Fabrication and characterization of double (W1/O/W2) emulsions loaded with bioactive peptide/polysaccharide complexes in the internal water (W1) phase for controllable release of bioactive peptide

Co-encapsulation of curcumin and fucoxanthin in solid-in-oil-in-water multilayer emulsions: Characterization, stability and programmed sequential release

To enhance the bioavailability of bioactives with varying efficacy in the gastrointestinal tract (GIT), a co-delivery system of solid-in-oil-in-water (S/O/W) emulsion was designed for the co-encapsulation of two bioactives in this paper. S/O/W emulsions were fabricated utilizing fucoxanthin (FUC)-loaded nanoparticles (NPs) as the solid phase, coconut oil containing curcumin (Cur) as the oil phase, and carboxymethyl starch (CMS)/propylene glycol alginate (PGA) complex as the aqueous phase. The high entrapment efficiency of Cur (82.3-91.3%) and FUC (96.0-96.1%) was found in the CMS/PGA complex-stabilized S/O/W emulsions. Encapsulation of Cur and FUC within S/O/W emulsions enhanced their UV and thermal stabilities. In addition, S/O/W emulsions prepared with CMS/PGA complexes displayed good stability. More importantly, the formed S/O/W emulsion possessed programmed sequential release characteristics, delivering Cur and FUC to the small intestine and colon, respectively. These results contributed to designing co-delivery systems for the programmed sequential release of two hydrophobic nutrients in the GIT.

Fabrication of the W1/O/W2 emulsions loaded with Torreya grandis protein hydrolysate/polysaccharide complexes in the internal water: Characterization and stability

In this study, the effect of Torreya grandis protein enzymatic hydrolysates (TGPH)/alginate dialdehyde (ADA) complexes in the internal aqueous phase on the physical stability of the water-in-oil-in-water (W1/O/W2) emulsions was studied. In the case of TGPH/ADA emulsions, the presence of ADA decreased the apparent viscosity of the emulsions and changed the flow behavior from shear thinning to Newtonian, leading to a decrease in volume-weighted average droplet diameter (D43) of the emulsions. Additionally, the emulsions at the TGPH/ADA ratios of 1:1 showed a lower turbiscan stability index (TSI) value, and smaller change in delta backscattering signal, compared to the emulsions. The enhanced pH stability and storage stability of the emulsions at the TGPH/ADA ratios of 1:1 was due to the formation of Schiff bases between TGPH and ADA. These results suggested that the covalent cross-linking of TGPH with ADA could significantly improve the stability of the emulsions, which provided an effective means for the development of new food-grade protein-polysaccharide complexes stabilized emulsions.

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.

Protein-polysaccharide nanoconjugates: Potential tools for delivery of plant-derived nutraceuticals

Protein-polysaccharide nanoconjugates are covalently interactive networks that are currently the subject of intense research owing to their emerging applications in the food nanotechnology field. Due to their biocompatibility and biodegradability properties, they have played a significant role as wall materials for the formation of various nanostructures to encapsulate nutraceuticals. The food-grade protein-polysaccharide nanoconjugates would be employed to enhance the delivery and stability of nutraceuticals for their real use in the food industry. The most common edible polysaccharides (cellulose, chitosan, pectin, starch, carrageenan, fucoidan, mannan, glucomannan, and arabic gum) and proteins (silk fibroin, collagen, gelatin, soy protein, corn zein, and wheat gluten) have been used as potential building blocks in nano-encapsulation systems because of their excellent physicochemical properties. This article broadens the discussion of food-grade proteins and polysaccharides as nano-encapsulation biomaterials and their fabrication methods, along with a review of the applications of protein-polysaccharide nanoconjugates in the delivery of plant-derived nutraceuticals.

Dietary-Polysaccharide-Modified Fish-Oil-Based Double Emulsion as a Functional Colloidal Formulation for Oral Drug Delivery

Oral delivery is the most convenient drug administration route. However, oral delivery of peptides is extremely challenging due to the physical and chemical barriers within the gastrointestinal tract. Polysaccharides are often utilized as polymeric biomaterials in drug delivery. Among these, dietary polysaccharides extracted from okra, yam, and spirulina have been reported to stimulate innate immunity with well-known nutritional benefits. In this study, we developed a dietary-polysaccharide-modified fish-oil-based emulsion for oral co-delivery of a hydrophilic PD-L1 blocking peptide and the hydrophobic small molecule simvastatin. The optimal emulsion was nano-sized and exhibited a negative surface charge, high drug encapsulation efficiency of over 97%, low viscosity, and sustained drug release manner. The formulation could significantly increase the uptake of peptides by intestinal Caco-2 cells, which demonstrated the great potential of the formulation for promoting the oral absorption of peptides. Additionally, these dietary polysaccharides could promote dendritic cell maturation and cytokine expression in macrophages, demonstrating that these nutraceutical polysaccharides had dual roles of functioning as promising colloidal delivery systems and as potential immune modulators or adjuvants. Thus, this food-based colloidal delivery system shows promise for the oral delivery of peptide drugs and lays a great platform for future applications in immunotherapy.

Impact of internal aqueous phase gelation on in vitro lipid digestion of epigallocatechin gallate-loaded W1 /O/W2 double emulsions incorporated in alginate hydrogel beads

Our objective was to investigate if the internal aqueous phase gelation of Water-in-oil-in-water double emulsions encapsulated in alginate beads would affect their structural stability and lipid hydrolysis during in vitro digestion. Therefore, bioactive molecules such as (-)-epigallocatechin gallate were encapsulated into different types of delivery systems: original double emulsions (as control) and incorporated double emulsions (filled in alginate hydrogel beads), both with non-gelled or gelled internal aqueous phase by locust bean gum and κ-carrageenan. After 2 h of gastric digestion, the gelled original emulsions showed smaller mean droplet diameters and less coalescence during the in vitro simulated gastrointestinal digestion compared to the non-gelled original emulsions. For the incorporated emulsions, oil droplets released from beads aggregated under intestinal conditions, and the rate of lipolysis was delayed. Interestingly, the internal aqueous phase gelation also impacted the rate and cumulative amount of free fatty acids (FFA) released. PRACTICAL APPLICATION: The combination of incorporating (-)-epigallocatechin gallate-loaded double emulsions into the alginate hydrogel matrix and gelling the internal aqueous phase was a benefit to regulating the rate and extent of lipid digestion for specific applications in foods, such as to control blood lipid levels and appetite.

Structural and mechanistic insights into starch microgel/anthocyanin complex assembly and controlled release performance

We report a self-assembly method for the fabrication of multilayer-starch-based microgels used for anthocyanin encapsulation. Alcohol-heating treatment and ionization reactions were employed to reduce the crystallinity of starch and introduce ionic groups on the molecule to further cross-link it with sodium trimetaphosphate and produce a starch microgel. The molecular interactions between the starch and the anthocyanins facilitated the anthocyanin encapsulation and the starch-microgel/anthocyanin complexes with one, two, and three self-assembled layers were obtained. The Lay-1 microgel exhibited an encapsulation efficiency of 50.1% when the anthocyanin concentration, cross-linking starch concentration, contact time, and temperature were 0.25 mg/mL, 1.5 mg/mL, 3 h, and 40 °C, respectively. An increase in the number of layers resulted in a more compact microgel structure with the zeta potential presenting variations upon structural changes. Furthermore, the encapsulated anthocyanins presented a slow release from Lay-1, while the multilayered microgels (Lay-2 and Lay-3) displayed outstanding encapsulation stability. This study gives an insight on the encapsulation and release of anthocyanins by starch microgels, and provides a novel strategy for the design of starch-based encapsulation materials presenting great stability.

Antimicrobial Activity Enhancers: Towards Smart Delivery of Antimicrobial Agents

The development of effective treatments against infectious diseases is an extensive and ongoing process due to the rapid adaptation of bacteria to antibiotic-based therapies. However, appropriately designed activity enhancers, including antibiotic delivery systems, can increase the effectiveness of current antibiotics, overcoming antimicrobial resistance and decreasing the chance of contributing to further bacterial resistance. The activity/delivery enhancers improve drug absorption, allow targeted antibiotic delivery, improve their tissue and biofilm penetration and reduce side effects. This review provides insights into various antibiotic activity enhancers, including polymer, lipid, and silver-based systems, designed to reduce the adverse effects of antibiotics and improve formulation stability and efficacy against multidrug-resistant bacteria.

Maillard-Type Protein-Polysaccharide Conjugates and Electrostatic Protein-Polysaccharide Complexes as Delivery Vehicles for Food Bioactive Ingredients: Formation, Types, and Applications

Due to their combination of featured properties, protein and polysaccharide-based carriers show promising potential in food bioactive ingredient encapsulation, protection, and delivery. The formation of protein–polysaccharide complexes and conjugates involves non-covalent interactions and covalent interaction, respectively. The common types of protein–polysaccharide complex/conjugate-based bioactive ingredient delivery systems include emulsion (conventional emulsion, nanoemulsion, multiple emulsion, multilayered emulsion, and Pickering emulsion), microcapsule, hydrogel, and nanoparticle-based delivery systems. This review highlights the applications of protein–polysaccharide-based delivery vehicles in common bioactive ingredients including polyphenols, food proteins, bioactive peptides, carotenoids, vitamins, and minerals. The loaded food bioactive ingredients exhibited enhanced physicochemical stability, bioaccessibility, and sustained release in simulated gastrointestinal digestion. However, limited research has been conducted in determining the in vivo oral bioavailability of encapsulated bioactive compounds. An in vitro simulated gastrointestinal digestion model incorporating gut microbiota and a mucus layer is suggested for future studies.

Fabrication and characterization of the W/O/W multiple emulsion through oleogelation of oil

W/O/W emulsions were easily prepared by oleogelation of the oil phase using rice bran wax (RBX) and their microstructure, stability, rheology and protection of proanthocyanidins and β-carotene were investigated. Formation of the W/O/W emulsion was confirmed using confocal laser scanning microscopy and staining of the inner aqueous phase by tartrazine. The average particle size and viscosity of the emulsion increased as the RBX concentration increased. Moreover, RBX increased the stability of the emulsion and the emulsion was the most stable when the RBX concentration was 8.0% or 10.0%. On the other hand, the W/O/W emulsions were used to simultaneously encapsulate proanthocyanidins and β-carotene. Specifically, proanthocyanidins and β-carotene in RBX-containing emulsions were more stable and had higher bioaccessibility than in the emulsion without RBX. Besides, both their chemical stability and bioaccessibility reached the maximum value when the RBX concentration was 8.0% or 10.0%. In summary, the optimal RBX concentration was 8.0%.