Ultrasonic mixing, homogenization, and emulsification in food processing and other applications

Abstract

The use of power ultrasound (US) to intensify physicochemical processes is now a large area of research. The most famous application of high-power US is cleaning, but many other processes may be dramatically enhanced or qualitatively improved by ultrasonic irradiation. Various industrial fields are concerned as materials ([nano]materials, polymers, surface coatings, and electrochemistry), the environment (especially water, sludge, and soil treatments), and cosmetic and food engineering (mainly through extraction of natural products from plants, dissolution, homogenization, and emulsification processes). Among these various applications of power US the main unit operations most often involve multiphase media for either production and/or dispersion of a solid phase in a liquid through precipitation, crystallization, or simple deaggregation or disruption and/or dissolution of particles, floc, curd, and cells. These operations may be highly improved by power US.This chapter analyzes the effects of power US on such physical operations, excluding any reactive process. First, it has to be emphasized that hydrodynamics connected with power US does control its mechanical effects through acoustic cavitation, a key phenomenon, and through acoustic streaming, albeit to a much lesser extent. Thus a brief survey of cavitation and acoustic streaming gives the minimum information necessary to understand local and global US-induced hydrodynamics. As a direct consequence of acoustic cavitation and streaming, US mixing-both at a reactor scale (macromixing) and a molecular scale (micromixing)-is presented, with reference to the engineering approach linking cavitation and acoustic streaming phenomena to micro-and macromixing, respectively.Concerning specific US applications for solid-liquid suspensions, dispersion, or deagglomeration, the process of separating and suspending tiny particles that are initially naturally aggregated by attraction forces, is reviewed first. Then particle size reduction, achieved either by mechanical erosion/disruption or by dissolution, is detailed, including the combination of simultaneous disruption and dissolution. Rather similar applications concerning cells disruption and the dissolution of their organic content, especially for sludge treatment, are detailed. Finally, two main Power Ultrasonics. http://dx.

Application of non‐thermal pretreatment techniques on agricultural products prior to drying: a review

“…hydroelectric power), then these processes will effectively contribute to reducing the pollution load, and help to preserve the environment. Furthermore, the NTP techniques such as HP for high pressure and PEF have been reported to reduce the utilization of cooling systems which often consume approximately 50% of the total electrical energy and are also responsible for pollutant emissions …”

“…Furthermore, the NTP techniques such as HP for high pressure and PEF have been reported to reduce the utilization of cooling systems which often consume approximately 50% of the total electrical energy and are also responsible for pollutant emissions. 29,112…”

Research into milk homogenization in the pulsation machine with a vibrating rotor

“…The major cause for uncertainty in the theories of dispersing of milk fat phase is the lack of experimental data on observing milk fat globules breakup [6,8]. Their microscopic dimension and high flow velocity in the operating units of homogenizers (up to 200 m/s in valve machines [5]) make it hard to visually observe fat particles breakup.…”

“…They are notable for the highest quality rates of dispersion of milk emulsion, but their energy consumption exceeds 7 kW/t [4,5]. Despite low energy consumption vacuum, ultrasonic and rotor homogenizers do not provide high degree dispersing [6][7][8]. On the contrary the ultra-high-pressure homogenizers and microfluidizers provide high degree dispersing of the processed emulsion but have superhigh energy consumption [9,10].…”

Acoustic Characterization of Fluorinert FC-43 Liquid with Helium Gas Bubbles: Numerical Experiments

“…Bubbles created by acoustic cavitation are employed in sonochemistry and other industrial processes, such as cleaning, mixing, and water treatment [1][2][3][4][5][6]. Sonoluminescence has been observed under some particular circumstances [7].…”