Ultrasonic emulsification: basic characteristics, cavitation, mechanism, devices and application

Abstract

Emulsion systems are widely applied in agriculture, food, cosmetic, pharmaceutical and biomedical industries. Ultrasound has attracted much attention in emulsion preparation, especially for nanoemulsion, due to its advantages of being eco-friendly, cost-effective and energy-efficient. This review provides an overview for readers to the area of ultrasonic emulsification technology. It briefly introduces and summarizes knowledge of ultrasonic emulsification, including emulsion characteristics, acoustic cavitation, emulsification mechanism, ultrasonic devices and applications. The combination of microfluidics and ultrasound is highlighted with huge advantages in controlling cavitation phenomena and emulsification intensification. A novel scale of dμ_C^0.6/μ_D^0.33−E_V is proposed to be able to compare the energy efficiency of emulsion preparation in different devices.

Graphical abstract

Keywords

nanoemulsion / ultrasound / microreactor / multiphase / energy

References

[1] Gupta A, Eral H B, Hatton T A, Doyle P S. Nanoemulsions: formation, properties and applications. Soft Matter, 2016, 12( 11): 2826– 2841

[2] Partheniadis I Shah R R Nikolakakis I. Application of ultrasonics for nanosizing drugs and drug formulations. Journal of Dispersion Science and Technology, 2021, https://doi.org/10.1080/01932691.2021.1878035

[3] Wilson R J, Li Y, Yang G, Zhao C X. Nanoemulsions for drug delivery. Particuology, 2021, 64 : 85– 97

[4] Leong T S, Martin G J, Ashokkumar M. Ultrasonic encapsulation—a review. Ultrasonics Sonochemistry, 2017, 35 : 605– 614

[5] Taha A, Ahmed E, Ismaiel A, Ashokkumar M, Xu X, Pan S, Hu H. Ultrasonic emulsification: an overview on the preparation of different emulsifiers-stabilized emulsions. Trends in Food Science & Technology, 2020, 105 : 363– 377

[6] Modarres-Gheisari S M M, Gavagsaz-Ghoachani R, Malaki M, Safarpour P, Zandi M. Ultrasonic nano-emulsification—a review. Ultrasonics Sonochemistry, 2019, 52 : 88– 105

[7] Leong T, Wooster T, Kentish S, Ashokkumar M. Minimising oil droplet size using ultrasonic emulsification. Ultrasonics Sonochemistry, 2009, 16( 6): 721– 727

[8] Mahdi Jafari S, He Y, Bhandari B. Nano-emulsion production by sonication and microfluidization—a comparison. International Journal of Food Properties, 2006, 9( 3): 475– 485

[9] Periasamy V S, Athinarayanan J, Alshatwi A A. Anticancer activity of an ultrasonic nanoemulsion formulation of Nigella sativaL. essential oil on human breast cancer cells. Ultrasonics Sonochemistry, 2016, 31 : 449– 455

[10] Kentish S, Wooster T, Ashokkumar M, Balachandran S, Mawson R, Simons L. The use of ultrasonics for nanoemulsion preparation. Innovative Food Science & Emerging Technologies, 2008, 9( 2): 170– 175

[11] Peshkovsky A S, Bystryak S. Continuous-flow production of a pharmaceutical nanoemulsion by high-amplitude ultrasound: process scale-up. Chemical Engineering and Processing, 2014, 82 : 132– 136

[12] Agrawal N, Maddikeri G L, Pandit A B. Sustained release formulations of citronella oil nanoemulsion using cavitational techniques. Ultrasonics Sonochemistry, 2017, 36 : 367– 374

[13] Gaikwad S G, Pandit A B. Ultrasound emulsification: effect of ultrasonic and physicochemical properties on dispersed phase volume and droplet size. Ultrasonics Sonochemistry, 2008, 15( 4): 554– 563

[14] Sivakumar M, Tang S Y, Tan K W. Cavitation technology—a greener processing technique for the generation of pharmaceutical nanoemulsions. Ultrasonics Sonochemistry, 2014, 21( 6): 2069– 2083

[15] Ghosh V, Mukherjee A, Chandrasekaran N. Ultrasonic emulsification of food-grade nanoemulsion formulation and evaluation of its bactericidal activity. Ultrasonics Sonochemistry, 2013, 20( 1): 338– 344

[16] Abbas S, Hayat K, Karangwa E, Bashari M, Zhang X. An overview of ultrasound-assisted food-grade nanoemulsions. Food Engineering Reviews, 2013, 5( 3): 139– 157

[17] Awad T, Moharram H, Shaltout O, Asker D, Youssef M. Applications of ultrasound in analysis, processing and quality control of food: a review. Food Research International, 2012, 48( 2): 410– 427

[18] Akdeniz V, Akalın A S. New approach for yoghurt and ice cream production: high-intensity ultrasound. Trends in Food Science & Technology, 2019, 86 : 392– 398

[19] Saani S M, Abdolalizadeh J, Heris S Z. Ultrasonic/sonochemical synthesis and evaluation of nanostructured oil in water emulsions for topical delivery of protein drugs. Ultrasonics Sonochemistry, 2019, 55 : 86– 95

[20] Rao J, McClements D J. Lemon oil solubilization in mixed surfactant solutions: rationalizing microemulsion & nanoemulsion formation. Food Hydrocolloids, 2012, 26( 1): 268– 276

[21] Fryd M M, Mason T G. Advanced nanoemulsions. Annual Review of Physical Chemistry, 2012, 63( 1): 493– 518

[22] Kong M, Chen X G, Kweon D K, Park H J. Investigations on skin permeation of hyaluronic acid based nanoemulsion as transdermal carrier. Carbohydrate Polymers, 2011, 86( 2): 837– 843

[23] Anton N, Benoit J P, Saulnier P. Design and production of nanoparticles formulated from nano-emulsion templates—a review. Journal of Controlled Release, 2008, 128( 3): 185– 199

[24] McClements D J. Nanoemulsions versus microemulsions: terminology, differences, and similarities. Soft Matter, 2012, 8( 6): 1719– 1729

[25] Davis S, Round H, Purewal T. Ostwald ripening and the stability of emulsion systems: an explanation for the effect of an added third component. Journal of Colloid and Interface Science, 1981, 80( 2): 508– 511

[26] Anton N, Vandamme T F. Nano-emulsions and micro-emulsions: clarifications of the critical differences. Pharmaceutical Research, 2011, 28( 5): 978– 985

[27] Thomson W. 4. On the equilibrium of vapour at a curved surface of liquid. Proceedings of the Royal Society of Edinburgh, 1872, 7 : 63– 68

[28] Yotsuyanagi T, Higuchi W I, Ghanem A H. Theoretical treatment of diffusional transport into and through an oil−water emulsion with an interfacial barrier at the oil−water interface. Journal of Pharmaceutical Sciences, 1973, 62( 1): 40– 43

[29] Davies J. Drop sizes of emulsions related to turbulent energy dissipation rates. Chemical Engineering Science, 1985, 40( 5): 839– 842

[30] Forgiarini A, Esquena J, Gonzalez C, Solans C. Formation of nano-emulsions by low-energy emulsification methods at constant temperature. Langmuir, 2001, 17( 7): 2076– 2083

[31] Davies J. A physical interpretation of drop sizes in homogenizers and agitated tanks, including the dispersion of viscous oils. Chemical Engineering Science, 1987, 42( 7): 1671– 1676

[32] Taylor G I. The formation of emulsions in definable fields of flow. Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, 1934, 146( 858): 501– 523

[33] Hinze J O. Fundamentals of the hydrodynamic mechanism of splitting in dispersion processes. AIChE Journal. American Institute of Chemical Engineers, 1955, 1( 3): 289– 295

[34] Gupta A, Eral H B, Hatton T A, Doyle P S. Controlling and predicting droplet size of nanoemulsions: scaling relations with experimental validation. Soft Matter, 2016, 12( 5): 1452– 1458

[35] Calabrese R V, Chang T, Dang P. Drop breakup in turbulent stirred-tank contactors. Part I: Effect of dispersed-phase viscosity. AIChE Journal, 1986, 32( 4): 657– 666

[36] Abismaïl B, Canselier J, Wilhelm A, Delmas H, Gourdon C. Emulsification processes: on-line study by multiple light scattering measurements. Ultrasonics Sonochemistry, 2000, 7( 4): 187– 192

[37] Rivas D F, Cintas P, Gardeniers H J. Merging microfluidics and sonochemistry: towards greener and more efficient micro-sono-reactors. Chemical Communications (Cambridge), 2012, 48( 89): 10935– 10947

[38] Ashokkumar M, Lee J, Kentish S, Grieser F. Bubbles in an acoustic field: an overview. Ultrasonics Sonochemistry, 2007, 14( 4): 470– 475

[39] Yasui K. Influence of ultrasonic frequency on multibubble sonoluminescence. Journal of the Acoustical Society of America, 2002, 112( 4): 1405– 1413

[40] Thompson L H, Doraiswamy L. Sonochemistry: science and engineering. Industrial & Engineering Chemistry Research, 1999, 38( 4): 1215– 1249

[41] Mettin R. From a single bubble to bubble structures in acoustic cavitation. In: Oscillations, Waves and Interactions. Göttingen: University of Göttingen, 2007

[42] Tho P, Manasseh R, Ooi A. Cavitation microstreaming patterns in single and multiple bubble systems. Journal of Fluid Mechanics, 2007, 576 : 191– 233

[43] Zhao S, Yao C, Zhang Q, Chen G, Yuan Q. Acoustic cavitation and ultrasound-assisted nitration process in ultrasonic microreactors: the effects of channel dimension, solvent properties and temperature. Chemical Engineering Journal, 2019, 374 : 68– 78

[44] Zhao S, Yao C, Dong Z, Chen G, Yuan Q. Role of ultrasonic oscillation in chemical processes in microreactors: a mesoscale issue. Particuology, 2020, 48 : 88– 99

[45] Leighton T. The Acoustic Bubble. Cambridge, Massachusetts: Academic Press INC, 1997,

[46] Faber T E. Fluid Dynamics for Physicists. London: Cambridge University Press, 1995,

[47] Offin D G, Birkin P R, Leighton T G. An electrochemical and high-speed imaging study of micropore decontamination by acoustic bubble entrapment. Physical Chemistry Chemical Physics, 2014, 16( 10): 4982– 4989

[48] Zhao S, Yao C, Dong Z, Liu Y, Chen G, Yuan Q. Intensification of liquid−liquid two-phase mass transfer by oscillating bubbles in ultrasonic microreactor. Chemical Engineering Science, 2018, 186 : 122– 134

[49] Longuet-Higgins M S. Resonance in nonlinear bubble oscillations. Journal of Fluid Mechanics, 1991, 224 : 531– 549

[50] Zholkovskij E K, Kovalchuk V I, Fainerman V B, Loglio G, Krägel J, Miller R, Zholob S A, Dukhin S S. Resonance behavior of oscillating bubbles. Journal of Colloid and Interface Science, 2000, 224( 1): 47– 55

[51] Minnaert M. XVI. On musical air-bubbles and the sounds of running water. London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, 1933, 16( 104): 235– 248

[52] Wang C, Jalikop S V, Hilgenfeldt S. Efficient manipulation of microparticles in bubble streaming flows. Biomicrofluidics, 2012, 6( 1): 12801– 1280111

[53] Dong Z, Zhao S, Zhang Y, Yao C, Yuan Q, Chen G. Mixing and residence time distribution in ultrasonic microreactors. AIChE Journal, 2017, 63( 4): 1404– 1418

[54] Wang C, Rallabandi B, Hilgenfeldt S. Frequency dependence and frequency control of microbubble streaming flows. Physics of Fluids, 2013, 25( 2): 022002

[55] Colmenares J C, Chatel G. Sonochemistry. Berlin: Springer, 2016, 225 : 254

[56] Dong Z, Fernandez Rivas D, Kuhn S. Acoustophoretic focusing effects on particle synthesis and clogging in microreactors. Lab on a Chip, 2019, 19( 2): 316– 327

[57] Zhao S N Yao C Q Liu Z K Zhang Q Chen G W Yuan Q. Process intensification of high viscosity extraction system in microreactor via ultrasound-driven microbubbles. CIESC Journal, 2020, 71(9): 4152– 4160 (in Chinese)

[58] Ahmed D, Mao X, Juluri B K, Huang T J. A fast microfluidic mixer based on acoustically driven sidewall-trapped microbubbles. Microfluidics and Nanofluidics, 2009, 7( 5): 727– 731

[59] Ahmed D, Mao X, Shi J, Juluri B K, Huang T J. A millisecond micromixer via single-bubble-based acoustic streaming. Lab on a Chip, 2009, 9( 18): 2738– 2741

[60] Huang P H, Zhao S, Bachman H, Nama N, Li Z, Chen C, Yang S, Wu M, Zhang S P, Huang T J. Acoustofluidic Synthesis of Particulate Nanomaterials. Advancement of Science, 2019, 6( 19): 1900913

[61] Dong Z, Yao C, Zhang X, Xu J, Chen G, Zhao Y, Yuan Q. A high-power ultrasonic microreactor and its application in gas−liquid mass transfer intensification. Lab on a Chip, 2015, 15( 4): 1145– 1152

[62] Iida Y, Yasui K, Tuziuti T, Sivakumar M, Endo Y. Ultrasonic cavitation in microspace. Chemical Communications (Cambridge), 2004, 20 : 2280– 2281

[63] Iida Y, Tuziuti T, Yasui K, Towata A, Kozuka T. Bubble motions confined in a microspace observed with stroboscopic technique. Ultrasonics Sonochemistry, 2007, 14( 5): 621– 626

[64] Dong Z, Yao C, Zhang Y, Chen G, Yuan Q, Xu J. Hydrodynamics and mass transfer of oscillating gas-liquid flow in ultrasonic microreactors. AIChE Journal. American Institute of Chemical Engineers, 2016, 62( 4): 1294– 1307

[65] Xu F, Yang L, Liu Z, Chen G. Numerical investigation on the hydrodynamics of Taylor flow in ultrasonically oscillating microreactors. Chemical Engineering Science, 2021, 235 : 116477

[66] Mc Carogher K, Dong Z, Stephens D S, Leblebici M E, Mettin R, Kuhn S. Acoustic resonance and atomization for gas−liquid systems in microreactors. Ultrasonics Sonochemistry, 2021, 75 : 105611

[67] Yang L, Xu F, Zhang Q, Liu Z, Chen G. Gas−liquid hydrodynamics and mass transfer in microreactors under ultrasonic oscillation. Chemical Engineering Journal, 2020, 397 : 125411

[68] Li M, Fogler H. Acoustic emulsification. Part 1. The instability of the oil−water interface to form the initial droplets. Journal of Fluid Mechanics, 1978, 88( 3): 499– 511

[69] Li M, Fogler H. Acoustic emulsification. Part 2. Breakup of the large primary oil droplets in a water medium. Journal of Fluid Mechanics, 1978, 88( 3): 513– 528

[70] Cucheval A, Chow R. A study on the emulsification of oil by power ultrasound. Ultrasonics Sonochemistry, 2008, 15( 5): 916– 920

[71] Perdih T S, Zupanc M, Dular M. Revision of the mechanisms behind oil−water (O/W) emulsion preparation by ultrasound and cavitation. Ultrasonics Sonochemistry, 2019, 51 : 298– 304

[72] Yamamoto T, Komarov S V. Liquid jet directionality and droplet behavior during emulsification of two liquids due to acoustic cavitation. Ultrasonics Sonochemistry, 2020, 62 : 104874

[73] Lauterborn W, Kurz T. Physics of bubble oscillations. Reports on Progress in Physics, 2010, 73( 10): 106501

[74] Philipp A, Lauterborn W. Cavitation erosion by single laser-produced bubbles. Journal of Fluid Mechanics, 1998, 361 : 75– 116

[75] Yamamoto T, Matsutaka R, Komarov S V. High-speed imaging of ultrasonic emulsification using a water–gallium system. Ultrasonics Sonochemistry, 2021, 71 : 105387

[76] Orthaber U, Zevnik J, Dular M. Cavitation bubble collapse in a vicinity of a liquid−liquid interface—basic research into emulsification process. Ultrasonics Sonochemistry, 2020, 68 : 105224

[77] Zhao S, Dong Z, Yao C, Wen Z, Chen G, Yuan Q. Liquid−liquid two-phase flow in ultrasonic microreactors: cavitation, emulsification, and mass transfer enhancement. AIChE Journal. American Institute of Chemical Engineers, 2018, 64( 4): 1412– 1423

[78] Nieves E, Vite G, Kozina A, Olguin L F. Ultrasound-assisted production and optimization of mini-emulsions in a microfluidic chip in continuous-flow. Ultrasonics Sonochemistry, 2021, 74 : 105556

[79] van Zwieten R, Verhaagen B, Schroën K, Rivas D F. Emulsification in novel ultrasonic cavitation intensifying bag reactors. Ultrasonics Sonochemistry, 2017, 36 : 446– 453

[80] Behrend O, Ax K, Schubert H. Influence of continuous phase viscosity on emulsification by ultrasound. Ultrasonics Sonochemistry, 2000, 7( 2): 77– 85

[81] Kanda T Kiyama Y Suzumori K. A nano emulsion generator using a microchannel and a bolt blamped type transducer. In: 2013 IEEE International Ultrasonics Symposium (IUS). New York: IEEE, 2013

[82] Kaci M, Meziani S, Arab-Tehrany E, Gillet G, Desjardins-Lavisse I, Desobry S. Emulsification by high frequency ultrasound using piezoelectric transducer: formation and stability of emulsifier free emulsion. Ultrasonics Sonochemistry, 2014, 21( 3): 1010– 1017

[83] Hübner S, Kressirer S, Kralisch D, Bludszuweit-Philipp C, Lukow K, Jänich I, Schilling A, Hieronymus H, Liebner C, Jähnisch K. Ultrasound and microstructures—a promising combination?. ChemSusChem, 2012, 5( 2): 279– 288

[84] Freitas S, Hielscher G, Merkle H P, Gander B. Continuous contact-and contamination-free ultrasonic emulsification—a useful tool for pharmaceutical development and production. Ultrasonics Sonochemistry, 2006, 13( 1): 76– 85

[85] Aljbour S, Yamada H, Tagawa T. Ultrasound-assisted phase transfer catalysis in a capillary microreactor. Chemical Engineering and Processing, 2009, 48( 6): 1167– 1172

[86] Dong Z, Udepurkar A P, Kuhn S. Synergistic effects of the alternating application of low and high frequency ultrasound for particle synthesis in microreactors. Ultrasonics Sonochemistry, 2020, 60 : 104800

[87] John J J Van Gerven T. Effect of ultrasound on parallel flow in a microchannel. Chemical Engineering and Processing, 2021, 171: 108465

[88] Dong Z, Zondag S D, Schmid M, Wen Z, Noël T. A meso-scale ultrasonic milli-reactor enables gas−liquid−solid photocatalytic reactions in flow. Chemical Engineering Journal, 2022, 428 : 130968

[89] Lenshof A, Evander M, Laurell T, Nilsson J. Acoustofluidics 5: building microfluidic acoustic resonators. Lab on a Chip, 2012, 12( 4): 684– 695

[90] Peshkovsky S L, Peshkovsky A S. Shock-wave model of acoustic cavitation. Ultrasonics Sonochemistry, 2008, 15( 4): 618– 628

[91] Peshkovsky A S, Peshkovsky S L, Bystryak S. Scalable high-power ultrasonic technology for the production of translucent nanoemulsions. Chemical Engineering and Processing, 2013, 69 : 77– 82

[92] Ezeanowi N Koiranen T. Effect of process parameters on a novel modular continuous crystallizer. In: Proceedings of the 2nd International Process Intensification Conference (IPIC2). Leuven: European Federation of Chemical Engineering, 2019

[93] Delacour C, Stephens D S, Lutz C, Mettin R, Kuhn S. Design and characterization of a scaled-up ultrasonic flow reactor. Organic Process Research & Development, 2020, 24( 10): 2085– 2093

[94] Tadros T, Izquierdo P, Esquena J, Solans C. Formation and stability of nano-emulsions. Advances in Colloid and Interface Science, 2004, 108 : 303– 318

[95] Gharibzahedi S M Jafari S M. Fabrication of nanoemulsions by ultrasonication. In: Nanoemulsions. Amsterdam: Elsevier, 2018

[96] Canselier J, Delmas H, Wilhelm A, Abismail B. Ultrasound emulsification—an overview. Journal of Dispersion Science and Technology, 2002, 23( 1-3): 333– 349

[97] Zhang Q, Dong Z, Zhao S, Liu Z, Chen G. Ultrasound-assisted gas-liquid mass transfer process in microreactors: the influence of surfactant, channel size and ultrasound frequency. Chemical Engineering Journal, 2021, 405 : 126720

[98] Merouani S, Hamdaoui O, Rezgui Y, Guemini M. Effects of ultrasound frequency and acoustic amplitude on the size of sonochemically active bubbles—theoretical study. Ultrasonics Sonochemistry, 2013, 20( 3): 815– 819

[99] Brotchie A, Grieser F, Ashokkumar M. Effect of power and frequency on bubble-size distributions in acoustic cavitation. Physical Review Letters, 2009, 102( 8): 084302

[100] Pokhrel N, Vabbina P K, Pala N. Sonochemistry: science and engineering. Ultrasonics Sonochemistry, 2016, 29 : 104– 128

[101] Jafari S M, He Y, Bhandari B. Production of sub-micron emulsions by ultrasound and microfluidization techniques. Journal of Food Engineering, 2007, 82( 4): 478– 488

[102] Higgins D M, Skauen D M. Influence of power on quality of emulsions prepared by ultrasound. Journal of Pharmaceutical Sciences, 1972, 61( 10): 1567– 1570

[103] Tang S Y, Manickam S, Wei T K, Nashiru B. Formulation development and optimization of a novel Cremophore EL-based nanoemulsion using ultrasound cavitation. Ultrasonics Sonochemistry, 2012, 19( 2): 330– 345

[104] Raso J, Manas P, Pagan R, Sala F J. Influence of different factors on the output power transferred into medium by ultrasound. Ultrasonics Sonochemistry, 1999, 5( 4): 157– 162

[105] Salvia-Trujillo L, Rojas-Graü A, Soliva-Fortuny R, Martín-Belloso O. Physicochemical characterization of lemongrass essential oil−alginate nanoemulsions: effect of ultrasound processing parameters. Food and Bioprocess Technology, 2013, 6( 9): 2439– 2446

[106] Salvia-Trujillo L, Rojas-Graü M A, Soliva-Fortuny R, Martín-Belloso O. Impact of microfluidization or ultrasound processing on the antimicrobial activity against Escherichia coli of lemongrass oil-loaded nanoemulsions. Food Control, 2014, 37 : 292– 297

[107] Tang S Y, Shridharan P, Sivakumar M. Impact of process parameters in the generation of novel aspirin nanoemulsions—comparative studies between ultrasound cavitation and microfluidizer. Ultrasonics Sonochemistry, 2013, 20( 1): 485– 497

[108] Tal-Figiel B. The formation of stable w/o, o/w, w/o/w cosmetic emulsions in an ultrasonic field. Chemical Engineering Research & Design, 2007, 85( 5): 730– 734

[109] Reddy S, Fogler H. Emulsion stability of acoustically formed emulsions. Journal of Physical Chemistry, 1980, 84( 12): 1570– 1575

[110] Nakabayashi K, Amemiya F, Fuchigami T, Machida K, Takeda S, Tamamitsu K, Atobe M. Highly clear and transparent nanoemulsion preparation under surfactant-free conditions using tandem acoustic emulsification. Chemical Communications (Cambridge), 2011, 47( 20): 5765– 5767

[111] Kamogawa K, Okudaira G, Matsumoto M, Sakai T, Sakai H, Abe M. Preparation of oleic acid/water emulsions in surfactant-free condition by sequential processing using midsonic— megasonic waves. Langmuir, 2004, 20( 6): 2043– 2047

[112] Nakabayashi K, Fuchigami T, Atobe M. Tandem acoustic emulsion, an effective tool for the electrosynthesis of highly transparent and conductive polymer films. Electrochimica Acta, 2013, 110 : 593– 598

[113] Jafari S M, Assadpoor E, He Y, Bhandari B. Re-coalescence of emulsion droplets during high-energy emulsification. Food Hydrocolloids, 2008, 22( 7): 1191– 1202

[114] Vankova N, Tcholakova S, Denkov N D, Ivanov I B, Vulchev V D, Danner T. Emulsification in turbulent flow: 1. Mean and maximum drop diameters in inertial and viscous regimes. Journal of Colloid and Interface Science, 2007, 312( 2): 363– 380

[115] Walstra P. Principles of emulsion formation. Chemical Engineering Science, 1993, 48( 2): 333– 349

[116] Li W, Leong T S, Ashokkumar M, Martin G J. A study of the effectiveness and energy efficiency of ultrasonic emulsification. Physical Chemistry Chemical Physics, 2018, 20( 1): 86– 96

[117] Yap B H, Dumsday G J, Scales P J, Martin G J. Energy evaluation of algal cell disruption by high pressure homogenisation. Bioresource Technology, 2015, 184 : 280– 285

[118] Behrend O, Schubert H. Influence of hydrostatic pressure and gas content on continuous ultrasound emulsification. Ultrasonics Sonochemistry, 2001, 8( 3): 271– 276

[119] John J J, Kuhn S, Braeken L, Van Gerven T. Ultrasound assisted liquid-liquid extraction with a novel interval-contact reactor. Chemical Engineering and Processing, 2017, 113 : 35– 41

[120] Dasgupta N, Ranjan S, Gandhi M. Nanoemulsions in food: market demand. Environmental Chemistry Letters, 2019, 17( 2): 1003– 1009

[121] McClements D J, Bai L, Chung C. Recent advances in the utilization of natural emulsifiers to form and stabilize emulsions. Annual Review of Food Science and Technology, 2017, 8( 1): 205– 236

[122] Sui X, Bi S, Qi B, Wang Z, Zhang M, Li Y, Jiang L. Impact of ultrasonic treatment on an emulsion system stabilized with soybean protein isolate and lecithin: its emulsifying property and emulsion stability. Food Hydrocolloids, 2017, 63 : 727– 734

[123] Shanmugam A, Ashokkumar M. Ultrasonic preparation of stable flax seed oil emulsions in dairy systems—physicochemical characterization. Food Hydrocolloids, 2014, 39 : 151– 162

[124] Taha A, Ahmed E, Hu T, Xu X, Pan S, Hu H. Effects of different ionic strengths on the physicochemical properties of plant and animal proteins-stabilized emulsions fabricated using ultrasound emulsification. Ultrasonics Sonochemistry, 2019, 58 : 104627

[125] Jambrak A R, Herceg Z, Šubarić D, Babić J, Brnčić M, Brnčić S R, Bosiljkov T, Čvek D, Tripalo B, Gelo J. Ultrasound effect on physical properties of corn starch. Carbohydrate Polymers, 2010, 79( 1): 91– 100

[126] Zhang L, Ye X, Ding T, Sun X, Xu Y, Liu D. Ultrasound effects on the degradation kinetics, structure and rheological properties of apple pectin. Ultrasonics Sonochemistry, 2013, 20( 1): 222– 231

[127] Sutradhar K B, Amin M L. Nanoemulsions: increasing possibilities in drug delivery. European Journal of Nanomedicine, 2013, 5( 2): 97– 110

[128] Jiang W, Kim B Y, Rutka J T, Chan W C. Nanoparticle-mediated cellular response is size-dependent. Nature Nanotechnology, 2008, 3( 3): 145– 150

[129] Foroozandeh P, Aziz A A. Insight into cellular uptake and intracellular trafficking of nanoparticles. Nanoscale Research Letters, 2018, 13( 1): 1– 12

[130] Danaei M, Dehghankhold M, Ataei S, Hasanzadeh Davarani F, Javanmard R, Dokhani A, Khorasani S, Mozafari M. Impact of particle size and polydispersity index on the clinical applications of lipidic nanocarrier systems. Pharmaceutics, 2018, 10( 2): 57

[131] Diril M, Karasulu Y, Toskas M, Nikolakakis I. Development and permeability testing of self-emulsifying atorvastatin calcium pellets and tablets of compressed pellets. Processes, 2019, 7( 6): 365

[132] de Araújo S C, de Mattos A C A, Teixeira H F, Coelho P M Z, Nelson D L, de Oliveira M C. Improvement of in vitroefficacy of a novel schistosomicidal drug by incorporation into nanoemulsions. International Journal of Pharmaceutics, 2007, 337( 1-2): 307– 315

[133] Li F, Wang T, He H B, Tang X. The properties of bufadienolides-loaded nano-emulsion and submicro-emulsion during lyophilization. International Journal of Pharmaceutics, 2008, 349( 1-2): 291– 299

[134] Doh H J, Jung Y, Balakrishnan P, Cho H J, Kim D D. A novel lipid nanoemulsion system for improved permeation of granisetron. Colloids and Surfaces B: Biointerfaces, 2013, 101 : 475– 480

[135] Verma P, Meher J G, Asthana S, Pawar V K, Chaurasia M, Chourasia M K. Perspectives of nanoemulsion assisted oral delivery of docetaxel for improved chemotherapy of cancer. Drug Delivery, 2016, 23( 2): 479– 488

[136] Suslick K S, Price G J. Applications of ultrasound to materials chemistry. Annual Review of Materials Science, 1999, 29( 1): 295– 326

[137] Teo B M, Prescott S W, Ashokkumar M, Grieser F. Ultrasound initiated miniemulsion polymerization of methacrylate monomers. Ultrasonics Sonochemistry, 2008, 15( 1): 89– 94

[138] John J J, Kuhn S, Braeken L, Van Gerven T. Ultrasound assisted liquid-liquid extraction in microchannels—a direct contact method. Chemical Engineering and Processing, 2016, 102 : 37– 46

[139] Sonawane S H, Teo B M, Brotchie A, Grieser F, Ashokkumar M. Sonochemical synthesis of ZnO encapsulated functional nanolatex and its anticorrosive performance. Industrial & Engineering Chemistry Research, 2010, 49( 5): 2200– 2205

[140] Price G J. Ultrasonically enhanced polymer synthesis. Ultrasonics Sonochemistry, 1996, 3( 3): S229– S238

[141] Liu H, Begley T. Comprehensive Natural Products. 3rd ed. Asmterdan: Elsevier, 2020, 263 : 236

[142] Agarwal C, Máthé K, Hofmann T, Csóka L. Ultrasound-assisted extraction of cannabinoids from Cannabis sativa L. optimized by response surface methodology. Journal of Food Science, 2018, 83( 3): 700– 710

[143] McClements D J, Rao J. Food-grade nanoemulsions: formulation, fabrication, properties, performance, biological fate, and potential toxicity. Critical Reviews in Food Science and Nutrition, 2011, 51( 4): 285– 330

Acknowledgements

We acknowledge gratefully the financial supports for this project from the National Natural Science Foundation of China (Grant Nos. 21991103 and 92034303).

RIGHTS & PERMISSIONS

2022 Higher Education Press