Characteristics and release of monosodium glutamate microcapsules obtained by spray drying

The present study aimed at investigating the characteristics of monosodium glutamate (MSG) microcapsules. Spray-drying was used to prepare the microcapsules, in which the core material (MSG) was coated with gum Arabic (GA) and maltodextrin (MD), and the weight ratio of MD with GA was 1:2. The characteristics of microcapsules were evaluated by scanning electron microscopy (SEM), moisture content, particle size, Fourier-transform infrared (FTIR), differential scanning calorimeter (DSC), thermogravimetry analysis (TGA), release behavior, the flavor, and taste in hot-pot. Few concave wrinkles were observed on the quasispheres surface of microcapsules coated with GA and MD. The particle size of the microcapsules ranged from 14.00 to 30.00 µm in the mean diameter, and moisture content was 2.08%. An FTIR study indicated a successful packet of MSG by wall materials and the formation of MSG microcapsules during spray drying. Results of DSC and TGA showed that hybrid encapsulation was conducive to the improvement of thermal stability of MSG. In the release of hot-pot study, tests of slow-release, electronic nose, and electronic tongue demonstrated that MSG microcapsules were available in hot water conditions to release. The MSG microcapsules coated with GA and MD exhibited long time for slow-release. Therefore, spraying drying is a suitable approach to manufacture slow-released powdered microcapsules.     

Establishing the Most Suitable Storage Conditions for Microencapsulated Allspice Essential Oil Entrapped in Blended Biopolymers Matrices

The adsorption isotherms of allspice essential oil microencapsulated in biopolymers blend (whey protein concentrate [WPC], mesquite gum [MG], and maltodextrin DE10 [MD]) in different proportions (WPC17%-MG17%-MD66% w/w and WPC66%-MG17%-MD17% w/w) with wall-to-core material ratios of 4:1 were determined at 25, 35, and 40°C. The isotherms were fitted using the Guggenheim-Anderson-de Boer (GAB) model and the enthalpies and entropies, both differential and integral, were estimated by the Clausius-Clapeyron method. The minimum integral entropy was considered as the point of maximum stability where strong bonds between the adsorbate and adsorbent occurred, and water would be less available and likely to participate in spoilage reactions. The point of maximum stability was found between 13.79 and 15.11 kg H₂O/100 kg d.s. (corresponding to water activity, a _W , of 0.444–0.551) for the microcapsules with WPC17%-MG17%-MD66% w/w as wall material and 18.71–19.63 kg H₂O/100 kg d.s. (a _W  = 0.591–0.713) for the microcapsules with WPC66%-MG17%-MD17% w/w as wall material in the temperature range studied.     

SORPTION ISOTHERMS AND THERMODYNAMIC PROPERTIES OF POWDERED MILK

Moisture sorption isotherms of powdered milk were obtained using the gravimetric static method at 30°, 40°, and 50°C. Peleg and Enderby equations were found to be the most suitable models for describing the sorption curves among six well-known tested equations. Thermodynamic properties such as differential enthalpy and entropy of sorption were determined from moisture adsorption and desorption data, using the Clausius-Clapeyron equation. The experimental data showed that enthalpy-entropy compensation theory was applicable to the moisture sorption behavior of powdered milk.     

Whey Protein-Pullulan (WP/Pullulan) Polymer Blend for Preservation of Viability of Lactobacillus acidophilus

In this study, whey protein isolate-pullulan (WP/pullulan) microspheres were developed to entrap the probiotic Lactobacillus acidophilus NRRL-B 4495 by spray-drying technique. Microcapsules were analyzed for physicochemical characteristics including morphology, particle size, moisture content, water activity, dissolution time, and color properties. Results revealed that microcapsules were spherical in shape and obtained particle sizes between 5 and 160 µm, with an average size of around 50 µm. Blending pullulan with WP provided enhanced survival of probiotic bacteria during spray drying with a final viable cell number of 8.81 log CFU/g of microcapsule. Encapsulated probiotics were also found to have significantly (p ≤ 0.05) higher survived cell numbers compared to free probiotics under detrimental gastrointestinal conditions. Moreover, dissolution analysis suggested that protein-polysaccharide powdered microcapsules showed pH-sensitive dissolution properties in simulated gastric juice and simulated intestinal juice.     

Sorption Properties of Wood Impregnated with Boron Compounds,Sodium Chloride and Glucose

Chemical protection is one of the possible treatment processes that influence the sorption characteristics of wood. In the present research we have investigated the influence of biocides (boric acid, borax) and their concentrations on the sorption characteristic of impregnated wood. For comparison, two other chemicals were included in the research as well (NaCl and glucose). The equilibrium moisture content during the adsorption and desorption process at five levels of relative humidity (?₁ = 20%, ?₂ = 33%, ?₃ = 65%, ?₄ = 88%, and ?₅ = 98%) was monitored. The results showed that impregnation does not influence the wood moisture content of specimens conditioned at low relative air humidity. In the upper hygroscopic region, moisture content is significantly influenced by the concentration and properties of impregnation chemicals. The Guggenheim-Andersen-deBoer (GAB) and Dent models of sorption isotherms was fitted to experimental data to explain the sorption mechanisms in detail.     

Sodium Humate as a Promising Coating Material for Microencapsulation of Beauveria bassiana Conidia Through Spray Drying

Microencapsulation of Beauveria bassiana (Bb) conidia with sodium humate (SH) was undertaken successfully through spray drying at a high inlet air temperature of 175°C with corresponding outlet air temperature of 86.5 ± 1.3°C using 0.2% SH. The obtained product was a free-flowing, dark-brown powder containing microcapsules of Bb conidia coated with sodium humate (Bb-SH). These microcapsules measured 2.47–3.57 µm and possessed an uneven, fluffy surface. The colony-forming units (CFU) of Bb-SH microcapsules spray-dried at 175°C were 21.54 LCFUg^?1, on par with 21.59 LCFUg^?1 for Bb conidial powder not subjected to spray drying. Bb-SH microcapsules resulted in a high mortality of 93.0% against six-day-old Helicoverpa armigera larvae within five days after treatment. Bb-SH microcapsules readily dispersed in water, releasing sodium humate from the conidial surface. Germination of conidia was not affected by sodium humate as visualized by scanning electron microscopy of the cuticular surface of treated larvae. Bb-SH microcapsules showed good viability (21.11 LCFUg^?1) at the end of six months of storage at room temperature (～30°). Thus, sodium humate is a promising biopolymer for encapsulation of Bb conidia for extended shelf-life at room temperature.     

Ternary Biopolymer Based on Wheat Gluten,Whey Protein Concentrate and Montmorillonite

The aim of the research was to obtain biopolymers based on wheat gluten, whey protein concentrate (WPC) and montmorillonite (MON). Ternary biopolymers were formed as heat-induced gels and they were hardened by water evaporation. Adding 7 % of MON and 5 % WPC to gluten caused ca. four times higher values of storage modulus. Increased moduli values with adding MON and WPC to gluten were probably caused by reinforcing effect of MON, which decreased mobility of gluten chains and possible interactions between gluten and whey proteins by disulphide interchange. Increase in gluten protein concentration and addition of WPC and MON caused increase in viscosity measured by dissipation of ultrasound vibrations. Evaporation of water from the gels formed very hard material with high puncture force values. Obtained gels were very plastic and it was easy to form any type of shapes. They could be used to produce biodegradable pottery (e.g. flowerpots) with the mechanical properties similar to non-degradable clay products.     

Dehumidifier-Assisted Drying Characteristics of Nutrient Enriched Gellan and Agar Gels

The characteristics of moisture removal and selected physical properties during the dehumidifier-assisted drying of model food gel systems like agar and gellan gels were studied. The effect of gel forming ingredients/nutrients like FeSO₄ (0.05%), whey protein concentrate (WPC; 5%), and flaxseed powder (FSP; 5%) were investigated with an overall intention of developing a delivery system for nutrients as a convenience food. Gellan and agar gels were prepared at concentrations of 1, 2, and 3% (w/w) and subjected to drying at a low temperature of 40°C in a dehumidifier-assisted dryer up to 12 h. The different quality parameters that were determined included the extent of shrinkage, moisture content, textural parameters, and the diffusion coefficient. Agar gels possessed higher moisture ratios compared to corresponding gellan samples. The diffusion coefficients for agar and gellan gels were 0.83 × 10^?7 ? 2.38 × 10^?7 m²s^?1. The gellan gels were much harder than their corresponding agar gels. The addition of WPC, FeSO₄, and FSP increased the textural indices like fracture force, fracture strain, fracture energy, and total energy for 50% compression for all the gels. Gellan and agar gels showed volume shrinkage; the lowest shrinkages were with WPC added gels followed by the FSP and FeSO₄ incorporated samples. Dehumidifier-assisted dried food gels can serve as a delivery system for nutrients.     

Effect of Relative Humidity on the Antioxidant Activity of Spray-Dried Banana Passion Fruit (Passiflora Mollisima Baley)-Coated Pulp: Measurement of the Thermodynamic Properties of Sorption

The antioxidant activity of the spray-dried banana passion fruit-coated pulp with maltodextrin10 DE was evaluated throughout 30 days of storage at a temperature of 25°C for different relative humidity values It was influenced by the relative humidity throughout the 30 days of storage. In addition, the sorption equilibria of water for spray-dried banana passion fruit-coated pulp with maltodextrin 10 DE at 25, 35, 45, and 55°C, over a range of relative humidity levels from 0.113 to 0.843, was determined using a gravimetric static method. The isosteric heat and Gibbs free energy were calculated from the sorption equilibrium. The Guggenheim-Anderson-Boer (GAB) and Brunauer-Emmett-Teller (BET) models were tested to fit the experimental data. The GAB model was found to be the most suitable for describing the sorption curves, exhibiting an error smaller than 10% and an r greater than 0.99. The monolayer moisture content values for the sorption at different temperatures that were calculated using the GAB model ranged between 0.05315 to 0.05716 g water/g dry matter. The sorption curves exhibited a Type III behavior. The isosteric heat decreased with increasing moisture content while the Gibbs free energy increased.     

Packaging‐related properties of alkyd‐coated,wax‐coated,and buffered chitosan and whey protein films

Packaging‐related properties of coated films of chitosan–acetic acid salt and whey protein concentrate (WPC) were studied. Chitosan (84.7% degree of deacetylation) and WPC (65–67% protein) were solution cast to films. These films are potential oxygen barriers for use in packaging. Coatings of wax or alkyds were used to enhance the water‐barrier properties. The packaging‐related properties of chitosan films treated in a buffering solution, with a pH of 7.8, were also investigated. The coated films were characterized with respect to Cobb absorbency, overall migration to water, water vapor transmission rate, and oxygen permeability. The creasability and bending toughness were determined. The wax was a more efficient barrier to liquid water and 90–95% relative humidity than the alkyd. However, the alkyd‐coated material had superior packaging‐converting properties. The alkyd‐coated WPC and chitosan–salt films were readily folded through 180° without any visible cracks or delamination. The overall migration from the alkyd‐coated materials was below the safety limit, provided the coat weight was higher than 7.5 mg/cm² on WPC and 2.1 mg/cm² on chitosan–salt. The barrier properties of chitosan film under moist conditions were improved by the buffer treatment. However, the buffering also resulted in shrinkage of the film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 60–67, 2004     

Effects of Storage Temperature and Water Activity on the Degradation of Carotenoids Contained in Microencapsulated Chili Extract

The aim of this work was to evaluate the effects of storage temperature and water activity on degradation of carotenoids contained in microencapsulates of non-aqueous extracts from chili (NAEC). Total carotenoids content and adsorption isotherms of microencapsulated NAEC in a 1:1 weight ratio with gum Arabic-maltodextrin DE 20 (GA 50%–MD50%) were determined at 25, 35, and 40°C. The isotherms were fitted using the Guggenheim-Anderson-de-Boer model and their enthalpies and entropies, both differential and integral, were estimated by the Clausius-Clapeyron method. The minimum integral entropy was considered as the point of maximum stability at which water less readily participates in degradation reactions. Zones of minimum integral entropy were found between 7.56–8.30, 6.10–6.95, and 5.15–6.04 kg H₂O/100 kg dried solids, corresponding to water activity (a_w) of 0.210–0.239, 0.238–0.277, and 0.262–0.313 at 25, 35, and 40°C, respectively. Total carotenoids content (CT) degraded over time, but degradation of carotenoids was lower in microcapsules stored at 25°C than those stored at 35 or 40°C. The morphology of microcapsules was altered at a_w > 0.6, including swelling of the polysaccharide matrix was presented, and possible subsequent dissolution of the wall material, which indicates a high rate of carotenoid degradation. When microencapsulated NAEC were storage between 0.2–0.6 of water activity, the highest glass transition temperatures were achieved. In this range, the wall materials of the microcapsules suffer less microstructural modifications, associated with the minimum level of degradation of carotenoids. Sometimes, in this water activity range, the zones of minimal entropy were observed.     

The Effect of Temperature and Moisture Content of Stored Rapeseed on the Phytosterol Degradation Rate

The effect of temperature (25 or 35 °C) and moisture content (10, 12.5, 15.5 %) on rapeseed phytosterol degradation was examined for 18 days. Statistical analysis showed that temperature, moisture and time of storage have a significant effect on phytosterol degradation. After 18 days of seed storage at a temperature of 25 and 30 °C losses of these compounds amounted to 11 and 13 % in seeds with moisture contents of 10, 12 and 16 % in seeds with a moisture content of 12.5 %, while they were 24 and 58 % in seeds with a moisture content of 15.5 %. Among all the identified sterols the greatest degradation rate was observed for stigmasterol and brassicasterol. Losses of stigmasterol and brassicasterol during storage of seeds with a 12.5 % moisture content at a temperature of 30 °C were 17 and 28 %, respectively, while in seeds with a moisture content of 15.5 % these losses increased to 73 and 63 %.     

Properties and Stability of Spray-Dried and Freeze-Dried Microcapsules Co-Encapsulated with Fish Oil,Phytosterol Esters,and Limonene

The objectives of this study were to investigate the properties and stability of microcapsules containing fish oil co-encapsulated with phytosterol ester and limonene, prepared by spray-drying and freeze-drying methods. Whey protein isolate and soluble corn fiber were used as wall materials in the encapsulation process. The properties of microcapsules, including structure, glass transition, volatile/non-volatiles retention, microencapsulation efficiency, oxidation stability, color measurement, and sensory profiles, were evaluated after drying and during a seven-day accelerated storage trial. The finding reveals that drying methods have an effect on the retention of volatile fraction and the physical structure of the wall matrix consisted of WPI and SCF, consequently influencing the storage stability of the powders. Significantly higher retention of volatile fraction (p < 0.05) and lower surface oil were found in the spray-dried samples, resulting in the higher microencapsulation efficiency. However, samples dehydrated by both methods have good redispersion properties, showing no statistical significance (p > 0.05). The oxidation of the encapsulated oils was comparable for both spray- and freeze-dried samples during the seven-day accelerated storage trial but the loss of limonene flavor was significantly higher in the freeze-dried samples (p < 0.05). Sensory evaluation indicated that the addition of limonene could mask the unpleasant fishy odor in the co-encapsulated microcapsules. Overall, freeze drying did not produce powders with superior properties and did not show better protection towards the core materials than spray drying.     

Effect of carrier agents on the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp

In this study, the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp produced with different carrier agents was evaluated. Powders were produced using sucrose, fructose, ethanol, and maltodextrin as carrier agents and characterized by differential scanning calorimetry, morphology, moisture sorption curves, and sorption kinetics. The GAB (Guggenheim-Anderson-de Boer) model was suitable to mathematically describe the adsorption isotherms. The treatments that had maltodextrin as the additive exhibited reduced adsorption both in low- and in high-water activities, promoting the reduction of the moisture content in the monolayer (X_m) and enhancing the stability of the powder product. The combination of sucrose and ethanol increased the glass transition temperature of the system compared to the in natura pulp. Treatments with fructose did not improve the sorption characteristics of the powders, featuring an amorphous structure. The kinetic curves, ratio of the increase of the water content against the storage time, of the passion fruit pulp treated with 10 g of maltodextrin/100 g of pulp and with 5 g of sucrose and 10 g of maltodextrin/100 g of pulp showed reduced adsorption and similar behaviors for water activity values of 0.113, 0.529, 0.753, and 0.903.     

Microencapsulation of chlorthalidone by spray-drying of double emulsion and melt granulation coating

Chlorthalidone (CH) is indicated in the management of hypertension either alone or in combination with other antihypertensive drugs, but it displays poor solubility and stability limiting its use in the development of new pharmaceutical alternatives. Spray-drying of double emulsions (SDE) and melt granulation coating (MGC) technologies were used for enhancing the stability of CH by using Eudragit® L30D-55 (EUD), Opadry® II (OPA), or Kollicoat® IR (KIR) as wall materials. SDE and MGC microcapsules containing CH were evaluated for particle size, morphology, release profiles, accelerated storage, and thermo-oxidative stability. Both types of microcapsules showed higher solubility (>80% in 20 min), lower degradation (<2%) under accelerated storage condition, and lower thermo-oxidative degradation than pure CH. However, SDE microcapsules showed smaller particle sizes (<16 µm) than MGC microcapsules (>700 µm), which widens the opportunity of incorporating microcapsules to dosage forms requiring different particle sizes for achieving their functionality.     

Preparation of paraffin-based phase-change microcapsules and application in geopolymer coating

A type of paraffin phase-change microcapsule for thermal insulation of exterior walls was prepared by in situ polymerization of low-softening-point paraffin (46°C) as core material and acrylic copolymer as shell. The surface morphology, phase-change thermal properties, and thermal stability were characterized by scanning electron microscopy, laser particle size distribution analysis, differential scanning calorimetry, and thermogravimetric analysis, respectively. The results showed that, for polymerization reaction temperature of 75°C and paraffin/acrylic copolymer mass ratio of 1.8, the microcapsules prepared at rotation speed of 1600 r/min with 8% emulsifiers were spherical particles with smooth surface and average particle size of 0.68 μm. The phase-change temperature and latent heat storage capacity of the microcapsules were 47.8°C and 174 J/g, respectively. The paraffin phase-change microcapsules obtained using the optimum synthesis condition were mixed in a metakaolin-based geopolymer coating at different proportions, and the thermal insulation ability of the resulting phase-change thermal energy storage coating characterized.     

The Effect of Germination on Phenolic Compounds and Antioxidant Activity of Pulses

In this study the changes of phenolic compounds and antioxidant activity of four different pulses namely white bean (Phaseolus vulgaris L), Common vetch (Vicia sativa), Lentil (Lens culinaris) and Chickpea (Cicer arietinum) seeds before and after germination were investigated. Seeds germinated in dark chambers maintained near 100 % relative humidity at 20 °C. Three different solvents namely acetone, hexane and methanol were employed to extract the phenolic compounds present in the seeds and sprouts. Total content of phenolic compounds was measured by the Folin–Ciocalteu method and antioxidant activity determined by the delay in fat oxidation. Different concentrations of extracts (0.02 and 0.1 % w/w) were added to tallow and the stabilities of the treatments were determined by the peroxide value and induction period measurements to evaluate the antioxidant activities. The results indicated that the increases in phenolic content from dormant seed to sprouted seed were significant (P ≤ 0.05) in all the samples. The significant differences between induction periods of tallow treated with sprouted seed extracts were observed (P < 0.05). The results indicated that the greatest increase in stability was obtained when tallow was treated with a 0.1 % concentration of acetone chickpea sprout extract. The pulses' sprout flour or extract might be recommended for use as a source of natural antioxidants in functional foods.     

Cyclic Sorption and Desorption of Cu(II) onto Coconut Shell and Iron Oxide Coated Sand

Sorption is a viable treatment technology for copper-rich gold mine tailings wastewater. For continuous application, the sorbent should be regenerated with an appropriate desorbent, and reused. In this study, the sequential sorption/desorption characteristics of Cu(II) on coconut shell (CS) and iron oxide coated sand (IOCS) were determined. In batch assays, CS was found to have a Cu(II) uptake capacity of 0.46 mg g^?1 and yielded a 93% removal efficiency, while the IOCS had a Cu(II) uptake capacity and removal efficiency of 0.49 mg g^?1 and 98%, respectively. Desorption experiments indicated that HCl (0.05 M) was an efficient desorbent for the recovery of Cu(II) from CS, with an average desorption efficiency of 96% (sustained for eight sorption and desorption cycles). HCl (0.05 M) did not diminish the CS's ability to sorb copper even after eight sorption/desorption cycles, but completely deteriorated the iron oxide structure of the IOCS within six cycles. This study showed that CS and IOCS are both good sorbents for Cu(II); but cyclical sorption/desorption using 0.05 M HCl is only feasible with CS.     

Design,synthesis, and evaluation of amino-terminated oxidization modified peanut shell as adsorbent of microcolumn for Sudan-I detection and efficient recovery

Sudan I, as a common pigment, is harmful to people’s health. In this work, the alkaline peanut shell as the base, epichlorohydrin and DMF as the solvent, with HBP-NH₂ as the ligand to compose terminal amino-branched peanut shell. Optimization of the modified peanut shell was carried out at different temperatures, different molar ratios of reagents, and different time intervals in HBP-NH₂ using response surface methodology (RSM) for the first attempt. The structure of modified peanut shell was characterized by FT-IR and elemental analysis. The adsorption properties of the modified peanut shell for Sudan I were investigated by batch and column experiments. Batch adsorption results suggested that modified peanut shell had a high adsorption capability for Sudan I and its maximum saturated adsorption capacity was 248.14 mg/g at 308 K, estimated from the Langmuir model. The modified peanut shell and its metal complexes were studied by TGA and SEM. Furthermore, the modified peanut shell can be eluted easily using 2 mol/L NaOH. HBP-NH₂-P not only has a potential application for the selective removal of Sudan I from waste solutions but also has an application in the analysis and detection areas.     

Moisture Sorption Isotherms of Wood and Wood-Plastic Composites (WPC)

Wood-plastic composites (WPC) were prepared with two monomers, methylmethacrylate (MMA) and butylmethacrylate (BMA), using ionizing radiation and two low-grade woods (simul and mango). Moisture adsorption characteristics of both wood and WPC were investigated. The equilibrium moisture contents of WPC were lower than the untreated wood in the entire water activity range. The experimental sorption data were fitted to the Henderson, Chung-Pfost, Smith, and Oswin models. Henderson's model gave the best prediction of the adsorption of wood and WPC.