Enhancing trans-Resveratrol loading capacity by forcing W1/O/W2 emulsions up to its colloidal stability limit

Water-in-oil-in-water (W/O/W) emulsions with antioxidant and bacteriostatic capabilities: A preliminary exploration of food preservation films

The development of stable water-in-oil-in-water (W/O/W) emulsions for edible preservation coatings and films, utilizing their properties, deserves scientific attention. In this study, oregano essential oil and D‑sodium erythorbate were simultaneously loaded into W/O/W emulsions, and the homogenization conditions of the W/O/W emulsions were optimized. The structure and interactions of gum Arabic (GA) and whey protein isolate (WPI) as the outer phase were analyzed. Stable W1/O/W2 emulsions with excellent antimicrobial and antioxidant activities could be produced under the conditions of GA: WPI at 1:1 and W2: W1/O at 5:5. The diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azinobis-(3-ethylbenzenthiazoline-6-sulphonic acid) (ABTS) radical scavenging rates were 86.35 % and 89.35 %, and the inhibition zone diameters for S. aureus and E. coli were 14.03 ± 0.42 mm and 14.17 ± 0.70 mm, respectively. Finally, the W1/O/W2 emulsions were successfully applied to prepare chitosan-based films. This study has the potential to promote the application of W/O/W emulsions in food preservation, emphasizing the need for advancements for real-world adaptability.

Co-encapsulation of collagen peptide and astaxanthin in WG/OG/W double emulsions-filled alginate hydrogel beads: Fabrication, characterization and digestion behaviors

The double emulsions-filled hydrogel beads delivery systems with controlled lipolysis and sustained-release property of co-encapsulated bioactive substances will be highly desired. Herein, the water-in-oil-in-water emulsion with gelled inner water phase and oil phase (WG/OG/W) filled hydrogel beads as a novel co-delivery system were developed with varied concentrations of rice bran wax and W/O emulsions to achieve effectively controlled release of lipolysis and nutraceuticals. Interestingly, the gelation of oil phase triggered by rice bran wax could enhance the storage stability of WG/OG/W emulsions due to the enhanced viscoelastic property. Increasing the mass fractions of W/O emulsions improved the stability of double emulsions due to increased viscosity and decreased particle size. Cryo-SEM observation showed that the double emulsion droplets were scattered in the three-dimensional network of alginate gel beads. Increased the addition of rice bran wax or W/O emulsions, the encapsulation efficiency of collagen peptide and astaxanthin was significantly improved. The in vitro digestion results indicated that increasing the concentrations of rice bran wax and W/O emulsion fractions in WG/OG/W emulsion-filled gel beads could effectively delay the release extent of free fatty acids and encapsulated nutraceuticals. The presence of rice bran wax contributed to increase the bioaccessibility of collagen peptide and astaxanthin.

Recent progress in the synthesis of all-aqueous two-phase droplets using microfluidic approaches

An aqueous two-phase system (ATPS) is a system with liquid-liquid phase separation and shows great potential for the extraction, separation, purification, and enrichment of proteins, membranes, viruses, enzymes, nucleic acids, and other biomolecules because of its simplicity, biocompatibility, and wide applicability [1-4]. The clear aqueous-aqueous interface of ATPSs is highly advantageous for their implementation, therefore making ATPSs a green alternative approach to replace conventional emulsion systems, such as water-in-oil droplets. All aqueous emulsions (water-in-water, w-in-w) hold great promise in the biomedical field as glucose sensors [5] and promising carriers for the encapsulation and release of various biomolecules and nonbiomolecules [6-10]. However, the ultralow interfacial tension between the two phases is a hurdle in generating w-in-w emulsion droplets. In the past, bulk emulsification and electrospray techniques were employed for the generation of w-in-w emulsion droplets and the fabrication of microparticles and microcapsules in the later stage. Bulk emulsification is a simple and low-cost technique; however, it generates polydisperse w-in-w emulsion droplets. Another technique, electrospray, involves easy experimental setups that can generate monodisperse but nonspherical w-in-w emulsion droplets. In comparison, microfluidic platforms provide monodisperse w-in-w emulsion droplets with spherical shapes, deal with the small volumes of solutions and short reaction times and achieve portability and versatility in their design through rapid prototyping. Owing to several advantages, microfluidic approaches have recently been introduced. To date, several different strategies have been explored to generate w-in-w emulsions and multiple w-in-w emulsions and to fabricate microparticles and microcapsules using conventional microfluidic devices. Although a few review articles on ATPSs emulsions have been published in the past, to date, few reviews have exclusively focused on the evolution of microfluidic-based ATPS droplets. The present review begins with a brief discussion of the history of ATPSs and their fundamentals, which is followed by an account chronicling the integration of microfluidic devices with ATPSs to generate w-in-w emulsion droplets. Furthermore, the stabilization strategies of w-in-w emulsion droplets and microfluidic fabrication of microparticles and microcapsules for modern applications, such as biomolecule encapsulation and spheroid construction, are discussed in detail in this review. We believe that the present review will provide useful information to not only new entrants in the microfluidic community wanting to appreciate the findings of the field but also existing researchers wanting to keep themselves updated on progress in the field.

Influence of the Dispersion Medium and Cryoprotectants on the Physico-Chemical Features of Gliadin- and Zein-Based Nanoparticles

The evaluation of the physico-chemical features of nanocarriers is fundamental because the modulation of these parameters can influence their biological and in vivo fate. This work investigated the feasibility of saline, 5% w/v glucose and phosphate-buffered saline solution, as polar media for the development of nanoparticles made up of two vegetal proteins, zein from corn and gliadin from wheat, respectively. The physico-chemical features of the various systems were evaluated using dynamic and multiple light scattering techniques, and the results demonstrate that the 5% w/v glucose solution is a feasible medium to be used for their development. Moreover, the best formulations were characterized by the aforementioned techniques following the freeze-drying procedure. The aggregation of the zein nanoparticles prepared in water or glucose solution was prevented by using various cryoprotectants. Mannose confirmed its crucial role in the cryopreservation of the gliadin nanosystems prepared in both water and glucose solution. Sucrose and glucose emerged as additional useful excipients when they were added to gliadin nanoparticles prepared in a 5% glucose solution. Specifically, their protective effect was in the following order: mannose > sucrose > glucose. The results obtained when using specific aqueous media and cryoprotectants permitted us to develop stable zein or gliadin nanoparticles as suspension or freeze-dried formulations.

Addition of Trans-Resveratrol-Loaded Highly Concentrated Double Emulsion to Yoghurts: Effect on Physicochemical Properties

Trans-resveratrol (RSV) needs to be encapsulated to maintain its beneficial properties on the human body. This is due to its extreme photosensitivity, short biological half-life, and easy oxidation. In this study, the use of double emulsions for RSV encapsulation and their further application on functional yoghurts was studied. Different types of yoghurts were prepared: with and without RSV and with two types of volumetric emulsion formulations (20/80 and 30/70). In order to study the influence of the addition of double emulsions to the physical properties of the prepared yoghurts, they were characterised fresh and after a month under storage at 4 °C, in terms of droplet size, morphology, stability, rheology, texturometry, colorimetry, and antioxidant capacity. Results obtained showed that the presence of emulsion in the yoghurts produced a generalised decrease in the predominant droplet size (from 48 µm to 15-25 µm) and an increase in the stability. Additionally, a predominantly elastic character was observed. The firmness values obtained were very similar for all the yoghurts analysed and did not suffer important modifications with time. A slight colour variation was observed with storage time in the control sample, whereas a more notable variation in the case of emulsion yoghurts was observed. An appreciable increase of the antioxidant capacity of the final functional yoghurt (100 g) was observed when it contained 5-8 mg of RSV. Encapsulated RSV added to yoghurts presented a larger protection against RSV oxidation compared with free RSV, presenting a larger antioxidant inhibition after one month of storage. Moreover, the antioxidant capacity of yoghurts with encapsulated RSV was not affected under storage, since slight reductions (3%) were registered after one month of storage at 4 °C.

Grape seed proanthocyanidin-loaded gel-like W/O/W emulsion stabilized by genipin-crosslinked alkaline soluble polysaccharides-whey protein isolate conjugates: Fabrication, stability, and in vitro digestion

The present work aims to fabricate the genipin-crosslinked alkaline soluble polysaccharides-whey protein isolate conjugates (G-AWC) to stabilize W/O/W emulsions for encapsulation and delivery of grape seed proanthocyanidins (GSP). After crosslinking reaction, the molecular weight was increased and surface hydrophobicity was decreased. Then, the G-AWC and polyglycerol polyricinoleate (PGPR, a lipophilic emulsifier) were employed to prepare a GSP-loaded W/O/W emulsion with the addition of gelatin and sucrose in W₁ phase via a two-step procedure. Creamed emulsion could be fabricated at W₁/O volume fraction (Φ) of 10%-70% and further increased Φ to 75% or even up to 90% could obtain gel-like emulsion with notably elastic behaviors. In the W₁/O/W₂ emulsion with Φ of 80%, the encapsulation efficiency (EE) of GSP reached up to 95.86%, and decreased by ca. 10% after a week of storage. Moreover, the encapsulated GSP in the emulsion showed a remarkably higher bioaccessibility (40.72%) compared to free GSP (13.11%) in the simulated gastrointestinal digestion. These results indicated that G-AWC-stabilized W/O/W emulsions could be an effective carrier to encapsulate water-soluble bioactive compounds with enhanced stability and bioaccessibility.

Simultaneous encapsulation of trans-resveratrol and vitamin D3 in highly concentrated double emulsions

BACKGROUND

Encapsulation of biocompounds is essential to protect them from environmental factors that could enhance their oxidation or cause them to lose their beneficial properties due to extreme photosensitivity, among other factors. The main goal of this work was to study the feasibility of preparing concentrated double emulsions with a high loading capacity containing simultaneously trans-resveratrol (RSV) and vitamin D₃ (VitD₃ ). Such emulsions could be used for food fortification or pharmaceutical formulations or as vehicles for targeted controlled release.

RESULTS

In order to achieve large concentrations of the encapsulated compounds, all the double emulsions were formulated using a W₁ /O in W₂ ratio of 80/20, while the ratios tested for W₁ in O where 20/80 and 30/70. All the emulsions were characterized by droplet size, morphology, colloidal stability and encapsulation efficiency (EE) over a period of 6 weeks. VitD₃ and RSV concentration were determined by a technique based on reverse-phase high-performance liquid chromatography. The viability of preparing concentrated W₁ /O/W₂ emulsions containing both biocompounds has been demonstrated with satisfactory results. Initial RSV concentrations in the concentrated double emulsions formulated varied from 5.0 to 8.3 mg L^-1 , while for VitD₃ values of 28-32 mg L^-1 were obtained. The presence of VitD₃ retarded RSV release in the formulated emulsions. It was observed that after 1 week of storage RSV EE increased around 10-50% when VitD₃ was simultaneously encapsulated.

CONCLUSION

Simultaneous encapsulation of RSV and VitD₃ was possible in high internal phase emulsions. The emulsions presented high colloidal stability, being suitable for food fortification applications. © 2020 Society of Chemical Industry.

Impact of Adding Polysaccharides on the Stability of Egg Yolk/Fish Oil Emulsions under Accelerated Shelf-Life Conditions

Polysaccharides can form interfacial complexes with proteins to form emulsions with enhanced stability. We assessed the effect of adding gum guar or gum arabic to egg yolk/fish oil emulsions. The emulsions were produced using simple or high-pressure homogenization, stored for up to 10 days at 45 °C, and characterized for their particle size and distribution, viscosity, encapsulation efficiency, oxidative stability, and cytotoxicity. Emulsions containing gum guar and/or triglycerides had the highest viscosity. There was no significant difference in the encapsulation efficiency of emulsions regardless of the polysaccharide used. However, emulsions containing gum arabic displayed a bridging flocculation effect, resulting in less stability over time compared to those using gum guar. Emulsions produced using high-pressure homogenization displayed a narrower size distribution and higher stability. The formation of peroxides and propanal was lower in emulsions containing gum guar and was attributed to the surface oil. No significant toxicity toward Caco-2 cells was found from the emulsions over time. On the other hand, after 10 days of storage, nonencapsulated fish oil reduced the cell viability to about 80%. The results showed that gum guar can increase the particle stability of egg yolk/fish oil emulsions and decrease the oxidation rate of omega-3 fatty acids.

Application of Advanced Emulsion Technology in the Food Industry: A Review and Critical Evaluation

The food industry is one of the major users of emulsion technology, as many food products exist in an emulsified form, including many dressings, sauces, spreads, dips, creams, and beverages. Recently, there has been an interest in improving the healthiness, sustainability, and safety of foods in an attempt to address some of the negative effects associated with the modern food supply, such as rising chronic diseases, environmental damage, and food safety concerns. Advanced emulsion technologies can be used to address many of these concerns. In this review article, recent studies on the development and utilization of these advanced technologies are critically assessed, including nanoemulsions, high internal phase emulsions (HIPEs), Pickering emulsions, multilayer emulsions, solid lipid nanoparticles (SLNs), multiple emulsions, and emulgels. A brief description of each type of emulsion is given, then their formation and properties are described, and finally their potential applications in the food industry are presented. Special emphasis is given to the utilization of these advanced technologies for the delivery of bioactive compounds.

Resveratrol loaded Pickering emulsions stabilized by OSA modified rice starch granules

Resveratrol is a photosensitive, bioactive molecule which has received increasing research interest during the past decade for its antioxidant properties. However, it has low solubility in water or common triglyceride oils. Resveratrol solubilization in oil can only be achieved in essential oils, such as flavour oils, but the stability of emulsions produced with this type of oils is low as they are prone to creaming phenomena and Oswald ripening. In this study, resveratrol was first dissolved in orange oil which was mixed into a medium-chain triglyceride (Miglyol) at different ratios and used as the internal phase of oil-in-water emulsions (O/W). The emulsions were stabilized by octenyl succinic anhydride (OSA) modified rice starch granules using two different ratios of starch particle:oil to study the influence of interfacial coverage on the final emulsion droplet size and emulsion stability. The results of this study indicated that stable Pickering emulsions could be prepared using OSA-modified rice starch granules even at partial coverage conditions. Emulsions prepared at an oil fraction of 0.5 using 30% v/v mixture of orange oil in Miglyol as the dispersed phase seemed to be an appropriate resveratrol carrier system, obtaining encapsulation efficiency values close to 90% which results in emulsions with a resveratrol concentration of 8.45 mg/L. Hence, the emulsions prepared are suitable for food fortification applications.

Physical and turbidimetric properties of cholecalciferol- and menaquinone-loaded lipid nanocarriers emulsified with polysorbate 80 and soy lecithin

The present study aimed to investigate the physical and turbidimetric properties of cholecalciferol- and menaquinone-loaded lipid nanocarriers emulsified with different ratios of polysorbate 80 and soy lecithin. The lipid nanocarriers were subjected to three different heat treatments, LTLT (low temperature long time), HTST (high temperature short time), and autoclave treatments. Both cholecalciferol and menaquinone were successfully encapsulated in lipid nanocarriers and there was little loss of them during preparation. The droplet size of lipid nanocarriers emulsified with only polysorbate 80 increased and its PDI became larger than 0.3 after autoclave treatment. Moreover, 30.9% and 49.4% of cholecalciferol and menaquinone, respectively, were lost. In turbidimetric analysis, the destabilization by creaming formation in the upper layer of the lipid nanocarriers emulsified with a high polysorbate ratio was observed. However, the use of combination of both emulsifiers inhibited destabilization by flocculation as well as retained the cholecalciferol and menaquinone after all heat treatments.