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1.
The ultrasonic formation of stable emulsions of a bioactive material, black seed oil, in skim milk was investigated. The incorporation of 7% of black seed oil in pasteurised homogenized skim milk (PHSM) using 20 kHz high intensity ultrasound was successfully achieved. The effect of sonication time and acoustic power on the emulsion stability was studied. A minimum process time of 8 min at an applied acoustic power of 100 W was sufficient to produce emulsion droplets stable for at least 8 days upon storage at 4 ± 2 °C, which was confirmed through creaming stability, particle size, rheology and color analysis. Partially denatured whey proteins may provide stability to the emulsion droplets and in addition to the cavitation effects of ultrasound are responsible for the production of smaller sized emulsion droplets.  相似文献   

2.
《Ultrasonics sonochemistry》2014,21(6):2131-2137
The effects of ultrasound application on skim milk (10% w/w total solids at natural pH 6.7 or alkali-adjusted to pH 8.0) prior to the renneting of milk at pH 6.7 were examined. Skim milk, made by reconstituting skim milk powder, was sonicated at 20 kHz and 30 °C (dissipated power density 286 kJ kg−1) in an ultrasonic reactor. The rennet gelation time, curd firming rate, curd firmness, and the connectivity of the rennet gel network were improved significantly in rennet gels made from milk ultrasonicated at pH 8.0 and re-adjusted back to pH 6.7 compared to those made from milk sonicated at pH 6.7. These renneting properties were also improved in milk sonicated at pH 6.7 compared to those of the non-sonicated control milk. The improvements in renneting behavior were related to ultrasound-induced changes to the proteins in the milk. This study showed that ultrasonication has potential to be used as an intervention to manipulate the renneting properties of milk for more efficient manufacturing of cheese.  相似文献   

3.
High intensity low frequency ultrasound was used to process dairy ingredients to improve functional properties. Based on a number of lab-scale experiments, several experimental parameters were optimised for processing large volumes of whey and casein-based dairy systems in pilot scale ultrasonic reactors. A continuous sonication process at 20 kHz capable of delivering up to 4 kW of power with a flow-through reactor design was used to treat dairy ingredients at flow rates ranging from 200 to 6000 mL/min. Dairy ingredients treated by ultrasound included reconstituted whey protein concentrate (WPC), whey protein and milk protein retentates and calcium caseinate. The sonication of solutions with a contact time of less than 1 min and up to 2.4 min led to a significant reduction in the viscosity of materials containing 18% to 54% (w/w) solids. The viscosity of aqueous dairy ingredients treated with ultrasound was reduced by between 6% and 50% depending greatly on the composition, processing history, acoustic power and contact time. A notable improvement in the gel strength of sonicated and heat coagulated dairy systems was also observed. When sonication was combined with a pre-heat treatment of 80 °C for 1 min or 85 °C for 30 s, the heat stability of the dairy ingredients containing whey proteins was significantly improved. The effect of sonication was attributed mainly to physical forces generated through acoustic cavitation as supported by particle size reduction in response to sonication. As a result, the gelling properties and heat stability aspects of sonicated dairy ingredients were maintained after spray drying and reconstitution. Overall, the sonication procedure for processing dairy systems may be used to improve process efficiency, improve throughput and develop value added ingredients with the potential to deliver economical benefits to the dairy industry.  相似文献   

4.
In this study, emulsion gels were prepared by sonicated grass pea protein isolates (GPPI) at different ultrasonic amplitudes (25, 50 and 75 %) and times (5, 10 and 20 min). Formation of emulsion gels was induced by transglutaminase. Enzymatic gelation of emulsions stabilized by sonicated GPPI occurred in two stages. A relatively fast stage led to the formation of a weak gel which was followed by a slow stage that strongly reinforced the gel structure. Emulsion gels fabricated by sonicated GPPIs showed a homogeneous and uniform droplet distribution with higher elastic modulus compared to the native protein. A stiffer emulsion gel with a higher G' was formed after the protein was treated at 75 % amplitude for 10 min. After sonication of GPPI, the water holding capacity (WHC) of emulsion gels increased in accordance with the mechanical properties. Higher intermolecular cross-linking within the gel network increased the thermal stability of emulsion gels fabricated by sonicated GPPI. Although sonicated-GPPI emulsion gels clearly displayed homogenous microstructure in comparison to that made with native GPPI, the microstructures of these gels were nearly identical for all sonication amplitudes and times.  相似文献   

5.
《Ultrasonics sonochemistry》2014,21(3):1044-1049
The plant derived essential oil nanoemulsion was prepared using a mixture of components containing eucalyptus oil as organic phase, water as continuous phase, and non ionic surfactant, Tween 80, as emulsifier at a particular proportion of 1:1 v/v%. The ultrasonication was applied for varied processing time from 0 to 30 min to study the effect of time on the formation of nanoemulsion and physical stability of formulation by this method. The transparency and stability of emulsion was enhanced when the sonication time was increased compared to hand blender emulsion. The most stable nanoemulsion was obtained in 30 min sonication having the mean droplet diameter of 3.8 nm. The antibacterial studies of nanoemulsion against Staphylococcus aureus by time kill analysis showed complete loss of viability within 15 min of interaction. Observations from scanning electron microscopy of treated bacterial cells confirmed the membrane damage compared to control bacteria. Furthermore, the wound healing potential and skin irritation activity of the formulated nanoemulsion in Wistar rats, suggested non-irritant and higher wound contraction rate with respect to control and neomycin treated rats. These results proposed that the formulated system could be favourable for topical application in pharmaceutical industries.  相似文献   

6.
The ultrasonic fractionation of milk fat in whole milk to fractions with distinct particle size distributions was demonstrated using a stage-based ultrasound-enhanced gravity separation protocol. Firstly, a single stage ultrasound gravity separation was characterised after various sonication durations (5–20 min) with a mass balance, where defined volume partitions were removed across the height of the separation vessel to determine the fat content and size distribution of fat droplets. Subsequent trials using ultrasound-enhanced gravity separation were carried out in three consecutive stages. Each stage consisted of 5 min sonication, with single and dual transducer configurations at 1 MHz and 2 MHz, followed by aliquot collection for particle size characterisation of the formed layers located at the bottom and top of the vessel. After each sonication stage, gentle removal of the separated fat layer located at the top was performed.Results indicated that ultrasound promoted the formation of a gradient of vertically increasing fat concentration and particle size across the height of the separation vessel, which became more pronounced with extended sonication time. Ultrasound-enhanced fractionation provided fat enriched fractions located at the top of the vessel of up to 13 ± 1% (w/v) with larger globules present in the particle size distributions. In contrast, semi-skim milk fractions located at the bottom of the vessel as low as 1.2 ± 0.01% (w/v) could be produced, containing proportionally smaller sized fat globules. Particle size differentiation was enhanced at higher ultrasound energy input (up to 347 W/L). In particular, dual transducer after three-stage operation at maximum energy input provided highest mean particle size differentiation with up to 0.9 μm reduction in the semi-skim fractions. Higher frequency ultrasound at 2 MHz was more effective in manipulating smaller sized fat globules retained in the later stages of skimming than 1 MHz. While 2 MHz ultrasound removed 59 ± 2% of the fat contained in the initial sample, only 47 ± 2% was removed with 1 MHz after 3 ultrasound-assisted fractionation stages.  相似文献   

7.
《Ultrasonics sonochemistry》2014,21(6):2092-2098
This study showed that temperature influences the rate of separation of fat from natural whole milk during application of ultrasonic standing waves. In this study, natural whole milk was sonicated at 600 kHz (583 W/L) or 1 MHz (311 W/L) with a starting bulk temperature of 5, 25, or 40 °C. Comparisons on separation efficiency were performed with and without sonication. Sonication using 1 MHz for 5 min at 25 °C was shown to be more effective for fat separation than the other conditions tested with and without ultrasound, resulting in a relative change from 3.5 ± 0.06% (w/v) fat initially, of −52.3 ± 2.3% (reduction to 1.6 ± 0.07% (w/v) fat) in the skimmed milk layer and 184.8 ± 33.2% (increase to 9.9 ± 1.0% (w/v) fat) in the top layer, at an average skimming rate of ∼5 g fat/min. A shift in the volume weighted mean diameter (D[4,3]) of the milk samples obtained from the top and bottom of between 8% and 10% relative to an initial sample D[4,3] value of 4.5 ± 0.06 μm was also achieved under these conditions. In general, faster fat separation was seen in natural milk when natural creaming occurred at room temperature and this separation trend was enhanced after the application of high frequency ultrasound.  相似文献   

8.
Simultaneous direct irradiation with microwaves and ultrasound was used to determine total Kjeldahl nitrogen. The method involves chemical digestion in two steps, mineralization with sulfuric acid and oxidation with H2O2. The most influential variables for the microwave/ultrasound (MW/US)-assisted digestion were optimized using tryptophan as the model substance. The optimum conditions were: H2SO4 volume, 10 mL; H2O2 volume, 5 mL; weight of sample, 0.05 g; MW power, 500 W; US power, 50 W; digestion time, 7 min (i.e., 5 min mineralization and 2 min oxidation). A modification of the classical Kjeldahl (Hach) method and an US-assisted digestion method were used for comparison. The latter was also optimized; the optimum conditions were: H2SO4 volume, 10 mL; H2O2 volume, 5 mL; sonication time with H2SO4, 15 min; sonication time with H2O2,10 min; US power, 50 W; weight of sample, 0.05 g. Five pure amino acids and two certified reference materials (NIST standard reference materials 1547 (peach leaves), and soil, NCS DC 73322) were analyzed to assess the accuracy of our new MW/US-assisted digestion method, that was successfully applied to five real samples. The significant reduction in digestion time (being 30 min and 25 min for classical Kjeldahl and US-assisted digestion methods, respectively) and consumption of reagents show that simultaneous and direct MW/US irradiation is a powerful and promising tool for low-pressure digestion of solid and liquid samples.  相似文献   

9.
The influence of high intensity ultrasound (HIUS) on physicochemical and functional properties of sunflower protein isolates was investigated. Protein solutions (10% w/v) were treated with ultrasound probe (20 kHz) and ultrasound bath (40 kHz) for 5, 10, 20 and 30 min. Thermal stability of protein isolates was reduced as indicated by differential scanning calorimetry. Minimum thermal stability was observed at 20 min of sonication and increased further with increase in treatment time indicating aggregation at prolonged sonication. SDS-PAGE profile of proteins showed a significant reduction in molecular weight. Further, surface hydrophobicity and sulfhydryl content increased after HIUS treatment indicating partial unfolding of proteins and reduction in the intermolecular interactions. The particle size analysis showed that HIUS treatment reduced the particle size. Less turbid solution were observed largely due to reduction in particle size. HIUS decreased the available lysine content in protein isolates. Solubility, emulsifying capacity, emulsion stability, foaming capacity, foam stability and oil binding capacity were improved significantly, while as, water binding capacity was decreased. The effect of HIUS on physicochemical and functional properties of sunflower protein isolates was more pronounced in probe sonication rather than bath sonication. Protein isolates with improved functional properties can be obtained using high intensity ultrasound technology.  相似文献   

10.
A study was initiated with the objective of evaluating the effects of sonication treatment on important quality parameters of extract of Pinus massoniana pollen. Sonication of extract was done (frequency 20 kHz and various amplitude levels) for 10, 30, 50 min, respectively. As results, total polysaccharide, phenolics and flavonoids significantly increased (P < 0.05). And sonicated P. massoniana pollen displays strong immuno-stimulating activity by increasing proliferations of splenic lymphocytes and subsets of CD4+ T cells (CD3+CD4+), CD8 T cells (CD3+CD8+), and increased Ig secretion. Sonicated P. massoniana pollen also showed anti-tumor function by inhibition of tumor cell proliferation, inhibition of ROS production, up-regulation of GSH/GSSG ration, up-regulating the gene expression of P53, Bax and down-regulating the gene expression of Bcl-2. Findings of the present study suggested the sonication treatment of P. massoniana pollen could improve the quality and bioactivity of P. massoniana pollen, indicating that sonication is effective in processing of pollen and could be a potential process in tumor prevention and treatment.  相似文献   

11.
《Ultrasonics sonochemistry》2014,21(6):2165-2175
Ultrasonic processing can suit a number of potential applications in the dairy industry. However, the impact of ultrasound treatment on milk stability during storage has not been fully explored under wider ranges of frequencies, specific energies and temperature applications. The effect of ultrasonication on lipid oxidation was investigated in various types of milk. Four batches of raw milk (up to 2 L) were sonicated at various frequencies (20, 400, 1000, 1600 and 2000 kHz), using different temperatures (4, 20, 45 and 63 °C), sonication times and ultrasound energy inputs up to 409 kJ/kg. Pasteurized skim milk was also sonicated at low and high frequency for comparison. In selected experiments, non-sonicated and sonicated samples were stored at 4 °C and were drawn periodically up to 14 days for SPME–GCMS analysis. The cavitational yield, characterized in all systems in water, was highest between 400 kHz and 1000 kHz. Volatile compounds from milk lipid oxidation were detected and exceeded their odor threshold values at 400 kHz and 1000 kHz at specific energies greater than 271 kJ/kg in raw milk. However, no oxidative volatile compounds were detected below 230 kJ/kg in batch systems at the tested frequencies under refrigerated conditions. Skim milk showed a lower energy threshold for oxidative volatile formation. The same oxidative volatiles were detected after various passes of milk through a 0.3 L flow cell enclosing a 20 kHz horn and operating above 90 kJ/kg. This study showed that lipid oxidation in milk can be controlled by decreasing the sonication time and the temperature in the system depending on the fat content in the sample among other factors.  相似文献   

12.
The effects and mechanism of phycocyanin removal from water by high-frequency ultrasound treatment were studied. The efficiency of sonication treatment in removing proteins derived from algal cells was investigated, and the factors influencing the process, including the effects of coagulation, were also studied. In addition, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), the three-dimensional fluorescence spectrum, and mass spectrum were used to illustrate the removal mechanism. The results indicated that phycocyanin can be degraded to the point where it is barely detectable in water samples after 180 min of high-frequency sonication. While the total nitrogen (TN) concentration remained consistent during the entire sonication process (240 min), about 78.9% of the dissolved organic nitrogen (DON) was oxidized into inorganic nitrogen. The sonication effect was greatly influenced by the ultrasound frequency, with 200 kHz having the highest removal performance due to the large production of hydroxyl (HO) radicals. Coagulation was adversely influenced by sonication in the first 60 min due to the cross-linking reaction between protein molecules caused by the sonication. The influence of sonication weakened with sonication time due to the further degradation of the proteins by ultrasound. The variation of the TN, DON, and inorganic nitrogen indicated that the main mechanism occurring during the high-frequency sonication of the phycocyanin was the direct oxidation of the radicals, which was totally different from of the mechanism occurring during ultrasound with low frequency.  相似文献   

13.
High intensity ultrasonic (HUS, 20 k Hz, 400 W) pre-treatments of soybean protein isolate (SPI) improved the water holding capacity (WHC), gel strength and gel firmness (final elastic moduli) of glucono-δ-lactone induced SPI gels (GISG). Sonication time (0, 5, 20, and 40 min) had a significant effect on the above three properties. 20 min HUS-GISG had the highest WHC (95.53 ± 0.25%), gel strength (60.90 ± 2.87 g) and gel firmness (96340 Pa), compared with other samples. Moreover, SH groups and non-covalent interactions of GISG also changed after HUS pre-treatments. The HUS GISG had denser and more uniform microstructures than the untreated GISG. Rheological investments showed that the cooling step (reduce the temperature from 95 to 25 °C at a speed of 2 °C/min) was more important for the HUS GISG network formation while the heat preservation step (keep temperature at 95 for 20 min) was more important for the untreated GISG. HUS reduced the particle size of SPI and Pearson correlation test showed that the particle size of SPI dispersions was negatively correlated with WHC, gel strength and gel firmness.  相似文献   

14.
A rapid, environmental friendly and low-cost method to prepare hydroxyapatite nanoparticles is proposed. In this method, hydroxyapatite is produced in a sonicated pseudo-body solution. The sonication time was found effective in the formation of the crystalline phase of nanoparticles. In our experimental condition, 15 min sonication resulted in the most pure hydroxyapatite phase. Also it was shown that growth temperature is a crucial factor and hydroxyapatite crystallizes only at 37 °C. The particles formed by sonication were generally smaller and more spherical than those obtained without sonication. Sonication increased the hydroxyapatite crystal growth rate up to 5.5 times compared to non-sonication condition. The comparison between the specific surface area of hydroxyapatite nanoparticles obtained by sonication and without sonication demonstrated that sonication increased the specific surface area from 63 m2/g to 107 m2/g and decreased the size of nanoparticles from 30 nm to 18 nm. Analysis on the pore structure demonstrated that the fractal structures obtained with and without sonication were considerably different.  相似文献   

15.
The present research focus on designing an appropriate dispersive solid-phase microextraction (UA-DSPME) for preconcentration and determination of Eriochrome Cyanine R (ECR) in aqueous solutions with aid of sonication using lead (II) dioxide nanoparticles loaded on activated carbon (PbO-NPs-AC). This material was fully identified with XRD and SEM. Influence of pH, amounts of sorbent, type and volume of eluent, and sonication time on response properties were investigated and optimized by central composite design (CCD) combined with surface response methodology using STATISTICA. Among different solvents, dimethyl sulfoxide (DMSO) was selected as an efficient eluent, which its combination by present nanoparticles and application of ultrasound waves led to enhancement in mass transfer. The predicted maximum extraction (100%) under the optimum conditions of the process variables viz. pH 4.5, eluent 200 μL, adsorbent dosage 2.5 mg and 5 min sonication was close to the experimental value (99.50%). at optimum conditions some experimental features like wide 5–2000 ng mL−1 ECR, low detection limit (0.43 ng mL−1, S/N = 3:1) and good repeatability and reproducibility (relative standard deviation, <5.5%, n = 12) indicate versatility in successful applicability of present method for real sample analysis. Investigation of accuracy by spiking known concentration of ECR over 200–600 ng mL−1 gave mean recoveries from 94.850% to 101.42% under optimal conditions. The procedure was also applied for the pre-concentration and subsequent determination of ECR in tap and waste waters.  相似文献   

16.
Water removal is an essential step during crude oil production due to several problems such as increased transportation costs and high corrosion rate due to dissolved salts. Indirect low frequency ultrasonic energy (US), using baths, has been recently proposed as an effective alternative for crude oil demulsification. However, the reactor position during sonication and its influence on the demulsification efficiency for crude oil has not been evaluated. In this sense, the aim of this study was to develop an automated system based on an open source hardware for mapping the acoustic field distribution in an US bath operating at 35 kHz using a hydrophone. Data acquired with this system provided information to evaluate the demulsification efficiency in the different positions of the US bath and correlate it with the acoustic intensity distribution. The automated 3D-mapping system revealed a higher acoustic intensity in the regions immediately above the transducers (ca. 0.6 W cm−2), while the other regions presented a relatively lower intensity (ca. 0.1 W cm−2). Experimental data demonstrated that reactors positioned in the most intense acoustic regions provided a much higher efficiency of demulsification in comparison with the ones positioned in the less intense acoustic field regions. Demulsification efficiency up to 93% was obtained with 15 min of sonication (100% amplitude) using few amount of chemical demulsifier. Hence, this work demonstrated that the information acquired with the developed mapping system could be used for inducing a higher efficiency of demulsification only by finding the more suitable position of reactor in the US bath, which certainly will help development of appropriate reactors design when looking for such approach.  相似文献   

17.
We examined the feasibility of using two types of fly ash (an industrial waste from thermal power plants) as a low-cost catalyst to enhance the ultrasonic (US) degradation of ibuprofen (IBP) and sulfamethoxazole (SMX). Two fly ashes, Belews Creek fly ash (BFA), from a power station in North Carolina, and Wateree Station fly ash (WFA), from a power station in South Carolina, were used. The results showed that >99% removal of IBP and SMX was achieved within 30 and 60 min of sonication, respectively, at 580 kHz and pH 3.5. Furthermore, the removal of IBP and SMX achieved, in terms of frequency, was in the order 580 kHz > 1000 kHz > 28 kHz, and in terms of pH, was in the order of pH 3.5 > pH 7 > pH 9.5. WFA showed significant enhancement in the removal of IBP and SMX, which reached >99% removal within 20 and 50 min, respectively, at 580 kHz and pH 3.5. This was presumably because WFA contains more silicon dioxide than BFA, which can enhance the formation of OH radicals during sonication. Additionally, WFA has finer particles than BFA, which can increase the adsorption capacity in removing IBP and SMX. The sonocatalytic degradation of IBP and SMX fitted pseudo first-order rate kinetics and the synergistic indices of all the reactions were determined to compare the efficiency of the fly ashes. Overall, the findings have showed that WFA combined with US has potential for treating organic pollutants, such as IBP and SMX, in water and wastewater.  相似文献   

18.
The use of emulsifying methods is frequently required before spray drying food ingredients, where using high concentration of solids increases the drying process yield. In this work, we used ultrasound to obtain kinetically stable palm oil-in-water emulsions with 30 g solids/100 g of emulsion. Sodium caseinate, maltodextrin and dried glucose syrup were used as stabilizing agents. Sonication time of 3, 7 and 11 min were evaluated at power of 72, 105 and 148 W (which represents 50%, 75% and 100% of power amplitude in relation to the nominal power of the equipment). Energy density required for each assay was calculated. Emulsions were characterized for droplets mean diameter and size distribution, optical microscopy, confocal microscopy, ζ-potential, creaming index (CI) and rheological behavior. Emulsions presented bimodal size distribution, with D[3,2] ranging from 0.7 to 1.4 μm and CI between 5% and 12%, being these parameters inversely proportional to sonication time and power, but with a visual kinetically stabilization after the treatment at 148 W at 7 min sonication. D[3,2] showed to depend of energy density as a power function. Sonication presented as an effective method to be integrated to spray drying when emulsification is needed before the drying process.  相似文献   

19.
Suspension of nanocrystalline cellulose (NCC) produced from bleached cotton by controlled sulphuric acid hydrolysis was treated with low frequency ultrasound at 20 kHz and 60% amplitude for 0, 1, 2, 5 and 10 min and the effects of sonication on the properties of both the cellulose nanocrystals and their aqueous suspensions were investigated. Furthermore, a series of nanocellulose films were manufactured from the suspensions that were sonicated for different periods of time and tested. Laser diffraction analysis and transmission electron microscopy proved that sonication not only disintegrated the large NCC aggregates (Dv50 14.7 μm) to individual nanowhiskers with an average length and width of 171 ± 57 and 17 ± 4 nm, respectively, but also degraded the nanocrystals and yielded shorter and thinner particles (118 ± 45 and 13 ± 3 nm, respectively) at 10-min sonication. The ultrasound-assisted disintegration to nano-sized cellulose whiskers decreased the optical haze of suspensions from 98.4% to 52.8% with increasing time from 0 to 10 min, respectively. Sonication of the suspensions significantly contributed to the preparation of films with low haze (high transparency) and excellent tensile properties. With the increasing duration of sonication, the haze decreased and the tensile strength rose gradually. Irrespectively of sonication, however, all films had an outstanding oxygen transmission rate in a range of 5.5–6.9 cm3/m2 day, and a poor thermal stability.  相似文献   

20.
《Ultrasonics sonochemistry》2014,21(4):1343-1348
A study was initiated with the objective of evaluating the effects of sonication treatment on important quality parameters of extract of Bursa of Fabricius. Sonication of extract was done (frequency 20 kHz and various amplitude levels) at 0 °C for 10 min, 30 min, 50 min, respectively. As results, the yield of bursa peptides significantly increased (p < 0.05). Then we found sonicated bursa extract promoted the content of bursin and the CFU pre-B formation, exerted immunomodulatory function on antigen-specific immune responses in C57/BL6 mice immunized with inactivated Japanese encephalitis b virus (JEV) vaccine, including enhancing JEV-specific antibody and cytokine production, T-cell immunophenotyping and lymphocyte proliferation. Findings of the present study suggested the sonication treatment of Bursa of Fabricius could improve the yield as well as the quality of bursa peptides, indicating that sonication is effective in processing of bursa extract and could be a potential process for future immuno-pharmacological use.  相似文献   

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