External Gelation Research Articles

Thermo-controlled microfluidic generation of monodisperse alginate microspheres based on external gelation.

Droplet-based microfluidic systems have received much attention as promising tools for fabricating monodisperse microspheres of alginate solutions with high accuracy and reproducibility. The immediate and simple ionotropic gelation of alginate, its biocompatibility, and its tunability of mechanical properties make it a favorable hydrogel in the biomedical and tissue engineering fields. In these fields, micron-sized alginate hydrogel spheres have shown high potential as cell vehicles and drug delivery systems. Although on-chip microfluidic gelation of the produced alginate droplets is common, several challenges remain. Complicated chemical and microfabrication processes are required, and the risk of microchannel clogging is high. In the current study, we present an easy-to-use microfluidic external gelation process to produce highly spherical and monodisperse microspheres from very low-concentrated alginate-RGD solution [0.5% (w/v)]. To accomplish this, gelatin, a thermo-sensitive and inexpensive biomaterial, was incorporated into the alginate solution as a sacrificial biomaterial that mediates the off-chip external gelation of the alginate with Ca2+, and avoids droplet coalescence. Utilizing the methodology mentioned above, we successfully generated monodisperse alginate microspheres (AMs) with diameters ranging from 27 μm to 46 μm, with a coefficient of variation of 0.14, from a mixture of Arg-Gly-Asp (RGD)-modified very low viscosity alginate and gelatin. These RGD-AMs were used as microcarriers for human umbilical vein endothelial cells. The described easy-to-use and cost-effective microfluidic off-chip external gelation strategy exhibits comparable advantages to on-chip external gelation and demonstrates superiority over the latter since clogging is impossible.

Enhanced antibacterial activity of starch-alginate beads by a synergistic effect between Cu2+ and Zn2+ ions with a potential wound dressing application

The synthesis and characterization of starch/alginate composite beads, crosslinked with Cu2+, Zn2+, and Cu:Zn mixtures were investigated, focusing on their potential application in exudative wound dressings. Hydrogel beads were prepared using the external gelation method and then dried via freeze-drying to create cryogels and air-drying to create xerogels. Microstructural characterization was performed using SEM and EDS, showing the typical porous structure with a homogeneous distribution of cations across the beads. Unimetallic beads exhibited higher equilibrium water uptake compared to Cu:Zn bimetallic beads (500 % vs. 300 %). After the swelling study, the total amount of Cu2+ released was significantly below the maximum allowed level as a safeguard against copper toxicity. All beads demonstrated excellent antimicrobial activity against E. coli, S. aureus, and P. aeruginosa. Bimetallic materials, particularly cryogels with equal or greater amount of zinc relative to copper, were particularly effective against P. aeruginosa. Hence, the synthesized bimetallic starch-alginate materials presented superior water absorption capacity and significantly enhanced antibacterial response compared to unimetallic beads, due to the synergistic effect between Cu2+ and Zn2+ ions, making then suitable for use in exudative wound dressings.

Co-encapsulation of two antidepressant agents, Lactiplantibacillus plantarum and chrysin flavonoid, by external ionic gelation: Feasibility, properties and stability

In this work, co-encapsulation of Lactiplantibacillus plantarum LP-01 (L. plantarum) and chrysin flavonoid, two antidepressant agents, by external ionic gelation was evaluated regarding feasibility, properties and stability. L. plantarum was encapsulated at a concentration of 10 CFU mL−1, and chrysin at concentrations of 0.1, 0.25 and 0.5 % (m/m). Encapsulation proved to be feasible, as observed by the excellent encapsulation efficiency of probiotics (90 %) and chrysin (54–84 %), and the absence of any acute or chronic toxicity of chrysin to probiotics. The properties of the capsules showed results consistent with this type of encapsulation and the encapsulated materials, such as average size, morphology and color. Through in vitro gastrointestinal digestion, it was found that encapsulation provided progressive release of probiotics in the digestive tract, and protected chrysin from its degradation in the gastric phase. The stability of the microparticles was evaluated for 120 days under 3 different temperature conditions (25, 8 and −18 °C). The best stability of L. plantarum occurred at a temperature of −18 °C, followed by 8 and 25 °C. The chrysin content was not substantially modified over the 120 days of study at any of the concentrations and at none of the temperatures. In short, this work showed the feasibility, properties and stability of microparticles containing L. plantarum and chrysin, and future studies should focus on the application of these microparticles in food, pharmaceutical or nutraceutical formulations and in bioassays, especially experimental models of depression.

Synthesis of agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads: Characterization and application as controlled-release microencapsulated fertilizers

Synthesis of novel agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads, micromeritic/morphometric characteristics of the prepared formulations, greenhouse trials using controlled-release microencapsulated fertilizers, and acute fish toxicity testing were conducted simultaneously for the first time within the scope of an integrated research. In the present analysis, for the first time, 16 different morphometric features, and 32 disinct plant growth traits of the prepared composite beads were explored in detail within the framework of a comprehensive digital image analysis. The hydrogel beads composed of 19 different agro-industrial wastes/materials were successfully synthesized using the ionotropic external gelation technique and CaCl2 as cross-linker. According to micromeritic characteristics, the ionotropically cross-linked beads exhibited 77.86 ± 3.55 % yield percentage and 2.679 ± 0.397 mm average particle size. The dried microbeads showed a good swelling ratio (270.02 ± 80.53 %) and had acceptable flow properties according to Hausner's ratio (1.136 ± 0.028), Carr's index (11.94 ± 2.17 %), and angle of repose (25.03° ± 5.33°) values. The settling process of the prepared microbeads was observed in the intermediate flow regime, as indicated by the average particle Reynolds numbers (169.17 ± 82.81). Experimental findings and non-parametric statistical tests reveal that dried fertilizer matrices demonstrated noteworthy performance on the cultivation of red hot chili pepper plant (Capsicum annuum var. fasciculatum) according to the results of greenhouse trials. Surface morphologies of the best-performing fertilizer matrices were also characterized by Scanning Electron Microscopy. Moreover, the static fish bioassay experiment confirmed that no abnormalities and acute toxic reactions occurred in shortfin molly fish (Poecilia sphenops) fed with dried leaves of red hot chili pepper plants grown with formulated fertilizers. This study showcased a pioneering investigation into the synthesis of microcapsules using synthesized hydrogel beads along with digital image processing for bio-waste management and sustainable agro-application.

Encapsulated pomegranate peel extract as a potential antimicrobial ingredient from food waste.

Pomegranate peel waste is a valuable reservoir of heat-sensitive total hydrolysable tannins (THT), with potential applications in food and pharmaceuticals. Preserving THT is challenging due to degradation post-extraction. We explore ionic gelation as an encapsulation method to optimize THT utilization. Through external gelation, we optimized the process variables using Box-Behnken design. At 40 g kg-1 sodium alginate, 25 g kg-1 calcium chloride, and 300 g kg-1 pomegranate peel extract (PPE), we achieved an 83.65% encapsulation efficiency. Compared to spray drying, external gelation demonstrated superior performance, with enhanced release percentages and stability. Physical, phytochemical, and release profiles of encapsulates were extensively analysed. External gelation achieved an 87.5% release in 30 min, outperforming spray-dried counterparts (69.7% in 25 min). Encapsulated PPE exhibited robust antibacterial activity against Staphylococcus aureus (ATCC 25923) in powdered infant formula, with a 32 ± 0.01 mm zone of inhibition and 300 μg mL-1 minimum inhibitory concentration. Insights into S. aureus growth curves underlined the mechanism of action via membrane potential alterations. The results of carried investigations also showed that the antibacterial activity of the encapsulated PPE extracts against the targeted organism was identical to the antibacterial activity exhibited by synthetic antibiotics used generally to kill microorganisms in food. Therefore, from the findings, it can be concluded that the PPE encapsulate produced using the external gelation technique at the optimized condition displayed superior storage stability possessing strong antimicrobial activity when compared to encapsulate produced using the spray drying technique. External gelation emerges as a potent technique for developing effective encapsulates enriched with natural antimicrobials or antibiotics. This approach holds promise for applications in food, pharmaceuticals, and nutraceuticals, enhancing stability and efficacy while reducing reliance on synthetic antibiotics. © 2024 Society of Chemical Industry.

Advancing bacterial endophyte encapsulation in alginate for sustainable agriculture: Method comparisons, morphology and viability assessment

This study focused on encapsulating Kosakonia radicincitans in alginate beads and capsules using the Ionic External Gelation (IEG) and Reverse Gelation (RG) methods. The results showed that both IEG and RG methods provided high encapsulation efficiencies (84.61% and 85.22%, respectively) without additives. The beads and capsules displayed distinct morphological characteristics, with beads exhibiting smooth and homogeneous surfaces, while capsules appeared rougher and more irregular. The biodegradability study revealed that the encapsulated materials exhibited higher mass loss at elevated temperatures, indicating the potential rapid release of bacterial cells into the soil-plant system. However, the viability of bacteria persisted around the particles even after 60 days in the soil, suggesting that drying temperature and ambient temperature play crucial roles in determining the biofertilizer's persistence in the soil. This research highlights the complexities associated with the long-term effects of encapsulated biofertilizers, which are critical for advancing toward sustainable environmental and agricultural solutions.

Preparation of UN microspheres by external gelation

Uranium mono-nitride (UN) microspheres are expected to play an important role in various miniaturization module reactors. The combination of UN core and tri-structural-isotropic (TRISO) coatings will bring improved efficiency and safety. Carbon-containing gel microspheres were prepared by external gelation, followed by carbothermal reduction and nitridation to synthesize UN. The effects of C/U molar ratios and heat-treatment schemes on the composition and microstructures of UN microspheres were studied. The results indicated that the external gelation could be used to prepare UN microspheres, with the highest UN content of 93 wt%.

Encapsulation of beetroot extract (Beta vulgaris L.) obtained by internal and external ionic gelation: a comparative study

Natural pigments, like betalains found in beets, are sensitive to environmental conditions, which may impact their reactivity and shelf-life. Microencapsulation is an attractive alternative for delivering these compounds, offering protection through polymeric microcapsules. The aim of this study was to compare two ionic gelation methodologies, external (EG) and internal gelation (IG), in the microencapsulation of beet aqueous extract. Particles were obtained by mixing sodium alginate with the aqueous extract of beetroot and crosslinking with calcium chloride solution using the extrusion method. Encapsulation characteristics and physical, morphological features were evaluated. The particles showed 10.72 and 89.90% encapsulation efficiency for EG and IG, respectively. Loading capacity was 18.90% for EG and 25.60% for IG. Those IG particles showed superior water absorption capacity during rehydration. Texture analysis indicated that EG particles showed greater hardness. Release kinetics indicated that EG particles followed the Korsmeyer-Peppas model, while IG particles followed the Higuchi model. Thus, the appropriate encapsulation technique should be selected depending on the food matrix to be used and the specific objective of delivering the active encapsulated molecules.

Exploring the Nutritional and Bioactive Potential of Olive Leaf Residues: A Focus on Minerals and Polyphenols in the Context of Spain's Olive Oil Production.

Lyophilized plant-origin extracts are rich in highly potent antioxidant polyphenols. In order to incorporate them into food products, it is necessary to protect these phytochemicals from atmospheric factors such as heat, light, moisture, or pH, and to enhance their bioavailability due to their low solubility. To address these challenges, recent studies have focused on the development of encapsulation techniques for antioxidant compounds within polymeric structures. In this study, lyophilized olive leaf extracts were microencapsulated with the aim of overcoming the aforementioned challenges. The method used for the preparation of the studied microparticles involves external ionic gelation carried out within a water-oil (W/O) emulsion at room temperature. HPLC analysis demonstrates a high content of polyphenols, with 90% of the bioactive compounds encapsulated. Meanwhile, quantification by inductively coupled plasma optical emission spectroscopy (ICP-OES) reveals that the dried leaves, lyophilized extract, and microencapsulated form contain satisfactory levels of macro- and micro-minerals (calcium, potassium, sodium). The microencapsulation technique could be a novel strategy to harness the polyphenols and minerals of olive leaves, thus enriching food products and leveraging the antioxidant properties of the polyphenolic compounds found in the lyophilized extract.

Human muscle stem cell responses to mechanical stress into tunable 3D alginate matrices

Preclinical data acquired for human muscle stem (hMuStem) cells indicate their great repair capacity in the context of muscle injury. However, their clinical potential is limited by their moderate ability to survive after transplantation. To overcome these limitations, their encapsulation within protective environment would be beneficial. In this study, tunable calcium-alginate hydrogels obtained through molding method using external or internal gelation were investigated as a new strategy for hMuStem cell encapsulation. The mechanical properties of these hydrogels were characterized in their fully hydrated state by compression experiments using Atomic Force Microscopy. Measured elastic moduli strongly depended on the gelation mode and calcium/alginate concentrations. Values ranged from 1 to 12.5 kPa and 3.9 to 25 kPa were obtained for hydrogels prepared following internal and external gelation, respectively. Also, differences in mechanical properties of hydrogels resulted from their internal organization, with an isotropic structure for internal gelation, while external mode led to anisotropic one. It was further shown that viability, morphological and myogenic differentiation characteristics of hMuStem cells incorporated within alginate hydrogels were preserved after their release. These results highlight that hMuStem cells encapsulated in calcium-alginate hydrogels maintain their functionality, thus allowing to develop muscle regeneration protocols to improve their therapeutic efficacy.

R-phycoerythrin alginate/shellac beads by external gelation: Process optimization and the effects of gastrointestinal digestion for nutraceutical applications

This study aimed to evaluate an alginate/shellac mixture as wall material to develop an aqueous phycoerythrin (R-PE) encapsulation system by external gelation and to determine the effect of encapsulation on the biological properties of R-PE released during simulated gastrointestinal digestion. The Taguchi method was implemented to formulate beads with a high R-PE encapsulation efficiency (EE). The effect of the variables: feeding flow (90 and 20 mL h−1), distance (5 and 10 cms), and CaCl2 (5 and 15 g L−1) were optimized, and the bead size, sphericity factor (SF), and total R-PE content were characterized. Finally, the optimal alginate/shellac beads were subjected to in vitro dynamic gastrointestinal digestion. The results show that the beads formed under optimal conditions reached an EE value of 97.5 %. The CaCl2 concentration and feeding flow most affected the R-PE EE. The release of R-PE from alginate/shellac was affected at acid pH 1; however, the concentration was under 10 % of the total R-PE content showing promising targeting properties in terms of time and pH. The R-PE extracts and capsules were partially degraded in gastric and intestinal conditions; the mouth did not detect signals from the protein profile. The encapsulation of alginate/shellac led to higher R-PE contents at the end of digestion than non-encapsulated R-PE, suggesting a protective role. Significantly, from permeate streams, equivalent to the absorption of encapsulated R-PE, the bioavailability was 2.5 times higher than non-encapsulated R-PE. NMR results indicate the presence of R-PE and its methyl amino acids and oligosaccharides between 0.5 and 2.5 and 3.8–6.8 ppm, respectively. Cytotoxicity activity was observed for the R-PE extract on the HCT-116 human colon cancer cell line. The alginate/shellac as a wall material and ionic gelation technology used may determine the release of the R-PE pigment at an intestinal site and its antiproliferative effect on health.

Nutrient controlled release behaviors and plant growth of NPK encapsulated hydroxyapatite/alginate biocomposite toward agricultural and environmental sustainability

Abstract Controlled release fertilizers (CRFs) promote sustainable agriculture by gradually releasing nutrients into the soil while also mitigating environmental pollution. Nitrogen-phosphorus-potassium embedded hydroxyapatite/alginate (NPK-HA/Alg) biocomposite beads were developed using a simple, cost-effective, and environmentally friendly dropping and external gelation method. Addition of eggshell biowaste-derived HA to the alginate matrix improved the structural, thermal, and structural stability of the alginate beads, and enabled the inclusion of significantly high plant nutrients. The biocomposite beads exhibited a prolonged and controlled nutrient release in deionized water over 35 days. Biocomposite bead addition was assessed for the growth of flowering Chinese cabbage in a controlled greenhouse environment. Results confirmed vegetative growth with high values of plant height, number of leaves, and fresh and dry weights. The non-toxic and cost-effective NPK-HA/Alg biocomposite beads demonstrated controlled nutrient release as promising CRF materials to promote sustainable agricultural production.

A review on micro beads: Formulation, technological aspects, and extraction

Any drug delivery system's purpose is to deliver a therapeutic amount of medicine to the appropriate place in the body while also achieving and maintaining the correct drug concentration. This could be accomplished by using numerous unit dosage forms such as microgranules/spheroids, pellets, microcapsules, and beads, which are divided into many separate units, referred to as subunits, each of which possesses certain desired features. The advantages of micro particle drug delivery systems over single unit dose form are well documented. One of the solutions that does not entail the use of harsh chemicals or elevated temperatures is the production of microbeads medication delivery systems. The traditional procedures require the use of ionotropic gelation methods, which include internal and external gelation methods, emulsion gelation methods, polyelectrolyte complexation methods, and so on. Because of the ease of preparation, the majority of work has been done on the preparation of microbeads using the ionotropic gelation process rather than alternative approaches.

In-situ quantification of dispersity and sphericity of uranyl nitrate sol droplets using holographic imaging

Uniform-sized and highly spherical nuclear fuel microspheres are pivotal components in high-temperature gas-cooled reactors. In the manufacturing process of microspheres through external gelation, monodispersed droplets with high sphericity at the dispersion stage establishes the fundamental basis for the subsequent production of superior-quality microspheres. Addressing the monitoring requirements for droplet size and sphericity in dispersion process, this study develops a measurement apparatus based on digital in-line holography. The apparatus records droplet holograms within distances ranging from 96 mm to 183 mm, achieving imaging resolutions between 64 lp/mm to 32 lp/mm. Droplet measurements are conducted for nine operational conditions encompassing varied excitation frequencies and liquid flow rates. Observation under various dispersion parameters reveals diverse droplet morphologies. Polydisperse conditions manifest an abundance of satellite droplets, agglomerated droplets, coalesced droplets, and deformed droplets. The statistical results indicate that at 100 Hz, monodisperse droplets with high sphericity are produced, exhibiting a standard deviation below 30 μm. Moreover, droplet sizes demonstrate a deviation from theoretical calculations within 2.5%. Additionally, preliminary measurements are conducted during the dispersion process of a six-nozzle head, confirming the accuracy on locating droplets of the holographic system within a depth range of more than 30 mm.

Alginate-Based Carriers Loaded with Mulberry (Morus alba L.) Leaf Extract: A Promising Strategy for Prolonging 1-Deoxynojirimicyn (DNJ) Systemic Activity for the Nutraceutical Management of Hyperglycemic Conditions.

The iminosugar 1-deoxynojirimicyn (DNJ) contained in mulberry leaves has displayed systemic beneficial effects against disorders of carbohydrate metabolism. Nevertheless, its effect is impaired by the short half-life. Alginate-based carriers were developed to encapsulate a DNJ-rich mulberry extract: Ca-alginate beads, obtained by external gelation, and spray-dried alginate microparticles (SDMs). Mean size and distribution, morphology, drug loading, encapsulation efficiency, experimental yield, and release characteristics were determined for the two formulations. Ca-alginate beads and SDMs exhibited an encapsulation efficiency of about 54% and 98%, respectively, and a DNJ loading in the range of 0.43-0.63 μg/mg. The in vitro release study demonstrated the carriers' capability in controlling the DNJ release in acid and basic conditions (<50% in 5 h), due to electrostatic interactions, which were demonstrated by 1H-NMR relaxometry studies. Thus, alginate-based particles proved to be promising strategies for producing food supplements containing mulberry leaf extracts for the management of hyperglycemic state.

Narrownose smoothhound (Mustelus schmitti) shark liver: From a residue to a high added value biocompounds

The exploration of fishery wastes for the extraction of value-added biocompounds has become a topic of current interest. The aim of this work was to promote a circular economy model by obtaining oil by enzymatic hydrolysis from Mustelus schmitti livers and incorporating it into bread. The oil extraction reaction was carried out using Alcalase® 2.4 L at pH 8.0, 55 °C of temperature for 60 min. Fatty acid analysis showed that the oil was rich in ω-3 long chain fatty acids (LCω3PUFAs), with the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) being the main constituents (13 and 70 % of total PUFAs, respectively). Then, an external gelation method was developed to produce alginate capsulates loaded with the extracted oil. The encapsulation efficiency (EE) was 93.41 %. Finally, capsulated and unencapsulated fish oil were used to develop breads and more than 95 % of EPA and DHA were recovered after baking. Thus, 20 g of baked product can provide about 45 % of the recommended minimum daily intake of EPA plus DHA. The results suggest that it is possible to use the liver from the narrownose smoothhound (Mustelus schmitti) shark fishery to produce value-added products based on a circular economy.

Use of Double Gelled Microspheres to Improve Release Control of Cinnamon-Loaded Nanoemulsions.

The use of nanoemulsions as encapsulation systems for active ingredients, such as cinnamon oil, has been studied. A surfactant based on polyoxyethylene glycerol esters from coconut/palm kernel oil has been used. The nanoemulsions were obtained by the two most commonly low-energy emulsification methods, the composition inversion phase (PIC) and the temperature inversion phase (PIT) methods. Nanoemulsions were successfully obtained by both methods, with very small droplet sizes (5-14 nm) in both cases, but a greater stability was observed when the PIT method was used. Nanoemulsions were encapsulated by external gelation using two different polysaccharides, alginate or chitosan, dissolved in the continuous phase of the nanoemulsion. Then, the nanoemulsion was dropped into a bath with a gelling agent. To improve the release control of cinnamon oil and avoid the burst effect, beads prepared with one of the polysaccharides were coated with the second polysaccharide and then gelled again. Double gelled beads were successfully obtained, the core with chitosan and the outer layer (shell) with alginate. SEM images showed the morphology of the single beads presenting high porosity. When the beads were coated, the porosity decreased because the second polysaccharide molecules covered the pre-existing pores. The smoother surface was obtained when this second layer was, in turn, gelled. The release patterns at pH = 2 and pH = 7 were studied. It was observed that the double gelled bead provided a more gradual release, but maintained approximately the same amount of final released oil. The release patterns were fitted to the Korsmeyer-Peppas model. The fitting parameters reflected the effect of the different coating layers, correlating with different diffusion mechanisms according to the bead core and shell materials.

Structure, dynamics, and functional properties of hybrid alginate-pectin gels dually crosslinked by Ca2+ and Zn2+ ions designed as a delivery device for self-emulsifying systems for lipophilic phytotherapeutics

Alginate gels are outstanding biomaterials widely applicable in food and pharmaceutical industries. This contribution provides comprehensive insight into the design of advanced hybrid alginate/pectin co-networks double crosslinked by Ca2+/Zn2+ ions encapsulating self-emulsifying systems (SES). The tunable mucoadhesive properties, structural stability, integrity, dissolution profiles, and enhanced in-vivo bioavailability make the synthesized hybrid systems ideal vehicles for the delivery of lipophilic phytotherapeutics, allowing the long-term site-specific treatment of intestinal inflammation. This work also provides a thorough understanding of the structure-property relationships of alginate-pectin gels at the atomic resolution level. It was found out that SES molecules form well-distributed, phase-separated microparticles that interact with the polysaccharide matrix through a well-defined interface. The hybrid alginate-pectin gel is highly cross-linked, with both types of polysaccharides participating in the network formation. The observed surface interactions of SES droplets increase the intrinsic mobility of the network. The plasticizing effect can be regulated by the amount of pectin macromolecules, whose interaction with alginate chains enables a strengthening of the polysaccharide network. Overall, the domain-like architecture of hybrid alginate-pectin gels synthesized by external ionic gelation is revealed; the key structural motifs responsible for their properties are discovered; and the pathways allowing their regulation are identified. Biological in-vivo tests then confirmed positive effects of the synthesized systems in living organisms. The strategy presented thus offers a new perspective for the rational design of alginate-based materials for the microencapsulation of bioactive compounds for advanced orally administered delivery systems or controlled-release decontaminators applicable in the food and nutraceutical processing industries.

Optimization of Citrus aurantifolia peel extract encapsulation in alginate-gelatin hydrogel microbeads for antibacterial wound dressing applications

The extract of Citrus aurantifolia peel has been encapsulated into alginate-gelatin-based microbeads using an external ionotropic gelation method to apply antibacterial wound dressings. Such variables, like the alginate-gelatin ratio, extract quantity, and CaCl2 cross-linkers, were optimized to produce a good yield, well-distributed size, and encapsulation efficiency. Antibacterial efficacy was tested against both S. aureus and E. coli. Optimal microbead characteristics were obtained at alginate:gelatin concentration ratio of 1.75 %:0.25 % (w/v), with 15 mg of extract and a 2 % CaCl2 cross-linker. These conditions resulted in the microbeads with 82.94 ± 1.056 % yield, particle sizes between 1.080–1.244 µm, and encapsulation efficiency of 79.127 ± 0.186 %. The microbeads exhibited an almost spherical morphology with a slightly rough surface. The extract release mechanism out of the microbeads was governed by both diffusion and erosion of the shells following the Korsmeyer-Peppas kinetic model (k = 1.014 ± 0.007/min). Upon immobilizing the microbeads on gauze, an add-on percentage of 73.98 % was observed. Moreover, the gauze-immobilized microbeads inhibited S. aureus and E. coli growth with inhibition zones of 11±1.48 and 12.56±4.89 mm, respectively. In conclusion, the antibacterial alginate-gelatin-based microbeads have demonstrated optimal characteristics and exhibited effective inhibition against S. aureus and E. coli, showcasing their potential as antibacterial wound dressings.

Development of snacks based on Macadamia integrifolia nuts enriched with omega-3

Over the past decade, research in all areas of food product development has focused on meeting changing needs and current consumer demands by creating new healthy food alternatives. The aim of this study was to develop innovative, healthy snacks enriched with long-chain omega-3 fatty acids from fish oil (LCω3PUFAs). These snacks were made using waste from the Macadamia integrifolia nut beverage industry. The fish oils rich in LCω3PUFAs were incorporated as emulsion oil and in alginate-based coatings prepared by the external gelation method. The alginate-based coatings achieved a high encapsulation efficiency of over 90%, and all products showed stable levels of omega-3 fatty acids. The obtained snacks showed a protein content ranging from 7.73% to 9.02%, and the dietary fiber content was around 14% in all the formulations. Furthermore, the snacks provided more than 30% of the minimum recommended daily intake of omega-3 fatty acids. In light of the results obtained, the developed beads were beneficial in LCω3PUFAs retention rate and improved oxidative stability. Thus, this research proposes a promising alternative for enhancing food sustainability by creating nut snacks as nutritious functional food utilizing beverage waste to increase value and reduce environmental impact.