form spherical particle micelles. When applied jointly, UP was found to limit the glycation process by promoting aggregation during the initial heating, which may bury a portion of the glycation sites. According to these findings, UP and glycation are promising methods that can be used independently or jointly to regulate both fibrillation kinetics and fibril conformation in the food industry. [ABSTRACT FROM AUTHOR]

Ultrasound treatment could change the conformation of β -lactoglobulin ( β -Lg) and improve the glycation reaction in aqueous solution under neutral condition. However, the effect of ultrasound pretreatment on glycation of β -Lg with pentose at dry-state remains ambiguous, and the relationship between glycation and allergenicity of β -Lg with ultrasound pretreatment is unclear. This study aimed to evaluate the effect of ultrasound pretreatment on glycation and allergenicity of β -Lg. Markedly decreased allergenicity of β -Lg was observed after glycation with ribose before and after ultrasound pretreatment with the minimum found at 400 W. Orbitrap LC–MS/MS showed that the glycation degree of some peptides in glycated β -Lg with and without ultrasound pretreatment were different although the content of free amino group and molecular mass were insignificantly different. Therefore, ultrasound pretreatment promoted the reduction in allergenicity by improving the glycation extent of some glycation sites although it hardly enhanced the whole glycation degree of β -Lg. [ABSTRACT FROM AUTHOR]

In this study, a series of functional oils rich in feruloylated structured lipids (FSLs) was prepared by enzymatic transesterification of ethyl ferulate (EF) with triglycerides under ultrasound pretreatment. A conversion of more than 92.7% and controllable FSLs (3.1%–26.3%) can be obtained under the following conditions: 16% enzyme, substrate ratio 1:5 (oil/EF, mol/mol), 85 °C, ultrasound 1 h, pulse mode 3 s/3s (working/waiting), and 17.0 W/mL. Compared to conventional mechanical stirring, the activation energy decreased from 50.0 kJ/mol to 40.7 kJ/mol. The apparent kinetic constant increased by more than 13 times, and the time required for the maximum conversion reduced sharply from 20–60 h to 4–6h, which was the fastest rate for enzymatic synthesis of FSLs. The antioxidant activities of the functional oil significantly increased 1.0- to 8.1-fold more than that of the raw oil. The functional oil could be widely applied in various fields of functional foods. [ABSTRACT FROM AUTHOR]

In this work, the synthesis of 28 and 38 nm Na-Y zeolite nanocrystals is reported. The process was performed via green synthesis without any organic structure directing agents (SDAs), at low temperature and applying ultrasound-assisted aging. The zeolite nanoparticles obtained were characterized by X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N 2 adsorption – desorption isotherm at 77 K. A simple, fast, efficient and environmentally friendly procedure to synthetize nanocrystalline FAU zeolite is described in the present study. The sonochemical pretreatment was found to directly affect the Na-Y zeolite properties. The final product obtained via ultrasound pretreatment shows high phase purity and crystallinity degree with crystal size smaller than 38 nm and elevated surface area (S BET  ∼ 950 m 2  g −1 ). The hierarchical micro- and mesoporous FAU zeolites exhibit a pore volume of ∼0.4 cm 3  g −1 . [ABSTRACT FROM AUTHOR]

Intensified synthesis of tricaprylin from caprylic acid and glycerol has been investigated based on novel approach of using ultrasound only in initial stages of the esterification under solvent free conditions. The effect of ultrasonic conditions such as time and power during the pretreatment as well as the reaction conditions such as substrate molar ratio, reaction time and catalyst loading during the conventional reaction on the yield of tricaprylin has been investigated. It was observed that the optimum pretreatment conditions were irradiation time of 60 min with 240 W supplied power and 60% duty cycle. The optimum reaction conditions were 4:1 molar ratio of caprylic acid to glycerol, catalyst loading as 1% and operating temperature of 170 °C. Three different catalysts as sulphuric acid, hydrochloric acid and para -toluene sulphonic acid (PTSA) have been used to investigate the effect of type of catalyst and also the effect of the presence of adsorbent as silica gel was investigated. The obtained results confirmed that the activity of H 2 SO 4 was higher as compared to HCL and PTSA. It was conclusively established that ultrasound pretreatment based approach greatly influenced the rate of reaction in comparison to the conventional approach and resulted in a green processing approach with maximum tricaprylin yield of 96.6% achieved in 9 h of reaction time compared to 24 h with conventional approach. [ABSTRACT FROM AUTHOR]

SSZ-13 zeolite has been identified as effective material for catalysts and membranes for years because of its structure, but the long crystallization time is the main obstacle for the industry application. The sonochemical-assisted method was identified as one of the potential pre-treatment methods which could reduce the formation duration of zeolites as well as other microporous and mesoporous materials. In this work, zeolite SSZ-13 was prepared by ultrasound pretreatment prior to hydrothermal crystallization. For comparison, samples by the conventional pretreatment and hydrothermal method were also prepared. The synthesized powders were characterized by XRD, SEM, BET, FTIR, NMR and TGA. The results showed that the complete crystallization of SSZ-13 synthesized by the ultrasound-assisted hydrothermal method was achieved within 72 h, and much faster than conventional hydrothermal synthesis (120 h). Furthermore, the ultrasound pretreatment showed very little effect on the structure properties of the final product compared with the conventional aging method. [ABSTRACT FROM AUTHOR]

The current work deals with ultrasound assisted intensification of synthesis of tricaprylin based on the enzyme catalyzed reaction of caprylic acid and glycerol with novel approach of using ultrasound in only the initial stages of the reaction. Two types of immobilized lipases as Lipozyme RM ( Rhizomucor miehei ) and Novozym 435 ( Candida antarctica ) have been used in the work. The effect of ultrasonic conditions such as treatment time and power as well as the reaction conditions such as substrate molar ratio, reaction time and enzyme loading on the yield of tricaprylin has been investigated. It was established that the optimum pretreatment conditions were irradiation time as 30 min with ultrasonic frequency of 20 kHz, supplied power of 240 W, 70% duty cycle (7 s on 3 s off cycle) whereas the optimum reaction conditions were 4:1 molar ratio of caprylic acid to glycerol, enzyme loading as 3% and operating temperature of 50 °C. It was also established that reuse of enzymes for 10 cycles was possible without any significant effect on the activity of lipase. It was also conclusively established that compared to the conventional approach of synthesis, ultrasound pretreatment based approach greatly influenced the rate of reaction and maximum tricaprylin yield of 94.8% was achieved in 7 h of reaction time under the optimum conditions. [ABSTRACT FROM AUTHOR]

As an initial step to increase the use of renewable biomass resources, this study was aimed at investigating the effects of ultrasound pretreatment on structural changes of wood. Samples were pretreated by ultrasound with the power of 300 W and frequency of 28 kHz in aqueous soda solution, aqueous acetic acid, or distilled water, then pretreated and control samples were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The results shown that ultrasound pretreatment is indeed effective in modifying the physiochemical structure of eucalyptus wood; the pretreatment decreased the quantity of alkali metals (e.g., potassium, calcium and magnesium) in the resulting material. Compared to the control group, the residual char content of samples pretreated in aqueous soda solution increased by 10.08%–20.12% and the reaction temperature decreased from 361 °C to 341 °C, however, in samples pretreated by ultrasound in acetic solution or distilled water, the residual char content decreased by 12.40%–21.45% and there were no significant differences in reactivity apart from a slightly higher maximum reaction rate. Ultrasound pretreatment increased the samples’ crystallinity up to 35.5% and successfully removed cellulose, hemicellulose, and lignin from the samples; the pretreatment also increased the exposure of the sample to the treatment solutions, broke down sample pits, and generated collapses and microchannels on sample pits, and removed attachments in the samples. [ABSTRACT FROM AUTHOR]

There is an increasing demand for natural resources for biorefining purposes. In this regard, the efficient use of seaweed seems promising as they represent a sustainable feedstock with advantageous characteristics, given their abundant concentration of carbohydrates and low lignin levels. However, in the context of sugar platform biorefineries, to make this activity sustainable, high availability of seaweed biomass is required. In this respect, beach-cast seaweed biomass represents an attractive alternative, reducing the negative impact associated with its accumulation and decomposition on the beaches, which affects the financial income of the region. In this study, Dictyota dichotoma deposited on the coasts of Cadiz (Spain) was collected at the end of the autumn season and used as raw material for the production of simple sugars in the frame of a biorefinery approach. The potential of ultrasound pretreatment was applied to two biomass concentrations (2.1 and 4.3 % w/v), at different amplitude percentages (20, 40 and 60 %) and pretreatment times (15, 40 and 60 min) to enhance algal biomass saccharification. The best condition for reducing sugars (RS) production was: 4.3 % w/v of algal suspension and 40 min pretreatment at 40 % amplitude. This condition supposes specific energy (Es) of 6.78 MJ/kg and leads to a total sugar concentration of 163.64 ± 0.93 mg RS/g dried biomass. A slight improvement in RS production could be attained by increasing the amplitude to 60 % (165.52 ± 3.89 mg/g) but requiring 50 % higher specific energy. Experimental data were fitted to simple first-order kinetics. The hydrolysis rate constant k was a function of the biomass concentration and practically independent of the energy applied. In addition, the average value of k was 8.6 times higher than that for non-pretreated seaweed. [Display omitted] • Beach-cast seaweed are used to obtain reducing sugars (up to 164–166 mg/g biomass). • Ultrasound pretreatment improves the subsequent enzymatic hydrolysis of seaweed. • Optimum pretreatment conditions are 40 % amplitude and 40 min of sonication time. • Lower specific energy is required than in other physical-mechanical pretreatments. • The hydrolysis constant rate is 8.6 times higher than for non-pretreated biomass. [ABSTRACT FROM AUTHOR]

In this paper, the dominance of the physical effects of ultrasound (US) pretreatment in improving the delignification of wheat straw at a 1:20 solid/liquid (biomass/water) ratio is reported showing low-frequency/high power (25 kHz, 2 or 3 kW) as preferred conditions. The sonochemical pretreatment with alkali was identified as an optimal method to make the cellulose more susceptible to further enzymatic hydrolysis, thereby increasing the yield of soluble sugars. Previous bench-scale studies have shown that US pretreatment has a positive effect on delignification, nevertheless this has not yet been demonstrated on a larger scale. The objective of this study was to demonstrate the effectiveness of US pretreatment for wheat straw delignification from lab to semi-industrial scale (40 kg biomass) in terms of sugar yield and energy efficiency. A 59.2% of lignin removal was recorded after the cavitational treatment of wheat straw with a subsequent 68 ± 5.7% yield in terms of enzymatic hydrolysis (52.6% glucose, 42.9% xylose and 4.5% arabinose). It was demonstrated that the positive effect of US alkali pretreatment of wheat straw on sugar yield was due to a combination of factors, including (i) an easier accessibility of the biomass carbohydrate network to enzymes due to the increased wheat straw porosity, (ii) the partial removal of lignin, which increases the relative proportion of carbohydrates in the treated biomass, and (iii) the disordering (amorphization) of the cellulose structure, which promotes carbohydrate hydrolysis as well as saponification of the acetyl groups in the hemicellulose. With respect to the Life Cycle Assessment (LCA) and the Cost Benefit Analysis the US pretreatment process herein reported was compared to an alternative Steam Explosion pretreatment. The results of the LCA analysis showed, that for all five environmental categories (energy consumption, global warming potential, water and fossil depletion, and the land occupation) the US pretreatment has advantages in comparison with the standard industrial Steam Explosion pretreatment. [Display omitted] • Residual biomass as sustainable source for the production of fermentable sugars. • Ultrasound as alternative technology for the scalability of biomass conversion. • First study on ultrasound pretreatment of wheat straw at semi-industrial scale. • First study on enzymatic hydrolysis of pretreated biomass at semi-industrial scale. • Life Cycle Assessments of wheat straw valorization at semi-industrial scale. [ABSTRACT FROM AUTHOR]

• Different micromave-assisted drying methods can affect the quality of kidney beans. • Ultrasound pretreatment markedly improved drying rate, color and rehydration ability. • Ultrasound processing increased the loss of active compounds. • Functional compounds and amino acid content were affected by different drying methods. • Ultrasound pretreatment produced dried kidney beans with a more porous structure. This study aimed to investigate the effects of ultrasound pretreatment combined with pulse-spouted microwave vacuum drying (PSMVD) and microwave hot air rolling drying (MHARD) on the drying characteristics, microstructure and physicochemical properties of pregelatinized kidney beans. The results showed that ultrasound pretreatment significantly improved the drying efficiency and physical properties of the samples during PSMVD and MHARD, and contributed to the formation of porous structures in the dried beans. Meanwhile, ultrasound promoted the hydrolysis of protein, free amino acids content was significantly increased by 3.69 %–11.4 %. However, the combination of ultrasound pretreatment and drying also resulted in a decreased polyphenolic content and antioxidant capacity of the dried beans. PSMVD with ultrasound for 30 min had the best color (Δ E = 14.17), the shortest drying time (50 min) and had a higher content of amino acids (206.15 mg/g) compared with other products. Overall, ultrasound pretreatment can effectively improve the drying process of kidney beans. [ABSTRACT FROM AUTHOR]

• Low amplitude ultrasound improved the solubility, EAI and WAC of SPI nanofibrils. • High amplitude ultrasound improved the foaming capacity and foaming stability. • Antioxidant activity of SPI nanofibrils was improved by 20% amplitude ultrasound. • In vitro digestion rate of 80% amplitude ultrasound-SPI nanofibrils were the highest. Nanofibrils, an effective method to modulate the functional properties of proteins, can be promoted by ultrasound pretreatment. This study investigated the effect of ultrasound pretreatment on the structure, functional property, antioxidant activity and digestibility of soy protein isolate (SPI) nanofibrils. The results showed that high amplitude ultrasound had a significant effect on structure of SPI nanofibrils. SPI nanofibrils pretreated by 80% amplitude ultrasound showed a blueshift of the amide II band in Fourier transform infrared spectroscopy (FTIR), resulted in more tryptophan residues being buried and increased the crystallinity. Low amplitude ultrasound (20%) pretreatment significantly improved the solubility, emulsifying activity index (EAI) and water absorption capacity (WAC) of SPI nanofibrils, but 80% amplitude ultrasound pretreatment of SPI nanofibrils reduced emulsifying stability index (ESI). High amplitude ultrasound (60% and 80%) pretreatment of SPI nanofibrils improved the foaming capacity and foaming stability and decreased denaturation temperature. DPPH radical scavenging activity of SPI nanofibrils were significantly improved by ultrasound pretreatment. 20% amplitude ultrasound pretreatment improved DPPH, ABTS radical scavenging activity and ferric reducing antioxidant power of SPI nanofibrils. The digestion rate of 80% amplitude ultrasound-pretreated nanofibrils were consistently higher, and SPI nanofibrils pretreated by ultrasound were more fragmented and shorter after simulating gastrointestinal digestion. This study would expand the application of food-grade protein nanofibrils in the food industry. [ABSTRACT FROM AUTHOR]

The ultrasound treatment on whey protein before enzymatic hydrolysis using vegetable proteases was studied. Ultrasound density, temperature, and pretreatment time effects were evaluated on enzymatic degree of hydrolysis, release of Angiotensin I-Converting Enzyme (ACE) inhibitors, and antioxidant activity of the hydrolysates generated. In addition, thermal properties as measured by Differential Scanning Calorimetry (DSC) and changes in secondary structure by circular dichroism (CD) were measured. The results showed that ultrasound density was the only factor that exerted a significant effect on proteolysis increasing the ACE inhibition by 13% and a 95% reduction of hydrolysis time in bromelain hydrolysates, but did not improve the ACE inhibition on papain hydrolysates. Observed changes in denaturation enthalpy (ΔH), reduction of reactive thiol groups, and changes in secondary structure suggest protein rearrangements and aggregate formation. The effect of ultrasound on the whey protein structure produced changes increasing the bioactivity of hydrolysates that could enhance the enzymatic hydrolysis process. Industrial relevance Whey proteins are an important source of bioactive peptides. However, due to their globular structure, they are a complex substrate for enzymatic hydrolysis. Ultrasonic pretreatment could induce changes increasing susceptibility to enzymatic hydrolysis resulting in production of more bioactive peptides. Therefore, treatment of whey proteins with ultrasound waves before enzymatic hydrolysis, offers higher efficiency of enzymatic bioconversion of proteins and production of new biologically active peptide mixtures. [ABSTRACT FROM AUTHOR]

The effects of alternate dual-frequency ultrasound (ADFU) pretreatment on the degree of hydrolysis (DH) of wheat gluten (WG) and angiotensin I-converting enzyme (ACE) inhibitory activity were investigated in this research. The surface topography, nano-mechanics and secondary structure of WG were also determined using atomic force microscope (AFM) and circular dichroism (CD). The correlations of ACE inhibitory activity and DH with surface topography, nano-mechanics and secondary structure of WG were determined using Pearson’s correlation analysis. The results showed that with an increase in either pretreatment duration or power, the ACE inhibitory activity of the hydrolysate also increases, reaching maximum at 10 min and 150 W/L, respectively, and then decreases thereafter. Similarly, AFM analysis showed that as the pretreatment duration or power increases, the surface roughness also increase and again a decrease occurs thereafter. As the pretreatment duration or power increased, the Young’s modulus and adhesion of WG also increased and then declined. Young’s modulus and adhesions average values were compared with ACE inhibitory activity reversely. The result of the CD spectra analysis exhibited losses in the relative percentage of α-helix of WG. Pearson’s correlation analysis showed that the average values of Young’s modulus and the relative percentage of α-helix correlated with ACE inhibitory activity of the hydrolysates linearly and significantly ( P < 0.05); the relative percentage of β-sheet correlated linearly with DH of WG significantly ( P < 0.05). In conclusion, ADFU pretreatment is an efficient method in proteolysis due to its physical and chemical effect on the Young’s modulus, α-helix and β-sheet of WG. [ABSTRACT FROM AUTHOR]

The effect of ultrasound pretreatment prior to convective drying on drying kinetics and selected quality properties of mulberry leaves was investigated in this study. Ultrasound pretreatment was carried out at 25.2–117.6 W/L for 5–15 min in a continuous mode. After sonication, mulberry leaves were dried in a hot-air convective dryer at 60 °C. The results revealed that ultrasound pretreatment not only affected the weight of mulberry leaves, it also enhanced the convective drying kinetics and reduced total energy consumption. The drying kinetics was modeled using a diffusion model considering external resistance and effective diffusion coefficient D e and mass transfer coefficient h m were identified. Both D e and h m during convective drying increased with the increase of acoustic energy density (AED) and ultrasound duration. However, D e and h m increased slowly at high AED levels. Furthermore, ultrasound pretreatment had a more profound influence on internal mass transfer resistance than on external mass transfer resistance during drying according to Sherwood numbers. Regarding the quality properties, the color, antioxidant activity and contents of several bioactive compounds of dried mulberry leaves pretreated by ultrasound at 63.0 W/L for 10 min were similar to that of mulberry leaves without any pretreatments. Overall, ultrasound pretreatment is effective to shorten the subsequent drying time of mulberry leaves without damaging the quality of final product. [ABSTRACT FROM AUTHOR]

Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H 2 /mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H 2 /g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H 2 /g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste. [ABSTRACT FROM AUTHOR]

In recent years, the research on functional peptide generation for the development of functional foods has focused, among other issues, on the enhancement of enzymatic hydrolysis by means of high-intensity ultrasound (HIU) application. It has been suggested that the use of HIU in pretreatment and during the hydrolysis process can modify protein conformation by affecting hydrogen bonds and hydrophobic interactions, disrupting the quaternary and/or tertiary structure of proteins due to the effects of cavitation. Therefore, these structural modifications may expose more hydrolysis sites to be accessible by the enzyme, causing an increase in degree of hydrolysis and bioactivity. The main objective of this work was to review recent advances in food science and technology on the application of HIU for the enhancement of enzymatic hydrolysis of proteins of both animal and plant origin in order to generate novel protein hydrolysates and bioactive peptides which could be used as functional-food ingredients. [ABSTRACT FROM AUTHOR]

• The first study about the impact of ultrasound pretreatment (UP) on bioactivity of LPH. • MALDI-TOF-MS confirmed the UP effect on the molecular weight of LPH. • ACE inhibitory and antioxidant activities significantly increased after UP. • UP improved α-glucosidase and α-amylase inhibitory activities. • Bioactivity enhancement was dependent on protease type and sonication time. This study evaluated the impact of ultrasound pretreatment (UP) and enzyme type (flavourzyme, alcalase) on amino acid composition, antihypertensive, antidiabetic, and antioxidant activities of lupin protein hydrolysate (LPH). The UP altered molecular weight of the hydrolysates as revealed by SDS-PAGE and MALDI-TOF and their surface hydrophobicity and thermal stability. Amino acid analysis revealed that glutamic acid, aspartic acid, arginine, and leucine were the dominant amino acids lupin protein. Generally, sonicated hydrolysates exhibited higher biological activity than non-sonicated samples and the original LPI. Alcalase hydrolysate pretreated for 10 min showed the highest DPPH and metal chelating activities. Highest ACE inhibitory activity was observed in flavourzyme hydrolysate after 5 min of UP, while maximum α-amylase and glucosidase inhibitory activity was achieved after 10 min of UP in flavourzyme hydrolysate. The results obtained in this study demonstrated the potentials of UP as a valuable tool for enhancing the biological activity of lupin proteins. [ABSTRACT FROM AUTHOR]

• Prolonged saucing reduced the yield of chicken gizzards. • Ultrasound pretreatment improved the water holding capacity of saucing samples. • Ultrasound pretreatment could strengthen the flavor of saucing chicken gizzards. • Ultrasound technology effectively shortened the saucing time of chicken gizzards. The purpose of this study was to evaluate the effects of ultrasound-assisted saucing on the quality of chicken gizzards. The results showed that with the prolonging of the saucing time, the yield, water holding capacity (WHC), lightness (L *), redness (a *) and springiness of chicken gizzards significantly decreased, while the shear force, hardness and chewiness significantly increased (P < 0.05). When the saucing time was the same, the yield, WHC, springiness and tenderness of the ultrasound group were significantly higher than those of the non-ultrasound group (P < 0.05). In particular, when the saucing time was 30 min, the yield, WHC and springiness of the ultrasound group increased by 2.13%, 0.97% and 10.53%, and the shear force decreased by 21.22% compared with those of the non-ultrasound group, respectively. Besides, ultrasound pretreatment increased the content of aromatic compounds, short-chain alkanes, alcohols, aldehydes and ketones, and the principal component analysis displayed that C-50 (saucing for 50 min without ultrasound pretreatment) and U-30 (saucing for 30 min with ultrasound pretreatment) were similar in flavor. Therefore, ultrasound pretreatment is a potential way to improve the quality of saucing chicken gizzards and shorten the processing time. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of different ultrasound pretreatment were investigated. • Gelation properties of shrimp surimi pretreated by ultrasound were improved. • Ultrasound promotes the interaction and aggregation of MP molecules. • Ultrasound pretreatment promoted the formation of disulfide bonds. • The optimum ultrasound pretreatment was 360 W/20 min according to gel properties. The effects of different ultrasonic pretreatments (120–600 W, 20 min; 360 W, 10–30 min) on the gel properties of shrimp surimi were investigated. Gel properties and protein functional properties were analysed to clarify the mechanism of action of ultrasound. The gel strength, water holding capacity and surface hydrophobicity of shrimp surimi gel increased initially and then decreased with the increase in ultrasound power or time, but the change in total sulfhydryl content showed the opposite trend, which indicated that proper ultrasound pretreatment could improve the gel properties of shrimp surimi, expand the protein to a greater extent and expose more SH groups and hydrophobic groups. According to scanning electron microscopy observation, ultrasound made shrimp surimi gel form a denser gel network. Fourier transform infrared analysis indicated that the α-helix content in shrimp surimi gel decreased initially and then increased with the increase of in ultrasound power or time, whereas the change in β-sheet content showed the opposite trend. And the protein was the most stable in 360 W/20 min pretreatment. SDS-PAGE patterns showed that proper ultrasound inhibited the degradation of actin and troponin C. In addition, dynamic rheology illustrated that the G′ values of the ultrasonic pretreatment group were higher than that of the control group, indicating that ultrasound could improve the elasticity and stability of shrimp surimi gel. The results suggested that the shrimp surimi gel pretreated by 360 W/20 min ultrasound showed the best gel properties. Furthermore, the correlation between the indexes affecting the properties of the gel was analyzed. This study provides a new technical means to improve the gel properties of shrimp surimi. [ABSTRACT FROM AUTHOR]

[Display omitted] • Natural Deep Eutectic Solvents (NADESs) were used to extract essential oil. • Higher yield of essential oil was obtained by the NADESs method. • The microstructure of leaf was changed by the NADESs. • The EO showed high phenol concentration, antimicrobial and antioxidation activities. Natural deep eutectic solvents (NADESs) have received considerable attention for green extraction. In this study, ultrasonic-assisted natural deep eutectics were applied for hydrodistillation to extract essential oil from perilla leaves. Compared to hydrodistillation assisted with ultrasound, this novel method effectively raised the yield of perilla leaf EO from 0.21% to 0.69% (choline chloride: malic acid, molar ratio 2:1) and broadened the types of chemical compositions (71 in total), especially aliphatic and aromatic compounds. Stronger antimicrobial and antioxidant activity was confirmed, and phenolics were increased. Additionally, the pH of the final solution was detected. The leaf residues were dried, weighed and analyzed by scanning electron microscopy to show the influence of NADESs' strong extractability. This new extraction method may be applicable in edible natural product extraction and provide a reference for further exploration of NADESs. [ABSTRACT FROM AUTHOR]

Abstract: To enhance the anaerobic digestion of municipal waste-activated sludge (WAS), ultrasound, thermal, and ultrasound+thermal (combined) pretreatments were conducted using three ultrasound specific energy inputs (1000, 5000, and 10,000kJ/kg TSS) and three thermal pretreatment temperatures (50, 70 and 90°C). Prior to anaerobic digestion, combined pretreatments significantly improved volatile suspended solid (VSS) reduction by 29–38%. The largest increase in methane production (30%) was observed after 30min of 90°C pretreatment followed by 10,000kJ/kg TSS ultrasound pretreatment. Combined pretreatments improved the dimethyl sulfide (DMS) removal efficiency by 42–72% but did not show any further improvement in hydrogen sulfide (H2S) removal when compared with ultrasound and thermal pretreatments alone. Economic analysis showed that combined pretreatments with 1000kJ/kg TSS specific energy and differing thermal pretreatments (50–90°C) can reduce operating costs by $44–66/ton dry solid when compared to conventional anaerobic digestion without pretreatments. [Copyright &y& Elsevier]

Abstract: An ultrasound-assisted liquefaction as a pretreatment for bioethanol production by simultaneous saccharification and fermentation (SSF) of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. Ultrasound pretreatment (at a frequency of 40kHz) was performed at different sonication times and temperatures, before addition of liquefying enzyme. An optimal duration of the treatment of 5min and sonication temperature of 60°C were selected, taking into account glucose concentration after the liquefaction step. Under the optimum conditions an increase of glucose concentration of 6.82% over untreated control sample was achieved. Furthermore, the SSF process kinetics was assessed and determined, and the effect of ultrasound pretreatment on an increase of ethanol productivity was investigated. The obtained results indicated that the ultrasound pretreatment could increase the ethanol concentration by 11.15% (compared to the control sample) as well as other significant process parameters. In this case, the maximum ethanol concentration of 9.67% w/w (which corresponded to percentage of the theoretical ethanol yield of 88.96%) was achieved after 32h of the SSF process. A comparison of scanning electron micrographs of the ultrasound-pretreated and untreated samples of corn meal suspensions showed that the ultrasound stimulated degradation of starch granules and release of glucose, and thereby accelerated the starch hydrolysis due to the cavitation and acoustic streaming caused by the ultrasonic action. [Copyright &y& Elsevier]

Abstract: The effects of ultrasound and heat pretreatments on ethanol yields from cassava chips were investigated. Cassava slurries were sonicated for 10 and 30s at the amplitudes of 80, 160, and 320μmpp (peak to peak amplitude in μm) corresponding to low, medium, and high power levels, respectively. The sonicated and non-sonicated (control) samples were then subjected to simultaneous liquefaction-saccharification and ethanol fermentation. Cassava starch-to-ethanol conversion efficiencies showed that higher ethanol yields were directly related to sonication times, but not to power levels. Significantly higher ethanol yields were observed only for sonicated samples at the high power level. The ethanol yield from the sonicated sample was 2.7-fold higher than yield from the control sample. Starch-to-ethanol conversion rates from sonicated cassava chips were also significantly higher; the fermentation time could be reduced by nearly 24h for sonicated samples to achieve the same ethanol yield as control samples. Thus, ultrasound pretreatment enhanced both the overall ethanol yield and fermentation rate. When compared to heat-treated samples, the sonicated samples produced nearly 29% more ethanol yield. Combined heat and ultrasound treatment had no significant effect on overall ethanol yields from cassava chips. Ultrasound is also preferable to heat pretreatment because of lower energy requirements, as indicated by energy balances. Integration of ultrasound application in cassava-based ethanol plants can significantly improve ethanol yields and reduce the overall production costs. [Copyright &y& Elsevier]

Abstract: The effects of high-powered ultrasonics on the conversion of sugary-2 maize (Zea Mays L.) to fermentable sugars were studied in this research. Ground sugary-2 maize mash was sonicated at 20kHz and varying amplitudes (192–320μmpeak-to-peak) for 5, 10, 15, 20 and 40s. Stargen™ 001 enzyme, which contained both α-amylase and gluco-amylase was added to the samples following sonication to hydrolyze the starch into fermentable sugars. There was a 3-fold increase in sugar conversion rate of the sonicated samples in comparison with the control (unsonicated) samples. The ultrasonic relative net energy gain in the majority of the experimental design space was greater than 1.0. This indicates that the released of stored energy (output energy) from additional sugar released was greater than the dissipated ultrasonic energy (input energy), thus making ultrasonics an efficient treatment. Scanning electron microscopy (SEM) pictures revealed that the sugary starch was partially gelatinized during sonication. This observation was confirmed by polarized-light microscopic images, where a deformed “Maltese cross” was found. Swelling power for samples sonicated at 40s reached 5.0g/g while samples treated in conventional heating reached 4.0g/g at 4min treatment. It was also found that swelling power in the ultrasonicated sample initiated as quickly as 5s and increased rapidly. These results are evident that ultrasonics can enhance swelling and gelatinization compared to conventional heating. As the saccharification time increased, a model was formulated to fit the sugar release curve. The findings indicated that there was a significant effect on enzymatic activity when enzymes were added to the sample during sonication. Additionally, jet cooking and ultrasonication obtained similar theoretical starch conversion results after 3h saccharification. Thus, it is evident that ultrasonication could be considered a potential alternative to jet cooking. [Copyright &y& Elsevier]

• Ultrasonic treatment can improve dry-cured yak meat tenderness. • Ultrasonic treatment accelerated lipid oxidation. • Ultrasonic treatment had no effect on the TVB-N content. • Ultrasonic treatment could significantly increase the essential FAA (EFAA). • SFA content significantly increased with the increase of ultrasonic power. The objective of the present study was to assess the effects of ultrasound pretreatment on the quality of dry-cured yak meat. The ultrasonic power with 0, 200, 300 and 400 W (ultrasonic frequency of 20 kHz) were used to assist processing of dry-cured yak meat. The meat quality, nutrient substances, sensory quality, electronic nose, electronic tongue and volatile compounds of dry-cured yak meat were determined. The results indicated that the moisture content and hardness value of ultrasonic treatment group was significantly lower compared to the control group (P < 0.05). Ultrasonic treatment increased the value of b*, and decreased the value of L*, a*, pH, chewiness, melting temperature and enthalpy. Springiness value significantly increased from control group to 300 W of ultrasonic power group. Shear force significantly decreased with the increase of ultrasonic power (P < 0.05). Ultrasonic treatment had no effect on the TVB-N content, but it could increase the TBARS content. Ultrasonic treatment could significantly increase the essential FAA (EFAA) and total FAA (P < 0.05). In addition, the saturated fatty acid (SFA) content significantly increased with the increase of ultrasonic power (P < 0.05). Ultrasound treatment negatively affected the meat's color, smell, and taste but increased its tenderness and the overall acceptability. It also significantly increased alcohols and aldehydes contents (P < 0.05), which were consistent with the measurement of electronic nose and electronic tongue. The results demonstrated that the the appropriate ultrasonic power assisted in the processing improves quality of dry-cured yak meat, particularly for the power of 300 W. [ABSTRACT FROM AUTHOR]

[Display omitted] • PF + US pretreatment improved the methane yield potential and hydrolysis rate. • The sludge disintegration was accelerated by PF + US pretreatment. • PF + US pretreatment promoted the biodegradability of dissolved organics. • PF + US pretreatment enriched the functional microbes in sludge anaerobic digestion. This study explored the effect of potassium ferrate (PF) combined with ultrasound (US) pretreatment on methane generation from sludge by a series of experiments and simulations. Batch experiments showed that the pretreatment of PF coupled with US exhibited positively synergy on the methane yield. And by the pretreatment of 0.05 g/g TSS (total suspended solids) PF cooperated with US (1 W/mL, 25 kHz, 15 min), the methane yield was enhanced from 180.62 ± 3.26 to 228.83 ± 4.76 mL/g VSS (volatile suspended solids). Mechanism studies confirmed that the co-pretreatment of PF and US efficiently promoted sludge disintegration, and the biodegradability of sludge organics was obviously enhanced. Microbial community analysis showed that the functional microorganisms participating in sludge anaerobic digestion were enriched by PF cooperated with US pretreatment, with the total abundance enhanced from 12.96% in the control to 17.96% in PF + US pretreated reactor. [ABSTRACT FROM AUTHOR]

Abstract: Slow degradation of sewage sludge is a disadvantage of anaerobic digestion leading to high sludge retention times in conventional digesters. Hydrolysis has been pointed as the rate-limiting step in this process. Thermophilic anaerobic digestion has been proved effectively to reduce the retention time needed for sludge stabilization. Sludge pretreatment has been also proposed as a strategy to accelerate the hydrolytic step. The effectiveness of high and low temperature thermal pretreatment, ultrasonic and microwave pretreatments in secondary sludge disintegration has been studied by means of the increment in filterable volatile solids to total volatile solids ratio (FVS/TVS) respect to untreated sludge. Increments in this parameter ranging from three-fold for microwave treatment to nine-fold for high temperature thermal treatment have been obtained. Biogas production under thermophilic (55°C) conditions for treated and untreated secondary sludge has also been evaluated. In spite of the values of FVS/TVS ratio obtained for all the treatments studied, no differences in biogas production were observed when high temperature thermal treatment, ultrasonic and microwave treatments are compared with untreated sludge. A 50% increment in biogas production was observed for low temperature (70°C) thermally treated sludge. This type of treatment has been pointed as a predigestion step enhancing biological activity of some thermophilic hydrolytic bacteria. [Copyright &y& Elsevier]

To alleviate difficult degradation of lipids and its inhibition on anaerobic digestion of food waste, ultrasound and microwave heating were used to pretreat lipid and food wastes for promoting methane production. The soluble COD (10,130 mg/L) of lipid waste pretreated with ultrasound of 50,000 kJ/kg-total volatile solids (TVS) was higher than that (1910 mg/L) with microwave heating of the same energy input. This was because the thermal and mechanical effects of the ultrasound pretreatment were stronger than the thermal and solid dissolution effects of the microwave heating pretreatment. The methane yield of lipid waste pretreated with ultrasound during anaerobic digestion increased by 43.3%–927.97 mL/g-TVS, higher than that of 738.63 mL/g-TVS with microwave heating. Fourier transform infrared spectrometer (FTIR) and Scanning electronic microscopy (SEM) analysis demonstrated that the residual lipids were reduced and microorganism coating was relieved after anaerobic digestion of lipid waste pretreated with ultrasound. The energy conversion efficiency of lipid waste pretreated with ultrasound to methane product was 69.89%, which was higher than that of 58.98% with microwave heating. Ultrasound efficiently degraded lipid waste and released more energy to be converted into methane. [Display omitted] • Ultrasonic/microwave strongly degraded lipids (>36%) prior to anaerobic digestion. • Increasing pretreatment energy input led to increased methane yield from lipids. • Coating of methanogens by lipids was substantially relieved after pretreatment. • ECE of waste lipids of anaerobic digestion was increased from 48.78% to 69.89%. • 1000 kJ/kg-TVS of ultrasonic/microwave pretreatment showed the best energy conversion. [ABSTRACT FROM AUTHOR]

In the current study, the influence of ultrasound pretreatment followed by far-infrared drying on the drying rate, color difference and microstructure of saffron was investigated. The effect of pretreatment duration (30 and 60 s) and drying temperature (50, 60, 70 and 80 °C) on the main chemical composition, total flavonoid, antioxidant activity and volatile flavor compounds in saffron was also evaluated. The results indicated that the total drying time decreased with the increase of pretreatment duration. Especially at 50 °C, the drying time was reduced by 21.05% after 60 s pretreatment. It could also be found that 30 s ultrasound pretreatment with far-infrared drying at 50 °C was the best combination to obtain a good quality of the dried saffron. Under this condition, the samples had the highest chemical properties and volatile compounds, including crocin Ⅰ (20.78%), crocin Ⅱ (10.41%), flavonoid content (10.84 mg/g), antioxidant scavenging activity (58.92%), and major volatile flavor components (54.52%), as well as the acceptable drying time (35 min) and low color difference (26.32). The results of this study confirmed that ultrasound pretreatment had obvious effects and could be recommended for far-infrared drying of saffron. • Combined pretreatments were investigated to improve saffron far-infrared drying. • The ultrasound pretreatments reduced the drying time of saffron. • Aldehydes and ketones are the major aroma compounds of the dried saffron. • The nutritional values were higher at 30 s pretreatment with 50 °C drying. [ABSTRACT FROM AUTHOR]

With stricter regulations and concerns over sustainability, combustion can be a beneficial handling method as dried sludge can be used as an energy source. Anaerobic digestion of sludge also provides energy in the form of biogas without the need for sludge drying. Yet, anaerobic digestion reduces the calorific value (CV) of sludge. In this study, the effect of anaerobic digestion (with or without ultrasound pretreatment) on the fuel properties of sludge were examined through laboratory experiments. Additionally, a number of sludge management strategies were evaluated to maximize energy gain. Temporal changes in fuel properties of sludge were tracked during digestion. Results showed that sonication provided a 3.4-fold increase in soluble COD, 15% increase in biogas production and 32% increase in methane production, while the CV of sludge reduced from 14.7 kJ/g to 10 kJ/g. Energy balances for a number of sludge management process trains showed that the optimal method was the combination of thickening, dewatering, thermal drying and combustion. Addition of digestion and ultrasound pretreatment to this scenario reduced the energy gained from sludge. Yet, high ambient temperatures impacted results such that the net energy gain by the scenario including digestion and combustion was close to that of combustion only. [Display omitted] • Ultrasound pretreatment to enhance digestion provides 32% more methane. • Temporal decline in sludge calorific value can be tracked during anaerobic digestion. • Digestion reduces organics and solids, and disadvantageous for sludge combustion. • Energy consumption of sonication overcomes the benefits of higher methane yield. • Thickening, dewatering, thermal drying and combustion yield the highest net energy. [ABSTRACT FROM AUTHOR]

The effects of pretreatments with ultrasound (UP), heat (HP), and combinations of heat-ultrasound (HP-UP) and ultrasound-heat (UP-HP) on the flesh enzymolysis of clam (Aloididae aloidi) and the flavor characteristics of hydrolysates were investigated. The optimum UP pretreatment conditions for the hydrolysis were obtained at ultrasound power of 500 W, ultrasound time of 20 min, and liquid/solid (L/S) ratio of 2:1 (v/w), yielded 41.33% of hydrolysis degree (DH). Among the different pretreatments, the UP pretreatment had the highest DH value, while the HP-UP pretreatment obtained the highest soluble peptide content. The UP pretreatment efficiently enhanced the contents of taste-active components, including free amino acids, 5′-nucleotides, and succinic acid. The HP pretreatment promoted the formation of pleasant volatile compounds and reduced the content of unpleasant volatile compounds, such as 1-octen-3-ol and 2-ethyl-1-hexanol. The combined HP-UP pretreatment was an effective method for improving the enzymatic hydrolysis of clam and the flavor of hydrolysate. • Ultrasound/heat pretreatment for the enzymolysis of Aloididae aloidi was investigated. • Ultrasound pretreatment improved the enzymolysis and the production of flavor compounds. • Heat pretreatment promoted a pleasant flavor while reducing the unpleasant aroma. • Heat-ultrasound pretreatment improved both hydrolysis and the hydrolysate flavor. [ABSTRACT FROM AUTHOR]

• Developed ultrasound + alkaline pretreatment for the saccharification of wheat waste biomass. • Optimized process parameters to achieve higher delignification & reducing sugar production. • Utilized WS enzymatic hydrolysates for inexpensive and sustainable PHB synthesis. • Thermal and structural properties of produced PHB coincides with standard PHB. Development of an effective pretreatment method is a vital stage to enhance biomass-based biopolymers production. The present study aims on the pretreatment of wheat waste biomass (WS) with alkaline and in combination with ultrasound (US) treatment to enhance enzymatic saccharification of WS into monomeric sugars. Effects of chemical dosage, substrate loading, US power and US pretreatment time on the pretreatment efficiency were systematically investigated. Under optimized conditions; US + NaOH pretreatment attained maximum 70% delignification of WS, with 84.5% hydrolysis yield, 90% glucose yield and 65% xylose yield after enzymatic hydrolysis (30 FPU/g of dry WS) which is substantially higher than the individual pretreatment. Analytical studies (XRD, FTIR, and SEM) revealed that the combined US + NaOH pretreatment can effectively destroyed the ultrastructure of biomass and improved the accessibility to hydrolyzing enzymes. The resulted enzymatic hydrolysates were utilized as a possible biomass feedstock for polyhydroxybutyrate (PHB) production using Ralstonia eutropha. Effects of supplementation of nutrients, stressing agents and initial concentration of US + NaOH pretreated WS hydrolysates (20 to 40 g/L) on PHB production were evaluated. The maximum 74% PHA accumulation, PHB titer of 7.85 g/L and yield of PHB about 0.441 g/g of reducing sugar production was obtained. Analytical characterization and thermal characteristics of extracted biopolymer showed the poperies of standard PHB. The foregoing results suggested the potential of WS as an alternate renewable resource for sustainable biopolymer production and enables WS waste biomass disposal concerns. [ABSTRACT FROM AUTHOR]

• Ultrasound pretreatment (UP) induced unfolding and aggregation of BSA and β-Lg. • The structure change of BSA and β-Lg induced by UP changed the Lys accessibility. • Up affected glycation of β-CN minimally due to its flexible structure. • UP is a promising method to up- and down-regulate the glycation of dietary proteins. The influence of ultrasound treatment on the subsequent glycation process of proteins is controversial. Glycation behaviors of bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and β-casein (β-CN) after ultrasound pretreatment (UP) were compared by both evaluating glycation kinetics and analyzing structural changes of proteins. UP resulted in both unfolding and aggregation behavior in protein samples, which altered the accessibility of the Lys and Arg. Five cycles of UP up-regulated the glycation degree of BSA and β-Lg, possibly due to the unfolding behavior induced by UP, which exposed additional glycation sites. In contrast, 30 cycles of UP induced a dramatic increase (by 97.9 nm) in particle size of BSA, thus burying portions of glycation sites and suppressing the glycation process. Notably, UP had minimal influence on glycation kinetics of β-CN, due to its intrinsic disordered structure. Based on proteomics analysis, the preference of Lys and Arg during glycation was found to be changed by UP in BSA and β-Lg. Four, 3 and 3 unique carboxyethylated lysine residues were identified in glycated BSA after 0, 5 and 30 cycles of UP, respectively. This study suggests that the protein glycation can be affected by UP, depending on the ultrasonication duration and native structure of the protein. [ABSTRACT FROM AUTHOR]

• Three different pretreatments of sugarcane straw were evaluated. • Best condition for hydrothermal pretreatment removed about 60% of hemicellulose. • Ultrasound pretreatment was not very effective in removing the cell wall components. • Acid pretreatment was able to remove high amounts of hemicellulose (77%) and lignin (54%). • Enzymatic hydrolysis reached high conversion in the combinations hydrothermal + NaOH (84%) and acid + NaOH (86%). The potential of sugarcane straw (SCS) as feedstock for 2G ethanol production was investigated. Three different pretreatments (hydrothermal, ultrasound and acid) and the enzymatic hydrolysis of SCS were evaluated. Pretreated materials were delignified with NaOH and after that the enzymatic hydrolysis of all materials was conducted. The best conditions for hydrothermal pretreatment removed a massive amount of hemicellulose (about 60%), preserving the most portions of lignin and cellulose. In general, ultrasound pretreatment was not very effective in removing the cell wall components. Acid pretreatment was able to remove high amounts of hemicellulose (77%) and lignin (54%). After NaOH treatment, a low quantity of lignin remained. The enzymatic hydrolysis achieved high conversion for the combinations hydrothermal + NaOH (84%) and acid + NaOH (86%). These results show that hydrothermal and acid pretreatment were more suitable in the process of ethanol obtainment of from SCS. [ABSTRACT FROM AUTHOR]