Wall Material Concentration Research Articles

Fountain streaming contributes to fast tip-growth through regulating the gradients of turgor pressure and concentration in pollen tubes.

Fountain streaming is a typical microfluidic pattern in plant cells, especially for cells with a high aspect ratio such as pollen tubes. Although it has been found that fountain streaming plays crucial roles in the transport of nutrients and metabolites, the positioning of organelles and the mixing of cytoplasms, its implications for the fast tip growth of pollen tubes remain a mystery. To address this, based on the observations of asiatic lily Lilium Casablanca, we developed physical models for reverse fountain streaming in pollen tubes and solved the hydrodynamics and advection-diffusion dynamics of viscous Stokes flow in the shank and apical region of pollen tubes. Theoretical and numerical results demonstrated that the gradients of turgor pressure and concentration of wall materials along the length of pollen tubes provide undamped driving force and high-efficiency materials supply, which are supposed to contribute to the fast tip-growth of pollen tubes. The sample experimental results show that the tip-growth will be abnormal when the gradients of turgor pressure change under osmotic stress induced by different concentrations of PEG-6000 (a dehydrant).

Preparation of Microcapsules and Half Life of the Kiwi Fruit Seed Oil by Complex Coacervation

The experiment adopts complex coacervation to prepare microcapsules. Through the experimental comparison, soybean protein isolated-maltodextrin is determined as the wall material for the experimental preparation of the microcapsules of kiwi fruit seed oil. This paper researched the effects of wall material concentration, core wall ratio and other factors on complex coacervation of kiwi fruit seed oil microcapsules embedding rate, determining that the best wall material concentration is 1%, core wall ratio is 1:1, and the optimum pH ratio is 3.0, temperature is 40°C, and the optimum curing time is 6 hours. The experiment carried out half life research on the microcapsules prepared by the complex coacervation of kiwi fruit seed oil microcapsule. By calculation: the degradation rate constant of kiwi fruit seed oil microcapsules prepared by complex coacervation is 2.793. According to the regression equation it can calculate the half life of kiwi fruit seed oil microcapsules is 18.58 months, about a year and a half.

Formulation and characterization of Turkish oregano microcapsules prepared by spray-drying technology

The aim of this study was optimization of spray-drying process conditions for microencapsulation of Turkish oregano extract. Different concentrations of maltodextrin and gum arabic as encapsulating agents (wall material) as well as influence of selected processing variables were evaluated. The optimal conditions were maintained on the basis of the load of main bioactive compounds – ursolic, rosmarinic acids and carvacrol – in prepared microparticles after comparison of all significant response variables using desirability function. Physicomechanical properties of powders such as flowability, wettability, solubility, moisture content as well as product yield, encapsulation efficiency (EE), density, morphology and size distribution of prepared microparticles have been determined. The results demonstrated that the optimal conditions for spray-drying mixture consisted of two parts of wall material solution and one part of ethanolic oregano extract when the feed flow rate was 40 mL/min and air inlet temperature –170 °C. Optimal concentration of wall materials in solution was 20% while the ratio of maltodextrin and gum arabic was 8.74:1.26.

Preparation, properties and in vivo antimicrobial activity in yacon roots of microencapsulation containing cinnamon oil

Preparation, properties and in vivo antimicrobial activity in yacon roots of microencapsulated cinnamon oil were investigated. The encapsulation efficiency was affected by the concentration of wall materials. Result indicated that cinnamon oil microencapsulation exhibited different particles size and irregular shape. Thermogravimetric analysis showed that the first mass loss in curves for microparticles without oil and microencapsulated oil were observed from 43.78 to 73.59 °C and from 43.78 to 73.59 °C, respectively. The oil release of from mciroparticles could increase with improving the relative humidity and/or the temperature. The counts of bacteria and, yeast and moulds in fresh-cut yacon roots treated by microencapsulated cinnamon oil with PVC film reached the level of 4.5 × 102 and 6.3 × 103 after 12 day storage, respectively. Treatment of microencapsulated cinnamon oil could also keep the overall good visual quality for fresh-cut yacon roots.

Optimization of broccoli microencapsulation process by complex coacervation using response surface methodology

Abstract This work is intended to optimize the microencapsulation process of broccoli particles preserving their chemical healthy composition, in terms of chlorophylls and polyphenol contents and antioxidant activity, increasing its chemical stability and hiding the characteristic broccoli odor that might have a negative impact in consumer's acceptance. Thus, the microencapsulated broccoli could be easily added to processed foodstuff increasing their healthy properties without altering their sensory attributes. Experimental design and response surface methodology (RSM) was applied to optimize operating conditions and the variables that affect broccoli microencapsulation. Based on that, the optimum process conditions determined by RSM were as follows: pH value 4.5; broccoli–wall material ratio 50% and concentration of wall material 4%, where the theoretical and practical encapsulation efficiency was 60% and 58%, respectively. Industrial relevance Nowadays, consumers are increasingly interested in beneficial effects of vegetables on health. In this sense, broccoli has been highly valued for their chemopreventive effects, attributed to its composition in glucosinolates, flavonoids, carotenoids, ascorbic acid and amino acids. All these substances are easily degraded by the action of oxygen, thus reducing their potential health benefit. Microencapsulation process has the advantage of reducing the reactivity to factors such as water, oxygen or light, while reducing evaporation or transmission rate to the outside environment.

Microencapsulation of Ginger Volatile Oil Based on Gelatin/Sodium Alginate Polyelectrolyte Complex.

The coacervation between gelatin and sodium alginate for ginger volatile oil (GVO) microencapsulation as functions of mass ratio, pH and concentration of wall material and core material load was evaluated. The microencapsulation was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and thermal gravimetric analysis (TGA). SEM and FT-IR studies indicated the formation of polyelectrolyte complexation between gelatin and sodium alginate and successful encapsulation of GVO into the microcapsules. Thermal property study showed that the crosslinked microparticles exhibited higher thermal stability than the neat GVO, gelatin, and sodium alginate. The stability of microencapsulation of GVO in a simulated gastric and an intestinal situation in vitro was also studied. The stability results indicated that the release of GVO from microcapsules was much higher in simulated intestinal fluid, compared with that in simulated-gastric fluid.

Microencapsulation of Refined Liquid Smoke Using Maltodextrin Produced from Broken Rice Starch

Liquid smoke contained many bioactive compounds, one of which is phenol. Besides, its liquid form causes handling complication during distribution and application; thus, the microencapsulation method was used to solve this complication. At present, various inlet air temperatures were applied (120, 130 and 140C) with feed flow rate of 5 mL/min. The total soluble solid (TSS) contents of maltodextrin from broken rice starch were 20, 25 and 30%. The observed parameters were moisture content, yield, total phenol contents, microencapsulation efficiency, shape and morphology, particle size distribution and volatile compound profile identification. All data were taken in triplicate using completely randomized design. The results showed that the increase in wall material concentration and inlet air temperature was able to improve yield, total phenol content, microencapsulation efficiency and solubility of microcapsules. The best results with the highest microencapsulation efficiency of 52.24 ± 2.84% and 20 min phenol release period were obtained using 25% TSS and inlet temperature of 140C. Volatile compound identification using gas chromatography–mass spectrometry (GC-MS) showed that the combination between wall material and inlet air temperature was effective to retain phenol as one of the liquid smoke bioactive compounds. Microcapsule morphology analysis showed that the average diameter of microcapsules was 4.28 μm and had nearly spherical shape, little shriveled and without agglomeration with low levels of damage. Practical Applications Microencapsulation is a technology that is widely used for the transformation of liquid to solid form. Wall material and temperature are the most important factors in microencapsulation process to make a good quality microcapsule. The results of this work contribute to the understanding of factors affecting the microencapsulation process, including wall material concentration and inlet air temperature of spray drying on the yield, total phenol content, microencapsulation efficiency and stability of microcapsules of refined liquid smoke using maltodextrin produced from broken rice starch.

Design of liquid emulsions to structure spray dried particles

The formulation and structure of initial liquid emulsion have an impact on the efficiency of encapsulation (encapsulated oil quantity) in spray dried particles (dried emulsions) and must be adapted to spray drying. Two different protocols were tested varying the concentration of emulsifier (Tween® 20), conditions of homogenization and concentration of wall material (Maltodextrin and Agave Inulin). The concentration of emulsifier and wall material should allow avoiding micelle formation or coalescence. Results show that it was possible to produce stable emulsions with an oil droplet size around 2μm containing 40% w/w of total dry matter (g/100g emulsion) using maltodextrin as wall material and 3.5% Tween® 20 (3.5g/100g oil) or using Agave Inulin in emulsions with a total dry mater content of 50% w/w (50g/100g emulsion) with a minimal concentration of emulsifier (1.17g/100g oil). The spray drying of these emulsions produced fine powders (<22μm) with a monodispersed size distribution and good oil encapsulation efficiency (>88%).

Obtention of dietary fibre enriched fractions from peach bagasse using ethanol pre-treatment and microwave drying

A process involving ethanol pre-treatment and subsequent microwave drying was proposed to obtain fractions enriched in dietary fibre from peach bagasse Prunus persica L. The processing conditions that allow to obtain samples with optimal functional properties involved the use of 4.6 mL of ethanol (96mL/100 mL) per gram of tissue in the extraction step performed at 20 °C for 15 min and a temperature of 55.0 °C for drying in a microwave equipment working at a maximum power of 450 W. In general, high values were observed for functional properties evaluated, fact that indicates the potential of the fractions for being used for technological as well as for nutritional purposes. Physicochemical and microstructural analysis were carried out for the product obtained with the optimal process conditions, observing that the concentration of cell wall material was 80 g/100 g dry fraction and the optimum fraction also contained phenolic compounds.

Preparation of nanoemulsions containing unsaturated fatty acid concentrate–chitosan capsules

HypothesisFish oil is rich in unsaturated fatty acids (ω-3), which are highly susceptible to oxidative degradation. The use of encapsulation process to retard the fatty acid oxidation is an interesting alternative. In this work, nanoemulsions containing capsules of unsaturated fatty acids concentrate (UFAC) using chitosan as wall material were prepared and characterized. ExperimentsThe UFAC were obtained from carp viscera and chitosan was obtained from shrimp wastes. The nanocapsules were prepared by the emulsion method. Four formulations were tested, using different combinations of chitosan concentration and homogenization times. In the more suitable conditions, the emulsion was freeze-dried to obtain a microstructure with capacity to increase the capsules stability. FindingsThe results showed that the nanocapsules presented a spherical shape. The use of low wall material concentration and high homogenization time provided nanocapsules with smallest size (332nm) and lowest polydispersity index (0.214). The microstructure obtained by freeze drying was irregular and porous. The peroxide values demonstrated that the microstructure was able to protect the UFAC regarding to primary oxidation. The encapsulation efficiency was 74.1%, showing that chitosan has potential to be used as encapsulating agent for unsaturated fatty acid concentrate (UFAC).

Microstructural properties and distribution of components in microparticles obtained by spray-drying

The aim of this work was to analyse the relationship between microstructural development, distribution of elemental components and characteristics related to functional properties of powders obtained by spray drying process. Blends of soy protein isolate (SPI), gum Arabic (AG) and maltodextrin 20 DE (MD) at 20% TS were prepared and spray-dried at 250°C, 200°C, 175°C and 150°C as inlet temperatures of drying air, and the outlet temperature at 70°C was kept constant. Bulk density, hygroscopicity and wetting time were affected by concentration of wall material, drying air temperature did not suggest effect on these characteristics. Using combined microscopy techniques, the internal microstructure of particles obtained at 150°C/70° as inlet/outlet drying air temperatures were analysed, results revealed that 26% was the highest percentage of hollow microparticles and the shell thickness from 264nm to 290nm. In these microparticles, the elemental analysis revealed that nitrogen was present from 2.93% to 15.37% in particles surface. Additional, a descriptive model to explain the possible assemble of wall material of a microparticle was proposed.

Influence of emulsion composition and ultrasonication time on flaxseed oil powder properties

Emulsification step of flaxseed oil microencapsulation was optimized using the Box–Behnken design of the response surface methodology in wall material concentration, oil loading and ultrasonic emulsification time. The optimization was performed to optimize the microencapsulation efficiency (MEE) and product yield (PY). Bulk density, particle size and hygroscopicity of the microcapsules were additionally determined. MEE showed a positive correlation with wall material concentration and ultrasonication time; however, increasing oil loading had an adverse effect. PY was mainly affected by wall material concentration and increasing the wall material concentration resulted in lower product yield. Longer ultrasonication time decreased particle size of the flaxseed oil emulsion, but particle size of the microcapsules did not significantly change. The particle size of the microcapsules was increased by increasing wall material concentration. Optimum conditions for the microencapsulation of flaxseed oil were predicted as a wall material concentration of 20g·100g−1, an oil loading of 20goil·100g−1 wall material and an ultrasonication time of 120s and this conditions provided 92.4% MEE and 68.7% PY. For practical conditions, wall material concentration of 20g·100g−1, oil loading of 35.1goil·100g−1 wall material and ultrasonication time of 120s can be suggested in the flaxseed oil microencapsulation process.

Optimization and evaluation of microencapsulated artificial diet for mass rearing the predatory ladybird Propylea japonica (Coleoptera: Coccinellidae)

Artificial diet optimization is a key aspect in mass rearing of natural enemies since it influences the quality and feeding effectiveness, and thus the success of the biological control program. Here, we introduced the microencapsulation method to package liquid artificial diet for feeding of the ladybird Propylea japonica. An orthogonal test of the quality of microencapsulated artificial diets (ADMs) was performed on key variables in production; Ca-alginate concentration, chitosan concentration and weight ratio of wall material to inner diet. We compared the development and reproduction of P. japonica fed on the ADMs under different cold-stored periods with those fed on fresh aphids and liquid artificial diets, in addition to a comparison of respiration, locomotion and predation. Our results indicated that chitosan concentration and ratio of shell to core significantly influence the quality of ADMs. The optimal recipe is 1.0% Ca-alginate, 1.6% chitosan and shell:core= 1:2. Insects reared on fresh optimized ADMs were similar to those fed on fresh prey in all developmental and reproductive characteristics except for survival ratio and female fertility. ADMs appeared more beneficial than using a liquid artificial diet, although this may decrease with the prolonging of the cold-storage period. P. japonica fed either on fresh ADMs or fresh prey showed improved respiration and predation abilities compared to where liquid artificial diet was used. Our study indicates advantages of microencapsulation in the production of artificial diet for predatory ladybird rearing. A microencapsulated diet can directly increase the efficiency and stability of mass rearing.

Microencapsulation of Gac Oil by Spray Drying: Optimization of Wall Material Concentration and Oil Load Using Response Surface Methodology

The objective of this study was to optimize the wall material concentration and the oil load on the encapsulation of Gac oil using spray drying by response surface methodology. Results showed that the quadratic polynomial model was sufficient to describe and predict encapsulation efficiencies in terms of oil, β-carotene, lycopene, peroxide value (PV), moisture content (MC), and total color difference (Δ E) with R 2 values of 0.96, 0.95, 0.86, 0.89, 0.88, and 0.87, respectively. Under optimum conditions (wall concentration of 29.5 % and oil load of 0.2), the encapsulation efficiencies for oil, β-carotene, lycopene, PV, MC, and Δ E were predicted and confirmed as 92 %, 80 %, 74 %, 3.91 meq/kg, 4.14 % and 12.38, respectively. The physical properties of the encapsulated oil powders obtained by different formulations were also determined. It was concluded that the protein-polysaccharide matrix as the wall material was effectively used for spray-drying encapsulation of Gac oil.

Production and characterization of multinuclear microcapsules encapsulating lavender oil by complex coacervation

ABSTRACTThe aim of this work was to encapsulate lavender oil by complex coacervation using gelatin and gum Arabic as encapsulants. The effects of various factors including pH value, the core/wall ratio, wall material concentration, stirring speed, cross‐linkers and homogenization rate on the appearance, mean particle size, yield, loading capacity (LC) and encapsulation efficiency (EE) were investigated. The optimal conditions (pH 3.5, core/wall 3:2, wall material concentration 1%, stirring speed 450 rpm, homogenization rate 19 000 rpm and glutaraldehyde as cross‐linker) for preparing spherical multinuclear microcapsules were obtained. At the optimal conditions, the highest yield is 65.8 ± 1.0%; the maximum LC is 61.3 ± 0.7%; the highest EE is 66.0 ± 0.3%. The effect of three different cross‐linkers on the hardening effectiveness of multinuclear microcapsules containing lavender oil was investigated. Glutaraldehyde and transglutaminase exhibit similar microcapsule hardening effectiveness. When tannic acid was used instead of glutaraldehyde and transglutaminase, the mean particle size and EE remained the same as that when hardening with glutaraldehyde or transglutaminase, but the morphology obviously changes, while the yield and LC significantly decrease. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Microencapsulation of Rosemary Essential Oil: Characterization of Particles

This study evaluated the influence of wall material concentration (10–30%), inlet temperature (135–195°C), and feed rate (0.5–1.0 L · h−1) on the properties of rosemary oil microencapsulated by spray-drying, with gum arabic as carrier. Powder recovery, surface oil, oil retention, and hygroscopicity varied from 17.25%–33.96%, 0.03%–0.15%, 7.15%–47.57%, and 15.87%–18.90%, respectively. The optimized conditions were determined to be a wall material concentration of 19.3%, an inlet air temperature of 171°C, and a feed flow rate of 0.92 L · h−1. At this condition, particles presented no fissures and the compositions of pure and microencapsulated oil were similar. The sorption isotherms could be described by the GAB model.

Encapsulation of Peppermint Oil with Arabic Gum-gelatin by Complex Coacervation Method

The gelatin/gum Arabic microcapsules encapsulating peppermint oil were prepared by complex coacervation using tannic acid as hardening agent. The effects of various parameters, including concentration of wall material, core material, tannic acid and tween80 were investigated on particle size and encapsulation efficiency. For statistical evaluation of the parameters, Taguchi method has been used. The size of prepared spherical microcapsules was 19-66 micrometers. The results showed that, particle size increased with increasing core and wall concentration and decreased with increasing Tannic acid and Tween80 concentration. The efficiency increased by increasing the core and wall concentration, Tannic acid and Tween80 concentration had no effect on efficiency. Maximum efficiency of 82% was under optimal conditions: 4% wall material, 5% core material, 0.75% tannic acid and 0.02% tween80. The release of microcapsules was investigated in gastric and intestinal fluid. The microcapsules were release most of the core material in simulated gastric fluid (pH 1.2).

Effects of process parameters on the physical properties of poly (urea–formaldehyde) microcapsules prepared by a one-step method

The physical properties of microcapsules are strongly influenced by the synthetic conditions used for their preparation. To prepare microcapsules possessing a smooth surface morphology, high mechanical strength, and reduced permeability of the core material, in situ polymerization in an oil-in-water emulsion was performed using poly (urea–formaldehyde) and tetrachloroethylene as the shell and core materials, respectively. The influence of the synthetic conditions, including the initial pH value, concentration of wall material, concentration of NaCl, and heating rate, on the properties of the resulting microcapsules was investigated systematically by an orthogonal factorial design. The physical properties of the microcapsules were characterized using scanning electron microscopy and optical-photographic microscopy. The results showed that the concentration of shell material has a substantial effect on the mechanical strength of the microcapsules. Additionally, a slow heating rate and high initial pH value enhance the preparation of well-defined spherical microcapsules having excellent barrier properties. Finally, a moderate concentration of sodium chloride can remarkably improve the compactness of the capsule wall. The optimum conditions, determined on the basis of utilization of wall material, are as follows: initial pH value: 3.5; concentration of shell material: 3.6 × 10−2 g/mL; heating rate: 0.5 °C/min; and concentration of sodium chloride: 5.0 × 10−2 g/mL.

Influence of spray drying operating conditions on microencapsulated rosemary essential oil properties

Spray drying is an important method used by the food industry in the production of microencapsulated flavors to improve handling and dispersion properties. The objective of this study was to evaluate the influence of the process conditions on the properties of rosemary essential oil microencapsulated by spray drying using gum Arabic as encapsulant. The effects of the wall material concentration (10-30%), inlet air temperature (135-195 °C), and feed flow rate (0.5-1.0 L.h –1 ) on the moisture content, hygroscopicity, wettability, solubility, bulk and tapped densities, particle density, flowability, and cohesiveness were evaluated using a 2 3 central composite rotational experimental design. Moisture content, hygroscopicity and wettability were significantly affected by the three factors analyzed. Bulk density was positively influenced by the wall material concentration and negatively by the inlet air temperature. Particle density was influenced by the wall material concentration and the inlet air temperature variables, both in a negative manner. As for the solubility, tapped density, flowability, and cohesiveness, the models did not fit the data well. The results indicated that moderate wall material concentration (24%), low inlet air temperature (135 °C), and moderate feed flow rate (0.7 L.h –1 ) are the best spray drying conditions.

Optimization of Wall Material Concentration in Preparation of Flaxseed Oil Powder Using Response Surface Methodology

The aim of this work was to optimize oil and wall material concentrations in microencapsulation of spray drying. Gum Arabic, maltodextrin and skim milk powder were used as wall material. Response surface methodology with three-level, two-factor central composite design was employed. The independent variables selected for set of experiments were oil concentration (X1: 10, 15, 20); solids content (X2: 20, 22.5, 25) while bulk density, encapsulation efficiency, peroxide value and moisture content were analyzed as responses. The results revealed that microencapsulated powder containing 8% oil and 22.5% wall material was optimum among investigated samples in terms of its encapsulation efficiency, peroxide value and moisture content. Practical Applications This research has practical applications for developing flaxseed oil power as a novel ingredient for food fortification. Ameliorations in wall material and oil content during spray drying of flaxseed oil into powder is helpful in establishing the relationship for optimization of flaxseed oil powder preparation. Data obtained during present investigation suggests use of wall materials in combination at high concentrations for superior microencapsulation of flaxseed oil to explore its utility in formulating functional foods with higher omega fatty acid content.