Electrohydrodynamic atomization assisted encapsulation of bioactive compounds

Electrohydrodynamics atomization (Electrospraying) is a versatile technique to produce microspheres or beads from various materials by means of electrical forces. Electrospraying has numerous advantages over traditional methods in encapsulation: there is high encapsulation efficiency without unfavorable denaturation of bioactive molecules and an enhanced control over the size distribution of particles. This technique could be used for encapsulating bioactive molecules such as proteins, enzymes, vitamins, polyphenols, drugs and sensitive ingredients, for lots of purposes such as masking the bitter test of compounds, sustained releasing, the stability of compounds during process or shelf life of foods, etc. Living cells and spores could be encapsulated by this method for bioenvironmental purposes. Beads can be made by a wide range of food grade and natural biodegradable polymers including alginate, starch, carrageenan, chitosan zein, etc., which makes their use suitable in the development of new foods with enhanced properties and characteristics. Encapsulation by this method also achieves the ability of sustained and controlled release of bioactive compounds by foods, and increasing the effectiveness of such compounds along the time

Electrohydrodynamic atomization of Balangu (Lallemantia royleana) seed gum for the fast-release of Mentha longifolia L. essential oil: characterization of nano-capsules and modeling the kinetics of release

The aim of this study is to optimize encapsulation of Mentha longifolia L. essential oil into Balangu (Lallemantia royleana) seed gum nano-capsules, to increase their utility as flavoring and bioactive agents in foods and beverages. Essential oil emulsions with Balangu seed gum (0.25 and 0.5% w/w) and various polyvinyl alcohol (PVA) concentrations (0.5, 1 and 2%) combined with Tween-20 (0.06, 0.08 and 0.1%) were electrosprayed. Increasing the concentration of PVA increased the emulsion viscosity and improved both loading capacity (77.56 to 84.68%) and encapsulation efficiency (81.54 to 87.82 %) of the essential oil within the structure of the Balangu gum nano-capsules. Field emission scanning electron microscopy (FESEM) indicated that by increasing the amount of the gum (from 0.25 to 0.5%) and PVA (from 1 to 2%), the process could be made to produce nanofibers. The Mentha longifolia L. essential oil was entrapped in nanostructures without any chemical interaction with encapsulant material, this was demonstrated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The release mechanisms and kinetics of loaded Mentha longifolia L. essential oil were evaluated in different simulated food models (aqueous, acidic, alcoholic or alkalic and oily food models) and release profiles data were fitted to first order, Kopcha, Korsmeyer-Peppas, and Peppas-Sahlin models. The essential oil release profiles fitted well to the Peppas-Sahlin model for a range of simulated foods. The release mechanism of the essential oil from the nanostructure of the Balangu seed gum is mainly controlled by the Fickian diffusion phenomenon

Enrichment of cellulose acetate nanofibre assemblies for therapeutic delivery of L-tryptophan

The essential amino acid L-tryptophan is naturally present in the body, and is also available as a water soluble dietary supplement. The feasibility of preparing enriched cellulose acetate (CA)-based fibres as a vehicle for therapeutic delivery of such biomolecules was investigated. A new ternary solvent system consisting of acetone: N,N-dimethylacetamide: methanol (2:1:2) has been demonstrated to permit the solution blending of CA with the water soluble L-tryptophan. Nanofibrous webs substantially free of structural defects were continuously produced with mean fibre diameters in the range of 520-1,010nm, dependent on process parameters. Morphology and diameter of fibres were influenced by concentration of CA spinning solution, applied voltage and flow rates. The kinetic release profile of L-tryptophan from electrospun CA nanofibres was described by the pseudo-second order kinetic model. Fibres with mean diameter of 720 nm provide both the highest initial desorption rate and rate constant, which was partially attributed to the low fibre diameter and high relative surface area, but also the fact that the fibres with mean diameter of 720 nm produced were the most bead-free, providing diffusion advantages over the fibres with lowest mean diameter (520 nm). The feasibility of combining L-tryptophan within fibres provides a promising route for manufacture of transdermal delivery devices

Electrospray-assisted encapsulation of caffeine in alginate microhydrogels

One of the major challenges with microencapsulation and delivery of low molecular weight bioactive compounds is their diffusional loss during storage and process conditions as well as under gastric conditions. In an attempt to slow down the release rate of core material, electrospray fabricated calcium alginate microhydrogels were coated with low molecular weight and high molecular weight chitosans. Caffeine as a hydrophilic model compound was used due to its several advantages on human behavior especially increasing consciousness. Mathematical modeling of the caffeine release by fitting the data with Korsmeyer-Peppas model showed that Fick's diffusion law could be the prevalent mechanism of the release. Electrostatic interaction between alginate and chitosan (particularly in the presence of 1% low molecular weight chitosan) provided an effective barrier against caffeine release and significantly reduced swelling of particles compared to control samples. The results of this study demonstrated that calcium alginate microhydrogels coated by chitosan could be used for encapsulation of low molecular compounds. However, more complementary research must be done in this field. In addition, electrospray, by producing monodisperse particles, would be as an alternative method for fabrication of microparticles based on natural polymers

Millifluidic-assisted ionic gelation technique for encapsulation of probiotics in double-layered polysaccharide structure

A unique double-layered vehicle was fabricated for the first time based on a millifluidic/direct gelation to encapsulate probiotics. Free probiotic bacteria are usually very sensitive to severe gastrointestinal conditions and maintaining their survival when passing through the digestive tract is essential. The effects of alginate concentration (20–30 g/L), flow rates of alginate (0.8–1.2 mL/min), and W/O emulsion (0.5–0.7 mL/min) on encapsulation efficiency (EE), size, and sphericity of core–shell millicapsules were optimized for encapsulation of Bifidobacterium animalis subsp. lactis and Lactobacillus plantarum. The optimized calcium-alginate millicapsule was spherical (0.97 ± 0.01 SF), with an average diameter of 4.49 ± 0.19 mm, and encapsulation efficiency of 98.17 ± 0.5 %. Two strains were encapsulated separately in W/O emulsion as a core of the millicapsule. After coating with chitosan, the encapsulation yield of the bacteria, survival rates under simulated gastrointestinal (GI) conditions, and viability during storage were determined. Survival efficiency of B. animalis subsp. lactis and L. plantarum after millifluidic encapsulation were found to be 92.33 and 90.81 %, respectively. Cell viability of encapsulated probiotics after passing through the GI system was improved (7.5 log CFU mL−1 for both strains). Although the viability of the encapsulated probiotics stored at −18 °C for five months significantly decreased (p<0.05), the number of live cells was approximately in accordance with the standard definition of long-term probiotic survival (6 log CFU/g). This work provides a pathway for the construction of an innovative delivery system with high efficiency and protective effects for probiotics

Production and properties of electrospun webs for therapeutic applications

The electro spinning and properties of fibrous webs containing drugs, biomolecules and other potentially therapeutic compounds was studied. Two different technologies were investigated. The first dealt with incorporation and release of compounds including drugs using insoluble electrospun fibres comprised of cellulose acetate. A systematic parameter study was completed for producing electro spun cellulose acetate fibres that were substantially free of bead defects and the effect of different solvent systems and process parameters during electrospinning cellulose acetate were evaluated in respect of mean fibre diameter. A ternary solvent system consisting of AcetonelDimethylacetamide (DMAc) /Methanol (2:1:2) enabled a variety of molecules including L-Tryptophan. Ibuprofen, Nicotine and creatinine to be introduced in to cellulose acetate electrospinning solutions and converted in to fibres. The molecular diffusion kinetics in water of the as-spun electrospun fibres was studied. Using the same electrospinning production platform and solvent system, the research was then extended to investigate the feasibility of a second technology. The molecular imprinting of Cellulose Acetate electrospun fibres was investigated using the metabolite, creatinine as the template molecule. The study was extended to explore the feasibility of molecular-imprinting polysulphone electrospun fibres using the same template molecule. To facilitate this, a new solvent system was developed for electrospinning polysulphone that enabled low temperature solvation of the polymer. Both of technology platforms (molecular loading and molecular-imprinting of electrospun fibres) were relevant to the design of improved therapeutic products for applications in healthcare.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Production and properties of electrospun webs for therapeutic applications

The electro spinning and properties of fibrous webs containing drugs, biomolecules and other potentially therapeutic compounds was studied. Two different technologies were investigated. The first dealt with incorporation and release of compounds including drugs using insoluble electrospun fibres comprised of cellulose acetate. A systematic parameter study was completed for producing electro spun cellulose acetate fibres that were substantially free of bead defects and the effect of different solvent systems and process parameters during electrospinning cellulose acetate were evaluated in respect of mean fibre diameter. A ternary solvent system consisting of AcetonelDimethylacetamide (DMAc) /Methanol (2:1:2) enabled a variety of molecules including L-Tryptophan. Ibuprofen, Nicotine and creatinine to be introduced in to cellulose acetate electrospinning solutions and converted in to fibres. The molecular diffusion kinetics in water of the as-spun electrospun fibres was studied. Using the same electrospinning production platform and solvent system, the research was then extended to investigate the feasibility of a second technology. The molecular imprinting of Cellulose Acetate electrospun fibres was investigated using the metabolite, creatinine as the template molecule. The study was extended to explore the feasibility of molecular-imprinting polysulphone electrospun fibres using the same template molecule. To facilitate this, a new solvent system was developed for electrospinning polysulphone that enabled low temperature solvation of the polymer. Both of technology platforms (molecular loading and molecular-imprinting of electrospun fibres) were relevant to the design of improved therapeutic products for applications in healthcare.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fundamentals of electrospinning as a novel delivery vehicle for bioactive compounds in food nanotechnology

Encapsulation of bioactive compounds and probiotic bacteria within prebiotic substances to protect or even enhance their survival whilst passing upper gastro-intestinal tract, is an area of great interest for both academia and the food industries. Different methods have been suggested, examined and applied to encapsulate and dry probiotics and bioactive compounds, for example spray drying. However, the harsh processing conditions of these methods can significantly reduce the viability of bacteria or damage the structure of the target molecules. Electrospinning (and the related process of electrospraying) both show promise as a novel delivery vehicle for supplementary food compounds because the process can work with an aqueous solution, at room temperature and without coagulation chemistry to produce matrices in the micro- and nano-range. The production of nanofibers (fiber diameters less than 1 μm) is a commonplace. Nanofiber materials produced by electrospinning have attracted particular attention in the food industry because of their potential as vehicles for sustained and controlled release. The room temperature process route is compatible with food grade polymers and biopolymers, and allows efficient encapsulation by reducing denaturation, and enhancing stability of bioactives. Consequently, there is clear potential to develop electrospun fibrous assemblies to advance the design and performance of novel products and delivery systems for supplementary food compounds. To optimize production conditions and maximize throughput, a clear understanding the mechanism of electrospinning is essential. This paper presents a comprehensive review of the fundamentals of electrospinning to produce nanofibers suitable for food technology application particularly for use in encapsulation and as nano-carriers

Delivery of nanotech food ingredients

Encapsulation of bioactive compounds and probiotic bacteria within prebiotic material to protect the payload molecules during their passage through the digestive system is an emerging area of interest for the food industry. The construction of nanoscale encapsulations by electrospinning presents a method that does not cause damage to either sensitive biochemicals or probiotic bacteria. The presentation of payload ingredients at the nano-scale improves targetability to specific areas of the digestive tract and gives improved control of release rate. Adoption of the technologies described in this article will allow the industry to develop a wide range of novel high added value functional foods

Designing a colorimetric nanosensor based on dithizone and cholesteric liquid crystals loaded in electrospun cellulose acetate nanofibers: Monitoring the quality of pistachio as a case study

We describe colorimetric electrospun nanosensors designed to work at temperatures of 35–36�C. The mode of operations is based on a combination of the ability of dithizone to exhibit appropriate color and cholesteric liquid crystals presenting a wide range of melting points at various mixing ratios. To this end, different levels of dithizone (IUPAC name 1-anilino-3-phenyliminothiourea), different ratios of cholesteric liquid crystals to cellulose acetate and cholesteryl oleyl carbonate to cholesteryl nanoate were defined as independent variables and the total color difference was considered as the response in the response surface methodology approach. The results showed that the range of color palette changes of the designed samples was diverse and could be applied to different products. As a case study, the applicability of the sensor was evaluated on the 4-month shelf life of pistachio nuts at 35�C whilst the spoilage criteria were reconciled with the color changes in the designed senso