Encapsulation Efficiency Of Microcapsules Research Articles

Fabrication of chitosan-encapsulated microcapsules containing wood wax oil for antibacterial self-healing wood coatings

Wood multifunctional smart coating is a new functional coating that combines smart material technology with traditional wood. In this study, wood wax oil based on thistle oil and flaxseed oil was used as the core material, and chitosan was used as the wall material to prepare self-repairing antibacterial microcapsules. The optimal preparation conditions were found to be an oil-water ratio (OWR) of 2:1, a core-to-wall ratio of 3:1, using OP-10 as the emulsifier at a concentration of 10.0 %, and a crosslinker concentration of 0.18 g/mL. The encapsulation efficiency of microcapsules was 73.7 % by spray drying, and the thermal stability was improved. The chitosan microcapsules exhibit the characteristics of water sensitivity and acid selective response, with rapid release at pH 7.0. Blending microcapsules at concentrations of 2.0 %, 5.0 %, and 8.0 % with UV topcoat and applying them to walnut plywood resulted in a multifunctional wood coating. Artificially simulated daily scratch damage was effectively repaired within 7 d. Furthermore, the 10.0 % microcapsules demonstrated antibacterial properties against Escherichia coli (E. coli) and Escherichia coli (E. coli), with an antibacterial E. coli and S. aureus rate of up to 75.82 % and 42.96 %. The IC50 of the wood coatings against E. coli was 5.667, while against S. aureus it was 15.45. The minimum inhibitory concentration (MIC) of the microcapsules against both E. coli and S. aureus was 10.0 %. The coating film containing 2.0 % microcapsules demonstrated superior overall performance. This research established a foundation for the development of self-healing antibacterial coatings for wood and addressed the gap in dual-functional self-healing antibacterial paint films for wood.

Probiotics encapsulated by gelatin and hyaluronic acid via layer-by-layer assembly technology for enhanced viability

The viability of probiotics is often affected by external adverse factors during food processing. In this study, hyaluronan (HA) and gelatin (GL) were used to protect probiotics by an encapsulator combined with layer-by-layer (LBL) assembly. The effect of probiotics survival during adverse conditions such as gastrointestinal digestion, heating and storage were studied. The encapsulation efficiency of microcapsules was high (78%–92%) during the preparation process. FT-IR and XRD analysis showed that the multilayer microcapsules were assembled LBL through hydrogen bonding and electrostatic interactions. When microcapsules were subjected to monolayer embedding during gastrointestinal digestion, the dissolution of the wall material exposed the cells to harsh conditions more quickly. However, with the increase of the coating, this adverse effect on the vitality of the probiotics became less. In addition, multilayer microcapsules greatly improved the antioxidant properties and cell extract viability of probiotics under adverse conditions. Therefore, the findings provide valuable information for the development of functional probiotic foods.

Improved physicochemical properties and in vitro digestion of walnut oil microcapsules with soy protein isolate and highly oxidized konjac glucomannan as wall materials

This study investigated the effect of the oxidation degrees of oxidized konjac glucomannan (OKGM) on the encapsulation efficiency (EE), physicochemical and in vitro digestive properties of soy protein isolate (SPI)-based microcapsules walnut oil using experimental and computational approaches. Microcapsules had the highest EE when the ratio of OKGM and SPI to oil was 2.5:1. With increasing the oxidation degree of OKGM, the EE of microcapsules was increased and the hygroscopicity was decreased. Molecular dynamics simulation results showed that SPI/oil/highly OKGM had relatively low binding energy (−4.03 × 106 kJ/mol) and strong electrostatic interactions, which may contribute to a higher EE and lower hygroscopicity of microcapsules, respectively. The oxidative stability of the oil was markedly improved by SPI and OKGM, and microcapsules prepared with SPI and highly OKGM had the highest in vitro digestion. This study provided theoretical support for broadening the application of microcapsules prepared with SPI and OKGM.

Effects of citrus essential oils on the oxidative stability of microencapsulated fish oil by spray-drying.

The effects of citrus essential oils (orange, lemon, mandarin, and grapefruit) on the oxidative stability of microencapsulated fish oil by spray-drying were evaluated. The encapsulation efficiency of microcapsules was in the range of 42.25 and 62.43%. Twelve active substances were determined as major volatile components of citrus essential oils. The highest phenolic content was obtained from grapefruit essential oil (44.32 mg GAE/g). Lower values of thiobarbituric acid reactive substances (TBARs) were obtained for microencapsulated fish oils with essential oils compared to control. At the end of storage, the highest peroxide value (PV) was observed in the control group (25.30 meq O2/kg oil) while the lowest value was in the lemon (13.40 meq O2/kg oil) and orange group (13.91 meq O2/kg oil). The results of this study showed that citrus essential oils can be used to improve the oxidative stability of fish oil microcapsules.

Multifunctional Linen Fabric Obtained through Finishing with Chitosan-gelatin Microcapsules Loaded with Cinnamon Oil

ABSTRACT In the 21st century, the occurrences of deadly viruses, mosquito-borne and pathogenic diseases have increased significantly. To avoid the spread of these diseases, one of the best strategies is to use protective textile products such as functional (antibacterial, antioxidant, antiviral, mosquito repellent) mask, scarf, gowns, curtains, bedsheets, etc. The present work deals with the preparation of chitosan-gelatin microcapsules loaded with cinnamon bark oil and the application of prepared microcapsules to the linen to develop multifunctional protective linen fabric. The scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and Fourier transform infrared (ATR-FTIR) spectroscopy were utilized to characterize the prepared microcapsules and the finished fabric. The encapsulation efficiency of microcapsules was also calculated to optimize the concentration of polymers and oil. The chitosan-gelatin shell on cinnamon bark oil core provided a controlled-release system, which delivers excellent washing durability to the functionalities of the finished linen. The finished linen with an excellent antibacterial property against E. coli and S. aureus bacteria and outstanding mosquito repellency (up to 100%) durable up to 20 washes was obtained. The finished fabric also showed durable and efficient antioxidant property and a fragrance. The use of bio-materials for the functional finishing of linen was reported.

Study of vitamin E microencapsulation and controlled release from chitosan/sodium lauryl ether sulfate microcapsules

Potential benefit of microencapsulation is its ability to deliver and protect incorporated ingredients such as vitamin E. Microcapsule wall properties can be changed by adding of coss-linking agents that are usually considered toxic for application. The microcapsules were prepared by a spray-drying technique using coacervation method, by depositing the coacervate formed in the mixture of chitosan and sodium lauryl ether sulfate to the oil/water interface. All obtained microcapsules suspensions had slightly lower mean diameter compared to the starting emulsion (6.85 ± 0.213 μm), which shows their good stability during the drying process. The choice and absence of cross-linking agents had influence on kinetics of vitamin E release. Encapsulation efficiency of microcapsules without cross-linking agent was 73.17 ± 0.64 %. This study avoided the use of aldehydes as cross-linking agents and found that chitosan/SLES complex can be used as wall material for the microencapsulation of hydrophobic active molecules in cosmetic industry.

MALTODEKSTRİN-NOHUT PROTEİNİ İZOLATI MATRİSİNDE KARABİBER TOHUMU YAĞININ PÜSKÜRTMELİ KURUTMA METODU İLE ENKAPSÜLASYONU

Bu çalışmada karabiber tohumu yağının maltodekstrin ve yerel üreticiden temin edilen Kabuli çeşidi nohuttan alkali ekstraksiyon/izoelektrik çöktürme metodu ile elde edilen protein izolatı kullanılarak püskürtmeli kurutma metodu ile enkapsülasyonunun incelenmesi amaçlanmıştır. Bu amaçla yalnızca maltodekstrin içeren kontrol numunesi ve farklı oranlarda (%1-4) nohut proteini izolatı ve %8 oranında karabiber tohumu yağı içeren emülsiyonlar hazırlanmış ve püskürtmeli kurutma metodu ile kurutulmuştur. Elde edilen karabiber tohumu yağı mikrokapsüllerinin nem içeriği 4,7-6,5 g/100 g arasında; su aktivitesi ise 0,22-0,27 arasında değişmiştir. Formülasyonda kullanılan nohut proteini izolatı oranı arttıkça elde edilen toz ürünün nem içeriğinin düştüğü, renginin ise koyulaştığı görülmüştür. Karabiber tohumu yağı mikrokapsüllerinin yüzey yağı %0,2-1,3 arasında; enkapsülasyon verimi ise %74,1-99,3 arasında değişmiştir. Nohut proteini izolatı kullanılarak elde edilen karabiber tohumu yağı mikrokapsüllerinde protein kullanılmayan kontrol numunesine göre enkapsülasyon verimi artmıştır. Bu çalışma sonucu elde edilen bulgular, maltodekstrin ve nohut proteini izolatının karabiber tohumu yağı gibi hassas uçucu yağların enkapsülasyonunda taşıyıcı matris olarak kullanılabileceğini göstermiştir.

Preparation and application performance of lignin-polyurea composite microcapsule with controlled release of avermectin

Pickering emulsion stabilized by lignin/sodium dodecyl sulfate composite nanoparticles (LSNP) was used as template to prepare the avermectin @ lignin/polyurea composite microcapsules (AVM@LPMC) through ion cross-linking and interfacial polymerization. The inner wall of the microcapsules is a firm and compact polyurea layer, and the outer wall is a loose lignin layer. The effects of stirring speed, dosage of sodium dodecyl sulfate (SDS), and pH value in aqueous phase on the formation of microcapsules were systematically studied. The results showed that the optimal stirring speed was 200 rpm, and the optimal dosage ratio in water phase was HCl (mmol):SDS (mmol):lignin AL (g) = 0.375:1.25:1 in fixed oil-water ratio (1:9) and oil phase composition. In this way, the encapsulation efficiency of microcapsules could reach up to 85.4%, while it would slightly decrease with the increase of lignin content in the wall materials. The polyurea layer played a key role in supporting the spherical structure of the capsule wall and delaying the release of avermectin, while the loose lignin layer contributed less to the slow release performance of microcapsule. By changing the amount of lignin, the polyurea-layer thickness could be regulated to adjust the release rate of microcapsule. Remarkably, a small amount of lignin introduced in the wall material could significantly improve the anti-photolysis performance of avermectin in microcapsules.

Optimization of preparation conditions of eucalyptus essential oil microcapsules by response surface methodology

In order to improve the microencapsulation efficiency of the eucalyptus essential oil (EEO) microcapsules, the preparation process was optimized using response surface methodology (RSM). The preferred key factors were chosen firstly by Plackett–Burman design (PBD) experiments, steepest ascent experiments results which were used to determine the central level of the RSM experiment. A three-level-three-variable Box–Behnken design was used to further optimize the synthesis parameters. The results of PBD experiments showed that the ratio of wall to core, encapsulation temperature and encapsulation time were the key factors affecting the microencapsulation efficiency of the EEO microcapsules. Through the RSM, the optimal preparation process of the EEO microcapsules was as follows: encapsulation temperature 46°C, encapsulation time 108 min, ratio of wall to core 9.59, ratio of ethanol to essential oil 20:1, and ratio of water to β-cyclodextrin 10:1. The microencapsulation efficiency of the EEO microcapsules prepared under these conditions was 71.17%. Practical applications In order to expand the application range of liquid eucalyptus leaves essential oil, the essential oil was prepared into solid for use and preservation. By optimizing the preparation conditions of eucalyptus leaves essential oil microcapsules, the encapsulation efficiency of microcapsules was improved. There was great potential in the research and development of new natural antibacterial and antiseptic products.

Development and characterization of soybean oil microcapsules employing kafirin and sodium caseinate as wall materials

Microcapsules containing soybean oil were developed with kafirin and sodium caseinate as wall materials by spray drying and characterized by gas chromatographic (GC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), physical properties and oxidative stability. The results showed that the encapsulation efficiency of microcapsules was 40.15% under the optimal conditions. Less than 3% loss of unsaturated fatty acids was observed after encapsulation. Particles were spherical, most of the particle surfaces were concave and shriveled, and there were almost no cracks or fissures. In addition, the microencapsulated soybean oil showed lower oxidation values compared to unencapsulated oil, highlighting a protective effect against free oil. In conclusion, kafirin and sodium caseinate as wall materials can potentially be applied to the microencapsulation of vegetable oil for food applications.

Preparation and characterisation of polylactic acid modified polyurethane microcapsules for controlled-release of chlorpyrifos

Polyurethane modified with polylactic acid microcapsules were fabricated for controlled release of chlorpyrifos (one of the high usage solid phosphorous insecticides) via interfacial polymerisation with diphenylmethane diisocyanate, polyether triol, 1,4-butanediol and polylactic acid as modifier. The structure, morphology and release properties of synthesised microcapsules were characterised by Fourier transform infra-red spectroscopy, thermogravimetric analyser, scanning electron microscope, particle size analyser and high-performance liquid chromatography. More benign solvents, namely ethyl acetate and n-butyl acetate were used as replacement for toxic solvents commonly used in the preparation of polyurethane microcapsules, namely xylene. The spherical microcapsules prepared in this study were 1–20 μm in diameter. Fourier transform infra-red spectroscopy indicated that polylactic acid had successfully participated in the interfacial polymerisation of polyurethane. Encapsulation efficiency of microcapsules can amount up to 71.0% w/w with a loading efficiency of 26.2% w/w. The microcapsules exhibited a sustained release period above 60 days. Combining polylactic acid into the soft segment of polyurethane proves to effectively accelerate the release rate.

Preparation and Characterization of PLA Modified Chloropyrifos/Polyurethane Microcapsules

Polyurethane(PU) modified with polylactic acid (PLA) microcapsules were fabricated for controlled release of Chloropyrifos (Cp, one of the high usage solid phosphorous insecticides) via interfacial polymerization method using MDI50, N306, 1,4-butanediol (BDO) and PLA serve as modifier. The structure, morphology and encapsulation performance of synthesized microcapsules were characterized by FTIR, SEM, and HPLC. More benign solvents, namely ethyl acetate (EA) and n-butyl acetate (BA) were used in the preparation of PU microcapsules. The spherical microcapsules prepared in this study had a diameter of 1-20 μm. FTIR indicated that PLA had successfully participated in the interfacial polymerization of polyurethane. The encapsulation efficiency of microcapsules can reach up to 71.0%, and loading content to 26.2%.

Encapsulation of grape seed extract in polylactide microcapsules for sustained bioactivity and time-dependent release in dental material applications

ObjectiveTo sustain the bioactivity of proanthocyanidins-rich plant-derived extracts via encapsulation within biodegradable polymer microcapsules. MethodsPolylactide microcapsules containing grape seed extract (GSE) were manufactured using a combination of double emulsion and solvent evaporation techniques. Microcapsule morphology, size distribution, and cross-section were examined via scanning electron microscopy. UV–vis measurements were carried out to evaluate the core loading and encapsulation efficiency of microcapsules. The bioactivity of extracts was evaluated after extraction from capsules via solvent partitioning one week or one year post-encapsulation process. Fifteen human molars were cut into 7mm×1.7mm×0.5mm thick mid-coronal dentin beams, demineralized, and treated with either encapsulated GSE, pristine GSE, or left untreated. The elastic modulus of dentin specimens was measured based on three-point bending experiments as an indirect assessment of the bioactivity of grape seed extracts. The effects of the encapsulation process and storage time on the bioactivity of extracts were analyzed. ResultsPolynuclear microcapsules with average diameter of 1.38μm and core loading of up to 38wt% were successfully manufactured. There were no statistically significant differences in the mean fold increase of elastic modulus values among the samples treated with encapsulated or pristine GSE (p=0.333), or the storage time (one week versus one year storage at room temperature, p=0.967). SignificancePolynuclear microcapsules containing proanthocyanidins-rich plant-derived extracts were prepared. The bioactivity of extracts was preserved after microencapsulation.

Preparation and characterization of polyurea/polyurethane double‐shell microcapsules containing butyl stearate through interfacial polymerization

AbstractDouble‐shell microcapsules containing butyl stearate were prepared through interfacial polymerization. The outer shell is polyurea formed through polymerization of toluene‐2,4‐diisocyanate (TDI) and diethylene triamine, and the inner shell is polyurethane (PU) formed through polymerization of TDI and polypropylene glycol 2000 (PPG2000). Styrene maleic anhydride copolymer was used as emulsifier. The effects of core to monomer ratio and dosage of PPG2000 on core content and encapsulation efficiency of microcapsules were investigated. The core content has a maximum at core to monomer ratio of 3–4, and the encapsulation efficiency has a maximum value of 95% at core to monomer ratio of 2. The prepared microcapsules were smooth and compact and have an obvious latent heat of 85 J/g. The shell structure of microcapsules was polyurea and PU. The average diameter of the microcapsules was 1–5 μm. The stabilities of the double‐shell microcapsule, such as anti‐ethanol wash and antiheat properties are obviously improved than those of single‐shell microcapsule. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011