Types Of Microcapsules Research Articles

Influence of Electromagnetic Inductive Microcapsules on Self-Healing Ability of Limestone Calcined Clay Cement (LC3) Mortar.

In order to promote the sustainability of cementitious materials, it is imperative to reduce the level of environmental pollution and energy consumption during their production, as well as extend the service life of building elements. This study utilized limestone, calcined clay and gypsum as supplementary cementitious materials to prepare LC3 mortar, replacing 50% of ordinary silicate cement. Three types of microcapsules (M1, M2 and M3) were prepared using IPDI as a healing agent and polyethylene wax, polyethylene wax/nano-CaCO3 or polyethylene wax/ferrous powder as shell materials. The microcapsules were added to the LC3 mortar and tested for their effects on the mechanical properties, pore structure and permeability of mortars. Pre-loaded and pre-cracked mortar specimens were subjected to room temperature or under an applied magnetic field to evaluate the self-healing ability of the microcapsules on mortars. The kinetics of the curing reaction between IPDI and moisture were investigated using quasi-first-order and quasi-second-order reaction kinetic models. The experimental results showed that the mortar (S3) mixed with electromagnetic inductive microcapsules (M3) exhibited the best self-healing ability. The compressive strength retention, the percentage of pores larger than 0.1 μm, recovery of chloride diffusion coefficient and maximum amplitude after self-healing of S3 were 92.2%, 42.6%, 78.9% and 28.87 mV, respectively. Surface cracks with an initial width of 0.3~0.5 mm were healed within 24 h. The curing reaction between IPDI and moisture during self-healing followed a quasi-second-order reaction kinetic model.

Effects of polymeric microcapsules on self-healing composites reinforced with carbon fibers: a comparative study

Abstract Three different microcapsules, namely dicyclopentadiene (DCPD)-urea formaldehyde (UF) based single-walled microcapsules, DCPD-UF-Siloxane (DCPD-UF-Si) based double-walled microcapsules and DCPD-Carbon nanotubes-UF based dual-core microcapsules were synthesized, and their corresponding self-healing composites were prepared. This paper mainly focuses on the synthesis procedure of various microcapsules and a comparative study on the effect of microcapsules over the final composite properties. The core content of the microcapsules was measured and compared with theoretical calculations. DSC & TGA analyses have shown that the novel microcapsules (DCPD-UF-Si, DCPD-CNT-UF) and their composites have better thermal stability compared to DCPD-UF microcapsules. Epoxy-carbon fiber (2 wt.%) composite specimens with three different microcapsules were tested for surface morphology, mechanical, thermal and electrical properties. SEM analysis has shown that the microcapsules have a rough outer surface and smooth inner surface. The average diameter and shell thickness of the microcapsules were measured for all types of microcapsules. Addition of double-walled and dual-core microcapsules has reduced the glass transition temperature of the composites by 10 °C. Also, SHC with DCPD-UF-Si and DCPD-CNT-UF microcapsules have shown better thermal stability (300 °C) compared to DCPD-UF microcapsules (220 °C). The incorporation of CNT based microcapsules inside the composite has also improved the electrical conductivity by 2.2 times, without compromising on self-healing efficiency (78 %). Therefore, these novel microcapsules can be potential candidates for making multifunctional polymer composites for aerospace, windmills and automotive applications.

Multifunctional BiOI/SiO2/Fe3O4@n-Docosane Phase-Change Microcapsules for Waste Heat Recovery and Wastewater Treatment

Waste heat and organic contaminants are significant issues in water pollution, which has caused ecological problems and threatened human health. To provide an effective solution for wastewater recovery, we designed a novel type of multifunctional phase-change microcapsule. This type of microcapsule was synthesized using n-docosane as a core and a SiO2/Fe3O4 composite as a base shell through in situ interfacial polycondensation with the assistance of a Fe3O4 nanoparticle as a Pickering emulsion stabilizer, followed by the deposition of BiOI nanosheets on the surface of the SiO2/Fe3O4 composite shell. Benefiting from the n-docosane core, the resultant microcapsules obtained phase-change enthalpies of 46.8-115.7 J/g for absorbing waste heat from wastewater. The deposited BiOI nanosheets promoted photocatalysis for the microcapsules to degrade organic contaminants in wastewater. Owing to the magnetic response of the Fe3O4 nanoparticles, the separability and recyclability of the microcapsules were improved significantly by magnetic separation. Moreover, the microcapsules demonstrate outstanding phase-change reversibility, thermal cycling stability, and shape stability due to the tight SiO2/Fe3O4 composite shell. This study provides a promising approach for designing and developing multifunctional phase-change microcapsules for waste heat recovery and wastewater treatment.

Balance the rapid release of insecticide microcapsules using double-layer shielding effect when the foliar application

The development of microencapsulation is currently blocked by the mismatch between the release rate and pest-control demand in terms of improving the photostability of pesticides. Achieving both long-term stability and quick release of pesticides through the use of microcapsules (MCs) is an effective way to increase pesticide efficiency. Sodium lignosulfonate and four types of polyalkyl quaternary ammonium salts (PQAS) were used as shell materials in the fabrication of four types of microcapsules by electrostatic self-assembly. The effects of the PQAS alkyl chain length on the morphology, zeta potential, molecular electrostatic potential, particle size distribution, encapsulation efficiency, release behaviour, anti-photolysis performance, and field application effects of the MCs were investigated. The four types of MCs were spherical and 0.5–3 μm in size, and they had an encapsulation efficiency of more than 75 %. The X-ray diffraction results showed that the longer the alkyl chain of PQAS was, the looser the material formed by electrostatic attraction was. With the increase of the alkyl chain length of PQAS, the MCs shell was looser and easier to deform, leading to rapid nuclear release. Therefore, the MCs shells were looser and more prone to deformation with increasing PQAS alkyl chain length, resulting in the quick release of the core. This quick release of the core to the bottom of the microcapsules and the loose shell formed a double-layer structure, which effectively prevented ultraviolet degradation. Therefore, abamectin MCs with quick-release and favourable anti-photolysis performances showed advantages in controlling Plutella. xylostella and Pieris. rapae insect pests. Octadecyl dimethyl benzyl ammonium chloride can be used to fabricate loose MCs by electrostatic self-assembly, which achieves both rapid and long-term pest control.

Fatty acids and free amino acid composition of synbiotic goat cheese with free and encapsulated probiotics

The aim of this study was to determine the changes in free fatty acids and amino acids during storage of synbiotic microcapsule-added goat cheeses and determine the effect of microencapsulation on these changes during storage. Another objective was also to determine the effects of probiotics and synbiotics (probiotic + prebiotics) added in free form during the production of white goat cheese on amino acid and fatty acid values. In the study, three types of microcapsules including probiotic bacteria (Lacticaseibacillus casei and Bifidobacterium longum), probiotic + fructooligosaccharide (FOS), and probiotic + inulin containing microcapsules were prepared and cheeses were produced using these microcapsules. Cheese samples were stored at +4 °C for 180 days and the amino acids and free fatty acid content of the cheeses were determined during the storage period. The saturated fatty acid with the highest ratio in goat cheeses was palmitic acid (C16) whereas the unsaturated fatty acid with the highest ratio was determined as oleic acid (C18:1). At the end of ripening, the amino acid with the highest amount was glutamic acid in cheese samples, followed by leucine, proline, aspartic acid, and lysine, respectively. It has been determined that inoculation of probiotic cultures, either in free or microencapsulated form, into cheese milk positively influences the total amino acid and fatty acid levels. The addition of inulin along with probiotics on the 180th day of storage was effective in amino acid formation compared to cheeses with free FOS added. It could also be concluded that the addition of free or microencapsulated FOS was effective in the formation of free fatty acids. In addition, regardless of the used form (free or microcapsules), inulin was more effective in amino acid formation.

Regulating asphalt pavement temperature using microencapsulated phase change materials (PCMs)

The use of phase change materials (PCMs) to regulate pavement temperatures has been previously studied, with the most successful studies using porous aggregates to stabilize the PCMs. However, this technique can lead to issues with PCM leakage and low PCM content. A less studied method is the use of PCM microcapsules, which also presents challenges since most microcapsules are not strong nor stable enough to survive the high temperatures and compressive forces experienced during asphalt mixture production and placement. This work presents a study of the properties of a new commercial microcapsule type with robust walls and high thermal stability, that are expected to overcome the aforementioned issues. Results from differential scanning calorimetry and thermogravimetric analysis confirmed the microcapsules exhibited high latent heats (200 J/g) and are thermally stable below 400 °C. Additionally, approximately 90% of the capsules remained unbroken after being milled at 140 °C for 20 min, suggesting they are capable of withstanding the mixing and compaction stages of asphalt pavement construction. When PCM microcapsules were added to HMA, thermal cycling experiments showed that specimens containing 10 and 20 vol% PCM exhibited temperature lags of 5 to 10 °C from the control mixture, as they approached the PCM melting/freezing temperature. These results confirm the ability of microencapsulated PCMs to regulate asphalt pavement temperature. However, results from measurements conducted at 40 °C and 1 Hz showed a 75% reduction of the dynamic modulus in specimens containing PCM microcapsules, which could indicate that the addition of these materials also affect asphalt mixture stiffness.

New all-nanoparticle microcapsules for ultrasound release and laser remote killing of cancer cells

Being extra strong but super easy to break – entities with such properties would be desired for many applications, particularly in drug delivery, where polyelectrolyte multilayer capsules took a prominent place due to applications in catalysis, intracellular delivery, and carriers of biomolecules and enzymes. Assembly of such capsules has been typically performed either by using polymers or a mixture of polymers and nanoparticles, which facilitated improvement of mechanical properties. In this work, we have assembled a new type of microcapsules, where multilayers are constructed solely by using nanoparticles in all layers. X-ray diffraction (XRD) studies confirmed the dissolution of calcium carbonate, while mechanical properties of such capsules probed by atomic force microscopy (AFM) reveal an essential increase in the stiffness and density in the walls. Dual functionality of such new capsules has been achieved by actions of ultrasound and laser. Since ultrasound acts more effectively on denser objects, low intensity (below 1 W/cm2) of ultrasound has been used to enable release of encapsulated content. Laser has been used to illuminate microcapsules located in cells and effective killing of cancer cells was achieved. Further applications of the assembled microcapsules are expected in conducting catalytic reactions and biomedicine.

Synthesis and characterization of microencapsulated phase change material with phenol-formaldehyde resin shell for thermal energy storage

Microencapsulation technique of phase change materials (phase change materials, PCM) is considered as one of the most prospective and useful methods for thermal energy storage. In this study, a novel type of microcapsule for thermal energy storage based on an n-eicosane core and a phenol-formaldehyde resin shell was fabricated via in-situ polymerization process. The research studied the effects of the emulsification concentration, core/shell mass ratio and agitation speed on the thermal properties and morphology of microcapsules to confirm the optimal reaction conditions. The chemical compositions, surface morphology and thermal properties and stability were characterized by X-ray diffractometer (X-ray diffractometer, XRD), Fourier-transform infrared spectroscopy (Fourier-transform infrared spectroscopy, FTIR), field emission scanning electron microscopy (field emission scanning electron microscopy, FSEM), transmission electron microscopy (transmission electron microscopy, TEM) and differential scanning calorimetry (differential scanning calorimetry, DSC), respectively. The synthesized microcapsules were found to show a relatively spherical shape and a well-defined core-shell structure as well as a compact shell. Furthermore, the results showed that when the emulsification concentration was 1%, the core/shell mass ratio was 3:6.47, the agitation speed is 1000r/min, the highest encapsulation efficiency and energy storage efficiency achieve 84.2% and 83.4%, respectively, meanwhile the melting enthalpy and phase transition temperature of the obtained microcapsules reached as high as 173.83 J g-1 and 36.6 °C. In addition, the microcapsule samples prepared under optimal condition also exhibited an excellent thermal reliability even after 500th thermal cycles.

The mode II interlaminar fracture toughness and healing efficiency of repeatable self-healing composite

Hollow glass fibers containing self-healing resin (SR) and two types of microcapsules (HGFs-Ms) that can repeatedly heal the crack at the same place were manufactured. The repeatable self-healing carbon-epoxy composites (RSH-CFRPs) were made by incorporating the HGFs-Ms and microcapsules containing hardener into the mid-plane. The effects of the diameter and length of HGFs-Ms, the content of SR and the diameter of the microcapsules containing SR inside HGFs-Ms on the mode II interlaminar fracture toughness, 1st and 2nd healing efficiencies of the RSH-CFRPs were studied by performing end-notched flexure tests. The optimal combination of the above parameters was obtained which could result in 69.77% improvement in the fracture toughness compared to virgin CFRPs and could accomplish 100% healing efficiency at the same place twice. The toughening and healing mechanisms of the RSH-CFRPs were deeply analyzed, which proved the effectiveness of the self-healing method proposed in this study.

Development of smart epoxy coating through click reaction using a vegetable oil

Two-component microcapsules of acrylated epoxidized soybean oil (AESO) as a healing agent and trimethylolpropane tris(3-mercaptopropionate) as hardener (TMPMP), were encapsulated with the poly(methyl methacrylate) (PMMA) shell by solvent evaporation method.The chemical structure and morphologies of the core/shell microcapsules were confirmed using Fourier-transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FE-SEM), respectively. The thermal properties of the microcapsules were investigated through thermogravimetric analysis (TGA). FE-SEM confirmed that both types of microcapsules have a spherical shape with an average diameter of approximately 6.2 μm.The two-component microcapsules were included in epoxy resin, and the healing performance of the system was assessed. From Electrochemical impedance spectroscopy (EIS) and salt spray test, the best self-healing performance was obtained for 0.5 wt% two-component microcapsules. For epoxy coatings containing 0.5 wt% of microcapsules, after five months of exposure under salt water 3.5 %, no corrosion effect was observed on the epoxy coating, indicating that there are enough high-performance materials in the microcapsules to heal cracks and the click reaction has been a very effective reaction to create this healing resin.

Preparation of BTA@PDA/PANI microcapsules and anti-corrosion performance of self-healing epoxy coatings on low carbon steel

Benzotriazole-loaded polydopamine/polyaniline (BTA@PDA/PANI) microcapsules are prepared vis the combination of a hard template method and in-situ polymerization. The PDA/PANI hollow microspheres are first prepared using SiO2 as a hard template and etching them with hydrofluoric acid. The BTA corrosion inhibitor is then loaded into the PDA/PANI hollow microspheres to obtain the BTA@PDA/PANI microcapsules. The mean particle size and shell thickness of the synthesized microcapsules are 8.3 and 2.1 µm, respectively. The load capacity of BTA is above 20 wt%. The corrosion resistance of epoxy coatings with different contents and types of microcapsules is compared by saline immersion and electrochemical impedance tests. A scratched coating with 1 wt% BTA@PDA/PANI microcapsules has the best anti-corrosion effect. The synergistic anticorrosion mechanism of BTA, PDA and PANI is revealed and confirmed.

Preparation and characterization of low-yellowing cross-linked shell microencapsulated phase change materials for latent thermal energy storage

A Cross-linked microencapsulated phase change material (MEPCM) was prepared using butyl stearate as the core material and isophorone diisocyanate (IPDI) and triethanolamine (TEA) as the reaction monomers, while a Linear MEPCM was prepared using 2,4-toluene diisocyanate (TDI) and diethylenetriamine (DETA) as the reaction monomers. The thermal stability, densification, chemical structure, phase change properties and surface morphology of the two types of microcapsules were characterized and analyzed, respectively, and the thermal storage properties and whiteness of the finished fabrics with the two microcapsules were measured. The results showed that the surface of the prepared Cross-linked MEPCMs was smooth and dense, with good wrapping effect and no leakage of core material, while the Linear microcapsules had serious leakage of core material and adhesion between particles; the thermal stability and denseness of the cross-linked microcapsules were significantly improved compared with the linear-shell microcapsules. After continuous drying at 120 °C for 6 h, the mass loss rate of cross-linked microcapsules was only 6.23%, while the mass loss rate of the linear microcapsules was up to 22.35%. The fabric finished with the cross-linked microcapsules had a great phase change properties and wash resistance, the whiteness was significantly higher than that of the linear microcapsules, had an obvious low yellowing characteristic. The prepared microcapsules had good prospects for textile applications.

Spray-Drying Microencapsulation of Pink Guava (Psidium guajava) Carotenoids Using Mucilage from Opuntia ficus-indica Cladodes and Aloe Vera Leaves as Encapsulating Materials.

In this work, the capacity of the mucilage extracted from the cladodes of Opuntia ficus-indica (OFI) and aloe vera (AV) leaves as wall material in the microencapsulation of pink guava carotenoids using spray-drying was studied. The stability of the encapsulated carotenoids was quantified using UV–vis and HPLC/MS techniques. Likewise, the antioxidant activity (TEAC), color (CIELab), structural (FTIR) and microstructural (SEM and particle size) properties, as well as the total dietary content, of both types of mucilage microcapsules were determined. Our results show that the use of AV mucilage, compared to OFI mucilage, increased both the retention of β-carotene and the antioxidant capacity of the carotenoid microcapsules by around 14%, as well as the total carotenoid content (TCC) by around 26%, and also favors the formation of spherical-type particles (Ø ≅ 26 µm) without the apparent damage of a more uniform size and with an attractive red-yellow hue. This type of microcapsules is proposed as a convenient alternative means to incorporate guava carotenoids, a natural colorant with a high antioxidant capacity, and dietary fiber content in the manufacture of functional products, which is a topic of interest for the food, pharmaceutical, and cosmetic industries.

Symbiotic microencapsulation to enhance Bifidobacterium longum and Lactobacillus paracasei survival in goat cheese

In the study, the microencapsulation method was applied in the production of white cheese from goat milk to prevent the loss of viability of Lactobacillus paracasei and Bifidobacterium longum due to environmental factors during their storage period. For this purpose, the cheese was obtained using three types of microcapsules - symbiotic microcapsules containing probiotic bacteria and probiotic + fructooligosaccharide, probiotic + inulin. In addition, probiotics, fructooligosaccharide and inulin have been added to cheese in free form, and a total of 7 different cheeses have been produced with the control sample. In the microencapsulation, 1% sodium alginate was used as coating material and the extrusion method was applied. The cheese samples have been stored at +4 0C for 180 days. It has been determined that the viability of L. paracasei and B.longum has been preserved with the microencapsulation technique, while the viability of probiotic bacteria is preserved at a higher level in cheese samples obtained with the addition of prebiotics to microencapsules. It has been concluded that probiotic microorganisms are available above the minimum therapeutic effect value in grams of cheese samples containing microcapsules and these cheese could be considered as probiotic.

Determination of probiotic characteristics and resistance to biological barriers under in vitro gastrointestinal conditions in goat cheese produced using microencapsulated probiotic bacteria

Abstract The method of microencapsulation has been performed on the probiotic microorganisms (Lactobacillus paracasei and Bifidobacterium longum), which are used in conjunction with the starter cultures in white cheese production from goat‘s milk. For this purpose, 3 types of microcapsules, namely, one containing the probiotic bacteria and another symbiotic microcapsule containing the probiotic bacteria and fructooligosaccharides have been obtained in the study and the cheese containing these microcapsules were produced. The cheese samples have been stored at +40C for 180 days and during storage, loss in viabiality that might be consisted at in-vitro conditions at gastrointestinal system is analyzed. The present study revealed that probiotic bacteria at different bile concentrations gained resistance during maturation, and the rate of resistance was higher in prebiotic and protein-supported microencapsulated probiotic bacteria. The resistance of lactic acid bacteria used in cheese production to gastric secretions was lower than that of probiotic bacteria. The determination of hydrophobicity of bacteria revealed that Bifidobacterium longum had the highest hydrophobicity level followed by Lactococcus, which forms the cheese culture, while Lactobacillus paracasei had the lowest level. It was determined that the microencapsulation method reduced the viability losses of probiotic microorganisms in the gastrointestinal tract.

Thermal stability of a functional probiotic food ingredient based on encapsulated microorganisms Lactobacillus plantarum SP-A3

Recently, there has been increased interest in the production of functional probiotic food products such as cheese, yogurt and ice cream, as well as beverages and products based on meat, fruit, chocolate, etc. However, the range of such products is extremely limited, partly due to the difficulty of maintaining the viability of probiotic microorganisms. The thermal stability of the encapsulated L. plantarum SP-A3 culture was evaluated under conditions simulating the heat treatment of fortified food products. The object of the study is nearly pure culture of L. plantarum SP-A3 from the probiotic drug Lactobacterin (Mitrogen NPO). We used deep culture method on a dense nutrient medium – MRS agar at 37°C. The test culture was encapsulated in a 2 % alginate gel by B-390 apparatus (Buchi) using a 2 % calcium lactate solution as a fixative. Two types of microcapsules were obtained and studied: 200-300 µm and 400-600 µm in size. The capsules had a rounded regular shape, matte white, uniform color and were elastic. The efficiency of encapsulation with the proposed parameters was about 89%. We studied the possibility of using a model system simulating cooling of a food product after heat treatment. Both objects pass the most critical temperature ranges from 70 to 60 °C in a similar way, the use of a model system to study the survival of microorganisms when cooling a real food product after heat treatment is adequate. The study did not identify statistically significant differences between the capsule size (200-300 µm and 400-600 µm) and the survival after heat treatment (74,7±0,7% and 68,8±1,2%, respectively). Compared to unencapsulated cells (0% in three independent experiments), microencapsulated probiotics showed higher survival rates of up to 75,4%. Thus, with the use of microencapsulated probiotics, the range of probiotic foods can be expanded.

The Discovery of the Buffer Capacity of Various Types of Polyelectrolyte Microcapsules.

Polyelectrolyte microcapsules, which are obtained by the method of alternate adsorption of oppositely charged polyelectrolytes onto colloidal particles of micron size, are widely used in science and industry. Nevertheless, the properties of microcapsules are still poorly understood. In particular, there is no information in the literature on the buffer capacity. However, information on the presence of a buffer capacity and an understanding of its mechanisms can both simplify the use of microcapsules and expand the scope of their application. In this regard, the buffer capacity of various types of microcapsules was studied. It was found that polyelectrolyte microcapsules consisting of polyallylamine, and polystyrene sulfonate have a buffer capacity. In addition, in an acidic medium, the buffer capacity of microcapsules containing BSA is significantly greater than that of microcapsules without protein. This is due to the fact that BSA contributes to the buffering of microcapsules. Differences in the behaviour of the buffer capacity of microcapsules with the composition (PAH/PSS)3 and (PSS/PAH)3 were found. In addition, a hypothesis has been proposed that regions of unbound polyallylamine are responsible for the buffering properties of polyelectrolyte microcapsules. This hypothesis is confirmed by the fact that incubation of microcapsules in 0.5 M NaCl increases the amount of unbound polyallylamine, which leads to an increase in the buffer capacity of microcapsules at alkaline pH values higher than the buffer capacity of capsules in an aqueous solution.

Evaluation of the Compatibility of Modified Encapsulated Sodium Silicate for Self-Healing of Cementitious Composites

Healing agent carriers play a significant role in defining the performance of the autonomous self-healing system. Particularly, the ability to survive during the mixing process and the release of the healing agent when cracks occur without affecting the mechanical properties of the cementitious composite. Up to now, these issues are still a concern since glass capsules are unable to survive the mixing process, while some types of microcapsules were reported to cause a decrement in strength as well as limited strength recovery. Therefore, this study was twofold, addressing the surface treatment of polystyrene (PS) capsules and the evaluation of the compatibility of the modified capsules for cement-based applications. Secondly, assessing the healing performance of modified PS capsules in cementitious composites. Furthermore, the study also evaluates the potential healing performance due to the synergic effect between the encapsulation method and the autogenous self-healing mechanism. The investigation was carried out by measuring the changes in the pH of pore solution, FTIR analysis, survival ratio, and bonding strength. For self-healing assessment, the compression cracks on the cement paste were created at an early age and the strength recovery was measured at the age of 28 and 56 days. To identify the chemical compounds responsible for the healing process, SEM-EDX tests were conducted. Moreover, the effect of silica fume (SF) on bonding strength and self-healing was also evaluated. Based on the results, the modified PS capsules by roughing approach showed promising performance in terms of survivability, bonding, and recovery. The modified PS capsule increased the strength recovery by about 12.5–15% for 100%OPC and 95%OPC + 5%SF, respectively. The finding observed that the combining of modified PS capsules and the inclusion of SF gave high strength recovery of about 20% compared to 100%OPC without capsules. Thus, the modified PS capsule has a good potential for self-healing of cementitious-based applications.

Effect of Alginate-Microencapsulated Hydrogels on the Survival of Lactobacillus rhamnosus under Simulated Gastrointestinal Conditions.

Thanks to the beneficial properties of probiotic bacteria, there exists an immense demand for their consumption in probiotic foods worldwide. Nevertheless, it is difficult to retain a high number of viable cells in probiotic food products during their storage and gastrointestinal transit. Microencapsulation of probiotic bacteria is an effective way of enhancing probiotic viability by limiting cell exposure to extreme conditions via the gastrointestinal tract before releasing them into the colon. This research aims to develop a new coating material system of microencapsulation to protect probiotic cells from adverse environmental conditions and improve their recovery rates. Hence, Lactobacillus rhamnosus was encapsulated with emulsion/internal gelation techniques in a calcium chloride solution. Alginate–probiotic microbeads were coated with xanthan gum, gum acacia, sodium caseinate, chitosan, starch, and carrageenan to produce various types of microcapsules. The alginate+xanthan microcapsules exhibited the highest encapsulation efficiency (95.13 ± 0.44%); they were simulated in gastric and intestinal juices at pH 3 during 1, 2, and 3 h incubations at 37 °C. The research findings showed a remarkable improvement in the survival rate of microencapsulated probiotics under simulated gastric conditions of up to 83.6 ± 0.89%. The morphology, size, and shape of the microcapsules were analyzed using a scanning electron microscope. For the protection of probiotic bacteria under simulated intestinal conditions; alginate microbeads coated with xanthan gum played an important role, and exhibited a survival rate of 87.3 ± 0.79%, which was around 38% higher than that of the free cells (49.4 ± 06%). Our research findings indicated that alginate+xanthan gum microcapsules have a significant potential to deliver large numbers of probiotic cells to the intestines, where cells can be released and colonized for the consumer’s benefit.

An Innovative Method for Microcapsule Based Functional Yarn Production

ABSTRACT Today, microcapsule application to textile materials is a widely used for the production of functional textile products. Microcapsule application methods used in practice have some significant disadvantages. There is a need for innovative methods to eliminate or minimize these disadvantages. From this point of view, in this study, it was aimed to develop an alternative method based on integrating microcapsule particles into the open staple fiber bundle before the spun yarn formation on the classical ring spinning. It was thought that this application method could allow the incorporating microcapsules not only the fibers on the yarn surface but also to the surface of the fibers in the yarn structure. Microcapsule doped and undoped ring spun yarns having Ne 16 yarn count with knitted twist were produced from viscose fibers. Obtained ring spun yarns were subjected to winding and knitting processes in order to analyze the effect of friction on the microcapsule presence. SEM images taken from yarn and fabric samples were examined. Additionally, yarn properties were analyzed. In order to evaluate the performance of the alternative method, microcapsule dispersion at the same concentration was applied to the knitted fabrics using pad-dry-cure method, which was widely used for production of the functional textile products. Two types of microcapsule applied knitted fabric samples were washed several times and presence of microcapsules was evaluated with SEM images. Furthermore, thermal properties of the both types of application methods were compared by examining T-history curves. The findings indicated that the alternative method offers comparable yarn and thermal properties with environmentally friendly application as well as washable and durable to the friction effects occurring in industrial processes.