Ultrasound Treatment Time Research Articles

Influence of ultrasound probe treatment time and protease type on functional and physicochemical characteristics of egg white protein hydrolysates.

The objective of this study was to discover the relationship between the ultrasound probe treatment (UPT) on egg white proteins (EWPs) before EWPs hydrolysis by different proteases, and the functional properties of the obtained hydrolysates. To fulfill this goal, the protein solubility, foaming, and emulsifying properties were studied as a function of the UPT time and then related to the surface characteristics and structural properties. The changes in the hydrolysates microstructures and macromolecular conformation, induced by the UPT, were followed using scanning electron microscope analyzis (SEM) and Fourier transforms infrared spectroscopy (FTIR). The results showed that UPT influenced (P < 0.05) the proteolysis of egg white proteins for all examined treatment times. Alcalase hydrolysates (AHs) and papain hydrolysates (PHs) were found to have a higher solubility, as a consequence of their relatively higher foaming, and emulsifying properties compared to the untreated hydrolysates. The changes in surface hydrophobicity, sulfhydryl content and surface charge of AHs and PHs indicated unfolding of EWPs affected by ultrasound. SEM analyzis showed that UPT destroyed the microstructures of AHs and PHs, while FTIR spectra indicated remarkable changes in the macromolecular conformation of AHs and PHs after UPT. This study revealed that by combining ultrasound pre-hydrolysis treatment under controlled conditions with thoughtful proteases selection, hydrolysates with improved functional properties could be produced, enhancing utilization of EWPs in food products.

Effects of Ultrasound Assisted Extraction in Conjugation with Aid of Actinidin on the Molecular and Physicochemical Properties of Bovine Hide Gelatin.

Actinidin was used to pretreat the bovine hide and ultrasonic wave (53 kHz and 500 W) was used for the time durations of 2, 4 and 6 h at 60 °C to extract gelatin samples (UA2, UA4 and UA6, respectively). Control (UAC) gelatin was extracted using ultrasound for 6 h at 60 °C without enzyme pretreatment. There was significant (p < 0.05) increase in gelatin yield as the time duration of ultrasound treatment increased with UA6 giving the highest yield of 19.65%. Gel strength and viscosity of UAC and UA6 extracted gelatin samples were 627.53 and 502.16 g and 16.33 and 15.60 mPa.s, respectively. Longer duration of ultrasound treatment increased amino acids content of the extracted gelatin and UAC exhibited the highest content of amino acids. Progressive degradation of polypeptide chains was observed in the protein pattern of the extracted gelatin as the time duration of ultrasound extraction increased. Fourier transform infrared (FTIR) spectroscopy depicted loss of molecular order and degradation in UA6. Scanning electron microscopy (SEM) revealed protein aggregation and network formation in the gelatin samples with increasing time of ultrasound treatment. The study indicated that ultrasound assisted gelatin extraction using actinidin exhibited high yield with good quality gelatin.

Ionic liquid ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of the aqueous phase for preconcentration of heavy metals ions prior to determination by LC-UV

Ionic liquid ultrasound-assisted dispersive liquid–liquid microextraction based on solidification of the aqueous phase was used for preconcentration of Ni2+, Co2+, Cd2+, Cu2+, Pb2+ in natural water samples prior to liquid chromatography with UV detection. In the proposed method, the ammonium pyrrolidinedithiocarbamate was used as a complexing agent and the phosphonium ionic liquid trihexyl(tetradecyl)phosphonium bis[(2,4,4-trimethyl)pentyl]phosphinate (Cyphos IL 104) was used as an extractant. Ultrasound energy was used to disperse the extractant in the aqueous phase. After microextraction, the ionic liquid and aqueous phases were separated by centrifugation. Then the aqueous phase was frozen and the lighter than water ionic liquid phase containing metal ions complexes with pyrrolidinedithiocarbamate was separated and dissolved in a small volume of methanol prior to injection into the liquid chromatograph. Several parameters including the volume of extractant, the pH of the sample, the concentration of complexing agent, the time of ultrasound energy treatment, the time and speed of centrifugation and the effect of ionic strength were optimized. Under the optimized conditions (10 µL of Cyphos IL 104, pH = 5, 0.3% w/v ammonium pyrrolidinedithiocarbamate, 60 s of ultrasound use, 5 min/5000 rpm (2516×g) of centrifugation, 2.0 mg of NaCl), preconcentration factors were 211, 210, 209, 207 and 211 for Ni2+, Co2+, Cd2+, Cu2+ and Pb2+ respectively. Linearity was observed in the ranges 0.2–75.0 µg L−1 for Pb2+, Cd2+, Co2+ and 0.5–100.0 µg L−1 for Cu2+, Ni2+. The limits of detection were 0.03 µg L−1 for Ni2+, 0.03 µg L−1 for Co2+, 0.03 µg L−1 for Cd2+, 0.02 µg L−1 for Cu2+, 0.02 µg L−1 for Pb2+, respectively.The accuracy of this method was evaluated by preconcentration and determination of Ni2+, Co2+, Cd2+, Cu2+, Pb2+ in certified reference materials (TMRAIN-04 and NIST 1643e) with the recovery values in the range of 97–102%. The presented method has been successfully applied for the determination of analytes in natural water samples (river and lake waters).

Efficacy of decontamination and a reduced risk of cross-contamination during ultrasound-assisted washing of fresh produce

Contamination of fresh produce with bacteria can occur during cultivation, harvest and post-harvest processing and the current sanitation approaches for post-harvest processing are not adequate for inactivation of pathogenic or spoilage bacteria that may be attached to the surface of fresh produce. This study evaluated the role of ultrasound with and without surfactants and sanitizers to improve decontamination of fresh produce and the impact of these treatments on the quality of fresh produce. Gram-positive bacterial strain Listeria innocua, and gram-negative bacterial strains Escherichia coli O157:H7 and Pseudomonas fluorescens were tested in this study. The reduction in bacterial concentration from inoculated leaf samples increased with an increase in ultrasound treatment time until 10 min for all the three strains. When compared to ultrasound treatment alone, combination of ultrasound treatment with surfactants did not significantly increase the removal of E. coli and L. innocua from the lettuce surfaces, however, the removal efficacy of P. fluorescens increased significantly under the same treatment conditions. The results of simultaneous washing of multiple leaves using ultrasound showed the net bacterial reduction from lettuce leaves decreased by approximately 0.5 log CFU/cm2 for all the selected strains compared to treatment of a single leaf. Similarly, combination of ultrasound with surfactants for simultaneous treatment of multiple leaves did not improve removal of E. coli and L. innocua from the surface of lettuce leaves, but improved removal of P. fluorescens by approximately 1 log unit when compared to ultrasound treatment alone. The evaluation of the risk of potential cross-contamination during ultrasound washing suggested ultrasound could significantly reduce the bacterial attachment to the uninoculated lettuce surface. Combination of ultrasound with adequate active free chlorine could prevent the transfer of E. coli and L. innocua cells from the inoculated leaf sample to uninoculated leaves. Evaluation of lettuce quality attributes in our study found that exposure to ultrasound treatment for less than 10 min had no significant effect on the quality of fresh lettuce. Thus, ultrasound treatment has a potential to be an alternative for maintaining the safety and quality of fresh produce during post-harvest processing.

Optimization of Ultrasound-Assisted Extraction of Oil from Canola Seeds with the Use of Response Surface Methodology

In the current study, response surface optimization of canola oil extraction assisted by 35 kHz, 800 W ultrasound waves and with the use of hexane and 3:2 hexane–isopropanol at the proportion of 3/2 as solvents was conducted. The influence of extraction temperature (35, 45, and 55°C), ultrasound treatment time (30, 60, and 90 min), and solvent-to-canola (sample) ratio (5, 10, and 15 (% v/w)) on the percentage of the extracted oil and oxidative stability of the extracted oil was analyzed through Box-Behnken design. The achieved results revealed that the optimized conditions for canola oil extraction (22.39% efficiency) by hexane was 87 min ultrasound treatment at 55°C and solvent-to-canola proportion of 6.39 (% v/w). On the other hand, the optimized conditions for canola oil extraction (30.66% efficiency) by hexane–isopropanol mixture were 69.5 min ultrasound treatment at 55°C and solvent-to-canola ratio of 9.12 (% v/w). The obtained outcomes revealed that ultrasound waves significantly improved the extraction efficiency compared to Soxhlet extraction. The extraction efficiency was improved when hexane–isopropanol mixture was applied. In optimized condition, oxidative stability of the extracted oil has been achieved at 12.55 and 40.9 h, respectively, once hexane and hexane–isopropanol were used as solvents for extraction. Oxidative stability presented considerable enhancement with an increase in ultrasound treatment. Extracted oil with the use of mixed solvent (hexane–isopropanol) presented higher value for oxidative stability compared to the extracted oil with the use of hexane as a solvent. Comparison between the ultrasound-assisted and Soxhlet extracted oils with the use of gas chromatography presented no significant difference in their fatty acid profiles.

Ultrasound-assisted melt mixing for the preparation of UHMWPE/OMMT nanocomposites

Ultrahigh molecular weight polyethylene (UHMWPE)/organic montmorillonite (OMMT) nanocomposites were prepared via a self-made vane mixer which could supply a synergy of ultrasound and extensional deformation. Structure and working principle of this novel mixer were illustrated in detail. Effects of the OMMT content, mixing time, and ultrasound treat time on composites’ morphology, rheological properties, and thermal properties were reported in terms of transmission electron microscopy (TEM), wide-angle X-ray scattering, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). X-ray diffraction (XRD) and TEM showed that the OMMT lay spacing increased from 2.82 nm to 3.29 nm and OMMT dispersed evenly in the matrix using this novel melt mixing equipment. It certified that the melt mixing procedure synergized by ultrasound and extensional deformation was very effective in the exfoliation of silicate layers and also the filler distribution and dispersion. DSC measurements revealed that the crystallization temperature ( Tc) had no visible change with increasing the OMMT content and the melting temperature ( Tm) and melting enthalpy crystallinity ( Xc) increased with the proper OMMT content. The higher Tm and Xc showed with the proper ultrasound treatment time, however, the Tc had no visible change. TGA showed that the onset temperature at which 20% weight loss of the material increased markedly in the case of UHMWPE/OMMT-1 wt% nanocomposite. The onset temperature slightly decreased with the use of ultrasound. Rheological analyses showed that all the samples exhibited non-Newtonian and shear thinning characteristics. Both the storage modulus and complex viscosity increased with continuous addition of the OMMT layers. It also indicated that the introduction of ultrasound tended to decrease the storage modulus and complex viscosity. Universal tensile test indicated that superior tensile strength occurred in samples containing OMMT layers.

One-directional modelling to assess the mechanistic actions of power ultrasound on NaCl diffusion in pork

A one-directional modelling method for the assessment of the influence of power ultrasound (US) (4–19Wcm−2, 25–40min) on NaCl diffusion in pork is presented. In doing so, the mechanistic actions of US salting in meat are elucidated. Temperature controls (4–21°C) were generated according to each US treatment. NaCl concentration profiles were fitted to Fick’s second law, generating the effective NaCl diffusion coefficient (Dseff). Dseff ranged from 1.34×10−10 to 4.01×10−10m2s−1, which is in agreement with the literature. The average Dseff was higher at increased temperature (p<0.05) and US intensity (p<0.01) and a lower Dseff was found with longer US treatment time as an effect of structural changes in the meat (p<0.05). The Dseff was higher at all US intensities than the corresponding temperature control indicating that mass transfer is accelerated by US mechanisms, such as cavitation, independent of temperature effects. This study provides further information on the mechanistic actions of ultrasonic enhanced mass transfer and further proves the potential of power US for the accelerated salting of pork.

Ultrasound treated potato peel and sweet lime pomace based biopolymer film development

Treatment and management of food processing waste is a major challenge for food industry. Potato processing industry generates tremendous amount of peel and consider it as zero valued waste. Again, pomace generated after juice extraction from sweet lime pulp is considered as waste and not properly utilized. Whereas these waste could be utilized for the development of biodegradable packaging film to overcome environmental issues. Composite films were prepared with varying proportion of potato peel powder (PP) and sweet lime pomace (SLP) in the ratio of 0:1(A), 0.5:1(B), 1:1(C), 1:0.5(D), 1:0(E) with an ultrasound treatment of 45min, and 0:1(F), 0.5:1(G), 1:1(H), 1:0.5(I), 1:0(J) with an ultrasound treatment of 60min. Ultrasound was applied for 45 and 60min to film forming solutions to break down biopolymer particles small enough to form a film. All the films were analyzed for their barrier and mechanical properties. It was observed that increasing ultrasound treatment times gives better result in film properties and less PP content also gives better film properties, from these observations film G prepared with 0.5:1 (PP:SLP) showed better characteristics among all other films. Water vapor permeability, moisture absorption, water solubility, breakage strength and elongation capacity of G film were reported as 7.25×10−9g/Pahm, 12.88±0.348%, 38.92±0.702%, 242.01±3.074g and 7.61±0.824mm respectively. However, thermal decomposition for film G took place above 200°C. The film forming solution of selected G film, added with clove essential oil (1.5%) as an antimicrobial agent was wrapped on bread and stored it for 5days. The film was successful in lowering the weight loss, reducing the hardness and inhibition of surface microbial load from bread sample.

Improving the hydrolysis efficiency of soy sauce residue using ultrasonic probe-assisted enzymolysis technology

Ultrasonic probe-assisted enzymolysis technology was developed to improve the hydrolysis efficiency of soy sauce residue (SSR). The effects of enzyme type and enzymatic hydrolysis parameters on the hydrolysis degree of SSR were studied firstly to obtain the optimal enzymatic hydrolysis conditions. Then the effects of ultrasound on protease activity and structure of SSR were investigated to elucidate the acting mechanism of ultrasound. Finally, the ultrasonic-assisted enzymatic hydrolysis modes were designed and compared, and the hydrolysates from SSR were characterized to evaluate their further application. The results showed that a hydrolysis degree of 15.53% could be obtained under the optimum enzymolysis conditions: enzyme amount 6000U/g, pH 7.8, temperature 50°C, the ratio of substrate to water phase 1:20, hydrolysis time 4h. Increasing ultrasound treatment time or power could reduce substrate size and consequently enhance the catalytic surface area. Prolonging ultrasound treatment time had a negative influence on enzyme activity, but low ultrasound power was helpful for increasing the enzyme activity. Ultrasound pretreatment of SSR followed by enzymatic hydrolysis increased the hydrolysis degree by 47.6%. When the ultrasound was applied directly to enzymolysis process, the hydrolysis degree of SSR exhibited an increase of 33.0%. The hydrolysates from SSR exhibited good antioxidant activities, and had a potential use as a functional ingredient in food or feed industry.

Stability, Antioxidant Capacity and Degradation Kinetics of Pelargonidin-3-glucoside Exposed to Ultrasound Power at Low Temperature.

As an alternative preservation method to thermal treatment, ultrasound is a novel non-thermal processing technology that can significantly avoid undesirable nutritional changes. However, recently literature indicated that anthocyanin degradation occurred when high amplitude ultrasound was applied to juice. This work mainly studied the effect of ultrasound on the stability and antioxidant capacity of pelargonidin-3-glucoside (Pg-3-glu) and the correlation between anthocyanin degradation and •OH generation in a simulated system. Results indicated that the spectral intensities of Pg-3-glu decreased with increasing ultrasound power (200–500 W) and treatment time (0–60 min). The degradation trend was consistent with first-order reaction kinetics (R2 > 0.9100). Further study showed that there was a good linear correlation between Pg-3-glu degradation and •OH production (R2 = 0.8790), which indicated the important role of •OH in the degradation of anthocyanin during ultrasound exposure. Moreover, a decrease in the antioxidant activity of solution(s) containing Pg-3-glu as evaluated by the DPPH and FRAP methods was observed after ultrasound treatment.

Sonodegradation of cyanidin-3-glucosylrutinoside: degradation kinetic analysis and its impact on antioxidant capacity in vitro.

As an alternative preservation method for thermal treatment, ultrasound comprises a novel non-thermal processing technology that can significantly avoid undesirable nutritional changes. However, the recent literature indicates that anthocyanin degradation occurs when ultrasound is applied in juice at high amplitude parameters. Such work has mainly focussed on the effect of ultrasound on stability, the antioxidant capacity of cyanidin-3-glucosylrutinoside (Cy-3-glc-rut) and the correlation between anthocyanin degradation and ·OH generation in a simulated system. The spectral intensities of Cy-3-glc-rut at 518 and 282 nm decreased with increasing ultrasound power and treatment time. The degradation of Cy-3-glc-rut was consistent with first-order reaction kinetics (r2 > 0.9000) and there was a good linear correlation between anthocyanin degradation and hydroxyl radical formation induced by ultrasound (r2 = 0.9258). Moreover, a decrease in the antioxidant activity of Cy-3-glc-rut after ultrasound evaluated by the 1,1-diphenyl-2-picrylhydrazyl and ferric reducing antioxidant power methods was observed. Overall, the results of the present study show that ultrasound will accelerate the degradation of Cy-3-glc-rut with the growth of power over time. © 2016 Society of Chemical Industry.

Acoustic Cavitation as a Novel Approach for Extraction of Oil from Waste Date Seeds

This work deals with the extraction of date seed oil using an acoustic cavitation. The process parameters such as sonication (extraction) time, power dissipation, operating temperature, and solvent to date seed ratio have been optimized on the basis of extracted oil yield. The obtained results have been compared with the frequently used extraction methods (such as maceration and Soxhlet extraction method). The highest extraction efficiency was found at a solvent (hexane) to seed ratio of 5, applied rated power of 30% of 750 W (actual dissipated power is 2.98 W), ultrasound treatment time of 45 min, and at a temperature of 20 °C. It was observed that as ultrasonic power dissipation increases the oil extraction yield also increases and declines with an increase in temperature. These results are attributed to only physical effects of cavitation occuring onto the surface of the date seeds which enhance the permeability of the solvent into the plant tissues due to the formation of cracks, crevices, and microfr...

Effect of low-intensity pulsed ultrasound on the activity of osteoclasts: An in vitro study

ObjectiveThe objective of this in vitro study was to evaluate the effect of low-intensity pulsed ultrasound on the resorption activity of osteoclast cell cultures. DesignRAW 264.7 cells were cultured and seeded over plates that were pre-coated with a synthetic carbonate apatite, and marked with fluoresceinamine-labeled sodium chondroitin polysulfate. Plates were randomly divided into 4 groups according to the treatment assigned to each one of them: NO RANKL (no RANK-L addition and no ultrasound application), NO LIPUS (addition of RANK-L and no ultrasound application), LIPUS 10 (addition of RANK-L and 10min of ultrasound application per day), and LIPUS 20 (addition of RANK-L and 20min of ultrasound application per day). The ultrasound device produced 1.5MHz pulses with a repetition rate of 1kHz and intensity of 30mW/cm2. The experiment extended for one week and afterwards, resorption activity was evaluated according to the fluorescence intensity analysis and pit resorption measurements (number of pits and mean area). ResultsOur experiment consistently demonstrated that low-intensity pulsed ultrasound application enhanced osteoclasts resorptive activity. In addition, it was demonstrated that when daily ultrasound application lasted longer (20min) the resorption was the highest. Results obtained from both evaluation methods were reasonably coherent. ConclusionsLow-intensity pulsed ultrasound increases osteoclast resorptive activity in the absence of osteoblasts. This effect seems to be influenced by ultrasound treatment time. Future research might be directed to investigate osteoclast response to different ultrasound application protocols (frequencies and intensities) and potential cellular mechanisms.

Effects of ultrasound treatment and storage time on the extractability and biosynthesis of nutraceuticals in carrot (Daucus carota)

In the present study, the effect of postharvest ultrasound (US) treatment on the extractability and biosynthesis of carotenoid and phenolic compounds in carrot was investigated. Carrot was submerged in water and treated with US (frequency 24kHz, amplitude 100μm) for 300s at 20°C. Variables such as total phenolic and carotenoid content, respiration rate, ethylene production, phenylalanine ammonia-lyase (PAL) gene expression and activity were evaluated after US treatment and during storage (0–3 d at 20°C). Immediately after treatment, the extractability of carotenoids increased, while total phenolic content decreased. Likewise, the respiration rate was increased as well as PAL gene expression. During storage, US treated carrots did not show accumulation of carotenoids, but showed higher levels of 3-O-caffeoylquinic acid, isocoumarin, and ethylene production as compared to the control. Results allowed the elucidation of a hypothetical model explaining the physiological mechanisms governing the ultrasound-induced accumulation of phenolics in carrot.

Effects of power ultrasound on oxidation and structure of beef proteins during curing processing

The aim of this study was to evaluate the effects of power ultrasound intensity (PUS, 2.39, 6.23, 11.32 and 20.96Wcm−2) and treatment time (30, 60, 90 and 120min) on the oxidation and structure of beef proteins during the brining procedure with 6% NaCl concentration. The investigation was conducted with an ultrasonic generator with the frequency of 20kHz and fresh beef at 48h after slaughter. Analysis of TBARS (Thiobarbituric acid reactive substances) contents showed that PUS treatment significantly increased the extent of lipid oxidation compared to static brining (P<0.05). As indicators of protein oxidation, the carbonyl contents were significantly affected by PUS (P<0.05). SDS–PAGE analysis showed that PUS treatment increased protein aggregation through disulfide cross-linking, indicated by the decreasing content of total sulfhydryl groups which would contribute to protein oxidation. In addition, changes in protein structure after PUS treatment are suggested by the increases in free sulfhydryl residues and protein surface hydrophobicity. Fourier transformed infrared spectroscopy (FTIR) provided further information about the changes in protein secondary structures with increases in β-sheet and decreases in α-helix contents after PUS processing. These results indicate that PUS leads to changes in structures and oxidation of beef proteins caused by mechanical effects of cavitation and the resultant generation of free radicals.

The ultrasound-assisted aqueous extraction of rice bran oil

In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil.

Viscosity and hydrodynamic radius relationship of high-power ultrasound depolymerised starch pastes with different amylose content

Corn starch pastes (5 or 10 w%) with different amylose content (∼2.7%, ∼5.1%, ∼29.6%, or ∼52.7%) were treated using high-power ultrasound (frequency 20 kHz, power 13.5 or 29.9 W) for up to 20 min. Changes in the physical properties were determined using viscosity measurements and dynamic light scattering. Results show that both the viscosity (η) and hydrodynamic radius (RH) decreased markedly with the increase in ultrasound treatment time. FT-IR showed that the molecular scission occurred at the C–O–C bond of α-1,6 glycosidic linkage, and that the extent of breakage was inversely correlated with amylose content. Further, high-amylose starch pastes were found to be more resistant to ultrasound treatment due to their aggregation. A master curve for the behaviour of η and RH is proposed, which is also confirmed by a similar study carried out on the ultrasound treatment of rice starch pastes with different amylose contents. The findings of this work can be used to tailor starch solutions with different viscosities using high-power ultrasound.

Microbial Inactivation and Physicochemical Properties of Ultrasound Processed Pomegranate Juice

The effects of ultrasound treatment at various amplitudes (50, 75, and 100%) and times (0, 6, 12, 18, 24, and 30 min) on Escherichia coli ATCC 25922 (a surrogate for E. coli O157:H7) and Saccharomyces cerevisiae ATCC 2366 levels and physicochemical characteristics (monomeric anthocyanins, color values, total phenolics, pH, and soluble solids) were determined in pomegranate juice. More than a 5-log inactivation of E. coli ATCC 25922 and a 1.36-log inactivation of S. cerevisiae ATCC 2366 were achieved after 30 min of ultrasound treatment at 100% amplitude. The log-linear and Weibull models were successfully used to estimate the microbial inactivation as a function of ultrasound treatment time (R(2) > 0.97). No significant changes were observed in total phenolics, pH, and soluble solids of the treated juice (P > 0.05). The ultrasound treatment for up to 30 min resulted in more than 92 and 89% anthocyanin retention at 75 and 100% amplitude, respectively. The redness (a*) of the juice did not change significantly after the ultrasound treatment at amplitudes of 75 and 100% for up to 24 and 12 min, respectively. No significant changes in L* and b* values were observed after ultrasound treatment at all amplitudes and after up to 30 min of treatment for 50 and 75% amplitudes. Small differences in juice color were noted based on total color difference scores.

Oleophobic Modification of Hollow Glass Microspheres and Its Effect on the Foaming Capacity and Stability of Foam Extinguishing Agent

We utilized tridecafluorooctyltriethoxysilane (F8261) for the surface modification of hollow glass microspheres (HGM). We then measured the contact angles and the residing time of oil droplets on the HGM surface under different conditions and investigated the effects of the modifier concentration, reaction time and reaction temperature, and other factors on the outcomes of the modification reaction. We also compared the effects of HGM on the expansion ratio and 25% drainage time of protein foam liquid before and after the modification treatment and investigated the effects of HGM surface oleophobic modification on the foaming capacity and stability of foam extinguishing agent. The results showed that when the F8261 concentration was 1.0%, the temperature was 60°C, and the ultrasound treatment time was 2.0 h, the contact angle was up to 132.5°, the oleophobic property of HGM could be significantly enhanced, and the foaming capacity and the oil surface stability were significantly improved by the oleophobic modification.

Characterisation of improved foam aeration and rheological properties of ultrasonically treated whey protein suspension

Suspensions of 10, 15 and 20% (w/v) whey protein concentrate (WPC) were treated with 20 kHz ultrasound for 5, 15 and 25 min at an amplitude of 20, 40 or 60%. The treated suspensions were whipped into foam and the aeration and rheological properties were investigated. With increasing ultrasound amplitude and treatment time, whey protein foam at 15% concentration produced the highest foaming capacity, while foam stability, storage modulus, loss modulus, consistency index and viscosity of foam increased with protein concentration. Foam viscosity correlated with foam stability with R2 = 0.7425 and significant at P < 0.001.