Xylitol Crystallization Research Articles

Concentration and crystallization of Microbial Xylitol from oil palm empty fruit bunch (OPEFB) using submerged direct contact membrane distillation (DCMD)

Xylitol possess high solubility in water and increase viscosity at high temperature, making the concentration process become challenging. This study demonstrated the applicability of Membrane Distillation (MD) in concentrating xylitol solutions and evaluates its performance at different conditions and feed compositions. MD was capable of concentrating pure xylitol solution to reach the supersaturated condition. However, when Oil Palm Empty Fruit Bunch (OPEFB) hydrolysate fermentation broth was used, fouling was observed due to the presence of impurities, despite the application of feed agitation. The batch crystallization of xylitol were conducted at 5 °C with a seed addition of 0.5–0.8%-wt. Higher seed concentrations were required to induce crystallization in OPEFB hydrolysate due to lower xylitol concentrations and impurity presence. Furthermore, impurities influenced the quality of the crystals, resulting in crystal purities of 98.98% and 94.56% in the synthetic solution and OPEFB hydrolysate, respectively. These findings indicated notable impact of crystallization temperature, seed addition, and impurity on xylitol crystallization.

Bubbling triggered crystallization of xylitol phase change material for controllable heat retrieval: The subcooling effect

Towards long-term seasonal latent heat storage, the PCMs with strong supercooling are recommended as the heat storage medium. Nevertheless, the suitable techniques activating latent heat release is also of significance in the period of heat supply. The present work investigated the N2 bubbling triggered crystallization of supercooled xylitol. Special attention was paid to the subcooling effect. The N2 bubbling was identified to be a potential technique to trigger crystallization of xylitol at moderate degrees of subcooling. It was found that efficient crystallization issues were obtained with degrees of subcooling from 40 °C to 60 °C, while uncrystallization was obtained with both lower and higher subcooling. The recorded temperature history curves show that subcooling effect has strong influence on the crystallization behavior. The crystallization points tend to decline from 51.9 °C to 42.3 °C with degree of subcooling rising from 40 °C to 50 °C. The crystallization durations extend with subcooling effect enhancing. Fortunately, bubbling technique has slight influence on the properties of formed xylitol crystals. Moreover, the subcooling significantly influences the transportation behavior of bubbles. Particularly, The specific growth rates of bubbles are determined to be as low as 0.005 mm/min with the lowest degree of subcooling 10 °C, and continue to rise over 20 times when the subcooling reaches to 60 °C. The interfaces of bubbles as potential nucleation sites were deemed to be one of the important issues to activate heterogeneous nucleation, thus trigger crystallization. The present investigation is helpful to understand the fundamentals of bubbling effect on crystallization with broad range of subcooling.

Xylitol Production by Candida tropicalis from Areca Nut Husk Enzymatic Hydrolysate and Crystallization.

Lignocellulosic biomasses are extensively used by researchers to produce a variety of renewable bioproducts. This research described an environment-friendly technique of xylitol production by an adapted strain of Candida tropicalis from areca nut hemicellulosic hydrolysate, produced through enzymatic hydrolysis. To enhance the activity of xylanase enzymes, lime and acid pretreatment was conducted to make biomass more amenable for saccharification. To improve the efficiency of enzymatic hydrolysis, saccharification parameters like xylanase enzyme loading were varied. Results exposed that the highest yield (g/g) of reducing sugar, about 90%, 83%, and 15%, were achieved for acid-treated husk (ATH), lime-treated husk (LTH), and raw husk (RH) at an enzyme loading of 15.0IU/g. Hydrolysis was conducted at a substrate loading of 2% (w/V) at 30°C, 100rpm agitation, for 12h hydrolysis time at pH 4.5 to 5.0. Subsequently, fermentation of xylose-rich hemicellulose hydrolysate was conducted with pentose utilizing the yeast Candida tropicalis to produce xylitol. The optimum concentration of xylitol was obtained at about 2.47g/L, 3.83g/L, and 5.88g/L, with yields of approximately 71.02%, 76.78%, and 79.68% for raw fermentative hydrolysate (RFH), acid-treated fermentative hydrolysate (ATFH), and lime-treated fermentative gydrolysate (LTFH), respectively. Purification and crystallization were also conducted to separate xylitol crystals, followed by characterization like X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Results obtained from crystallization were auspicious, and about 85% pure xylitol crystal was obtained.

Experimental study of screening polyols and their binary eutectic phase change materials for long-term thermal energy storage

Polyols are appealing long-term thermal energy storage materials due to their severe supercooling properties and high energy density. However, spontaneous crystallization during storage and slow crystallization during crystallization hinder their reliability and applicability. In this article, two single polyols (xylitol and sorbitol) and nine binary eutectic mixtures, prepared by a method based on Gibbs excess energy, were screened as long-term thermal energy storage phase change materials. The results conclusively demonstrated that xylitol and its binary eutectic mixtures (xylitol + inositol, xylitol + mannitol, and xylitol + dulitol, with a 150 g bulk scale) could be stored at room temperature in isolation from the air for more than 300 days without any crystallization. However, other samples either transformed into a glassy state (xylitol + sorbitol and sorbitol + erythritol) or crystallized (sorbitol, xylitol + erythritol, sorbitol + inositol, sorbitol + mannitol, and sorbitol + dulcitol). The exothermic performance test showed that three additives (xylitol particles, ethanol, and acetone) could effectively trigger the crystallization of xylitol and its binary eutectic mixtures after reheating to an appropriate temperature before or after storage. This process excludes sorbitol and its binary eutectic mixtures. Simultaneously, the exothermic performance test also indicated that xylitol, xylitol + erythritol, xylitol + inositol, xylitol + mannitol, and xylitol + dulcitol had attractive crystallization heat (164.71, 165.56, 130.58, 145.56, and 147.89 kJ/kg), high maximum crystallization temperatures (84.94, 73.75, 83.85, 83.52, and 83.13 °C), short times to reach maximum crystallization temperatures (186, 477, 204, 198, and 183 s), and satisfactory energy efficiency (57.77%, 56.68%, 51.01%, 54.52%, and 54.84%). After 300 days of storage, the crystallization heat of the supercooled samples decreased by merely 4.377%, 3.358%, 4.511%, 4.314%, and 6.309%. Finally, 30 cyclic tests were conducted on newly prepared xylitol and xylitol + erythritol. The pair exhibited relatively stable crystallization heat (145.60–175.64 kJ/kg and 134.52–169.97 kJ/kg, respectively) and high maximum crystallization temperature (82.8–88.1 °C and 72.3–76.2 °C, respectively).

Food-grade xylitol production from corncob biomass with acute oral toxicity studies

Xylitol, a sugar substitute, is widely used in various food formulations and finds a steady global market. In this study, xylitol crystals were produced from corncob by fermentation (as an alternative to the chemical catalytic process) by a GRAS yeast Pichia caribbica MTCC 5703 and characterized in detail for their purity and presence of any possible contaminant that may adversely affect mammalian cell growth and proliferation. The acute and chronic oral toxicity trials demonstrated no gross pathological changes with average weekly weight gain in female Wistar rats at high xylitol loading (LD50 > 10,000mg/kg body weight). The clinical chemistry analysis supported the evidence of no dose-dependent effect by analyzing blood biochemical parameters. The finding suggests the possible application of the crystals (> 98% purity) as a food-grade ingredient for commercial manufacture pending human trials.

Batch Crystallization of Xylitol by Cooling, Evaporative, and Antisolvent Crystallization.

Four different techniques for xylitol crystallization, namely cooling, evaporative, antisolvent, and combined antisolvent and cooling crystallization, were investigated regarding their influence on the product crystal properties. Various batch times and mixing intensities were studied, and the antisolvent used was ethanol. Real-time monitoring of the count rates of various chord length fractions and distributions using focused beam reflectance measurement was conducted. Several solid characterization methods were used for studying the crystal size and shape, such as scanning electron microscopy and laser diffraction-based crystal size distribution analysis. Crystals ranging in size from 200 to 700 μm were obtained based on the analysis results by laser diffraction. The dynamic viscosity of saturated and undersaturated xylitol solution samples was measured; the density and refraction index were measured to determine the xylitol concentration in the mother liquor. Saturated xylitol solutions were found to have relatively high viscosities up to 129 mPa s in the studied temperature range. Viscosity can have a key role in crystallization kinetics, especially in cooling and evaporative crystallization. Mixing speed had a great influence, mainly on the secondary nucleation mechanism. The addition of ethanol decreased the viscosity, resulting in more uniform crystal shape and better filterability.

Comparative study on bubbling and shearing techniques for the crystallization of xylitol in TES systems

Xylitol is a promising phase change material for thermal energy storage at low and medium temperatures, but its supercooling and low crystallization rate can hinder its performance in actual systems. This problem can be overcome with the application of external stimuli that promotes the nucleation and subsequent crystallization of the supercooled xylitol. Seeding combined with mechanical stirring or air-bubbling, the techniques used in this study, are proven to achieve the crystallization (and the release of the stored latent heat) of xylitol, but the effect was not instantaneous. Rheological measurements were performed firstly to study the influence of shear and temperature in the crystallization of xylitol. Then, the use of different mechanisms to promote the crystallization of the material was evaluated by two different laboratory-scale prototypes; one of them included a mechanical stirring system while the other employed a gas-bubbling mechanism. Thermal power and discharged energy of xylitol were evaluated in the bubbling system prototype and the influence of supercooling in both discharged power and energy were also studied. A methodology to calculate induction time is proposed to evaluate crystallization systematically in both systems. This new systematic evaluation proposed in this work is different from that of the literature and aims to be used to compare different crystallization systems.

Triggering Xylitol crystallization in a 42 kWhth shell and tubes latent heat thermal energy storage system

Xylitol is a very promising Phase Change Material for district heating networks decentralized Latent Heat Thermal Energy Storages. However, it presents a high and persistent supercooling that requires the implementation of specific ways to trigger its crystallization. In previous works, the coupling of bubbling and seeding has been successfully tested as an efficient way to trigger Xylitol crystallization in small-scale crystallizers. The present work first studies the feasibility of using Xylitol as PCM in a 42 kWhth shell and tubes Latent Heat Thermal Energy Storage prototype integrating a bubbling and seeding system. Then, the benefits of optimizing the seeding step is discussed. Indeed, if the coupling between bubbling and seeding results in a fast and reproducible PCM crystallization, optimizing the seeding step allows to completely remove the effects of Xylitol supercooling on the restituted temperature levels. Another effect of bubbling in a Latent Heat Thermal Energy Storage is also brought to light: during the beginning of the discharge, a vertical temperature homogenization is observed in the liquid PCM. The consequences of this vertical temperature homogenization on the heat transfers and the performances of the storage are discussed.

Crystalline xylitol production from corncob biomass with oral toxicity analysis

Xylitol, a five-carbon sugar alcohol, has a steady global market and finds application as a natural sugar substitute in various food and confectionery products. Biocatalytic xylitol production, although touted as a greener alternative to conventional chemical catalysis, suffers from certain challenges, the primary being high cost of production. This study demonstrates a process for food-grade xylitol production from corncob biomass with energy reduction through two major process modifications. A non-conventional fermentation strategy was adopted whereby adjusting aeration without agitation, xylitol with high yield (0.86 ± 0.015 g/g), and productivity (0.74 gL-1h-1) could be produced by a GRAS Pichia caribbica MTCC 5703 strain. Xylitol was recovered from the broth in the form of crystals using a combination of membrane-based filtration and crystallization. The crystals demonstrated ~98 % purity when quantified with 1H NMR. Oral toxicity analysis of the crystals demonstrated no adverse effect in female Winstar rats (at a loading of 2000 mg/kg body weight of animals). Overall process statistics showed that 0.584 kg of food-grade xylitol crystals could be produced from 3.5 kg of corncob biomass. The two-process modifications during fermentation and xylitol recovery enabled an energy saving of ~20.842 kW/kg of crystals, providing tremendous advantages for biorefinery-based large-scale xylitol production from corncob biomass.

Fermentation process optimisation based on ANN and RSM for xylitol production from areca nut husk followed by xylitol crystal characterisation

Areca nut husk is an agricultural bio-waste with massive potential for producing value-added chemicals by conversion of xylose present in it through fermentation. This study aimed to optimise the production of xylitol from areca nut husk hemicellulosic acid hydrolysate (as the substrate) by using Candida tropicalis (MTCC 6192). Response Surface Methodology (RSM) and Artificial Neural Network (ANN) were compared for fermentation process optimisation in modelling and prediction. Agitation, pH, temperature, xylose concentration and operation time were considered variable parameters. The maximum concentration of xylitol obtained was around 9.96 g/L under designed conditions. Crystallisation analysis was conducted to separate pure xylitol crystal from fermented broth, followed by characterisation of xylitol crystal such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Thermogravimetric Analysis (TGA), Differential scanning calorimetry (DSC) and Raman analysis. DSC analysis revealed that the melting process of commercial xylitol crystals after crystallisation (CXCAC) was observed at 93.71 °C with enthalpies of 210.7 J/g. However, almost similar results were observed for xylitol crystals from fermentation broth (XCFB), with a melting point at 91.73 °C and enthalpies of 220 J/g.

Xylitol production by Pseudomonas gessardii VXlt-16 from sugarcane bagasse hydrolysate and cost analysis.

Xylitol is a well-known sugar alcohol with exponentially rising market demand due to its diverse industrial applications. Organic agro-industrial residues (OAIR) are economic alternative for the cost-effective production of commodity products along with addressing environmental pollution. The present study aimed to design a process for xylitol production from OAIR via microbial fermentation with Pseudomonas gessardii VXlt-16. Parametric analysis with Taguchi orthogonal array approach resulted in a conversion factor of 0.64g xylitol/g xylose available in untreated sugarcane bagasse hydrolysate (SBH). At bench scale, the product yield increased to 71.98/100g (0.66g/Lh). 48.49g of xylitol crystals of high purity (94.56%) were recovered after detoxification with 2% activated carbon. Cost analysis identified downstream operations as one of the cost-intensive parts that can be countered by adsorbent recycling. Spent carbon, regenerated with acetic acid washing can be reused for six cycles effectively and reduced downstream cost by about ≈32%. The strategy would become useful in the cost-effective production of several biomass-dependent products like proteins, enzymes, organic acids, as well.

Improved xylitol production from olive stones hydrolysates by biological detoxification

Olive stones, currently used as a biosource of heat and power, is gaining research interest as a feedstock for a biorefinery based on olive derived wastes. In this work, pure xylitol crystals were obtained and fully characterized as one of the possibilities of taking full advantage of this by-product of olive oil production. The proposed process includes a two-step pretreatment (water and acid extractions), detoxification of the liquid fractions and fermentation of sugars. After the water extraction, a liquid fraction with antioxidant capacity was recovered; the second step was done with dilute sulfuric acid for solubilization of sugars, resulting in a solution containing more than 60 g/l of xylose as the main sugar. This liquor contained also up to 16 g/l acetic acid, which rendered it not fermentable. Also other compounds, potentially inhibitors in downstream operations, were produced during the pretreatment, requiring a detoxification procedure. In this work, a chemical-free, biological treatment with Saccharomyces cerevisiae proved to be the best detoxification method, as glucose, furfural, hydroxymethylfurfural and acetic acid were consumed. The subsequent inoculation of Candida boidinii produced xylitol concentrations above 38 g/l after 90 h fermentation time and a yield as high as 63%, equivalent to 12 g xylitol/100 g olive stones.

Research on xylitol crystallization by shearing and seeding for its use as a phase change material

As thermal energy storage is becoming more important, new materials are being studied. Sugar-alcohols (SA) are very promising as phase change materials (PCM) because they are non-toxic, affordable and their latent heat is high. However, undercooling and low crystallization rates are some of the problems present in these materials. The SA studied in this work is xylitol, and using a microscope connected to a transparent counter-rotating shear cell, the effect of secondary nucleation is studied, as well as the crystallization rate of xylitol and how undercooling affects it. From the results, it is deduced that a proper seed preparation and handling is needed. The crystal structure is also studied, using XRPD diffractograms and differential scanning calorimetry.

Preparation and characterization of a shape-stable xylitol/expanded graphite composite phase change material for thermal energy storage

Xylitol with high latent heat of 243.28 kJ/kg and a significant supercooling degree has been considered to be a potential phase change material (PCM) for long-term thermal energy storage (TES). Xylitol can be kept in a supercooled or supersaturated metastable for a long time. In our study, it took 23 days and 30 min respectively that xylitol liquid and xylitol liquid adding 5 wt% ethanol crystallized completely at room temperature of 15 ± 5 °C. Unfortunately, the low thermal conductivity and leakage of xylitol restrict its thermal performance. In this paper, xylitol/expanded graphite (EG) composite PCMs with 5, 8, 10, 12 and 15 wt% EG content were prepared by an “impregnation and compression” two-step method. The results of SEM, XRD and FT-IR show that xylitol is well impregnated into the micropores of EG and has good chemical compatibility. The thermal performance test shows that the thermal conductivity of composite PCMs increases dramatically and the latent heat decreases with the increase of EG. The experimental results show that the latent heat of 10 wt% EG is 209.73 kJ/kg and 192.18 kJ/kg, respectively, during the charging and discharging process. The thermal conductivity of 10 wt% EG is 3.91 W/(m·K), as 9.29 times as xylitol. Besides, the crystallization of xylitol in EG and the mass loss of the composites have also been studied. The results show that 10 wt% EG composites crystallized completely after 16 days. These results prove that xylitol/EG composite PCMs have broad application prospects in long-term TES. ∙ A shape-stable xylitol/expanded graphite composite phase change material was prepared. ∙ The crystallization process of xylitol liquid and xylitol liquid adding 5 wt% ethanol at ambient temperature was studied. ∙ The thermal properties of shape-stable xylitol/expanded graphite composite phase change material were studied. ∙ The composite was characterized and the feasibility of its application in long-term thermal energy storage was preliminarily proved.

Development of a purification process via crystallization of xylitol produced for bioprocess using a hemicellulosic hydrolysate from the cashew apple bagasse as feedstock.

Xylitol was biotechnologically produced by Kluyveromyces marxianus ATCC36907 using the hemicellulosic hydrolysate ofthe cashew apple bagasse (CABHH). Sequentially, the present study investigated the recovery and purification of xylitol evaluating different antisolvents [ethanol, isopropanol and the ionic liquid 2-hydroxyl-ethylammonium acetate (2-HEAA)], their proportion in the medium (10-90% v/v), and their cooling rate (VC 0.25-0.50°C/min). These processes were contrasted with the crystallization process of commercial xylitol. This study is the first to assess xylitol crystallization using a protic ionic liquid. The hydrolysate obtained from a mild treatment with sulfuric acid contained mainly glucose and xylose at concentrations of 15.7g/L and 11.9g/L, respectively. With this bioprocess, a maximum xylitol production of 4.5g/L was achieved. The performance of the investigated antisolvents was similar in all conditions evaluated in the crystallization process of the commercial xylitol, with no significant difference in yields. For the crystallization processes of the produced xylitol, the best conditions were: 50% (v/v) isopropanol as antisolvent, cooling rate of 0.5°C/min, with a secondary nucleation of yield and purity of 69.7% and 84.8%, respectively. Under the same linear cooling rate, using ethanol, isopropanol or the protic ionic liquid 2-hydroxyl-ethylammonium acetate (2-HEAA), crystallization did not occur, probably due to the presence of carbohydrates not metabolized by the yeast in the broth, which influences the solubility curve of xylitol. With the results of this work, a possible economical and environmentally friendly process of recovery and purification of xylitol from CABHH could be proposed.

Triggering and acceleration of xylitol crystallization by seeding and shearing: Rheo-optical and rheological investigation

The present study investigates the triggering and acceleration of xylitol crystallization for its use as a short-term TES. The combined effect of seeding and the action of shear on xylitol crystallization at a supercooled temperature has been investigated by direct observations under shear (rheo-optical approach) and by rheometry. The initial seed is an agglomerate of crystals of xylitol. In addition to the more classical erosion and rupture mechanisms leading to the dispersion of crystals, shear has shown to induce the detachment of crystalline dust adhered to the initial seed into the supercooled xylitol. These crystal fragments then serve as sites for secondary nucleation and subsequent crystallization. Rheo-optical observations have allowed the determination of shear conditions to control the size of crystals by dispersion. A second part has been dedicated to the effect of shear on crystallization of xylitol by seeding by means of rheology. The measurements, although not reproducible, clearly show that seeding in presence of shear (for the investigated conditions) is very efficient to trigger and accelerate the crystallization of xylitol. Post-mortem DSC and XRPD analyses of the final crystallized seeded and sheared samples have not shown any effect on the xylitol crystallinity degree.

Physicochemical Properties of Xylitol Crystals from Oil Palm Empty Fruit Bunches Hydrolysate

Xylitol, a low-calorie sugar made up of five carbon atoms, had the valuable characteristics suitably applied for pharmaceutical and food industries. This sugar can be produced from oil palm empty fruit bunches (OPEFB) through hydrolysis and followed by fermentation. The xylitol in the fermentation broth requires the downstream process to obtain the final product with high purity and yield. Among a series of xylitol downstream process, crystallization becomes a critical step since this process determines the properties of final products. The objective of this study was to evaluate the effect of evaporation temperature (55°C and 70°C) and seeding addition (0%, 0.1%, 0.5%, 1 %) in the crystallization step on the physicochemical properties of xylitol crystals obtained from the OPEFB hydrolysate. The main evaluation criteria were crystal contents, purity, melting point, water content, hygroscopicity, solubility, caloric content, and crystal xylitol yield. The result showed that the crystal form obtained was relatively sticky and had lower purity than commercial ones because the concentration of xylitol solution increased after evaporation. The differences of physicochemical properties of the crystals such as the purity, porosity, yield and crystal form were influenced by evaporation temperature. The crystals formed by 70°C evaporation temperature produced the crystals with higher caloric value and purity, but it had lower hygroscopicity and moisture content than crystals formed by 55°C. However, the percentage of seeding gave an insignificant impact on xylitol crystal properties.

Energy and life cycle impact assessment for xylitol production from corncob

The conversion of biobased feedstocks into energy and value-added chemicals is one main approach to address the current global challenge for waste mitigation through the biorefinery mode. Corncob biomass which is one of the most abundant agricultural residue in India with a high hemicellulose content, can serve as a potential low-cost raw material for food-grade xylitol production. The present study demonstrates a process for xylitol production from corncob biomass with detailed energy and life cycle analysis for viability assessment. The major highlight of the process is the use of microbial fermentation, where biomass-derived D-xylose is converted to xylitol with high selectivity. Overall, 0.502 kg of xylitol crystals could be produced from 3.5 kg of corncob biomass. Simulation analysis revealed that the evaporators are the primary consumers of energy, and the process of heat integration can significantly reduce the energy requirements of the overall process. Environmental impacts of the system evaluated showed emission results of 8.68 kg CO2 equivalent and revealed that marine aquatic and freshwater eco-toxicity are the only possible contributors to the environment. The results suggest that the process would have favourable energy balances, which can be used in pilot plant and heat exchanger network design and operation for xylitol production scale up to 500 L.

Directional xylitol crystal propagation in oriented micro-channels of boron nitride aerogel for isotropic heat conduction

Self-assembly and orientation of thermally conductive fillers into ordered scaffold often lead to composites with anisotropic thermal properties. Though large thermal conductivity (TC) can be achieved in the direction of filler orientation, TC in transverse direction is greatly restricted. In this work, boron nitride (BN) scaffold was prepared by an ice-template method and then filled with xylitol crystals to form a new family of composites featuring isotropic TC. The crystallization of ice facilitates the formation of aligned BN walls in the aerogel and the subsequent filling of xylitol in the microchannels of the BN aerogel pushes the crystallization of xylitol in transverse direction. Combination of aligned crystal packs and BN walls in these composites results in high TC in both horizontal and vertical directions. TC of the composites increases with increasing BN content and the TC reaches as high as 4.53 W m−1 K−1 at BN loading of 18.2 wt%. These new results offer an alternative strategy to fabricate isotropic thermally conductive composites that can be used for the next generation of heat dissipating materials.

Application of Near-Infrared Spectrometry to Evaluate the Mechanism of Wet Granulation Using a High-Speed Mixer with Porous Calcium Silicate and Sugar Alcohols.

The current study examined the mechanism of wet granulation with a high-speed mixer using porous calcium silicate (PCS) as the excipient and low-molecular-weight sugar alcohols (erythritol, mannitol, maltitol, or xylitol) as the binder. Granules did not form when erythritol or mannitol was used as the binder. No major changes in X-ray powder diffraction data and near-infrared (NIR) spectroscopy spectra were noted when erythritol was used in granulation. Meanwhile, granules formed when xylitol was used as the binder. The NIR spectra of the obtained granules had a widened band near 5100 cm-1 due to hydroxyl groups. From the peak fitting near 4800 cm-1 using the Gaussian-Lorentzian product function, the contribution of hydrogen bonds in water species increased during granulation. The NIR spectra of these potential binders revealed a band of hydroxyl groups for intramolecular hydrogen bonds near 6900 cm-1 when maltitol or xylitol was used as the binder, whereas no band was observed for erythritol and mannitol. Changes in the NIR spectra assigned to water were useful in evaluating the progression of granulation as a process analytical technology. Moreover, X-ray powder diffraction illustrated that the peak due to xylitol crystals disappeared. Xylitol existed in an amorphous state in the granules, suggesting molecular interactions. Thus, hydroxyl groups in sugar alcohols facilitate hydrogen bonding between PCS (silanol groups) and molecules via water, and this is considered to be the mechanism by which granules are formed.