Improving probiotic survival using water-in-oil-in-water (W1/O/W2) emulsions: Role of fish oil in inner phase and sodium alginate in outer phase

Optimization of a gelatin/carboxymethylcellulose-based probiotic microcapsule and its application in preventing dextran sodium sulfate-induced colitis in mice

Oral administration of probiotics has demonstrated substantial potential in alleviating colitis. However, most of the ingested microorganisms struggle to survive the harsh conditions of the gastrointestinal tract, leading to decreased efficacy. In the present study, using double emulsification (W1/O/W2) and complex coacervation methods, we developed a gelatin/carboxymethyl cellulose (CMC)-based probiotic microcapsule and analyzed the efficacy of encapsulated probiotics in preventing dextran sodium sulfate (DSS)-induced colitis in mice. Our results reveal that nearly 90% of the encapsulated probiotics remained viable after 30-day storage at 4°C and approximately 38.1% of viable bacteria (4.0 × 108 cfu/g) survived after 4-h simulated gastrointestinal digestion. In a DSS-induced colitis model, pretreatment with probiotics exerted significant protective effects, with the bacterial microcapsule-treated group having superior outcomes to those of the bacterial suspension plus empty carrier group. Probiotic treatments, especially those administered in the encapsulated form, significantly increased fecal short-chain fatty acid contents, and altered the intestinal microbial composition. The family Muribaculaceae, dominant bacteria in the mouse gut, may be the key microorganism involved in the BM regulation process. Our study presents an alternative approach to treating colitis using probiotics. PRACTICAL APPLICATION: The encapsuled probiotic showed remarkable storage stability at 4°C, maintained good vitality after simulated digestion, and gained superior outcomes in preventing colitis. Our results offer an alternative approach for the probiotic preparations aiming to prevent the intestinal inflammation.

The effects of different types of polysaccharides on the structure and physical properties of W/O/W emulsions under varying pH conditions

BACKGROUND

Biopolymer based water-in-oil-in-water double (W1/O/W2) emulsion systems comprise a complex emulsion system that might be affected by several factors and the status at multiple phases. The present study investigated the physicochemical properties of W1/O/W2 double emulsions with inner W1 phase incorporated with various polysaccharides and the outer phase stabilized by whey protein isolate (WPI). Six different polysaccharides were selected as co-emulsifiers in the inner phase, and their effects on morphology, droplet size, zeta potential and rheology properties were evaluated. Furthermore, the impact of WPI/polysaccharide concentration and pH on the physicochemical properties and storage stability of the emulsions was compared.

RESULTS

Emulsions with an inner phase incorporated with xanthan gum and carrageenan exhibited better stability than others. Increasing the concentration of WPI enhanced the overall stability of the double emulsion, although it compromised the integrity of the internal W1/O interface. On the other hand, a 1.0% concentration of polysaccharide, specifically when carrageenan is used, slowed down droplet floating and coagulation. An acidic external aqueous phase (pH 4) led to larger and more uniform particle size distributions, as well as enhanced stability. The lower pH decreased the viscosity and delayed molecular exchange in the oil phase, thereby preserving the structure of the double emulsion.

CONCLUSION

These findings contribute to a better understanding of the factors influencing the stability and properties of W1/O/W2 double emulsions with addition of anionic polysaccharides in the inner water phase. © 2024 Society of Chemical Industry.

Effect of a collagen peptide-fish oil high internal phase emulsion on the printability and gelation of 3D-printed surimi gel inks

The effect of a high internal phase emulsion (HIPE) on three-dimensional-printed surimi gel inks was studied. Increasing the concentration of collagen peptide decreased the particle size of HIPE droplets and improved the viscoelasticity and stability. For example, when the collagen peptide concentration was 5 wt%, the viscoelasticity of the HIPE was high, as indicated by the presence of small and uniform particles, which formed a monolayer in the outer layer of the oil droplets to form stable a HIPE. A HIPE was used as the filling material to fill the surimi gel network, which reduced the porosity of the network. Surimi protein and peptides have dual emulsifying effects on the stabilization of oil. After adding the emulsion, the texture, gel properties and rheological properties of the surimi were reduced, and its printing adaptability was improved. This study provides new ideas for the production of surimi and its application in 3D printing.

Dual-Responsive "Egg-Box" Shaped Microgel Beads Based on W1/O/W2 Double Emulsions for Colon-Targeted Delivery of Synbiotics

In this study, for enhancing the resistance of probiotics to environmental factors, we designed a microgel beads delivery system loaded with synbiotics. Multiple droplets of W1/O/W2 emulsions stabilized with zein-apple pectin hybrid nanoparticles (ZAHPs) acted as the inner "egg," whereas a three-dimensional network of poly-L-lysine (PLL)-alginate-CaCl2 (Ca) crosslinked gel layers served as the outermost "box." ZAHPs with a mass ratio of 2:1 zein-to-apple pectin showed excellent wettability (three-phase contact angle = 89.88°). The results of the ζ-potentials and Fourier transform infrared spectroscopy demonstrate that electrostatic interaction forces and hydrogen bonding were the main forces involved in the formation of ZAHPs. On this basis, we prepared W1/O/W2 emulsions with other preparation parameters and observed their microstructures by optical microscopy and confocal laser scanning microscope. The multi-chambered structures of W1/O/W2 emulsions were successfully visualized. Finally, the W1/O/W2 emulsions were coated with PLL-alginate-Ca using the solution extrusion method. The results of the in vitro colonic digestion stage reveal that the survival rate of probiotics in the microgel beads was about 75.11%, which was significantly higher than that of the free. Moreover, probiotics encapsulated in microgel beads also showed positive storage stability. Apple pectin would serve as both an emulsifier and a prebiotic. Thus, the results indicate that the "egg-box" shaped microgel beads, designed on the basis of pH-sensitive and enzyme-triggered mechanisms, can enhance the efficiency of probiotics translocation in the digestive tract and mediate spatiotemporal controlled release.

Encapsulation of Lactobacillus plantarum in W1/O/W2 double emulsions stabilized with the high-intensity ultrasound-treated pea protein and pectin

This study focuses on developing a water-in-oil-in-water (W1/O/W2) double emulsion system using high-intensity ultrasound (HIU)-treated pea protein isolate (HIU-PPI) and pectin to encapsulate Lactobacillus plantarum (L. plantarum). The effects of ultrasound treatment on pea protein isolate (PPI) characteristics such as solubility, particle size, emulsification, surface hydrophobicity, and surface free sulfhydryl group were examined, determining optimal HIU processing conditions was 400 W for 10 min. The developed W1/O/W2 double emulsion system based on HIU-PPI demonstrated effective encapsulation and protection of L. plantarum, especially at the HIU-PPI concentration of 4 %, achieving an encapsulation efficiency of 52.65 %. Incorporating both HIU-PPI and pectin as emulsifiers increased the particle size and significantly enhanced the emulsion's viscosity. The highest bacterial encapsulation efficiency of the emulsion, 59.94 %, was attained at a HIU to pectin concentration ratio of 3:1. These emulsions effectively encapsulate and protect L. plantarum, with the concentration of HIU-PPI being a critical factor in enhancing probiotic survival under simulated gastrointestinal digestion. However, the concurrent utilization of pectin and HIU-PPI as emulsifiers did not provide a notable advantage compared to the exclusive use of HIU-PPI in enhancing probiotic viability during in vitro simulated digestion. This research offers valuable perspectives for the food industry on harnessing environmentally friendly, plant-based proteins as emulsifiers in probiotic delivery systems. It underscores the potential of HIU-modified pea protein and pectin in developing functional food products that promote the health benefits of probiotics.

Effectiveness of probiotic- and fish oil-loaded water-in-oil-in-water (W1/O/W2) emulsions at alleviating ulcerative colitis

Ulcerative colitis (UC) is a common chronic inflammatory disease that causes serious harm to human health. Probiotics have the effect of improving UC. This study evaluated the preventative potential of water-in-oil-in-water (W1/O/W2) emulsions containing both probiotics and fish oil on UC and associated anxiety-like behavior using a mice model. UC model was established in mice by administering dextran sulfate sodium salt (DSS). Free probiotics, probiotic-loaded emulsions, or fish oil and probiotic co-loaded emulsions were then orally administered to the mice. Various bioassays, histological studies, 16s rDNA gene sequencing, and behavioral experiments were conducted to assess changes in the intestinal environment, microbiota, and anxiety-like behavior of the mice. The fish oil and probiotic co-loaded emulsions significantly reduced the inflammatory response by enhancing tight junction protein secretion (ZO-1, Occludin, and Claudin-1), inhibiting pro-inflammatory factors (TNF-α, and IL-1β), and promoting short-chain fatty acids (SCFAs) production. These emulsions also modified the gut microbiota by promoting beneficial bacteria and suppressing pathogenic bacteria, thereby restoring a balanced gut microbiota. Notably, the emulsions containing both probiotics and fish oil also ameliorated anxiety-like behavior in the mice. The co-delivery of probiotics and fish oil using W1/O/W2 emulsions has shown significant promise in relieving UC and its associated anxiety-like behavior. These findings provide novel insights into the development of advanced therapeutic strategies for treating UC.

Encapsulation of Probiotics within Double/Multiple Layer Beads/Carriers: A Concise Review

An increased demand for natural products nowadays most specifically probiotics (PROs) is evident since it comes in conjunction with beneficial health effects for consumers. In this regard, it is well known that encapsulation could positively affect the PROs' viability throughout food manufacturing and long-term storage. This paper aims to analyze and review various double/multilayer strategies for encapsulation of PROs. Double-layer encapsulation of PROs by electrohydrodynamic atomization or electrospraying technology has been reported along with layer-by-layer assembly and water-in-oil-in-water (W1/O/W2) double emulsions to produce multilayer PROs-loaded carriers. Finally, their applications in food products are presented. The resistance and viability of loaded PROs to mechanical damage, during gastrointestinal transit and shelf life of these trapping systems, are also described. The PROs encapsulation in double- and multiple-layer coatings combined with other technologies can be examined to increase the opportunities for new functional products with amended functionalities opening a novel horizon in food technology.

Oral delivery of probiotics using single-cell encapsulation

Adequate intake of live probiotics is beneficial to human health and wellbeing because they can help treat or prevent a variety of health conditions. However, the viability of probiotics is reduced by the harsh environments they experience during passage through the human gastrointestinal tract (GIT). Consequently, the oral delivery of viable probiotics is a significant challenge. Probiotic encapsulation provides a potential solution to this problem. However, the production methods used to create conventional encapsulation technologies often damage probiotics. Moreover, the delivery systems produced often do not have the required physicochemical attributes or robustness for food applications. Single-cell encapsulation is based on forming a protective coating around a single probiotic cell. These coatings may be biofilms or biopolymer layers designed to protect the probiotic from the harsh gastrointestinal environment, enhance their colonization, and introduce additional beneficial functions. This article reviews the factors affecting the oral delivery of probiotics, analyses the shortcomings of existing encapsulation technologies, and highlights the potential advantages of single-cell encapsulation. It also reviews the various approaches available for single-cell encapsulation of probiotics, including their implementation and the characteristics of the delivery systems they produce. In addition, the mechanisms by which single-cell encapsulation can improve the oral bioavailability and health benefits of probiotics are described. Moreover, the benefits, limitations, and safety issues of probiotic single-cell encapsulation technology for applications in food and beverages are analyzed. Finally, future directions and potential challenges to the widespread adoption of single-cell encapsulation of probiotics are highlighted.

An Updated Comprehensive Overview of Different Food Applications of W1/O/W2 and O1/W/O2 Double Emulsions

Double emulsions (DEs) present promising applications as alternatives to conventional emulsions in the pharmaceutical, cosmetic, and food industries. However, most review articles have focused on the formulation, preparation approaches, physical stability, and release profile of encapsulants based on DEs, particularly water-in-oil-in-water (W1/O/W2), with less attention paid to specific food applications. Therefore, this review offers updated detailed research advances in potential food applications of both W1/O/W2 and oil-in-water-in-oil (O1/W/O2) DEs over the past decade. To this end, various food-relevant applications of DEs in the fortification; preservation (antioxidant and antimicrobial targets); encapsulation of enzymes; delivery and protection of probiotics; color stability; the masking of unpleasant tastes and odors; the development of healthy foods with low levels of fat, sugar, and salt; and design of novel edible packaging are discussed and their functional properties and release characteristics during storage and digestion are highlighted.

Double Emulsions Stabilized by PGPR and Arabic Gum as Capsules: The Surprising Stabilizing Role of Inner Droplets

The encapsulation efficiency and stability over time of either vitamin B12, a model hydrophilic drug, or an aqueous suspension of Cydia pomonella granulovirus (CpGV), which is a biopesticide, using a water-in-sunflower oil-in-water (W1/O/W2) double emulsion, are studied. Two antagonistic stabilizers are used to prepare the double emulsion: the mainly lipophilic polyglycerol polyricinoleate (PGPR) and the mainly hydrophilic polysaccharide Arabic gum (AG). Combining ultraviolet-visible (UV-visible) titration, rheology, and oil globule size measurement allows assessing drug release, emulsion elasticity, and globule evolution as a function of time. A stability diagram is plotted as a function of two determining parameters: the nonadsorbed PGPR concentration in the oil and the inner water droplet fraction. To understand the presence of the nonstability domains, the influence of the two identified parameters on the outermost interfacial tension is examined. Surprisingly, the inner water drop volume fraction exhibits a stabilizing phenomenon that is discussed in terms of interfacial shielding to PGPR adsorption.

Co-Delivery System of Vitamin B12 and Vitamin E Using a Binary W/O/W Emulsion Based on Soybean Isolate Protein-Xanthan Gum/Carrageenan: Emulsification Properties, Rheological Properties, Structure, Stability, and Digestive Characteristics

In this study, the soybean protein isolate (SPI)-xanthan gum (XG) or carrageenan (CA) W/O/W emulsions for the co-delivery of vitamin B12 and vitamin E were prepared. The effects of XG and CA concentrations on the physicochemical properties and digestive characteristics of the emulsions were also investigated. The addition of XG and CA improved the SPI aggregation and increased its electrostatic repulsion so that more SPI was adsorbed at the phase interface. The emulsifying activity index and emulsifying stability index increased to 24.09 (XG 0.4%) and 14.00 (CA 0.5%) and 151.08 (XG 0.4%) and 135.34 (CA 0.5%), respectively. The adsorbed protein content increased to 88.90% (XG 0.4%) and 88.23% (CA 0.5%), respectively. Moreover, the encapsulation efficiencies of vitamin B12 and vitamin E were increased to 86.72% (XG 0.4%) and 86.47 (CA 0.5%) and 86.31% (XG 0.4%) and 85.78% (CA 0.5%), respectively. The bioaccessibility of vitamin B12 and vitamin E increased to 73.53% (XG 0.4%) and 71.32% (CA 0.5%) and 68.86% (XG 0.4%) and 68.74% (CA 0.5%). The best properties of the emulsions were obtained at a 0.4% concentration of XG and 0.5% of CA. This study offers a novel system for delivering bioactive substances, which is favorable for the advancement of food with delivery capability in food processing.