Plasticizing Effect Of Water Research Articles

Acceleration of Final Residual Solvent Extraction From Poly(lactide-co-glycolide) Microparticles.

The removal of the residual solvent dichloromethane from biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) microparticles was investigated by aqueous or alcoholic wet extraction or vacuum-drying. Microparticles were prepared by the O/W solvent extraction/evaporation method. The solidified microparticles were separated by filtration and the effect of subsequent drying and wet extraction methods were investigated. The residual solvent content was analysed with gas chromatography (organic solvents) and Karl Fischer titration (water). The effect of extraction conditions on microparticle aggregation, surface morphology and encapsulation of the drugs dexamethasone and risperidone was investigated. Residual dichloromethane was reduced to 2.43% (w/w) (20°C) or 0.03% (w/w)(35°C) by aqueous wet extraction. With vacuum-drying, residual dichloromethane only decreased from about 5% (w/w) to 4.34% (w/w) (20°C) or 3.20% (w/w) (35°C) due to the lack of the plasticizing effect of water. Redispersion of filtered, wet microparticles in alcoholic media significantly improved the extraction due to an increased PLGA plasticization. The potential of different extractants was explained with the Gordon-Taylor equation and Hansen solubility parameters. Extraction in methanol: or ethanol:water mixtures reduced residual dichloromethane from 4 - 7% (w/w) to 0.5 - 2.3% (w/w) within 1 h and 0.08 - 0.18% (w/w) within 6 h. Higher alcohol contents and higher temperature resulted in aggregation of microparticles and lower drug loadings. The final removal of residual dichloromethane was more efficient with alcoholic wet extraction followed by aqueous wet extraction at elevated temperature and vacuum drying of the microparticles.

Research on the Thermal Aging Mechanism of Polyvinyl Alcohol Hydrogel.

Polyvinyl alcohol (PVA) hydrogels find applications in various fields, including machinery and tissue engineering, owing to their exceptional mechanical properties. However, the mechanical properties of PVA hydrogels are subject to alteration due to environmental factors such as temperature, affecting their prolonged utilization. To enhance their lifespan, it is crucial to investigate their aging mechanisms. Using physically cross-linked PVA hydrogels, this study involved high-temperature accelerated aging tests at 60 °C for 80 d and their performance was analyzed through macroscopic mechanics, microscopic morphology, and microanalysis tests. The findings revealed three aging stages, namely, a reduction in free water, a reduction in bound water, and the depletion of bound water, corresponding to volume shrinkage, decreased elongation, and a "tough-brittle" transition. The microscopic aging mechanism was influenced by intermolecular chain spacing, intermolecular hydrogen bonds, and the plasticizing effect of water. In particular, the loss of bound water predominantly affected the lifespan of PVA hydrogel structural components. These findings provide a reference for assessing and improving the lifespan of PVA hydrogels.

Evaluation of surface structure, water sorption properties, water plasticizing effect, and color stability of dried chrysanthemums

The storage stability of two varieties of chrysanthemum (Chrysanthemum morifolium Ramat. cv. HSGJ and C. morifolium Ramat. cv. JSHJ)was evaluated in this study through an analysis of their water binding behavior. This involved examining the surface structure of the powdered dried chrysanthemums, studying the water sorption characteristics, and quantifying the water plasticizing effect. In comparison to JSHJ, powdered HSGJ had a smaller particle size and more hydrophilic groups on its surface. Additionally, it exhibited significantly higher characteristic values of adsorbed water, excluding the number of adsorbed monolayers (Nam). The sorption of water by the powdered chrysanthemums conformed to a type II isotherm. The Guggenheim–Anderson–deBoer (GAB) model was trustworthy for predicting water sorption within the range of aw from 0.112 to 0.907 and temperatures between 20 and 40 °C. The exothermic interactions between water molecules and the primary sorption sites of the powdered samples became more powerful when the temperature decreased. Powdered chrysanthemums can be preserved at 30 °C if the humidity is below 0.0852 g/g for HSGJ and 0.0766 g/g (d.b) for JSHJ. The color changes of powdered samples were not significantly affected when stored in a glassy state. This study is significant for identifying the drying endpoint, predicting shelf life, and choosing suitable packaging materials for dried chrysanthemums.

Water-lipid interface in lipidic mesophases with excess water.

This study investigates the influence of excess water on the lipidic mesophase during the phase transition from diamond cubic phase (Pn3̄m) to reverse hexagonal phase (HII). Using a combination of small angle X-ray scattering (SAXS), broadband dielectric spectroscopy (BDS), and Fourier transform infrared (FTIR) techniques, we explore the dynamics of lipids and their interaction with water during phase transition. Our BDS results reveal three relaxation processes originating from lipids, all of which exhibit a kink during the phase transition. With the excess water, these processes accelerate due to the plasticizing effect of water. Additionally, our results demonstrate that the headgroups in the HII phase are more densely packed than those in the Pn3̄m phase, which agrees with the FTIR results. Meanwhile, we investigate the influence of excess water on the lipid headgroups, the H-bond network of water, the lipid tail, and the interface carbonyl group between the head and tail of the lipid molecule. The results indicate that excess water permeates the lipid interface and forms additional hydrogen bonds with the carbonyl groups. As a result, the headgroups are more flexible in a lipidic mesophase with excess water than those in mesophases without excess water.

Properties of Eco-Friendly Composites Based on Post-Consumer Recycled Resin Filled with Walnut Shell Powder.

Increased demand for environmentally friendly materials resulted in a worldwide interest in manufacturing composite materials from agricultural wastes. Thus, this paper presents the results of research on the synthesis of eco-friendly composites and their properties. For their preparation, unsaturated polyester resin based on post-consumer recycled poly (ethylene terephthalate) was filled with walnut (Júglans régia L.) shell powder. After the filler incorporation, the deterioration of gloss and mechanical properties were observed. The flexural strength and modulus are significantly affected by the filler amount. Distilled water, 1% sodium hydroxide, toluene, and acetone were used as solvents in the chemical resistance test. Changes to the structure and properties of composites after 49 days of immersion in solvents were investigated. The immersion in water has no significant effect on the pure resin, but for its composites, the plasticizing effect of water was observed. The results show that all specimens show resistance toward toluene. In acetone, the resin and its composite shrink and fall into pieces, but the most destructive is an alkaline environment. After the immersion test, a huge increase in mass and a deterioration of gloss and mechanical properties were observed.

Biocomposites Based on Electrospun Fibers of Poly(3-hydroxybutyrate) and Nanoplatelets of Graphene Oxide: Thermal Characteristics and Segmental Dynamics at Hydrothermal and Ozonation Impact.

In order to create new biodegradable nanocomposites for biomedicine, packaging, and environmentally effective adsorbents, ultra-thin composite fibers consisting of poly(3-hydroxybutyrate) (PHB) and graphene oxide (GO) were obtained by electrospinning. Comprehensive studies of ultrathin fibers combining thermal characteristics, dynamic electron paramagnetic resonance (ESR) probe measurements, and scanning electron microscopy (SEM) were carried out. It is shown that at the addition of 0.05, 0.1, 0.3, and 1% OG, the morphology and geometry of the fibers and their thermal and dynamic characteristics depend on the composite content. The features of the crystalline and amorphous structure of the PHB fibers were investigated by the ESR and DSC methods. For all compositions of PHB/GO, a nonlinear dependence of the correlation time of molecular mobility TEMPO probe (τ) and enthalpy of biopolyether melting (ΔH) is observed. The influence of external factors on the structural-dynamic properties of the composite fiber, such as hydrothermal exposure of samples in aqueous medium at 70 °C and ozonolysis, leads to extreme dependencies of τ and ΔH, which reflect two processes affecting the structure in opposite ways. The plasticizing effect of water leads to thermal destruction of the orientation of the pass-through chains in the amorphous regions of PHB and a subsequent decrease in the crystalline phase, and the aggregation of GO nanoplates into associates, reducing the number of GO-macromolecule contacts, thus increasing segmental mobility, as confirmed by decreasing τ values. The obtained PHB/GO fibrillar composites should find application in the future for the creation of new therapeutic and packaging systems with improved biocompatibility and high-barrier properties.

Investigating the Water Relations in Aqueous Extract Powders of Mango (Mangifera indica) Peel and Seed Waste for Their Use in Food Matrices as a Value-Added By-Product.

This study investigated the potential uses of discarded mango peel and seed parts by analyzing their water sorption behavior, hydration kinetics, and stability when converted into extract powders at pH 3 and 10. The results revealed that peel extracts had a higher water adsorption capacity compared with seed extracts due to differences in their composition. Peel extracts were primarily composed of carbohydrates (approximately 75%) with a low protein content, while seed extracts contained fewer carbohydrates (less than 30%) but higher levels of proteins (more than 30%) and lipids. The critical water content for maintaining the glassy state of peel extract powders during storage was found to be 0.025 and 0.032 g of water/g for extracts obtained at pH 3 and 10, respectively. In contrast, the Tg values of seed extracts remained relatively unchanged across different water content levels, suggesting that proteins and lipids inhibited the water's plasticizing effect in the solid matrix. These findings indicate that both mango waste fractions exhibit distinct hygroscopic behaviors, necessitating different approaches to processing and utilization. These extracts hold potential applications for various food products such as beverages, gels, sauces, or emulsions, contributing to the reduction in waste and the creation of value-added products from mango residues.

Recyclability of poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBH) for food packaging applications

This study is the first to investigate the recyclability of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), a small chain length PHA, and evaluate the gas barrier properties of the recycled materials. A recycling simulation of PHBH was performed through five twin-screw extrusion cycles. Although the onset degradation temperature and the chemical structure of the processed PHBH remained stable, size exclusion chromatography and melt flow index revealed a drop of 24.3% in the molar mass of the recycled materials. However, the recycled samples showed higher impact strength and, therefore, are less brittle and more elastic. Gas barrier properties of PHBH were found to enhance after the first recycling step. A significant decrease in both permeability and diffusion coefficients was observed after the first extrusion cycle. At the same time, the calculated mean integral diffusion coefficient <D> as well as the plasticization factor (γCeq) demonstrate a weak water plasticization effect for recycled materials.

Assessment of physicochemical parameters in argentinian Yerba Mate: Variability among different commercial brands

Yerba mate (YM) is a traditional plant-based product used in the preparation of hot beverages. YM is composed of dried leaves of Ilex paraguariensis A. St.-Hil., which are slightly toasted and milled. The present study analyses the variability of physicochemical sensorial-linked characteristics among six of the most renowned argentinian brands of YM. The samples consist of particles that were categorised as coarse (61%), intermediate (34%), and fine (5%). The average moisture and ash content were 7.8% and 5.4%, respectively, and their average loose bulk density was 285 g/L. The average colour parameters were L* = 49, a* = − 1.25, b* = 15.5, with the total colour difference being lower than 1 among samples of the same brand. On average, 1 g of YM absorb 2.6 g of hot water. This study introduced a description of the mechanical response to compression for YM. All samples underwent easy compression under small stresses owing to the material’s open structure; compressibility exhibited a positive correlation with moisture due to the plasticizing effect of water. The relaxation response of the YM was associated with its spatial arrangement and the presence of smaller particles that could facilitate elastic behaviour. Mate tea presented an average pH of 5.77 and a refractive index of 1.3340. The content of phenolics in mate teas significantly differs among the studied YM brands, with its average equivalent to 2.32 g of chlorogenic acid per litre and its antioxidant capacity equivalent to 15 mM of Trolox. The phenolic concentration showed a negative correlation with the quantity of fine fraction and moisture content, and positive correlation was observed with water absorption capacity. This suggests that greater microporosity of the material might facilitate increased water-solid interaction, consequently leading to higher phenolic extraction. These results may contribute to explaining certain sensory attributes observed in YM samples.

Mechanical approach for the evaluation of the crispiness of food granular products.

Crispiness of food products is a key parameter for consumer acceptance. Available methods to evaluate this attribute are subjective and have limitations. They are particularly difficult to implement when granular products are considered. The present study aims to provide a physical characterization of the crispiness of food granular products (gari and grinded corn flakes) based on the compression cycle modeling and the determination of the Py (yield pressure) parameter of the Heckel model. High Py values attributed to the brittle behavior, are indicative of product crispiness. Furthermore, Py parameter showed sensitivity to the plasticizing effect of water. This developed physical method was validated through sensory analysis and acoustic measurements which are both considered as reference methods for crispiness evaluation. The brittle/plastic behavior attributed to crispy/non crispy products respectively was confirmed through image analysis using X-ray microcomputed tomography. The latter made it possible to distinguish the brittle from the plastic behavior through the particle size distribution evolution. This work suggests that the Py value is a relevant indicator for the crispiness evaluation of granular products. This physical characterization is expected to contribute in food engineering as an alternative method for granular products crispiness in a simpler and a more objective way.

Regulating mechanical performance of poly (l-lactide acid) stent by the combined effects of heat and aqueous media

Annealing process has been applied to the development of thermoforming polymer braided stent and treating its basic constitute monofilaments, especially for Poly (l-lactide acid) (PLLA) condensed by lactic acid monomer made from the plant starch. In this work, high performance monofilaments were produced by melting spun and solid-state drawing methods. Inspired by the effects of water plasticization on semi-crystal polymer, PLLA monofilaments were annealed with and without constraint in vacuum and aqueous media. Then, the co-effects of water infestation and heat on the micro-structure and mechanical properties of these filaments were characterized. Furtherly, mechanical performance of PLLA braided stents shaped by different annealing methods was also compared. Results showed that annealing in aqueous media generated more obvious structure change of PLLA filaments. Interestingly, the combined effects of aqueous phase and thermal effectively increased the crystallinity, and decreased the molecular weight and orientation of PLLA filaments. Therefore, higher modulus, smaller strength, and elongation at the break for filaments could be obtained, which could furtherly realize better radial compression resistance of the braided stent. This annealing strategy could provide new perspectives between anneal and material properties of PLLA monofilaments, and provide more suitable manufacturing technics for polymer braided stent.

Study of hydrolysis behaviour of polyborosiloxane

The hydrolysis behaviour of polyborosiloxane (PBS) was investigated, and the hydrolysis resistance was evaluated. The change in chemical structure during the hydrolysis of PBS was characterized by FTIR, 11B-NMR, etc. It was observed that the ternary borate ester in PBS was gradually hydrolyzed into binary and mono borate ester, and finally boric acid (BA) was produced. Rheological tests were used to investigate the effect of hydrolysis on the mechanical properties of PBS. It was observed that the plateau modulus and relaxation time of PBS decreased after immersion due to both the hydrolysis of PBS and the plasticizing effect of free water in the samples. It was also shown that as the free water evaporated during the drying process, the plateau modulus of the immersed PBS recovered somewhat. With regard to the hydrolysis resistance of PBS, the original PBS with a higher content of ternary borate ester has better hydrolysis resistance.

Thermal investigation on hydrated co-amorphous systems of nicotinamide and prilocaine

It is generally recognized that water, acting as a plasticizer, increases molecular mobility, leading to a decrease of the glass transition temperature (Tg) in amorphous systems. However, an anti-plasticizing effect of water was recently observed on prilocaine (PRL). This effect might be used in co-amorphous systems to moderate the plasticizing effect of water. Nicotinamide (NIC) can form co-amorphous systems with PRL. In order to investigate the effect of water on these co-amorphous systems, the Tgs and molecular mobility of hydrated co-amorphous NIC-PRL systems were compared with those of the respective anhydrous systems. Molecular mobility was estimated by considering the enthalpic recovery at the Tg using the Kohlrausch-Williams-Watts (KWW) equation. At molar ratios of NIC above 0.2, a plasticizing effect of water on co-amorphous NIC-PRL systems was observed with increasing the NIC concentration. In contrast, at molar ratios of NIC of 0.2 and below, water had an anti-plasticizing effect on the co-amorphous NIC-PRL systems, with increased Tgs and reduced mobility upon hydration.

Maltodextrin-trehalose miscible system-based bacteriophage encapsulation: Studies of plasticizing effect on encapsulated phage activity and food application as an antimicrobial agent

Although bacteriophage (phage) has great potential use as an antimicrobial material, its application is limited due to its high susceptibility to physical stress in a liquid state. In this study, phage T4 was spray-dried into fine dry powders to improve its usability as an antimicrobial agent. In specific, phage T4 was co-encapsulated with maltodextrin and trehalose, and the effects of the two miscible systems on phage lytic activity were investigated to identify the optimal formulation. The changes in physicochemical properties of the microcapsules were evaluated relative to differences in phage lytic activity after spray-drying. The formulation of 11% (w/w) maltodextrin and 4% (w/w) trehalose miscible system (MD11/TR4) was the best, with high phage lytic activity and strong antimicrobial activity. Because the two materials are hygroscopic, both water sorption isotherms with a Guggenheim-Anderson-de Boer model fitting and changes in thermal and structural properties were investigated. When the MD11/TR4 microcapsules were stored at various relative humidity conditions, the water-plasticizing effect affected the lytic activity of encapsulated phages. The MD11/TR4 formulation efficiently maintained the phage lytic activity at 22.6% RH, even when stored at 25 °C. The phage microcapsules were applied to control bacterial growth in foods, suggesting the utilization as alternative antimicrobial agents.

Exploring the effect of relative humidity on dynamic evolution of flax fibre’s microfibril angle through in situ tensile tests under synchrotron X-ray diffraction

Tensile properties of elementary flax fibres were investigated through in situ Synchrotron X-ray diffraction in order to understand the effect of tensile loading, on the internal reorganisation of crystalline cellulose; for the first time, these experiments were conducted for different RH conditions. Synchrotron radiation experiments were considered under reduced spot size and short acquisition times to quantify the variation of cellulose microfibril angle (MFA) in a single fibre during tensile loading, while limiting the fibre damage during X-ray exposure. The acquisitions were possible at various relative humidity (RH) conditions (from 25 % to 92 %) in order to quantify the effects of different hygro-mechanical actions upon elementary flax fibres. The results show that the MFA decreases with the increase of the applied loading, indicating a partial realignment of the cellulose microfibrils with the loading axis. The MFA at fracture point shows a decrease between − 11 and − 15 % compared to the initial MFA at all relative humidity conditions studied. The strain at break of the fibres increases with increasing relative humidity. This mechanical behaviour shows the plasticizing effect of water on the non-cellulosic amorphous matrix of cell wall.

Effect of sodium lauryl sulfate-mediated gelation on the suppressed dissolution of crystalline lurasidone hydrochloride and a strategy to mitigate the gelation

In dissolution test, the surfactant sodium lauryl sulfate (SLS) is usually added to increase the dissolution of insoluble drugs and achieve the sink condition. However, the current study found that 0.1 % SLS would significantly decrease the dissolution of crystalline lurasidone hydrochloride (LH, a BCS Ⅱ drug). The aim of this study was to clarify the mechanism of this unexpected phenomenon and explore a strategy for mitigating the negative effect of SLS on the dissolution of LH. Sample characterizations (such as PLM, DSC, PXRD, IR and NMR) confirmed that the insoluble single-phase amorphous LH-SLS complex (with a single Tg at 35.2 °C) formed during dissolution in 0.1 % SLS aqueous solution via electrostatic interaction, tetrel bond interaction, and hydrophobic effect. Due to the plasticization effect of water, the transition of amorphous LH-SLS from its glassy state to viscous supercooled liquid state led to the gel formation, and suppressd the dissolution of LH. Meanwhile, the solubility curve of LH in SLS aqueous solution at various concentrations exhibited an unusual V-shaped feature, with the CMC value of SLS serving as the inflection point, since the gel degree was attenuated due to the micelle solubilization of SLS. Additionally, an innovative strategy was developed to alleviate the inhibiting effect of SLS on LH dissolution based on the potential competitive interactions. This study not only enriches the internal mechanism of surfactant-inhibited drug dissolution but also informs an effective strategy to mitigate the gelation.

Sorption isotherms, glass transition and storage stability of drum-dried mango peels obtained with and without process additives

The study aimed to evaluate the stability of mango peel flakes obtained by drum-drying through sorption isotherms, glass transition temperature, and controlled storage. Two products were produced using drum-drying (146 °C/15 s): without (DMP) and with process additives (DMPA) (5% corn starch d.b.; 1% glyceryl monostearate d.b.). The isotherms, obtained by gravimetric method (25 °C), had the best fit with the GAB model (R 2=0.99), revealing a monolayer of 0.0954 g water/g d.b. (aw =0.5089) for DMP, and 0.0826 g water/g d.b. (aw =0.4818) for DMPA. The glass transition temperatures (Tg ) were fitted through Roos and Gordon-Taylor, demonstrating the plasticizing effect of water. Combined GAB-Gordon Taylor analysis pointed out critical storage conditions (25 °C): aw =0.061 and moisture content of 0.7 g/100 g for DMPA; aw =0.055 and moisture content of 0.6 g/100 g for DMP. The storage of DMPA (aw =0.219; moisture content of 1.27 g/100 g) at 25 °C (240 days) and 35 °C (120 days) showed high retention of vitamin C, color, and phenolic compounds.

PVC/EVA-based polymer inclusion membranes with improved stability and Cr(VI) extraction capacity: Water plasticization effect

Polymer inclusion membranes (PIMs) are far investigated for their ability to extract heavy metals and small organic compounds from aqueous media. Polyvinyl chloride (PVC) is one of the most widely used base polymers for the PIM elaboration. However, its use requires the incorporation of a relatively expensive liquid plasticizer. In the present work, poly(ethylene-co-vinyl acetate) (EVA) serves as a polymer plasticizer for the elaboration of PIMs based on PVC as a base polymer and Aliquat 336 as a carrier. The composition of PIMs was optimized in terms of the PVC/EVA ratio and the vinyl acetate (VA) groups content (x) of EVA (i.e. EVAx). Physical-chemical properties of the resulting membranes are analyzed and correlated with their structure. The results of SEM analysis revealed miscible PVC/EVA70 blends (i.e. with 70 wt% of VA groups) and partially miscible PVC/EVA40 blends. The plasticizing effect of the EVA copolymer was confirmed by the tensile test results. The results of transport measurements showed that PIMs containing EVA40 and PVC are more efficient for the Cr(VI) extraction than those with only PVC. Thus, EVA40 can effectively replace the conventional liquid plasticizers while improving the Cr(VI) permeability. Besides, it is stated that EVA40-based PIMs are more stable as compared with conventional PIMs due to the water plasticizing effect. After the membrane optimization, the highest Cr(VI) transport flux (54.7 µmol·m-2·s-1) was measured. Moreover, the addition of 10 wt% of tetradecanol causes the increase of the water plasticizing effect and allows obtaining a PIM with high stability (up to 24 cycles) required for the membrane long-term operation.

Influence of the plasticizer on rice bran-based eco-friendly bioplastics obtained by injection moulding

The manufacture of eco-friendly bioplastic materials from renewable resources to replace petroleum-based plastics has attracted increasing attention. For many years, proteins, lipids and polysaccharides have been proposed as natural biopolymers sources to obtain biodegradable plastic materials. As by-product from the rice industry, rice bran, is an available and non-expensive resource of both proteins and starches, food groups that, properly processed, can be employed in the development of bioplastics. Plasticizers are essential for the manufacture of bioplastics and, when carbohydrate/protein mixtures are used, an adequate selection of plasticizers must be addressed. By these means, a material suitable for thermo-mechanical processing methods is obtained if starches are subjected to shear forces under high temperatures and water excess (gelatinisation). Moreover, additional polyol-based plasticizers, such as glycerol and sorbitol, allow obtaining reinforced products with improved elasticity when protein-based bioplastics are processed. The aim of the present study was to analyse the plasticizing effect of water combined with different proportions of glycerol or sorbitol, as well as their influence on the final bioplastic properties. Results indicate that higher water ratios produce stiffer bioplastics with improved viscoelastic moduli, maximum stress and Young´s modulus, while increasing the glycerol and sorbitol content leads to higher elasticities and water uptake capacities in general. Moreover, sorbitol seems to provide more suitable bioplastics with better tensile (up to 500% in Young´s modulus) and functional properties compared to glycerol.

Effects of sucrose, carnosine, and their mixture on the glass transition behavior and storage stability of freeze-dried lactic acid bacteria at various water activities

Effects of sucrose, carnosine, and their mixture on the glass transition behavior and storage stability of freeze-dried Lactobacillus reuteri at various water activities (aw) were investigated. At aw = 0.328, the control (non-additive sample) showed viable cells as uncountable after storage at 25 °C for 4 weeks. The sucrose and sucrose-carnosine samples showed clear glass transition at a slightly lower temperature than the storage temperature, and maintained a large number of viable cells after storage. The carnosine sample crystalized during the storage, and a large reduction in viable cells was observed. At aw = 0.576, the samples showed a small endothermic shift due to glass transition, suggesting partial crystallization. The Tg decreased with increase in aw because of the water plasticizing effect. After storage, the sucrose-carnosine sample showed much higher viable cell numbers than the other samples. At aw = 0.753, the sucrose and sucrose-carnosine samples showed clear glass transition. The carnosine sample showed freeze-concentrated glass transition and subsequent ice melting. After storage, the sucrose and carnosine samples showed an uncountable and a low number of viable cells, respectively, but sucrose-carnosine maintained relatively high viable cell numbers. In addition, carnosine strongly supported the stabilizing effect of sucrose (even at low additive levels) depending on the aw. These results suggest that sucrose-carnosine shows a synergistic stabilizing effect.