In the last decades, several non-thermal technologies have been proposed as alternative to the traditional ones to improve the competitiveness of the food industry. The key to success was identified ...in offering to food industries the opportunity to improve food quality, to introduce new foods in the market, and to optimize the processing procedures while reducing energy costs. Pulsed electric fields (PEF) showed the potential to be one of the most promising novel technologies to reach these objectives. The application of PEF as a pretreatment of permeabilization of vegetable and animal tissue to enhance the efficiency of mass transfer of water or of valuable compounds from biological matrices demonstrated its efficiency in drying, extraction, and diffusion processes. This article reviews the basic mechanisms of electroporation of plant tissues, discusses the methods of detection of electrically induced cell damage, and analyses the influence of process parameters on the efficiency of the treatment. Furthermore, this article focuses on the applications of PEF, its advantages, and energy costs in different fields of food processing, such as juice expression, drying, and extraction, with special emphasis on the relevance of PEF to the winemaking industry.
The application of edible coatings (EC) in combination with pulsed light (PL) treatments represents an emerging approach for extending the shelf life of highly perishable but high value-added ...products, such as fresh-cut fruits and vegetables. The surface of these products would benefit from the protective effects of ECs and the PL decontamination capability. This review describes in detail the fundamentals of both EC and PL, focusing on the food engineering principles in the formulation and application of EC and the delivery of efficient PL treatments and the technological aspects related to the food characterization following these treatments and discussing the implementation of the two technologies, individually or in combination. The advantages of the combination of EC and PL are extensively discussed emphasizing the potential benefits that may be derived from their combination when preserving perishable foods. The downsides of combining EC and PL are also presented, with specific reference to the potential EC degradation when exposed to PL treatments and the screening effect of PL transmittance through the coating layer. Finally, the potential applications of the combined treatments to food products are highlighted, comparatively presenting the treatment conditions and the product shelf-life improvement.
•Main formulation issues of essential oil (EO) nanoemulsions.•Different fabrication methods of EO nanoemulsions.•In vitro activity of EO nanoemulsions against different microbial species.•Possible ...mechanisms of antimicrobial action of EO nanoemulsions.•Routes for in product applications of EO nanoemulsions.
The crescent interest in the use of essential oils (EOs) as natural antimicrobials and preservatives in the food industry has been driven in the last years by the growing consumers’ demand for natural products with improved microbial safety, and fresh-like organoleptic properties.
Nanoemulsions efficiently contribute to support the use of EOs in foods by increasing their dispersibility in the food areas where microorganisms grow and proliferate, by reducing the impact on the quality attributes of the product, as well as by enhancing their antimicrobial activity.
Understanding how nanoemulsions intervene on the mass transfer of EOs to the cell membrane and on the mechanism of antimicrobial action will support the engineering of more effective delivery systems and foster the application of EOs in real food systems.
This review focuses on the enabling contribution of nanoemulsions to the use of EOs as natural preservative agents in food, (a) specifically addressing the formulation and fabrication of stable EO nanoemulsions, (b) critically analyzing the reported antimicrobial activity data, both in vitro and in product, to infer the impact of the delivery system on the mechanisms of action of EOs, as well as (c) discussing the regulatory issues associated with their use in food systems.
The processing of selected foods by nonthermal technologies is gaining relevance in the food industry because, in many cases, the final product keeps the nutritional value and other fresh-like ...characteristics of the original one. There are several nonthermal technologies including high pressure processing, pulsed electric fields, ultrasound, and cold plasma which are at different stages of development. The impact of a given technology on bioactive compounds is a good indicator to assess changes on the nutritional attributes of a given food product before and after processing. Quite frequently, it is mentioned that nonthermal technologies are very appropriate to process foods minimizing changes in quality attributes. This broad claim only applies for certain processing, packaging and storage conditions, and as expected, on the food product. There are extensive scientific publications on how these processes alter the food products, but the reported results have been attained by a disparity of treatments; therefore, comparisons of these results are difficult and sometimes useless. Nevertheless, the gathered information allows to identify, in many cases, valuable trends on how a process affects the different bioactive compounds of a given food product. At the same time, the available data allows to assert, that in general, nonthermal processing is a very sound alternative to conventional thermal treatments to minimize the impact of processing on bioactive compounds. This review summarizes and analyzes the effects of these processes on relevant bioactive compounds present in selected food products as reported in the scientific literature.
The primary objective of the Sustainable Development Goals is to reduce food waste by employing various strategies, including the reuse of agri-food residues that are abundantly available and the ...complete use of their valuable compounds. This study explores the application of high-pressure homogenization (HPH), an innovative nonthermal and green treatment, for the recovery of bioactive compounds from agri-food residues. The results demonstrate that the optimized HPH treatment offers advantages over conventional solid/liquid extraction (SLE), including shorter extraction time, solvent-free operation, low temperatures, and higher yields of phenol extraction (an approximately 20% improvement). Moreover, the micronization of agri-food residue-in-water suspensions results in a decrease in the size distribution to below the visual detection limit, achieved by disrupting the individual plant cells, thus enhancing suspension stability against sedimentation. These findings highlight the potential of HPH for environmentally friendly and efficient extraction processes.
Nanocellulose (NC) has recently emerged as of high interest in water purification because of its high surface area, aspect ratio, and versatile surface chemistry. In the present study, nanocellulose ...has been isolated from cellulose pulp, extracted from barley straw residues via a mechanical pulping treatment, through a combination of chemical and mechanical refining treatments. The obtained cellulose pulp and (ligno)cellulose nanofibrils (L)CNFs, in the form of papers and nanopapers, respectively, were characterized in terms of mechanical properties. Finally, (L)CNFs-based aerogels were developed, and adsorption tests at 25 °C using 0.1 g of aerogels in 50 mL of methylene blue (MB) dye solution at 10 mg/L were studied. The results revealed that CNF-based aerogels can be exploited as an effective eco-adsorbent for the removal of methylene blue dye and provide a new platform for dye removal.
Nanoemulsions were successfully developed through high-pressure homogenization. The layer-by-layer electrostatic technique was used for the subsequent deposition of a chitosan and alginate ...polyelectrolyte layers, thus leading to the development of a multilayer nanoemulsion. The effect of polyelectrolytes concentration in the development of multilayer nanoemulsions was evaluated in terms of hydrodynamic diameter (
H
d
), polydispersity index (
PdI
), zeta potential (
Zp
), and curcumin encapsulation efficiency. The interactions between polyelectrolytes and nanoemulsion were further analyzed using Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance (QCM), while curcumin degradation was determined through the evaluation of the antioxidant capacity of the nanosystems. Results showed an encapsulation efficiency of 99.8 ± 0.8% and a loading capacity of 0.53 ± 0.03% (w/w). The presence of the multilayers leads to an increase of the
H
d
of the nanosystems, from 80.0 ± 0.9 nm (nanoemulsion) to 130.1 ± 1.5 nm (multilayer nanoemulsion). Release profiles were evaluated at different conditions, fitting a linear superposition model to experimental data suggests an anomalous behavior, being the relaxation of the surfactant and polyelectrolytes the rate-determining phenomena in curcumin release. The developed nanosystems showed great potential for the incorporation of lipophilic bioactive compounds, in view of their application in food and pharmaceutical products.
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•Rutin-rich extracts from R. chalepensis are encapsulated in zein colloidal particles.•Zein/gum arabic complex particles exhibit improved physicochemical stability.•Addition of gum ...arabic enhances the encapsulation efficiency.•Rutin present in the extract is less efficiently encapsulated than other components.•Addition of gum arabic promoted rutin release during simulated digestion.
Rutin, a plant flavonol characterized by a wide range of biological effects, has limited application in foods because of its low water solubility and scarce bioavailability. This work aimed to investigate the encapsulation of a rutin-rich extract (200.6 ± 1.5 mg/g of rutin) from Ruta chalepensis L. in zein nanoparticles (hydrodynamic diameter of 80–170 nm) prepared by antisolvent precipitation and stabilized by gum arabic (GA). The addition of GA (1:1 mass ratio with zein) significantly reduced the instability phenomena of zein nanoparticles through the deposition of a negatively charged layer as evidenced by the zeta potential and the UV–visible measurement, suggesting an electrostatic interaction between zein and GA. It also contributed to enhancing the encapsulation efficiency of rutin and inducing a rapid release during simulated digestion. These findings show that zein/GA nanoparticles represent a promising delivery system for natural extracts, fabricated through a facile and versatile process.
Production of food nanoemulsions by high pressure homogenization (HPH) is investigated, focusing on the effect on droplet nanonization of emulsifier type and concentration, as well as of the geometry ...of the homogenization chamber. Several food-grade emulsifiers were characterized, in comparison with artificial ones, in terms of their interfacial and dynamic properties, by pendant drop measurements. The kinetics of the emulsification process was determined by dynamic light scattering measurements on the emulsions produced at different pressure levels (70–280 MPa) and number of HPH passes, in four different homogenization chamber geometries. The results show that the kinetic parameters of the emulsification process can be primarily correlated with the interfacial and dynamic properties of the emulsifiers, while the fluid-dynamics regime establishing in the homogenization chamber contributes only to a lesser extent. Nevertheless, the correct design of the homogenization chamber may help in obtaining uniform fluid-dynamic conditions, which ensure a narrow droplet size distribution.
Phenolic compounds were extracted from grape marc by means of high pressure and temperature extraction. In order to increase their dispersability in the aqueous phase, the polyphenolic extracts were ...encapsulated at a final concentration of 0.1 % (
w
/
w
) in nanoemulsion-based delivery systems, which were formulated with natural ingredients, using either a liquid (sunflower oil) or a solid (palm oil) lipid phase, as well as the combination of a hydrophilic and hydrophobic emulsifier, and were produced by high-pressure homogenization. The delivery systems were characterized in terms of physicochemical stability under accelerated ageing (storage at 4 °C, 30 °C, and 55 °C for 14 days), by recording the evolution of the mean droplet size, the creaming index as well as the UV–vis absorption spectra of the encapsulated polyphenols. The antioxidant activity of the encapsulated extracts was measured with two different chemical assays (FRAP and ORAC) and a cellular antioxidant assay. Sunflower oil-based nanoemulsions resulted to be the most physically and chemically stable, with no significant variation of the mean droplet size and no degradation of the encapsulated compounds under the different conditions tested. The FRAP and ORAC assays showed that the antioxidant compounds, when encapsulated, are as available as unencapsulated polyphenols in scavenging the peroxyl radicals (ORAC), but are less available in reducing the ferric tripyridyltriazine complexes (FRAP). Remarkably, the cellular antioxidant activity was significantly higher for the encapsulated grape marc polyphenols than for the unencapsulated ones, suggesting the fundamental role of the nanoemulsions in favoring the delivery through the biological membranes.
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