High-Intensity Ultrasound and Its Interaction with Foodstuff and Nanomaterials

Abstract

In recent decades, food research has focused on hybrid systems, that is, the application of nanomaterials and the so-called emerging technologies, whose objective is to increase the quality of food. Among these technologies that are different from thermal is high intensity ultrasound. This chapter presents and describes the interaction of acoustic waves supported by classical physics and nanomaterials generated by nanotechnology carried out in contemporary physics, all integrated as a multidisciplinary knowledge applied to food. Acoustic waves have a spectrum called ultrasound, with an approximate frequency range between 20 kHz and 1 GHz, and this is divided into low-intensity ultrasound (LIU), whose objective is to characterize materials. On the contrary, high-intensity ultrasound (HIU) has the objective of carrying out destructive tests, modifying the study samples. This happens because the HIU generates a phenomenon called acoustic cavitation, which consists of the generation, growth, and implosion of microbubbles, causing alterations in the near and far acoustic field. The proposed review focuses on the application of high-intensity ultrasound to be used in the food industry. Subsequently, a brief approach is made to nanotechnology and nanomaterials and how they have been incorporated into the food industry.

1. Introduction

With the evolution of the human being from the time of the Homo’s, they tried to survive and explore nature (the environment). In 1859 Charles Darwin (1809–1882) published his book entitled the origin of the species [1], where he described that the species that would survive be those that adapted more quickly to its environment or the change of the environment. In such a way that a struggle for survival was generated and later for the observation of nature, learning, and understanding of it, answering questions that were raised and that nowadays, the scientific community continues to make new questions about it.

The advance of science and technology has grown thanks to a set of multidisciplinary groups generating knowledge and developing what we know as technology, however, some scientists have excelled for their most relevant contributions. This is the case of the area of physics as a cornerstone in the strengthening of science, which has had transcendental epochs, so to speak, since the time of ancient, classical, modern, and contemporary physics. For example, in ancient Greece, the knowledge developed and established up to that time was manifested by the natural philosophy of Aristotle (384–322 AC). At that time Democritus (460–370 BC) argued for the first time the word atom, which means indivisible and which he described as the smallest part that made up all “things.” This was the first approach to the description of very small things. Later in classical physics, the observations of Galileo Galilei (1564–1642) and Isaac Newton (1643–1727) laid the foundation of the behavior of bodies (dynamics). It was the latter who with his book entitled Mathematical Principles of Natural Philosophy [2], established the behavior of different natural phenomena under mathematical arguments. Similarly, the observations made in the laboratory by Michael Faraday (1791–1867) and the dazzling capacity of James Clerk Maxwell (1831–1879), unify the electricity and magnetism manifested in treaties bearing the same name [3]. And so-the transformation of natural philosophy to physics, classical physics, was presented.

After this, new contributions to knowledge emerged, as did J.J. Thomson (1886–1943), H. Becquerel (1852–1908), M. Plank (1858–1947), E. Rutherford (1871–1937), N. Bohr (1885–1962) E. Schrödinger (1887–1961), J. Chadwick (1891–1974), E. Fermi (1901–1954), and A. Einstein (1879–1955) and the entire generation of modern physics, where they laid the foundations of quantum mechanics and special and general relativity, that is, small particles moving at speeds of light and their interaction with gravity. And in that time a leap was generated in the era of electronics and the advancement of technology with the invention of the transistor made by J. Bardeen (1908–1991), W. H. Brattain (1902–1987), and W.B. Shockley (1910–1989) in 1947. Toward the macroscopic nature, and then microscopic, and later quantum, new questions and advances given by the contemporary physics were presented by P. Dirac (1902–1984), H. Yukawa (1907–1981), J.S. Schwinger (1918–1994), R.P. Feynman (1918–1988), M. Gell-Mann (1929–2019), S. Weinberg (1933–2021), P. Higss (1929- ), the world of elementary particles and their interactions. To generate, this knowledge also originated the technological development implemented in the European Center for Nuclear Research leading to a modern technological development [4].

The need to address gaps in knowledge for the development and manipulation of “very small” things led to the beginning of nanotechnology and its possible applications for the benefit of humanity, as it is in medicine, electronics, food, etc. This chapter presents the interactions of classical physics represented by acoustic waves and modern physics implemented in nanotechnology. All this is integrated as a multidisciplinary knowledge applied to food. This chapter describes the basic notions of acoustic waves and consequently of low and high-intensity ultrasound to continue with the effect of acoustic cavitation. Later, the progress of nanotechnology and how it has been incorporated into the food industry is addressed.

2. Acoustic waves

Acoustic waves have a wide field of application and can be interpreted as the physical science that studies the vibrations and elastic waves, and their interactions with the environment; both in macroscopic systems and in quantum systems (phonons). At the microscopic level, acoustic waves have an intermolecular collision process and unlike electromagnetic waves, a material medium is needed for the propagation of the acoustic wave. At the macroscopic level, acoustic waves have an intermolecular collision process and unlike electromagnetic waves, a material medium is needed for the propagation of the acoustic wave. At the macroscopic level, acoustic waves refer to variations in the amplitude of pressure-dependent on time or stress, so acoustic waves are also known as mechanical waves or elastic waves [5].

The linear wave equation is represented by the expression,

$${\nabla }^{2}P\left(\mathit{r},t\right)-\frac{1}{c^2}\frac{{\partial }^{2}P\left(\mathit{r},t\right)}{\partial t^2}=0,$$E1

where ∇² is the three-dimensional Laplacian operator, which can be applied to different geometries, and this will depend on the type of wave that is analyzed, which can be flat, cylindrical, and/or spherical waves. Pis the acoustic pressure of the wave. ris the position vector of the wave and is given by $\mathit{r}=x\widehat{i}+y\widehat{j}+x\widehat{k}$, in cartesian coordinates. $\widehat{i},\widehat{j},\widehat{k}$, they are the unit vectors. cis the longitudinal velocity of the propagation medium, tis time, ∂²represents the second partial derivate of the argument. The expression (1) represents a homogeneous wave equation, that is, it does not matter what or who generates the acoustic wave.

The solution of the harmonic flat wave equation is represented by the expression,

$$P=\mathit{A}{e}^{-i\left(\mathit{k}\bullet \mathit{r}-\mathit{\omega t}\right)}+\mathit{B}{e}^{i\left(\mathit{k}\bullet \mathit{r}-\mathit{\omega t}\right)},$$E2

where Aand Bare constants that can be determined by applying initial and/or boundary conditions; k is the wave propagation vector and is given by $\mathit{k}=k_x\widehat{i}+k_y\widehat{j}+k_z\widehat{k}$, iis the imaginary number, kis the wavenumber, and it is defined as $k=\frac{\omega }{c}$.ωis the angular frequency. Also, ccan be represented as $c=\lambda ·f$, where λis the wavelength and fis the frequency. Finally, λcan also be represented by $\lambda =\frac{2\pi }{k}$.

As mentioned in the previous paragraph, acoustic waves need a material medium for propagation, this medium can be solid, liquid, gas, or biological material. There are two main modes for the propagation of acoustic waves, which are longitudinal mode and transverse mode. In the longitudinal mode, the emitted acoustic energy propagates in the same direction in which the acoustic travels; on the contrary, in the transverse mode, the emitted acoustic energy propagates perpendicularly in the direction in which the acoustic wave travels. Figure 1 describes the main modes of propagation of acoustic waves [6].

Figure 1.

Propagation modes of acoustic waves, (a) longitudinal mode; (b) transverse mode.

Acoustic waves have well-defined parameters in steady state. Figure 2 shows the parameters of an acoustic wave represented by a sine wave.

Figure 2.

Sine wave. A→Amplitude, λ→Wavelength, T →Period, f →Frequency, P →Pressure, t →Time. Where P is the pressure [Pascal], A is the amplitude of the pressure [meters], t is the time [second], λ is the wavelength [meter], T is the period [second] and f is the frequency [Hertz], which T=f⁻¹ or f=T⁻¹, and it is the latter that provides the working spectrum of acoustic waves [7].

In Table 1 the spectrum of acoustic frequencies is described.

Infrasound is an acoustic wave whose frequency is below the audible spectrum of the human ear; some animals can detect these frequencies. The audible sound is conformed by the spectrum of frequencies that can be perceived by the human ear, such as, for example, the voice, the musical notes. Ultrasound is an acoustic wave whose frequency is above the audible spectrum of the human ear; ultrasound has several applications, such as non-destructive and destructive tests in medical diagnosis and rehabilitation therapies. The hypersound is an acoustic wave whose frequency spectrum is very high and has some applications in medicine and war systems.

In this context, acoustic waves also obey Snell’s law of optics [9], where the incident, reflected, and transmitted waves are involved in a propagation medium, $\frac{\mathit{Sin}{\theta }_i}{c_i}=\frac{\mathit{Sin}{\theta }_t}{c_t}$, where θ_i,θ _t, c_i,and c_trepresent the angle of the incident wave, transmitted wave, acoustic longitudinal propagation speed of the incident and transmitted wave, respectively. The phenomenon of attenuation is also presented, which is the loss of energy given the intrinsic properties of the medium of propagation, the frequency, and the thickness thereof, and is represented by the expression,

$$P={\mathit{P}}_{\mathit{o}}{e}^{-\mathit{i\alpha }\mathit{r}},$$E3

where P_ois the amplitude of the pressure, iis the imaginary number,αis the coefficient of attenuation of the medium and are included the losses by absorption, diffraction, dispersion, scattering, as well as the object of study; ris the position vector of the acoustic wave, as shown in Figure 3.

Figure 3.

With normal incidence to the surface of the propagation medium, the acoustic waves hit, are reflected and transmitted. α is the attenuation that exists when an incident crosses the propagation medium.

From Figure 3, the following expression can be described,

$$P_i={\stackrel{\sim }{\mathit{P}}}_{\mathit{i}}{e}^{i\left(\mathit{k}·\mathit{r}-\mathit{\omega t}\right)},$$E4

$$P_r={\stackrel{\sim }{\mathit{P}}}_{\mathit{r}}{e}^{-i\left(\mathit{k}·\mathit{r}+\mathit{\omega t}\right)},$$E5

$$P_t={\stackrel{\sim }{\mathit{P}}}_{\mathit{t}}{e}^{i\left(\mathit{k}·\mathit{r}-\mathit{\omega t}\right)},$$E6

where P_i, P_r, and P_t, represent the waves of incident waves, reflected, and transmitted. Expressions of pressure with the symbol ∼ represent a constant that can be determined by applying initial and/or boundary conditions.

Finally, all the materials have a very important acoustic property, and it is called the specific acoustic impedance (Rayls) that is given by the product of the volumetric density (kg/m³) and the velocity of propagation (m/s), this is, $Z=\rho ·c$. The specific acoustic impedance is the resistance that material presents to the flow of the propagation of the acoustic wave; it should be noted that in solid materials, the longitudinal and transverse acoustic propagation velocities are considered.

2.1 High-intensity ultrasound

Acoustic waves within the ultrasound spectrum range in frequencies between 16kHz and 1GHz. Ultrasound is divided into two categories, according to their acoustic intensities; low-intensity iltrasound (LIU) and high-intensity ultrasound (HIU). LIU is used for exploratory and characterization purposes; meanwhile, HIU is aimed at modifying the biological, physical, and chemical properties of materials. HIU is divided into three subcategories, according to their acoustic intensities depending on their frequency, as described in Table 2.

Name	Range (Hz)
Infrasound	IS < 20
Audible sound	20 < AS < 20k
Ultrasound	20k < US < 1G
Hypersound	HS > 1G

Table 1.

The spectrum of acoustic frequencies [8].

Subcategory	Acoustic intensity range (W/cm^2)	Frequency range (Hz)
Low	1 ≤ L < 2	< 1M
Medium	2 ≤ M < 10	100k ≤ f < 1M
High	10 ≤ H < 1000	20k ≤ f < 100k

Table 2.

Classification of acoustic intensities in high-intensity ultrasound depending on frequency [10].

The ultrasound field uses an ultrasonic sensor, which depends on a piezoelectric for its proper operation, ultrasonic sensor has low and high-intensity applications.

2.2 Piezoelectric materials

Piezoelectric materials are those that when subjected to mechanical stress (pressure) generate electrical polarization through the formation of dipoles causing electrical charges of their surface, from which the potential difference can be determined or measured. On the contrary, applying electrical pulses through both surfaces of the material (potential difference), generated mechanical deformations, or the reverse piezoelectricity effect. There are natural piezoelectric materials (quartz), piezopolymers (polyvinylidene difluoride, PVDF), piezoceramics (lead zirconate titanate, PZT), and piezocomposites (PSMNZT) [11, 12]. Piezoelectric materials have three physical properties—mechanical, electrical, and thermal. The relationship between mechanical and electrical properties has an electromechanical effect owning implicitly the piezoelectricity. The association between electrical and thermal properties as electrothermal effects holds the pyroelectric attributes. Finally, the relation between mechanical and thermal properties has the thermoelastic effect and has thermal pressure traits (Figure 4). The thermomechanical relationship is remarkable, as piezoelectric materials are also pyroelectric, hence, when the electrical charge changes, they become a thermal detector of electromagnetic waves on the infrared spectrum. However, when piezoelectric property exceeds its thermal threshold, loses its mechanical attributes, and keeps the thermal characteristics, retaining the pyroelectric effect.

Figure 4.

Heckmann piezoelectricity diagram [13].

Commercial HIU equipment basically has the same inner components. Figure 5 describes the stages of a HIU system; power supply, signal generator, power amplifier, and the high-intensity acoustic emitter. The high-intensity acoustic emitter has a backing, a pair of ceramic piezoelectric in a sandwich configuration, and an amplifier acoustic horn. The previously described ultrasonic emitters are called Langevin transducers [14].

Figure 5.

High-intensity ultrasound stages.

2.3 High-intensity ultrasound equipment

Ultrasonic baths and ultrasonic emitters (also known as sonotrode or probe types) within academia and research are used for sanitizing purposes (e.g., glassware, spare parts, surgical instruments, ballistics, and among others) because they are easy to handle. There is a wide market for these instruments worldwide, some of these are shown in Figure 6.

Figure 6.

High-intensity ultrasound equipment [15]. (a) High-intensity ultrasound system, sonotrode type [16]. (b) Ultrasonic bath [17].

2.4 Acoustic cavitation

The high-intensity acoustic wave within the ultrasound range frequency, under inertial or transient state conditions, induces a phenomenon known as acoustic cavitation, which includes generation, growth, and collapse of bubbles. The phenomenon occurs in the acoustic wave transition from the negative half cycle to the positive half cycle (expansion and compression). In a stable phase, bubbles generate an increase in number oscillating through the acoustic field (Figure 7).

Figure 7.

Description of stable and transient cavitation.

In a transitory state and under stochastics situations, the bubbles collapse causing various effects, such as acoustic microcurrents, nucleation of bubbles, shockwaves, sonoluminescence, radical formation, ultrasonic radiation, streams of cloud- and filamented-shaped bubbles form [18].

There is no general agreement on the area of knowledge that originated the study of the acoustic cavitation phenomenon, however, sonoluminescence, sonophysics, sonochemistry [19, 20, 21], and mechanochemistry [22] are the most likely.

The study of acoustic cavitation has developed various physic-mathematical models to describe detailly the phenomenology. The models represent a single bubble under ideal conditions, the description by Rayleigh [23], describes a spherical bubble embedded in an incompressible fluid, where R is the time-dependent radius of the bubble, R(t), p_eis the external pressure of the fluid. p_iis the pressure inside the bubble, and ρis the bulk density; see Figure 8. This model is represented by Eq. (7) and describes the kinetic energy in the system between the differences in the stress of the bubble as it expands through internal pressure and the stress of the fluid through the pressure subjected to the bubble.

Figure 8.

Physical parameters of the bubble, Rayleigh model.

$$\mathit{\rho R}\ddot{R}+\frac{3}{2}\rho {\dot{R}}^2=p_i-p_e,$$E7

where the points on the R (one and two points) mean first and second derivatives with respect to time (Newton’s notation), respectively.

The Rayleigh–Plesset model [24] was generated afterward. The parameters κ, μ, σ, from the original Rayleigh model were included, they are the polytropic exponent of the gas inside the bubble, the dynamic viscosity, and the surface tension of the fluid, respectively, as shown in Figure 9.

Figure 9.

Physical parameters of the bubble, Rayleigh–Plesset model.

The Rayleigh–Plesset model is represented by Eq. (8),

$$\mathit{\rho R}\ddot{R}+\frac{3}{2}\rho {\dot{R}}^2=p_{\mathit{gn}}{\left(\frac{R_n}{R}\right)}^{3\kappa }+p_v-p_{\mathit{\text{stat}}}-\frac{2\sigma }{R}-\frac{4\mu }{R}\dot{R}-p\left(t\right),$$E8

with

$$p_{\mathit{gn}}=\frac{2\sigma }{R_n}+p_{\mathit{\text{stat}}}-p_v,$$E9

and

$$p\left(t\right)=-p_{a}sin\left(2{\mathit{\pi \upsilon }}_{a}t\right),$$E10

where R_nis the radius of the resting sphere. p_gnis the pressure of the gas inside the bubble. p_statis the static pressure and p_vis the vapor pressure. p(t)is the external pressure applied to the wall of the bubble. v_ais the frequency and p_ais the amplitude of the pressure.

Later the Gilmore model was developed [25], as represented by Figure 10 and Eq. (1).

$$\left(1-\frac{\dot{R}}{C}\right)R\ddot{R}+\frac{3}{2}\left(1-\frac{\dot{R}}{3C}\right){\dot{R}}^2=\left(1+\frac{\dot{R}}{C}\right)H+\frac{\dot{R}}{C}\left(1-\frac{\dot{R}}{C}\right)R\frac{\mathit{dH}}{\mathit{dR}},$$E11

Figure 10.

Physical parameters of the bubble, Gilmore model.

with

$$H={\int }_{p\left|{}_{r\to \infty }\right.}^{p\left|{}_{r=R}\right.}\frac{\mathit{dp}\left(\rho \right)}{\rho },$$E12

$$p\left(\rho \right)=A{\left(\frac{\rho }{{\rho }_0}\right)}^{n_T}-B,$$E13

$$p\left|{}_{r=R}=\left(p_{\mathit{\text{stat}}}+\frac{2\sigma }{R_n}\right)\right.{\left(\frac{R_n^3-{\mathit{bR}}_n^3}{R^3-{\mathit{bR}}_n^3}\right)}^{\kappa }-\frac{2\sigma }{R}-\frac{4\mu }{R}\dot{R},$$E14

$$p\left|{}_{r\to \infty }\right.=p_{\mathit{\text{stat}}}+p\left(t\right),$$E15

$$C=\sqrt{c_0^2+\left(n_T-1\right)H},$$E16

where Cis the acoustic velocity near the bubble-wall, c₀is the acoustic velocity under normal conditions. His the enthalpy. A, Band nTare the van der Waals parameters.

Finally, the Keller–Miksis model [26] describes the behavior of a bubble under quasi-real conditions, as given by Eq. (17).

$$\left(1-\frac{\dot{R}}{C}\right)R\ddot{R}+\frac{3}{2}{\dot{R}}^2\left(1-\frac{\dot{R}}{3C}\right)=\left(1+\frac{\dot{R}}{C}\right)\frac{p_l}{\rho }+\frac{R}{\mathit{\rho c}}\frac{{\mathit{dp}}_l}{\mathit{dt}},$$E17

with

$$p_l=\left(p_{\mathit{\text{stat}}}+\frac{2\sigma }{R_n}\right)\left(\frac{R_n}{R}\right)3\kappa -p_{\mathit{\text{stat}}}-\frac{2\sigma }{R}-\frac{4\mu }{R}\dot{R}-p\left(t\right),$$E18

$$p\left(t\right)=p_{a}sin\left(2{\mathit{\pi \upsilon }}_{a}t\right).$$E19

Acoustic cavitation in a stable state given the oscillation in the acoustic field generates bubbles and divides them. On the other hand, acoustic cavitation in a transient state refers to the variation of pressure in short periods with respect to time and the breakage of the molecular bonds of the fluid, which will increase rapidly the temperature [27], as seen in Figure 11.

Figure 11.

Bubble generation transitions, growth, and collapse, in a transitory state.

If a fluid (liquid) is under shear stress, the bubbles within the fluid increase in size, hence, bubbles are generated within the fluid. The cavities with vapor increase their size until reaching a maximum volume, therefore, when the wave changes pressure from peak to valley, transforms potentials energy into kinetic energy during the implosion. The cavities collapse to sizes even smaller than the originally generated bubbles [28].

The implosions of the bubbles neighboring the surface of an interface are asymmetric; hence, they form microcurrents of the fluid that impinge on the surface of the interface. The average speed of the microcurrents is between 100 and 340 m/s; and they are dependent on the pressure profile and the initial diameter of the bubbles, which ranged between 10 and 100 μm [29].

There are two main types of formations in the generation and accumulation of bubbles in an acoustic field—bubble clouds and bubble filaments, as seen in Figure 12.

Figure 12.

Multibubble acoustic cavitation. (a) cloud-type, (b) filament-type.

The multibubble acoustic cavitation formation can be represented by the Keller–Miksis model [30], as shown in the Eq. (20).

$$\begin{array}{l}\left(1-M_i\right)R_i{\ddot{R}}_i+\frac{3}{2}\left(1-\frac{M_i}{3}\right){\dot{R}}_i^2\\ =\left(1+M_i\right)\frac{1}{{\rho }_{\mathit{li}}}\left[p_{\mathit{li}}-p_{\infty }-p_{\mathit{si}}\left(t+t_{R_i}\right)\right]+\frac{t_{R_i}}{{\rho }_{\mathit{li}}}{\dot{p}}_{\mathit{li}}-\sum _j\frac{{\left.\left(2R_j{\dot{R}}_j^2+R_j^2{\ddot{R}}_j\right)\right|}_{t-\frac{r_{\mathit{ij}}}{c_{l\infty }}}}{r_{\mathit{ij}}},\end{array}$$E20

where R_i(t)is the radius of the i-th bubble. ρ_liis the volumetric density of the fluid outside the i-th bubble. p_∞is the ambient pressure. $p_{\mathit{si}}\left(t\right)=p_{a_i}sin\left(\mathit{\omega t}\right),$is the modulated acoustic pressure on the i-th bubble. $t_{R_i}\equiv \raisebox{1ex}{$R_i$}\!\left/ \!\raisebox{-1ex}{$c_{\mathit{li}}$}\right.,$cli is the acoustic velocity of the fluid outside the i-th bubble. $p_{\mathit{li}}=p_{\mathit{gi}}\left(R_i,t\right)-\frac{4\eta {\dot{R}}_i}{R_i}-\frac{2\sigma }{R_i},$is the pressure on the fluid on the side of the i-th bubble wall.

3. Nanomaterials

Metrology states that in the international system of units, the meter [m] is the unit of measure of the length and is defined as the length of the path traveled by the light in the vacuum in a span of 1/299792458 of a second. Its primary standard or reference is at the International Office of Weights and Measures in Sévres, France. In such a way that its submultiples are given by cm, mm, nm, pm, etc. [31].

The unit of measure of the length is the origin to the reference of nanotechnology, due to the dimensions that the latter represents. Nanotechnology can be interpreted with the architecture of functional system and manipulation at nanometric scales, this is one billionth of the meter (1×10⁻⁹→ 0.000000001m) [32]. Figure 13 shows the comparison of sizes of some objects.

Figure 13.

Dimension comparison.

It all started in the American physics congress of 1959 when Richard P. Feynman gave a lecture entitled, “There´s plenty of room at the bottom” [33], and with this, he glimpsed the pioneering work of nanotechnology. Feynman described that it would be possible to manipulate systems at the atomic level individually with high-precision instruments. Also, he would be the first to propose the vision of quantum computing. In this way, the race for the exploration and development of nanotechnology and consequently of nanomaterials began [34, 35, 36, 37, 38, 39, 40]. So, a revolution in applications, such as the case of food.

There is a wide variety of nanomaterials, however, the main applications are by means of simple nanoparticles, nanoemulsion, liposome, nanostructured lipid carrier, multilayer nanoparticles, agglomerated nanoparticles, nanofilms, and nanocomposites [41]. There are five areas where studies and development in the field of food are focused [42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60], as seen in Figure 14.

Figure 14.

The five main areas in the study of food.

Subsequently, the interaction of nanomaterials and food interact on three fundamental processes [61, 62, 63, 64], as shown in Figure 15.

Figure 15.

Applications of nanomaterials in food, by means of the Sierpinski triangle.

In recent years, high-intensity ultrasound has been applied to foods involving nanomaterials and obtaining interesting results. Figure 16 shows the interaction of the HIU and the fields of study in nanomaterials focused on food [65, 66, 67].

Figure 16.

HIU application in nanomaterials.

4. Conclusions

Food is a fundamental part of the growth and development of the human being and has changed over time due to current needs. Today the agri-food industry has to use and apply every tool and technology within its reach due to consumer demands. This happens throughout the traceability procedure as it is in the processing, treatment, conservation, and distribution of food. Therefore, alternative or emerging tools are applied, which are different from thermal ones, whose objective is to increase the nutritional properties of foods with benefit for society. In addition to the conjugation of hybrid systems, such as the implementation of nanomaterials applying modern technologies. In this chapter, high-intensity ultrasound and the effect of acoustic cavitation were explained in a simple way, as a tool that is applied to food. Thus, the application of nanomaterials in the main areas of food was also superficially described. Even so, academic and laboratory studies are still being presented to explore the short-range impacts of these hybrid tools. However, there is the possibility of taking it to large-scale production levels, with the aim of carrying out acceptance and quality tests. Subsequently, the final impacts are to implement it in the food industry worldwide. Also, why not say so, have them as another utensil in every home.

Acknowledgments

R.A.R.V. acknowledges the support provided by Investigador por México-CONACYT.

Conflict of interest

The authors declare that they have no known competing financial interest or personal relationship that could have appeared to influence the work reported in this material.