Combined high-power ultrasound and high-pressure homogenization nanoemulsification: The effect of energy density, oil content and emulsifier type and content

Sonication as a potential tool in the formation of protein-based stable emulsion - Concise review

Emulsion systems are extensively used in the food processing sector and the use of natural emulsifiers like proteins for stabilizing emulsion has been in demand from consumers due to increased awareness about the consumption of healthy food. Numerous methods are available for the preparation of emulsion, but ultrasound got more attention among common methods owing to its economical and environment-friendly characteristics. The physical effects caused by to bursting of the cavity bubble, result in reduced droplet size, thus forming an emulsion with appreciable stability. Ultrasound ameliorates the emulsifying characteristics of natural emulsifiers like protein and improves the storage stability of the emulsion by positively boosting the rheological, emulsifying characteristics, improving zeta potential, and reducing average droplet size. The stability of protein-based emulsion is affected by environmental stresses hence conjugate of protein with polysaccharide showed good emulsifying characteristics. However, the data on the effect of ultrasound parameters on emulsifier properties is lacking and there is a need to develop a sonication device that can carry out large-scale emulsification operation. The review covers the principles and mechanisms of ultrasound-assisted formation of protein-based and protein-based conjugate emulsions. Further, the effect of ultrasound on various characteristics of protein-based emulsion is also explored. This review will provide concise data to the researchers to extend their experiments in the area of ultrasound emulsification which will help in commercializing the technology at the industrial scale.

An Updated Review on Nanoemulsion: Factory for Food and Drug Delivery

BACKGROUND

A nanoemulsion is a colloidal system of small droplets dispersed in another liquid. It has attracted considerable attention due to its unique properties and various applications. Throughout this review, we provide an overview of nanoemulsions and how they can be applied to various applications such as drug delivery, food applications, and pesticide formulations.

OBJECTIVE

This updated review aims to comprehensively overview nanoemulsions and their applications as a versatile platform for drug delivery, food applications, and pesticide formulations.

METHODS

Research relevant scientific literature across various databases, including PubMed, Scopus, and Web of Science. Suitable keywords for this purpose include "nanoemulsion," "drug delivery," and "food applications." Ensure the search criteria include recent publications to ensure current knowledge is included.

RESULTS

Several benefits have been demonstrated in the delivery of drugs using nanoemulsions, including improved solubility, increased bioavailability, and controlled delivery. Nanoemulsions have improved some bioactive compounds in food applications, including vitamins and antioxidants. At the same time, pesticide formulations based on nanoemulsions have also improved solubility, shelf life, and effectiveness.

CONCLUSION

The versatility of nanoemulsions makes them ideal for drug delivery, food, and pesticide formulation applications. These products are highly soluble, bioavailable, and targeted, providing significant advantages. More research and development are required to implement nanoemulsion-based products on a commercial scale.

Enhancing pea protein isolate functionality: A comparative study of high-pressure homogenization, ultrasonic treatment, and combined processing techniques

Pea protein has attracted widespread attention due to its high nutritional value, low allergenicity, non-GMO status, and broad availability. However, compared to animal proteins, pea protein has inferior functional properties, which limits its application in the food industry. This study used pea protein isolate (PPI) as the main raw material and investigated the effects of high-pressure homogenization (HPH), ultrasonic treatment (US), and the combination of the two in different orders on the structure and function of PPI. The results showed that HPH or US promoted the transformation of PPI insoluble suspension into a uniform protein dispersion, significantly reducing particle size, unfolding the spatial structure, exposing more amino acid residues. These structural changes resulted in a substantial increase in the solubility, foaming capacity and emulsifying activity of PPI. Moreover, the combined treatments further impacted the properties of PPI, largely depending on the order of the processing steps; the combination of HPH-US exhibited the best functional characteristics.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation

BACKGROUND

Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization.

SCOPE AND APPROACH

This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed.

KEY FINDINGS AND CONCLUSIONS

The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.

High pressure homogenization to boost the technological functionality of native pea proteins

Pea proteins are being increasingly used for the formulation of plant-based products, but their globular structure and the presence of aggregates can affect their technological properties. In this study, the effect of high pressure homogenization (HPH) at different intensities (60 and 100 MPa) was investigated as a pre-treatment to modulate the techno-functional properties of a pea protein isolate (IP) extracted through an alkaline extraction/isoelectric precipitation process. SDS-PAGE, circular dichroism, thermal properties, total free sulfhydryl groups, antioxidant capacity and reducing properties were evaluated along with technological indices as solubility, WHC and OHC, interfacial tension and emulsifying capacity. HPH treatments were able to unfold and modify proteins structure, leading also to a change of the relative abundance of pea protein globulins (SDS-PAGE) and of the vicilin to legumin ratio. Solubility, WHC and OHC were improved, while interfacial tension and emulsifying capacity were weakly affected. However, an enhanced physical stability over time of the emulsions prepared with the 60 MPa-treated protein was found, likely as an effect of the decreased ratio between vicilin and legumin after treatment. Results of this study will contribute to deepen the effect of the HPH technology used as pre-treatment, adding useful results and expanding knowledge about the structure and techno-functional properties of native and modified pea proteins.

Study and optimization of oil-in-water emulsions formulated by low- and high-frequency ultrasounds

OBJECTIVE

A combined treatment using both low-frequency (20 kHz) and high-frequency ultrasounds (1.63 MHz) is a promising new process to stabilize emulsions with minimalist formulation. In order to optimize process parameters, a Doehlert experimental design was performed with oil-in-water emulsions, presently used for cosmetic products, composed of water, caprylic/capric triglycerides and oleic acid.

METHODS

Effects of treatment time, oil content and oleic acid content were studied on emulsion properties (droplet size, polydispersity index, ζ-potential and yield of oil incorporation) and on emulsion stability after a 28-day storage (creaming index, Turbiscan stability index (TSI) and oil release).

RESULTS

From experimental data, a model was established that allowed to study effects of each parameter and their interactions on emulsion formation and stability. Oleic acid content had a great impact on emulsion formation: It reduced droplet size, PDI and ζ-potential and increased yield of oil incorporation. However, a critical value could be highlighted, beyond which oleic acid effects reversed. Treatment time had an important beneficial effect on emulsion stability as it decreased creaming index, TSI and oil release after 28 days of storage. Oil content had a negative effect on emulsion formation and on emulsion stability. However, treatment time and oil content often had a beneficial synergistic effect.

CONCLUSION

The optimized conditions for emulsion processing were obtained through a desirability approach. They were experimentally validated.

Understanding the effects of ultrasound processng on texture and rheological properties of food

The demand for the production of high quality and safe food products has been ever increasing. Consequently, the industry is looking for novel technologies in food processing operations that are cost-effective, rapid and have a better efficiency over traditional methods. Ultrasound is well-known technology to enhance the rate of heat and mass transfer providing a high end-product quality, at just a fraction of time and energy normally required for conventional methods. The irradiation of foods with ultrasound creates acoustic cavitation that has been used to cause desirable changes in the treated products. The technology is being successfully used in various unit operations such as sterilization, pasteurization, extraction, drying, emulsification, degassing, enhancing oxidation, thawing, freezing and crystallization, brining, pickling, foaming and rehydration, and so forth. However, the high pressure and temperature associated with the cavitation process is expected to induce some changes in the textural and rheological properties of foods which form an important aspect of product quality in terms of consumer acceptability. The present review is aimed to focus on the effects of ultrasound processing on the textural and rheological properties of food products and how these properties are influenced by the process variables.

Ultrahigh efficient emulsification with drag-reducing liquid gating interfacial behavior

Emulsification is a crucial technique for mixing immiscible liquids into droplets in numerous areas ranging from food to medicine to chemical synthesis. Commercial emulsification methods are promising for high production, but suffer from high energy input. Here, we report a very simple and scalable emulsification method that employs the drag-reducing liquid gating structure to create a smooth liquid-liquid interface for the reduction of resistance and tunable generation of droplets with good uniformity. Theoretical modeling and experimental results demonstrate that our method exhibits ultrahigh efficiency, which can reach up to more than 4 orders of magnitude greater energy-saving compared to commercial methods. For temperature-sensitive biological components, such as enzymes, proteins, and bacteria, it can offer a comfortable environment to avoid exposure to high temperatures during emulsifying, and the interface also enables the suppression of fouling. This unique drag-reducing liquid gating interfacial emulsification mechanism promotes the efficiency of droplet generation and provides fresh insight into the innovation of emulsifications that can be applied in many fields, including the food industry, the daily chemical industry, biomedicine, material fabrication, the petrochemical industry, and beyond.

Enhancement of storage stability of surimi particles stabilized novel pickering emulsions: Effect of different sequential ultrasonic processes

Preparation of highly stable Pickeringemulsions stabilized by food grade particles especially with low concentrations is of concern. In this study, the effects of two-step emulsification procedure with different sequential ultrasonic processes on the storage stability, droplets size, zeta potential, microstructures as well as the rheological behaviors of surimi particles-stabilized Pickeringemulsions with 0.6 oil-water ratio were investigated. The results showed that the surimi particles based-emulsions prepared by the homogenization-ultrasonic (H-U) or ultrasonic-homogenization (U-H) method both possessed excellent physical stability during 14 days storage. Particularly, the stability index of emulsions all exceeded 99.5% in the U-H groups. The confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscope (cryo-SEM) images provide evidence that more particles attached on the oil-water interfaces and the network structures formed via particle-particle interactions obviously arrested phase separation in H-U and U-H emulsions. Moreover, the Pickering emulsions obtained by two-step method all exhibited higher viscosity and storage modulus values, which were also conducive to the special storage stability of samples. In short, the storage stability of protein based-Pickering emulsions can be enhanced using homogenization-ultrasonic (H-U) or ultrasonic-homogenization (U-H) procedure.

Optimisation of Stingless Bee Honey Nanoemulsions Using Response Surface Methodology

Nanoemulsions (NEs) have been used in a wide range of products, such as those produced by the food, cosmetics, and pharmaceutical industries, due to their stability and long shelf life. In the present study, stingless bee honey (SBH) NEs were formulated using SBH, oleic acid, tween 80, glycerol, and double-distilled water. SBH NEs were prepared using a high-pressure homogeniser and were characterised by observing their stability and droplet size. Fourier Transform-Infrared (FTIR) analysis was used to observe the functional groups of the SBH NEs after being subjected to high-pressure homogenisation. Transmission Electron Microscopy (TEM) images were then used to confirm the particle size of the SBH NEs and to investigate their morphology. The effects of the independent variables (percentage of oleic acid, storage time, and storage temperature) on the response variables (particle size and polydispersity index) were investigated using the response surface methodology, along with a three-level factorial design. The results showed that the models developed via the response surface methodology were reliable, with a coefficient of determination (R²) of more than 0.90. The experimental validation indicated an error of less than 10% in the actual results compared to the predicted results. The FTIR analysis showed that SBH NEs have the same functional group as SBH. Observation through TEM indicated that the SBH NEs had a similar particle size, which was between 10 and 100 nm. Thus, this study shows that SBH NEs can be developed using a high-pressure homogeniser, which indicates a new direction for SBH by-products.

Design, Preparation, and Characterization of Effective Dermal and Transdermal Lipid Nanoparticles: A Review

Limited permeability through the stratum corneum (SC) is a major obstacle for numerous skin care products. One promising approach is to use lipid nanoparticles as they not only facilitate penetration across skin but also avoid the drawbacks of conventional skin formulations. This review focuses on solid lipid nanoparticles (SLNs), nanostructured lipid nanocarriers (NLCs), and nanoemulsions (NEs) developed for topical and transdermal delivery of active compounds. A special emphasis in this review is placed on composition, preparation, modifications, structure and characterization, mechanism of penetration, and recent application of these nanoparticles. The presented data demonstrate the potential of these nanoparticles for dermal and transdermal delivery.

Establishment of a standardized dietary model for nanoparticles oral exposure studies

Food matrices could affect the physicochemical properties of nanoparticles (NPs) and define the biological effects of NPs via oral exposure compared with the pristine NPs. We established a standardized dietary model based on Chinese dietary reference intakes and Chinese dietary guidelines to mimic the exposure of NPs in real life and to evaluate further the biological effect and toxicity of NPs via oral exposure compared with current models. The standardized dietary model prepared from the primary emulsion was dried into powder using spray drying compared with commercial food powder and then was reconstituted compared with the fresh sample. The average particle size (295.59 nm), potential (-23.78 mV), viscosity (0.04 pa s), and colors (L*, a*, b* = 84.13, -0.116, 8.908) were measured and characterized of the fresh sample. The flowability (repose angle = 37.28° and slide angle = 36.75°), moisture (2.68%), colors (L*, a*, b* = 94.16, -0.27, 3.01), and bulk density (0.45 g/ml) were compared with commercial food powder. The size (310.75 nm), potential (-23.98 mV), and viscosity (0.04 pa s) of reconstituted model were similar to the fresh sample. Results demonstrated that the model was satisfy the characterizations of easy to fabrication, good stability, small particle size, narrow particle size distribution, strong practicability, and good reproducibility similar to most physiological food state and will be used to evaluate NPs' safety.

The formation, stability of DHA/EPA nanoemulsion prepared by emulsion phase inversion method and its application in apple juice

This study prepared edible docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) nanoemulsion using EPI (emulsion phase inversion) method. The method for preparing DHA and EPA nanoemulsions is safe, convenient, low in energy consumption and can be used for food production. Factors affecting particle size and stability during preparation were investigated. Based on the optimal particle size combination, stability studies including particle size and residual rates of DHA and EPA at different temperature, pH and metal ions. The results showed that the nanoemulsion had good stability at low temperature storage, near neutral pH and in the absence of transition metal ions such as Fe³⁺, Cu²⁺, Al³⁺. The experiment initially studied the effect of nanoemulsion on apple juice beverage on the basic properties of juice itself. It was feasible in practical application of edible nanoemulsion.

Effect of dynamic ultra-high pressure homogenization on the structure and functional properties of whey protein

The effects of dynamic ultra-high pressure homogenization (UHPH) on the structure and functional properties of whey protein were investigated in this study. Whey protein solution of 10 mg/mL (1% w/w) was prepared and processed by a laboratory scale high pressure homogenizer with different pressures (25, 50, 100, 150, 200, and 250 MPa) at an initial temperature of 25 °C. Then, the solution samples were evaluated in terms of secondary structure, sulfhydryl and disulfide bond contents, surface hydrophobicity, average particle size, solubility, foaming capacity, emulsifying activity, and thermal properties. It was found that the secondary structure of whey protein changed with the dynamic UHPH treatment. The interchange reaction between the disulfide bond and the sulfhydryl group was promoted and the surface hydrophobicity significantly increased. The functional properties of the whey protein accordingly changed. Specifically, after dynamic UHPH treatment, the average particle size of the whey protein and emulsion decreased while the solubility, the foaming capability and the emulsification stability increased significantly. The results also revealed that with the dynamic UHPH at 150 MPa, the best improvement was observed in the whey protein functional properties. The whey protein solubility increased from 63.15 to 71.61% and the emulsification stability improved from 195 to 467 min.

Potential Applications of High Pressure Homogenization in Winemaking: A Review

High pressure homogenization (HPH) is an emerging technology with several possible applications in the food sector, such as nanoemulsion preparation, microbial and enzymatic inactivation, cell disruption for the extraction of intracellular components, as well as modification of food biopolymer structures to steer their functionalities. All these effects are attributable to the intense mechanical stresses, such as cavitation and shear forces, suffered by the product during the passage through the homogenization valve. The exploitation of the disruptive forces delivered during HPH was also recently proposed for winemaking applications. In this review, after a general description of HPH and its main applications in food processing, the survey is extended to the use of this technology for the production of wine and fermented beverages, particularly focusing on the effects of HPH on the inactivation of wine microorganisms and the induction of yeast autolysis. Further enological applications of HPH technology, such as its use for the production of inactive dry yeast preparations, are also discussed.

Formation of concentrated triglyceride nanoemulsions and nanogels: natural emulsifiers and high power ultrasound

The fabrication of concentrated nanoemulsions provides potential advantages such as loading capacity enhancement, storage and transportation costs reduction, and creation of novel textures. The current study investigated the capability of high power ultrasound on nanoemulsification of high concentration triglyceride using various natural emulsifiers (saponin, whey protein isolate, lecithin and sucrose monopalmitate). The impact of the emulsifier concentration (up to 6 wt%), oil content (up to 60 wt%) and exposure to sonication (up to 33 min) on the droplet size distribution, physical stability and rheological properties were evaluated. Regarding the dilute nanoemulsion (10 wt% oil), droplet size was inversely correlated with the concentration of emulsifiers, however only by using saponin (2 wt%) the droplet size was in nano range (d < 200 nm). The concentrated nanoemulsions (20–50 wt%) were also fabricated under sonication (15 min at saponin-to-oil ratio 2 : 10 w/w%). They also presented shear-thinning behavior with relatively low consistency coefficients. Surprisingly, the one with 60 wt% oil was easily converted to viscoelastic gel upon 3 min sonication. Owing to such characteristics, they could have potential applicability in formulation of soft foods, creams, sauces, salad dressings, pastes, lotions, cosmetics and pharmaceuticals.

The capability of ultrasonication and natural emulsifiers on nano-emulsification and nano-gelation of concentrated triglyceride oil was verified.

Coupling of high-intensity ultrasound and mechanical stirring for producing food emulsions at low-energy densities

In this study, coupling of ultrasound (US) device and rotor-stator (RS), operating at low-energy densities, was studied as an alternative process to individual US and RS to produce modified starch-stabilized oil-in-water emulsions, as well as its potential use to encapsulate eugenol. To this aim, a full factorial design was employed to evaluate the effects of the US nominal power (0, 360 and 720 W) and RS nominal power (0, 150 and 300 W) on the physical properties, encapsulation efficiency and kinetic stability of emulsions produced. Firstly, the action of modified starch and eugenol onto interface oil-water was evaluated. The emulsifier was rapidly adsorbed on the interface water-sunflower oil reducing the interfacial tension from 25 to 16 mN/m, while eugenol did not show surface activity. The increase of energy density, in general, resulted in droplet size reduction, indicating the relevant role of the forces involved in the droplet breakup on emulsion stability. Coupling was more efficient on the droplets breakup producing smaller droplet size with narrower size distribution. While the coupled system work during 5 min for an energy density of 583 J/mL, the corresponding emulsification time for operating singly US and RS were 7.09 min and 17.04 min, respectively. Therefore, the main advantage associate to coupled process is the reduction of processing time to produce an emulsion with better kinetic stability.

Ultrasonic-Assisted Fabrication of Concentrated Triglyceride Nanoemulsions and Nanogels

In many food products such as gels, pastes, jellies, creams, sausages, and selected dressings or spreads, it is desirable to formulate concentrated triglyceride nanoemulsions so as to deliver lipophilic functional agents. In this study, the ability of ultrasonication to form nanoemulsions and nanogels containing high concentration of sunflower oil was investigated in the presence of sodium dodecyl sulfate (SDS) as a surfactant. The influence of SDS and oil concentration and duration of sonication on the physical stability, mean droplet diameter, and rheological properties of emulsions were determined. Ultrasonication for up to 9 min was highly effective on fabrication of stable nanoemulsions (an average droplet size of 158-171 nm) at low oil/surfactant ratio (10:0.7). The viscosity and storage modulus increased with decreasing the droplet size particularly at higher oil concentrations. The viscous nanoemulsions (containing 60, 50, and 40 wt % oil) transformed into viscoelastic gels when sonicated for 3, 9, and 30 min, respectively. On the basis of the findings of the present study, such textural and rheological modifications, resulted from droplet size decreasing, could be potentially useful in designing reduced fat gel-like products.