Low Hygroscopicity Research Articles

Production and Characterization of Dehydrated Acerola Pulp: A Comparative Study of Freeze and Refractance Window Drying

Acerola is a perishable fruit with high vitamin C levels and an attractive nutrition property. The goal of the present work was to produce dehydrated acerola pulp with preserved vitamin C, selecting freeze-drying and refractance window (considered a novel and promising drying method) as suitable technologies. The final properties of dehydrated pulps using the drying technologies freeze-drying and refractance window were compared: i) water activity, ii)moisture content, iii) hygroscopicity, iv) color parameters, v) microstructure, vi) antioxidant activity, and vii) ascorbic acid stability (30 °C, 75% RH). The dried acerola pulps exhibited low moisture, water activity, and hygroscopicity regardless of the drying technology. However, the pulp dehydrated by refractance window presented significantly higher antioxidant activity than the freeze-dried pulp, with higher ABTS•+ (1,838.60 μM TE/g dehydrated pulp) and FRAP (1,290.00 μM TE/g dehydrated pulp) values. The ascorbic acid stability values were also higher for the pulp dried by the refractance window, which showed a final content of 98.03 mg/100 g dehydrated pulp after ten days of storage. The refractance window is a more appropriate technology to dehydrate acerola pulp with high vitamin C content, antioxidant activity, and ascorbic acid stability than freeze-drying.

Compositional evolution for mixed aerosols containing gluconic acid and typical nitrate and the effect of multiply factors on hygroscopicity

The aging process of atmospheric aerosols usually leads to a mixture of inorganic salts and organic compounds of anthropogenic origin. In organic compounds, polyhydroxy organic acids are important components, however, the study on composition and hygroscopic properties of the mixture containing inorganics and polyhydroxy organic acids is scanty. In this study, gluconic acid, the proxy of polyhydroxy organic acids, is mixed with the representative nitrate (Mg(NO3)2, Ca(NO3)2) to form aerosols. ATR–FTIR and optical microscopy are employed to study the component changes and hygroscopicity as a function of relative humidity. As relative humidity fluctuates, the FTIR–ATR spectra display that the internal mixed gluconic acid (CH2(CH)4(OH)5COOH) and nitrate can react to release acidic gases, forming relevant gluconate and further affecting the hygroscopicity. The specific presentation is particles cannot be recovered to their original size after the dehydration–hydration process and there will be some disparities in GF for mixed particles. For the gluconic acid–Ca(NO3)2/Mg(NO3)2 mixtures with molar ratios of 1:1, higher degree of reaction resulting in the production of large amounts of gluconate should be responsible to the lower hygroscopicity compared to ZSR model. For 1:2 gluconic acid–nitrate mixed systems (with higher nitrate content), the hygroscopicity of mixtures are higher than the ZSR prediction. A possible reason could be ‘salt-promoting effect’ on the organic fractions of the surplus inorganic salt in the mixture. These data can improve the chemical composition list evaluation, in turn hygroscopic properties and phase state of atmospheric aerosol, and then the climate effect.

High-Performance Lignocellulosic Self-Bonding Composites via Dialdehyde Modification and Water-Involved Low-Temperature Hot Pressing

Novel lignocellulosic self-bonding materials with high performance and low hygroscopicity are still in demand in the wood industry. We demonstrated a facile and efficient approach to prepare adhesive-free all-lignocellulosic composites with excellent performances via the dialdehyde modification replacing the conventional hydrogen groups. Less than 30% water involved as the plasticizer could successfully optimize the performances of self-bonding composites and, more importantly, realize low-temperature hot pressing at 75 °C. The internal sectional morphology showed that individual wood fiber cells collapsed, and lignin was repolymerized with hemicellulose and cellulose to enhance interfacial bonding. Chemical analysis demonstrated the intra- and intermolecular association of dialdehyde groups. The self-assembly lignocellulosic composites were superior to most of the reported adhesive-free bio-fiber materials, demonstrating better flexural strength (93.7 MPa), internal bond strength (6.2 MPa), tensile strength (20.2 MPa), and hardness (1.0 GPa). Thus, this technology can be extended to different wood species. The thickness swelling rate of lignocellulosic self-bonding composites was only 2.1% after soaking in water for 24 h. In addition, the adhesive-free lignocellulosic composites exhibited plastic body-like behavior and excellent machinability. The applications of all-lignocellulosic self-bonding composites can be extended to high-strength structural buildings and outdoor household material fields, which aligns with the concepts of eco-friendliness, degradation, and carbon storage.

Optimization of alkali-treated banana pseudo-stem fiber/PBAT/PLA bio-composite for packaging application using response surface methodology

The objective of this research was to prepare an optimized bio-composite for packaging based on alkali-treated banana pseudo-stem fiber (BPSF), PBAT, and PLA using response surface methodology (RSM). The effects of three factors, i.e., alkali-treated BPSF (0.8 to 2.4 g), PBAT (0.75 to 2.25 g), and PLA (1.6 to 3.2 g) on two dependent variables, i.e., bending strength and tensile strength of bio-composite, were investigated. Box-Behnken design (BBD) provided the combination for an optimum composite, which was 1.15 g of alkali-treated BPSF, 2.09 g of PBAT, and 2.66 g of PLA, respectively. The bending strength and tensile strength for alkali-treated BPSF/PBAT/PLA composite were 32.62 MPa and 30.91 MPa, which was 20.50% and 16.51% higher than native BPSF/PBAT/PLA composite. The bio-composite prepared using the optimized results was further characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetry, scanning electron microscopy (SEM), mechanical testing, contact angles, and water absorption tests. Analyses showed that alkali-treatment could improve the adhesion and compatibility of BPSF in the polymer matrix. These outcomes were associated with the use of treated-BPSF for better mechanical strength and lower hygroscopicity. This result demonstrated that alkali-treated agricultural residue and degradable polymer could be used to prepare composite materials for green packaging application.

Synergistic Design of Multifunctional Interfacial Zn Host toward Practical Zn Metal Batteries

AbstractAqueous Zn metal batteries (ZMBs) are receiving attention as large‐scale energy storage systems owing to their high theoretical capacity, low toxicity, and the abundance of Zn. However, Zn anodes still undergo undesired dendrite growth and intrinsic side reactions, thereby hindering the practical application of ZMBs. In this study, a multifunctional porous zincophilic carbon host (FPCH) assisted by a thin ZnO interphase (ZI) on bare Zn (FPCH‐ZI/Zn) is rationally designed as the interfacial host for stable Zn deposition/dissolution processes to reduce the limitations of Zn anodes. Hydrophobic FPCH with large specific surface areas and zincophilic oxygen‐based functional groups induce a uniform distribution of electric field/Zn2+ flux and low nucleation overpotential and restrain side reactions. Additionally, hydrophilic ZI ensures sufficient quantities of the electrolyte are absorbed into FPCH‐ZI/Zn; it complements the shortcomings (low hygroscopicity of the electrolyte) of hydrophobic FPCH, depositing Zn inside the host. Consequently, the symmetric FPCH‐ZI/Zn cells exhibit excellent cycling performances with low‐voltage polarization, even under harsh operating conditions. Furthermore, in the MnO2∥Zn full‐cell tests, the FPCH‐ZI/Zn full cells exhibit superb long‐term cyclability compared to that of bare Zn under real‐world operating conditions (N/P ratio: ≈7.3), indicating the availability of FPCH‐ZI/Zn for practical ZMBs.

An improved representation of aerosol mixing state for air quality–weather interactions

Abstract. We implement a detailed representation of aerosol mixing state in the Global Environmental Multiscale – Modelling Air quality and CHemistry (GEM-MACH) air quality and weather forecast model. Our mixing-state representation includes three categories: one for more hygroscopic aerosol, one for less hygroscopic aerosol with a high black carbon (BC) mass fraction, and one for less hygroscopic aerosol with a low BC mass fraction. The more detailed representation allows us to better resolve two different aspects of aerosol mixing state: differences in hygroscopicity due to aerosol composition and the amount of absorption enhancement of BC due to non-absorbing coatings. Notably, this three-category representation allows us to account for BC thickly coated with primary organic matter, which enhances the absorption of the BC but has a low hygroscopicity. We compare the results of the three-category representation (1L2B, (one hydrophilic, two hydrophobic)) with a simulation that uses two categories, split by hygroscopicity (HYGRO), and a simulation using the original size-resolved internally mixed assumption (SRIM). We perform a case study that is focused on North America during July 2016, when there were intense wildfires over northwestern North America. We find that the more detailed representation of the aerosol hygroscopicity in both 1L2B and HYGRO decreases wet deposition, which increases aerosol concentrations, particularly of less hygroscopic species. The concentration of PM2.5 increases by 23 % on average. We show that these increased aerosol concentrations increase cloud droplet number concentrations and cloud reflectivity in the model, decreasing surface temperatures. Using two categories based on hygroscopicity yields only a modest benefit in resolving the coating thickness on black carbon, however. The 1L2B representation resolves BC with thinner coatings than the HYGRO simulation, resulting in absorption aerosol optical depths that are 3 % less on average, with greater differences over strong anthropogenic source regions. We did not find strong subsequent effects of this decreased absorption on meteorology.

Substantial Uncertainties in Arctic Aerosol Simulations by Microphysical Processes Within the Global Climate‐Aerosol Model CAM‐ATRAS

AbstractAerosols can modulate the Arctic climate through their interactions with radiation, clouds, and snow and ice surfaces. Atmospheric simulations of Arctic aerosols remain highly uncertain, for which the importance of aerosol microphysical properties and processes has not been properly evaluated. To identify the cause of this large uncertainty, we evaluate the variability ranges of aerosols in the Arctic resulting from uncertainties in various aerosol microphysical properties/processes, including particle size distributions at emission, particle mixing states, activation efficiency, and wet removal processes, by using a global climate‐aerosol model Community Atmosphere Model with the Aerosol Two‐dimensional bin module for foRmation and Aging Simulation. We find that the combined uncertainties associated with these multiple microphysical properties/processes yield a factor of 10–50 differences (maximum‐to‐minimum ratio) in the concentrations and radiative effects of aerosols in the Arctic. Black carbon shows the highest variability among aerosol species because its lower hygroscopicity and higher critical supersaturation cause the fraction of activation and wet removal during transport to be highly sensitive to the model treatment of aerosol and cloud microphysics. Aerosol‐radiation‐cloud interactions at the top of atmosphere vary from −0.40 to +0.30 W m−2 in the Arctic (from the preindustrial to present day) and can be positive or negative depending on the treatment of microphysical properties/processes. These results indicate that microphysical properties/processes are more important than previously thought in aerosol simulations in the Arctic and demonstrate that a better understanding and more sophisticated model representation of aerosol microphysical properties/processes are required to improve the accuracy of Arctic aerosol simulations and their impacts on climate.

Improving the solubility, hygroscopicity and permeability of enrofloxacin by forming 1:2 pharmaceutical salt cocrystal with neutral and anionic co-existing p-nitrobenzoic acid

With the purpose of improving the solubility and reducing the hygroscopicity of enrofloxacin (ENR), an unreported pharmaceutical salt cocrystal of enrofloxacin with both neutral and anionic p-nitrobenzoic acid (PNB) (ENR-PNB, C19H23FN3O3·C7H4NO4·C7H5NO4) was designed and synthesized by changing the reaction molar ratio (1:2) of ENR and coformer PNB on the basis of summarizing the past experience of our group, and its crystal structure was characterized. Single-crystal X-ray diffraction (SCXRD) analysis revealed that the salt cocrystal consists of ENR+, PNB− and PNB neutral molecule in a 1:1:1 ratio. The two asymmetric units that become centrosymmetric form an X-shaped structure centered on the ENR dimer R22(20). The adjacent X-shaped structures are interconnected by hydrogen bonds to form 1D chain and form the octamer R88(42) at the same time. As we expected, the formation of the salt cocrystal ENR-PNB results in a simultaneous improvement in the solubility and hygroscopicity of ENR. This may be the fact that ENR and PNB depend on CAHBs to raise the hydrous enthalpy of salt cocrystal. And the presence of PNB neutral molecules lower hygroscopicity of ENR in high humidity environments. Unexpectedly, the permeability of ENR-PNB was also increased compared to that of pure ENR. It is speculated that the number of polar sites in the system is greatly reduced because of hydrogen bonds formation, which increases the permeability of the ENR salt cocrystal. In addition, the in vitro antibacterial activities of ENR-PNB are enhanced at different concentrations compared to ENR. The present study implies that it is possible to improve the solubility, hygroscopic stability, permeability and antibacterial activity of enrofloxacin by changing the chemical reaction molar ratio to form salt cocrystal containing both neutral and anionic coformers, which provides a new strategy and insight to simultaneously improve the solubility and hygroscopicity and even permeability of the active ingredients of solid drugs.

Solid-State Forms of Koumine Hydrochloride: Phase Transformations and the Crystal Structure and Properties of the Stable Form.

To investigate the solid-state forms of koumine hydrochloride (KMY), solid form screening was performed, and one amorphous form and five crystalline forms (forms A, B, C, D, and E) were identified by powder X-ray diffraction. Form A was the dominant crystal product, and its crystal structure and packing pattern were determined by single-crystal X-ray diffraction. The crystals displayed an orthorhombic crystal system and symmetry of space group P212121 with Z′ = 1. The amorphous form transformed to form A at 105–120 °C or 75% RH, while forms B, C, D, and E could only be intermediate phases and readily transformed to form A at room temperature. Therefore, the phase transformations of KMY solid-state forms were established. The properties of the amorphous form and form A were further elucidated by applying vibrational spectroscopy, moisture sorption analysis, and thermal analysis. Accordingly, form A, the KMY anhydrate, was found to be the thermodynamically stable form with low hygroscopicity under ambient conditions. These characteristics are crucial in the manufacture and storage of active pharmaceutical ingredients.

Design and Application of an Asymmetric Naphthalimide-based Molecule with Improved Hydrophobicity for Highly Stable Organic Solar Cells.

With the photovoltaic efficiency of organic solar cells (OSCs) exceeding 17%, improving the stability of these systems has become the most important issue for their practical applications. In particular, moisture in the environment may erode the interlayer molecules, which has been proved to be the main reason for the efficiency decay. At present, the development of moisture-resistant interlayer molecules remains a great challenge to the field. Herein, we designed two naphthalene diimide (NDI)-based organic compounds, namely, NDI-M and NDI-S, exhibiting suitable energy level and excellent electron extraction property. In addition to this, NDI-S has extremely low hygroscopicity. An efficiency of 17.27% was achieved for the NDI-S inverted cells, and the long-term stability under continuous illumination conditions was significantly improved with a T80 lifetime (the time required to reach 80% of initial performance) of over 28 000 h. More importantly, we demonstrated that, by using a covalent bond to link the counter ions with the host molecular structure in the zwitterion, the asymmetric molecule NDI-S can transform from amorphous to crystalline hydrate at high humidity and exhibited outstanding non-hygroscopic nature; this could decrease the interaction between the cell and the moisture, obviously improving the device stability under high humidity.

Heat and moisture transfer in fabric consisting of fibers with low hygroscopicity

The heat and moisture transfer through dry and wet fabric made up of hydrophobic fibers was modeled and experimentally verified. In the modeling, the governing equations are obtained with consideration of the energy balance and the mass balance of the liquid water, where the specific initial and boundary conditions were set according to measurement of the cooling property of fabric. By comparing temperature changes at the fabric inner surface, the model validity was confirmed by the agreements between the experimental results and numerical solutions. Thus, this simulation was able to predict the cooling performance of fabrics. The effects of internal and external factors on heating/cooling performances of fabrics were analyzed by this model. With an increasing evaporation rate, thermal conductivity and water content of fabric, the cooling capability of fabric was improved. Surrounding conditions with lower temperature, lower relative humidity and higher air velocity demonstrated a positive effect on fabric thermal and moisture transfer performances, which benefits the thermal comfort of the human body after excessive sweating.

Aerosol Hygroscopicity and its Link to Chemical Composition in a Remote Marine Environment Based on Three Transatlantic Measurements.

The hygroscopicity of marine aerosols may largely impact particle optical properties, cloud activation ability, and consequently the global climate system. This study highlights findings from real-time hygroscopicity and chemical composition measurements in three open-ocean cruises over the Atlantic Ocean. Spatial variations in hygroscopicity (κ) for marine boundary layer particles (≤300 nm) were provided for the first time covering nearly 100° of the latitude over the Atlantic Ocean, ranging from 0.14 to 1.06. Externally mixed particles with remarkably low hygroscopicity (0.14-0.16) were observed near the equator influenced by biomass burning emissions transported from Africa. For marine aerosols, a positive linear correlation evidently existed between κ and wind speed within a range of 5-15 m/s even for nanometer particles. A closure study shows that the measured κ of 300 nm particles is well explained by the bulk chemical composition. A good negative correlation between measured κ and the organic mass fraction in PM1 for marine aerosols was found (slope = -2.26, R2 = 0.44), while a different linear relationship appeared for continental aerosols at several sites (slope = -0.47, R2 = 0.77). Accordingly, we provide a parameterization method to estimate bulk aerosol hygroscopicity both in continental and marine environments using particulate organic fractions.

General aspects of extrusion-spheronisation as a pellet production technique

Various aspects of the extrusion-spheronisation technique as one of the most popular pellets production methods was considered in this review. The advantages of extrusion-spheronization in comparison with other methods are the ability to include high-dose pharmaceutical substances, combine two or more substances, as well as change the physical characteristics of initial material. In addition, the method allows to obtain particles with excellent flowability, low hygroscopicity, high sphericity, narrow particle size distribution and smooth surface The main advantages and disadvantages of the equipment used are shown, and the process initial parameters influence on the obtained material final properties is noted. Particular attention is paid to such stages of extrusion-spheronization as obtaining a wet mass and it’s following extrusion-spheronization, varying parameters of which is possible to change the pellets morphological and technological properties.

Assessment of personal protective equipment for medical personnel during a new coronavirus pandemic

BACKGROUND: The use of personal protective equipment in contact with patients with new coronavirus infection is the basic measure to ensure the safety of medical personnel. It is known that the use of protective equipment made of materials with low hygroscopicity, air and vapor permeability, under high ambient temperatures and physical activity, can cause overheating of the body. Objectively, during the pandemic, medical personnel reported a deterioration in the functional state up to and even fainting, caused by prolonged use of protective suits. Protective equipment made it difficult to perform routine tasks and led to a reduction in the quality of work performed.
 PURPOSE OF THE STUDY: Assessment of the effect of personal protective equipment on the functional status of medical personnel.
 MATERIALS AND METHODS: A survey of 156 medical workers of military medical organizations was carried out using the original questionnaire. The ease of use of protective equipment was assessed, and at the same time the negative aspects of its use were identified. A study of the thermal condition of 6 volunteers during the use of reusable and disposable personal protective equipment sets was carried out under laboratory conditions.
 RESULTS AND DISCUSSION: The majority of respondents reported a negative impact on the functional state of the body when using personal protective equipment. According to questionnaire data, skin damage occurred in 88% of cases; fogging of safety glasses in 81%; visual impairment in 70%; inadequate suit size in 61%; subjective feeling of heat at work in 61%; headaches in 45% of cases. An assessment of the thermal condition of the reusable and disposable suits at a temperature of 25C and light physical work indicated that the body heat levels of the volunteers were within acceptable normative values.
 CONCLUSIONS: The use of personal protective equipment has a negative effect on the functional state of the medical workers body, which requires a rational approach to the selection of protective the provision of an optimal regime of work and rest Considering the possibility of using personal protective equipment under different conditions, including increased ambient temperatures (over +30С) and/or intense physical exertion, there is a need for further study of their effects in order to develop preventive measures.

A Drug–Drug Multicomponent Crystal of Metformin and Dobesilate: Crystal Structure Analysis and Hygroscopicity Property

A drug–drug multicomponent crystal consisting of metformin (MET) and dobesilate (DBS) was prospectively connected by solvent cooling and evaporating co-crystallization using the multicomponent crystal strategy, not only to optimize the physicochemical properties of single drugs, but also to play a role in the cooperative effect of DBS with the potential vascular protective effects of MET against diabetic retinopathy (DR). The crystal structure analysis demonstrated that MET and DBS were coupled in a 3D supramolecular structure connected by hydrogen-bonding interactions with a molar ratio of 1:1. Almost all hydrogen bond donors and receptors of MET and DBS participated in the bonding, which hindered the combination of remaining potential hydrogen bond sites and water molecules, resulting in a lower hygroscopicity property than MET alone.

New Multicomponent Crystal Forms of Adiphenine with Low Hygroscopicity

New Multicomponent Crystal Forms of Adiphenine with Low Hygroscopicity

Electronic Structure of Tl<sub>4</sub>CdI<sub>6</sub>: First-Principles Calculations and X-Ray Photoelectron Spectroscopy Measurements

We report on experimental and theoretical studies of the electronic structure of ternary Tl4CdI6 alloy. Our XPS results indicate low hygroscopicity of its surface. The first-principle calculations indicate that the valence-band region of Tl4CdI6 is dominated by contributions of I 5p states (mainly at the top and the central portion), while its bottom is prevailed by contributions of Tl 6s states. The theoretical data indicate that the Tl4CdI6 compound is a direct gap semiconductor with the band gap value of Eg = 2.03 eV. The calculations reveal that the significant covalent component (in addition to ionic component) is characteristic for the chemical Tl–I and Cd–I bonds of Tl4CdI6.

The structural characterization, physicochemical properties, and stability of gardenia yellow pigment microcapsules

Gardenia yellow pigment (GYP) is a natural food coloring agent with a variety of pharmacological activities. However, the applications of GYP are limited due to its poor stability. The aim of this study was to prepare GYP microcapsules using different combinations of maltodextrin (MD), gum arabic (GA), soy protein isolate (SPI), and whey protein (WP) as wall materials to improve the stability of GYP, and evaluated its structural, physicochemical properties, and stability. Scanning electron microscopy (SEM), fourier transformed infrared spectrometer (FTIR), and X-ray diffraction (XRD) results confirmed inclusion of GYP within microcapsules. Thermogravimetric (TG) experiment indicated that GYP microcapsules had good thermal stability below 220 °C. Furthermore, the encapsulation efficiency (EE) and loading amount (LA) of GYP microcapsules were between 58.73 and 83.16% and 1.63–3.32 g/100 g, respectively. WP-MD microcapsule showed significantly higher EE and LA than other microcapsules. A significant lower hygroscopicity was observed in spray-dried double emulsion microcapsules (WP–O and WP-MD-O). The results of the stability studies revealed that the five kinds of microcapsules could significantly improve the thermal stability, light stability, and pH stability of GYP, and there was no significant difference. Overall, these results may guide the potential application of GYP microcapsules in nutraceutical and functional foods.

Surface nanocoating of high drug-loading spray-dried amorphous solid dispersions by atomic layer coating: Excellent physical stability under accelerated storage conditions for two years

Physical instability remains a major concern with amorphous solid dispersions (ASDs). In addition to bulk crystallization inhibition, another potential strategy to improve the physical stability of ASDs is surface engineering. However, coating processes are extremely challenging for ASD microparticles. Herein, we describe for the first time the application of atomic layer coating (ALC), a solvent-free technique, to deposit a pinhole-free, ultra-thin film of aluminum oxide onto the surface of spray-dried ASD particles containing high drug loadings of ezetimibe with hydroxypropyl methylcellulose acetate succinate. ALC affords excellent control over the thickness, uniformity and conformality of the coating at the atomic scale. The freshly prepared coated ASD powders exhibited less agglomeration, a lower hygroscopicity, as well as improved wettability, flowability and compressibility compared to the uncoated samples. Under accelerated storage conditions, crystallization was detected in the uncoated 50% and 70% drug loading ASDs after only a few days, whereas the coated samples showed no evidence of physical instability for two years. Consequently, there was a dramatic decrease in the drug release from the uncoated ASDs during storage, while little change was observed for the coated samples. Using ALC for surface nanocoating of ASD paves the way for the development of higher drug loading ASD without compromising physical stability, thereby reducing the pill burden.

Moisture absorption behavior and thermal properties of sucrose replacer mixture containing inulin or polydextrose

The increasing consumer awareness of healthier food choices with low calories and high fiber content has driven the development of sucrose-free dark compound chocolate enriched with dietary fiber. Therefore, this study aimed to determine the effect of adding dietary fiber-low digestible carbohydrate (LDC) polymer on the moisture sorption behavior and thermal properties of a sucrose replacer mixture. Duo-trio and acceptance tests were also conducted to identify the relative sweetness of sucrose replacer compared to that of sucrose. Among these samples, erythritol-polydextrose mixture and tagatose-inulin mixture have similar sweetness levels as sucrose at P ≥ 0.05. Most sucrose replacer mixtures were well-accepted by panelists, except the trehalose-polydextrose mixture. Moisture content, hygroscopicity, and thermal properties of the sucrose replacer mixture were also studied. The result showed that all sucrose replacer mixtures had significantly (P<0.05) higher moisture content than sucrose. The addition of LDC polymer altered the moisture content, hygroscopicity, and melting temperature of the samples due to its amorphous nature and large molecular structure. Considering the average relative humidity in tropical countries was reported at 65% RH, the sucrose replacer mixtures containing erythritol, mannitol, or tagatose could replace sucrose in dark compound chocolate of their low moisture content and hygroscopicity at aw of 0.65.