Influence of Convective and Vacuum-Type Drying on Quality,Microstructural, Antioxidant and Thermal Properties of Pretreated Boletus edulis Mushrooms

Freshly harvested Boletus edulis mushrooms are subjected to rapid loss of quality due to the high moisture content and enzymatic activity. Drying time, quality characteristics, microstructural and thermal properties were studied in mushrooms ground to puree subjected to hot air drying (HAD), freeze drying (FD) and centrifugal vacuum drying (CVD). The influence of hot water blanching and UV-C pretreatments was additionally investigated. The rehydration ability of mushroom powders was improved by FD, especially without pretreatment or combined to UV-C exposure. The HAD and CVD, with no pretreatment or combined to UV-C, ensured good preservation of phenolics and antioxidant activity of dried mushrooms. The total difference in color of mushroom pigments extracted in acetone was lower in samples dried by CVD and higher in ones by FD. Blanching before HAD produced whiter product probably due to the reduced polyphenoloxidase activity. Scanning Electron Microscopy (SEM) analysis showed fewer physical changes in FD-samples. Heat-induced structural changes were noticed by Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and Derivative Thermogravimetry (DTG) analysis, in particular of biopolymers, confirmed by ATR-FTIR analysis. Based on our complex approach, the UV pretreatment of mushrooms could be a better alternative to water blanching. Centrifugal vacuum emerged as a new efficient drying method in terms of bioactive compounds, color and thermal stability, while FD led to better rehydration ability and microstructure.     

Effect of Thermal and Non-Thermal Technologies on Kinetics and the Main Quality Parameters of Red Bell Pepper Dried with Convective and Microwave–Convective Methods

The drying process preserves the surplus of perishable food. However, to obtain a good-quality final product, different pretreatments are conducted before drying. Thus, the aim of the study was the evaluation of the effect of thermal (blanching treatments with hot water) and non-thermal technologies (pulsed electric field (PEF) and ultrasound (US)) on the kinetics of the drying process of red bell pepper. The convective and microwave–convective drying were compared based on quality parameters, such as physical (water activity, porosity, rehydration rate, and color) and chemical properties (total phenolic content, total carotenoids content, antioxidant activity, and total sugars content). The results showed that all of the investigated methods reduced drying time. However, the most effective was blanching, followed by PEF and US treatment, regardless of the drying technique. Non-thermal methods allowed for better preservation of bioactive compounds, such as vitamin C in the range of 8.2% to 22.5% or total carotenoid content in the range of 0.4% to 48%, in comparison to untreated dried material. Moreover, PEF-treated red bell peppers exhibited superior antioxidant activity (higher of about 15.2–30.8%) when compared to untreated dried samples, whereas sonication decreased the free radical scavenging potential by ca. 10%. In most cases, the pretreatment influenced the physical properties, such as porosity, color, or rehydration properties. Samples subjected to PEF and US treatment and dried by using a microwave-assisted method exhibited a significantly higher porosity of 2–4 folds in comparison to untreated material; this result was also confirmed by visual inspection of microtomography scans. Among tested methods, blanched samples had the most similar optical properties to untreated materials; however non-thermally treated bell peppers exhibited the highest saturation of the color.     

Effect of the crosslinking density and the method of sample preparation on the observed microstructure of macroporous and conventional poly(N,N-dimethylacrylamide) hydrogels

SEM micrographs of macroporous and conventional poly(N,N-dimethylacrylamide) hydrogels were obtained for specimens synthesized in different conditions and prepared for microscopy by different methods (freeze drying of different solvents and critical point drying). The crosslinking density of both types of samples was determined through T _g measurements. Open structures (honeycomb-like, fibrillar networks) were more frequently observed in specimens prepared by freeze drying of benzene, which was attributed to its large pressure and temperature at the triple point. In spite of the different structure in the millimeter scale, there is no significant difference in the mesh size of fibrillar networks observed for macroporous and conventional samples, and in both cases it decreases with increasing crosslinking density. Other effects of the crosslinking density are that only incomplete honeycomb-like structures were formed in low-crosslinking samples and that collapsed structures were developed by phase separation throughout polymerization in highly crosslinked samples. Fibrillar networks of 1-μm mesh size were observed for the uncrosslinked polymer.     

Chromatographic determination of changes in pigments in spinach (Spinacia oleracea L.) during processing

The content of individual chlorophyll and carotenoid pigments is determined in three spinach varieties (Lorelei, Springfield, and Ballet) after processing. Raw spinach and spinach that is steam-blanched for 3, 9, or 15 min is stored frozen at -24 degrees C for 6 months. In addition, spinach is air-dried at 75 degrees C, packed in atmospheric air or nitrogen, and stored at ambient temperature for 6 months. Processing has a significant effect on the content of individual chlorophyll and carotenoid pigments; however, there are no differences between varieties in their content of total and individual pigments in raw, frozen spinach. Increasing blanching time resulted in decreased contents of chlorophyll a and b and increased contents of chlorophyll a' and b' and pheophytin a and b because of pheophytinization. Changes in the color because of pheophytinization are only detected after 15 min blanching. The carotenoid pigments are more stable than the chlorophyll pigments during blanching. (all-E)-Violaxanthin is significantly reduced, caused by degradation to other xanthophylls, such as neochrome, during blanching. There are no significant differences in the content of chlorophyll a and b of dried spinach and blanched, frozen spinach. Formation of chlorophyll a' and b', pheophytin a and b, and chlorophyll a-1 and b-1 is observed after drying. The content of pheophytin a and b is significantly lower in dried versus blanched frozen samples. In dried spinach that is stored in atmospheric air, the content of beta-carotene [599 mg/kg dry matter (DM)] is significantly lower compared with nitrogen (766 mg/kg DM), and the content of (all-E)-lutein is lower than in blanched frozen spinach. Neochrome is not detected in raw spinach but in steam-blanched and dried spinach. No differences are observed in the content of (all-E)-neoxanthin, (9'Z)-neoxanthin, (all-E)-violaxanthin, (all-E)-lutein epoxide, or neolutein A and B between spinach that is stored frozen after 3 min blanching and dried spinach.     

Optimization of Microwave-Assisted Extraction (MAE) for the Isolation of Antioxidants from Basil (Ocimum basilicum L.) by Response Surface Methodology (RSM)

Abstract

The recovery of antioxidants from basil (Ocimum basilicum L.) was modeled with the aid of response surface methodology (RSM) using microwave-assisted extraction (MAE). Face-centered central design (FCCD) was employed to optimize the MAE operational parameters including the extraction time (1 to 7?min), extraction temperature (30 to 120?°C), solid-to-solvent ratio (0.1 to 0.4), and solvent concentration (20 to 80% ethanol, v/v), and to obtain the best possible combinations of these parameters for a high antioxidant yield from basil. The total antioxidant capacity (TAC) was expressed in trolox (TR) equivalents per gram of dried sample (DS). Three of the operational parameters (temperature, extraction time and solvent concentration) were shown to have significant effect on the extraction efficiency of antioxidants in basil extracts (p?<?0.05). The solvent concentration was shown to be the most significant factor on antioxidant yield obtained by MAE. There was a close relationship between experimental and predicted values using the proposed method. This optimized MAE method shows an application potential for the efficient extraction of antioxidants from basil in the food and pharmaceutical industries.     

Effect of Filtrated Osmotic Solution Based on Concentrated Chokeberry Juice and Mint Extract on the Drying Kinetics,Energy Consumption and Physicochemical Properties of Dried Apples

Background: Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD. Methods: Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined. Results and Discussion: The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g⁻¹ fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g⁻¹ fw), which is due to the differences in the time of drying and when these methods are applied. Conclusions: Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying.     

Effect of cellulase-assisted refining on the properties of dried and never-dried eucalyptus pulp

The effect of two different cellulases on the hornification phenomenon,in which drainability (Schopper–Riegler method) and mechanical propertiesdiminish when pulps are dried, was studied. The enzyme applications testedincluded a commercial enzyme named ComC (Pergalase A40 from CIBA) and alaboratory enzyme from Paenibacillus sp. strain BP-23namedCelB. Industrial never-dried Eucalyptus globulus bleachedkraft pulp was split in two halves and one of them was dried at ambientcontrolled conditions. We compared enzyme effects on both pulps (wet pulp anddried pulp) before and after PFI mill refining. Enzyme applications increaseddrainability (Schopper–Riegler method) and water retention value (WRV) ofnever-dried bleached pulp, although this did not imply an enhancement of themechanical properties of paper. Cellulase treatment of dried pulps, bycontrast,gave rise to increased drainability and WRV and also to improved mechanicalproperties. The changes caused by drying became less significant after enzymeapplication. Handsheets from CelB-treated dried pulps showed an improvement oftensile and burst indexes while tear decreased. The effect produced by CelB canbe considered a biorefining step. In fact, by means of enzyme treatment withCelB the properties of paper manufactured from dried pulp equalled theproperties attained from wet fibres, with the exception of tear index. Changeswere also found in surface fibre morphology, such as flakes and peeling due tocellulase treatment. The surface modification of fibres with cellulases givesrise to better bonding properties and a closer structure of paper. The finalconclusion is that treatment with cellulases could compensate the hornificationeffect and lead to an important saving of refining energy. The novel enzyme,CelB, was the most effective in improving paper properties and counterbalancingthe hornification effect caused by drying.     

Modification of the Peripheral Substituents in Chlorophylls a and b and Their Derivatives (Review)

The extensive published data on methods for the modification of peripheral substituents in chlorophylls a and b and their various semisynthetic derivatives are classified and analyzed. Special attention is paid to specific transformations arising from the presence of the unique macrocyclic tetrapyrrole fragment. Data on certain main pathways to modification of the exocyclic fragment of chlorophylls are also presented.     

Effect of Heat Exposure on Activity Degradation of Enzymes in Mango Varieties Sindri,SB Chaunsa,and Tommy Atkins during Drying

Mango has been described as a valuable source of nutrients and enzymes that are beneficial to human health. Drying at different temperatures not only affects the nutritional properties but can also contribute to the degradation of valuable enzymes in dried fruit. The novelty of this paper is to investigate the quality of hot air dried mango in terms of activity retention of the heat-sensitive enzymes (HSE). For this, HSE was first screened in fresh mango flesh of the variety Samar Bahisht (SB) Chaunsa. Later, the combined effect of different drying temperatures (40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) and air velocities (1.0 ms⁻¹ and 1.4 ms⁻¹) on the activity retention of HSE in dried mango slices of the varieties Sindri, SB Chaunsa, and Tommy Atkins were investigated. The results showed that the drying temperature had a significant impact on the degradation of HSE, while at the same time some influence of the air velocity was also observed. Drying at 40 °C and an air velocity of 1.4 ms⁻¹ retained more HSE compared to those samples dried at higher temperatures. The least retention of HSE was found in samples dried at 80 °C.     

Detailed Chemical Prospecting of Volatile Organic Compounds Variations from Adriatic Macroalga Halopteris scoparia

The present study aimed to isolate volatile organic compounds (VOCs) from fresh (FrHSc) and air-dried (DrHSc) Halopteris scoparia (from the Adriatic Sea) by headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) and to analyse them by gas chromatography and mass spectrometry (GC–MS). The impact of the season of growth (May–September) and air-drying on VOC composition was studied for the first time, and the obtained data were elaborated by principal component analysis (PCA). The most abundant headspace compounds were benzaldehyde, pentadecane (a chemical marker of brown macroalgae), and pentadec-1-ene. Benzaldehyde abundance decreased after air-drying while an increment of benzyl alcohol after drying was noticed. The percentage of pentadecane and heptadecane increased after drying, while pentadec-1-ene abundance decreased. Octan-1-ol decreased from May to September. In HD-FrHSc, terpenes were the most abundant in June, July, and August, while, in May and September, unsaturated aliphatic compounds were dominant. In HD-DrHSc terpenes, unsaturated and saturated aliphatic compounds dominated. (E)-Phytol was the most abundant compound in HD-FrHSc through all months except September. Its abundance increased from May to August. Two more diterpene alcohols (isopachydictyol A and cembra-4,7,11,15-tetraen-3-ol) and sesquiterpene alcohol gleenol were also detected in high abundance. Among aliphatic compounds, the dominant was pentadec-1-ene with its peak in September, while pentadecane was present with lower abundance. PCA (based on the dominant compound analyses) showed distinct separation of the fresh and dried samples. No correlation was found between compound abundance and temperature change. The results indicate great seasonal variability of isolated VOCs, as well among fresh and dried samples, which is important for further chemical biodiversity studies.     

Characterization of Alumina Gel Catalysts by Emanation Thermal Analysis (ETA)

Alumina gels made from the metal alkoxide is known to have high catalyst activity for the selective reduction of NO _x by hydrocarbons. It is also reported that the fine structure of the gels effects the activity. In this study, the effect of the preparation method on the fine structure and catalyst activity of the gels was investigated. Monolithic gels were obtained by hydrolysis of Al(sec-C₄H₉O)₃. The wet gels were dried at 90°C (xerogels), supercritically dried (aerogels), or dried after immersion in an ethanol solution of methyltrimethoxysilane (modified xerogels). The changes in the microstructure during heating were discussed using the results of TG-DTA, ETA and N₂ adsorption. The ETA curves show the ²²⁰Rn-release rate, E, of the samples, previously labelled with ²²⁸Th and ²²⁴Ra, during heating. The decrease in E of the xerogel at temperatures higher than 400°C indicates a gradual decrease in the surface area and porosity. A remarkable decrease in the BET surface area of the xerogel was found after heat-treating at 500°C. On the other hand, constant E of the aerogels and modified xerogels above 450°C suggests high thermal stability. The pore radii, estimated by BJH method, and the catalyst activities at 500°C of the aerogels and the modified xerogels were higher than those of the xerogels. The temperature range in which the alumina gels are applicable as catalysts was determined.     

Understanding isothermal semicrystalline polymer drying: Mathematical models and experimental characterization

The drying mechanism of semicrystalline poly(vinyl alcohol) (PVA) was investigated. PVA samples of various molecular weights were crystallized by annealing at temperatures slightly above the glass transition temperature of PVA, and swollen in water for different time periods. The water volume fraction in the sample was measured using a buoyancy technique. The samples were dried in air at constant temperatures, and the drying kinetics were investigated using thermogravimetric analysis. The change in degree of crystallinity of the swollen polymer during drying was measured by differential scanning calorimetry (DSC) as well as by Fourier transform infrared spectroscopy (FTIR). The degree of crystallinity of the samples increased during drying, which in turn was found to alter the drying rate. The drying kinetics were faster at higher temperatures, for lower molecular weights, and for lower degrees of crystallinity. A mathematical model was developed to predict drying rates of semicrystalline polymers by considering the crystallization kinetics during drying. The model predictions included the thickness of the polymer sample, the degree of crystallinity of the polymer, and the water weight loss as functions of drying time. Model predictions were found to agree reasonably well with the experimental results. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2771–2780, 1998     

Composition of the essential oil of Geocaryum cynapioides (Guss.) L. Engstrand

Volatile constituents from two fresh samples of the subendemic Geocaryum cynapioides (Guss.) L. Engstrand (Apiaceae) obtained by hydrodistillation were analyzed by GC and GC-MS. Forty four and one hundred-twenty three constituents identified in the oils accounted for 98.7 % and 98.4 % of the total oils, respectively. The major component of both oils was (E)-β-farnesene (73.3 % and 57.7 %) while the other major contributors were: (E,E)-α-farnesene (4.8 % and 14.6 %) and trans-sesquisabinene hydrate (12.2 % and 3.0 %). The constituents endo-fenchyl acetate, and three sesquiterpene lactones belonging to the selinane (callitrisin) and guaiane (grilactone and jalcaguaianolide) series, with a rather restricted natural occurrence, were present in only one of the samples (4.7 %, trace amount, 0.1 %, 0.5 %, respectively) and completely absent from the other distinguishing so the two samples. A chemotaxonomic discussion of the results is presented.     

Focused microwaves-assisted extraction and simultaneous spectrophotometric determination of vanillin and p-hydroxybenzaldehyde from vanilla fragans

A new method to quick extraction of vanillin and p-hydroxybenzaldheyde (PHB) of vanilla beans from vanilla fragans is proposed. Samples were irradiated with microwaves energy to accelerate the extraction process and photometric monitoring was performed at 348 and 329 nm (vanillin and PHB, respectively). The simultaneous determination of vanillin and PHB from extracts was performed using the Vierordt's method, which showed a precision, expressed as relative standard deviation, smaller 2.5% for both analytes. Conditions such as microwaves irradiation power, number of irradiation and non-irradiation cycles, irradiation time and ethanol concentration were optimized by means of multivariate screening that showed that irradiation power and number of irradiation cycles are the most significant condition in the vanilla extraction process. The focused microwave-assisted extraction (FMAE) was applied to commercial (dried vanilla beans from fresh green vanilla beans), lyophilised and dried (commercial vanilla dried at 135 °C in oven) vanilla beans samples. The results showed that the extraction of vanillin and PHB in the commercial vanilla samples were higher than in dried and lyophilised samples. With the proposed FMAE a decrease in the extraction time of 62 times and an increase in the vanillin and PHB concentrations between 40 and 50% with respect to the official Mexican extraction method, were obtained.     

Post-harvest alteration of the main chemical ingredients in Ligusticum chuanxiong Hort. (Rhizoma Chuanxiong)

Rhizoma Chuanxiong (Ligusticum chuanxiong HORT.) is a commonly used traditional Chinese medicinal herb for the treatment of cardiovascular disorders. Significant variations of the main components in this herb were observed in commercial samples. The present study investigated effects of post-harvest drying and processing methods on nine main components in the herb. Results showed that drying at 60 degrees C or under the sun the contents of three major constituents, namely senkyunolide A (4), coniferylferulate (5) and Z-ligustilide (6), decreased significantly, while the contents of ferulic acid (1), riligustilide (8) and levistolide A (9) increased significantly. Senkyunolide I (2) and senkyunolide H (3), which were not detected in fresh herbs, appeared in dried samples. Similar chemical alterations, such as decrease in the contents of three major ingredients and increase in the contents of compounds 1, 2, 3, 8 and 9, were also observed in differently processed herbal samples. The possible converting mechanisms of these components were clarified by employing pure major components treated under the same conditions.     

Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 °C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048±0.0005 before irradiation. Irradiation gives rise to typical “cellulose-like” EPR spectrum featuring one intensive line with g=2.0048±0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs—Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.     

Metabolomics method based on ultra high performance liquid chromatography with time‐of‐flight mass spectrometry to analyze toxins in fresh and dried toad venom

Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum‐drying at 60°C and air‐drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down‐regulated or up‐regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum‐drying at 60°C succeeded in raising the conjugated‐type bufadienolide content significantly, while the content of free‐type bufadienolides were slightly reduced. On the other hand, toad venom air‐dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti‐tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide bioassay further showed that venom air‐dried at room temperature had weaker anti‐tumor activity on human hepatocellular carcinoma SMMC‐7721 proliferation in vitro than samples vacuum‐dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines.     

Comparison of <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis> Lipase Immobilization Yield of Entrapment,Adsorption, and Covalent Bond Techniques

The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic properties. Sodium alginate and chitosan were the polymers selected to immobilize lipase by inclusion. The beads of each polymer were dried by freeze drying and fluidization. The results show that chitosan was more adapted to the inclusion of lipase. Even though freeze dried, bead activity was low compared to that of fluidized beads. The freeze-drying process seems to produce suitable beads for storage at 4 and 20 degrees C. The immobilization by adsorption was carried out on both celite and silica gel. Maximum immobilization yield of 76% was obtained with celite followed by 43% in silica gel. The enzyme adsorbed on the two supports exhibited greater stability at a certain temperature (50 degrees C) and in no polar solvents (Isooctane, n-heptane, and n-hexane). In addition, the lipase immobilized by covalent bond retained residual activity equitable to 70%. It was demonstrated that the enzyme immobilized by covalent bond showed greater activity (80%) after 5 months of storage.     

气相色谱-四极杆/飞行时间质谱筛查确证辣椒中244种农药残留及其代谢物

建立了辣椒中244种农药残留的QuEChERS前处理结合气相色谱-四极杆/飞行时间质谱(GC-Q-TOF/MS)快速筛查确证方法.鲜辣椒和干辣椒样品分别采用经-20℃冷冻的乙腈和1％(v/v)乙酸化乙腈提取,经盐析分层、分散固相萃取净化和浓缩后加入内标并复溶,HP-5MS UI色谱柱(30 m×0.25 mm×0.25...     

Preparation of nanoparticle colloids of methoxy poly(ethylene glycol)-<Emphasis Type="Italic">b</Emphasis>-poly(<Emphasis Type="SmallCaps">D</Emphasis>,<Emphasis Type="SmallCaps">L</Emphasis>-lactide): effects of surfactant and organic solvent

Nanoparticle colloids of methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (MPEG-b-PDLL) diblock copolymer were prepared by a modified spontaneous emulsification solvent diffusion method using acetone/ethanol as the mixture organic solvents. The MPEG-b-PDLL was synthesized by ring-opening polymerization of D,L-lactide using stannous octoate and MPEG with molecular weight of 5,000 g/mol as the initiating system. The MPEG-b-PDLL obtained was an amorphous polymer with molecular weight of 73,600 g/mol. Influences of acetone/ethanol (v/v) ratios and Tween 80 surfactant concentrations on characteristics of the colloidal nanoparticles were investigated and discussed. Light-scattering analysis showed that average diameters of the surfactant-free colloidal nanoparticles were in the range of 86–124 nm. The nanoparticle sizes decreased as the ethanol ratio increased. The Tween 80 did not show the significant effect on the nanoparticle sizes. Scanning electron micrographs of dried nanoparticles that demonstrated the aggregation of most particles suggested they were the soft nanoparticles. However, the dried nanoparticle morphology can be observed from scanning electron microscopy as having a spherical shape and smooth surfaces.