An Overview of Ultrasound-Assisted Food-Grade Nanoemulsions (original) (raw)
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The use of ultrasonics for nanoemulsion preparation
Innovative Food Science & Emerging Technologies, 2008
Oil-in-water emulsions are an important vehicles for the delivery of hydrophobic bioactive compounds into a range of food products. The preparation of very fine emulsions is of increasing interest to the beverage industry, as novel ingredients can be added with negligible impact to solution clarity. In the present study, both a batch and focused flow-through ultrasonic cell were utilized for
Evaluation of short cycles of ultrasound application in nanoemulsions to obtain nanocapsules
Ultrasonics Sonochemistry, 2015
Ultrasound is widely used in several chemical reactions and other process, including production of nanocapsules by in situ polymerization. In this work, the main objective was to evaluate the impacts and viability of successive ultrasound application in nanoemulsions to obtain nanocapsules. Initiator potassium persulfate (KPS) concentration, number of ultrasound cycles and reaction time influences on polymerization efficiency and droplet size were evaluated. This work revealed the successful in situ production of nanocapsules using successive shorts cycles of ultrasound. Number of cycles was the only parameter that not exerted significant influence in polymerization yield. Particle size decay was observed in all nanoemulsions after the first ultrasound application, the same was not observed in further cycles. Gravimetric assessment showed remarkable increase of monomer conversion, indicating that once started polymerization continued at least until 28 days after ultrasound application. Concluding, ultrasound short cycles can be used with no harm to formulation, if carefully performed and, furthermore is a potential cost-effective route for polymerization reactions.
Ultrasonics Sonochemistry, 2012
In the present study, response surface methodology (RSM) based on central composite design (CCD) was employed to investigate the influence of main emulsion composition variables, namely drug loading, oil content, emulsifier content as well as the effect of the ultrasonic operating parameters such as pre-mixing time, ultrasonic amplitude, and irradiation time on the properties of aspirin-loaded nanoemulsions. The two main emulsion properties studied as response variables were: mean droplet size and polydispersity index. The ultimate goal of the present work was to determine the optimum level of the six independent variables in which an optimal aspirin nanoemulsion with desirable properties could be produced. The response surface analysis results clearly showed that the variability of two responses could be depicted as a linear function of the content of main emulsion compositions and ultrasonic processing variables. In the present investigation, it is evidently shown that ultrasound cavitation is a powerful yet promising approach in the controlled production of aspirin nanoemulsions with smaller average droplet size in a range of 200-300 nm and with a polydispersity index (PDI) of about 0.30. This study proved that the use of low frequency ultrasound is of considerable importance in the controlled production of pharmaceutical nanoemulsions in the drug delivery system.
Ultrasound-assisted production and characterization of rice bran lecithin-based nanoemulsions
Journal of Dispersion Science and Technology, 2020
Rice bran lecithin (RBL) is a mixture of phospholipids which is obtained as a by-product during the refining of rice bran oil. The emulsifying properties of RBL help in the production of nanoemulsions. Ultrasonication is a high energy approach to produce nanoemulsions with small droplet size and high kinetic stability in comparison to the coarse emulsion. The current study aims to develop stable nanoemulsions using different concentrations of RBL as an emulsifier by ultrasonication (60% amplitude, 40 cycles). Xanthan gum is used as a stabilizing agent for the nanoemulsions. The stability of nanoemulsions under optimum conditions (pH 7, 25 C) was determined. The nanoemulsions were characterized by determining creaming index, droplet size, polydispersity index (PDI), microstructure analysis, zeta potential, and shear viscosity. The emulsion with the highest concentration of RBL showed maximum kinetic stability against phase separation. The size of nanoemulsions vary in the range of (10-150 nm), the droplet size analysis showed the stability of nanoemulsions on the 14th day of preparation. Microstructure analysis of droplets on different days of storage showed uniform distribution of droplets in the nanoemulsion, thus leading to high kinetic stability. The zeta potential remained negative due to the adsorption of anionic lecithin on the droplet surface. The viscosity of the nanoemulsion formed after ultrasonication exhibited lower viscosity than the preemulsion due to the formation of small droplets.
Potential Use of Ultrasound to Produce High Solids Emulsions
2016
Ultrasound was used to obtain kinetically stable emulsions for further spray drying. Sonication time of 3, 7 and 11 minutes were evaluated at power amplitudes of 50%, 75% and 100% (in relation to the nominal power of the equipment), where energy density required for each assay was calculated. Emulsions were characterized for droplets mean diameter and size distribution, optical microscopy, zeta potential, creaming index (CI) and rheological behavior. The products presented bimodal size distribution, with D[3,2] ranging from 0.7 to 1.4 μm and CI between 5% and 12%, being this parameters inversely proportional to the variables studied, but with an apparent stabilization after the treatment at 100% power amplitude at 7 min sonication. D[3,2] showed to depend of energy density as a power function. PALAVRAS-CHAVE: sonicação, óleo de palma, emulsificação por alta energia.
Phase transitions of nanoemulsions using ultrasound: Experimental observations
Ultrasonics Sonochemistry, 2012
The ultrasound-induced transformation of perfluorocarbon liquids to gases is of interest in the area of drug and gene delivery. In this study, three independent parameters (temperature, size, and perfluorocarbon species) were selected to investigate the effects of 476-kHz and 20-kHz ultrasound on nanoemulsion phase transition. Two levels of each factor (low and high) were considered at each frequency. The acoustic intensities at gas bubble formation and at the onset of inertial cavitation were recorded and subsequently correlated with the acoustic parameters.
Ultrasonics sonochemistry, 2013
In the present investigation, the operating efficiency of a bench-top air-driven microfluidizer has been compared to that of a bench-top high power ultrasound horn in the production of pharmaceutical grade nanoemulsions using aspirin as a model drug. The influence of important process variables as well as the pre-homogenization and drug loading on the resultant mean droplet diameter and size distribution of emulsion droplets was studied in an oil-in-water nanoemulsion incorporated with a model drug aspirin. Results obtained show that both the emulsification methods were capable of producing very fine nanoemulsions containing aspirin with the minimum droplet size ranging from 150 to 170 nm. In case of using the microfluidizer, it has been observed that the size of the emulsion droplets obtained was almost independent of the applied microfluidization pressure (200-600 bar) and the number of passes (up to 10 passes) while the pre-homogenization and drug loading had a marginal effect in...
Process optimization of ultrasound-assisted curcumin nanoemulsions stabilized by OSA-modified starch
Ultrasonics Sonochemistry, 2014
This study reports on the process optimization of ultrasound-assisted, food-grade oil-water nanoemulsions stabilized by modified starches. In this work, effects of major emulsification process variables including applied power in terms of power density and sonication time, and formulation parameters, that is, surfactant type and concentration, bioactive concentration and dispersed-phase volume fraction were investigated on the mean droplet diameter, polydispersity index and charge on the emulsion droplets. Emulsifying properties of octenyl succinic anhydride modified starches, that is, Purity Gum 2000, Hi-Cap 100 and Purity Gum Ultra, and the size stability of corresponding emulsion droplets during the 1 month storage period were also investigated. Results revealed that the smallest and more stable nanoemulsion droplets were obtained when coarse emulsions treated at 40% of applied power (power density: 1.36 W/mL) for 7 min, stabilized by 1.5% (w/v) Purity Gum Ultra. Optimum volume fraction of oil (medium chain triglycerides) and the concentration of bioactive compound (curcumin) dispersed were 0.05 and 6 mg/mL oil, respectively. These results indicated that the ultrasound-assisted emulsification could be successfully used for the preparation of starch-stabilized nanoemulsions at lower temperatures (40-45°C) and reduced energy consumption.
Scientific Reports
Emerging formulation technologies aimed to produce nanoemulsions with improved characteristics, such as stability are attractive endeavors; however, comparisons between competing technologies are lacking. In this study, two formulation techniques that employed ultrasound and microfluidic approaches, respectively, were examined for relative capacity to produce serviceable oil in water nanoemulsions, based on hempseed oil (HSO). The ultrasound method reached > 99.5% entrapment efficiency with nanoemulsions that had an average droplet size (Z-Ave)
Ultrasonics Sonochemistry, 2006
A novel concept was developed here for the continuous, contact-and contamination-free treatment of fluid mixtures with ultrasound. It is based on exciting a steel jacket with an ultrasonic transducer, which transmitted the sound waves via pressurised water to a glass tube installed inside the jacket. Thus, no metallic particles can be emitted into the sonicated fluid, which is a common problem when a sonotrode and a fluid are in direct contact. Moreover, contamination of the fluid from the environment can be avoided, making the novel ultrasonic flow-through cell highly suitable for aseptic production of pharmaceutical preparations. As a model system, vegetable oil-in-water emulsions, fed into the cell as coarse pre-emulsions, were studied. The mean droplet diameter was decreased by two orders of magnitude yielding Sauter diameters of 0.5 lm and below with good repeatability. Increasing the residence time in the ultrasonic field and the sonication power both decreased the emulsion mean diameter. Furthermore, the ultrasonic flow-through cell was found to be well suited for the production of nanoparticles of biodegradable polymers by the emulsion-solvent extraction/ evaporation method. Here, perfectly spherical particles of a volume mean diameter of less than 0.5 lm could be prepared. In conclusion, this novel technology offers a pharmaceutically interesting platform for nanodroplet and nanoparticle production and is well suited for aseptic continuous processing.