Freeze-dried Research Articles

Comparison of different drying methods for Wushan Codonopsis pilosula: Changes in color, microstructure, nutrients, bioactive compounds, and volatile

This study evaluated the effects of different drying methods, namely hot air drying (HAD), heat pump drying (HPD), microwave drying (MD), vacuum freeze drying (VFD), and sun drying (SD) on the quality of Wushan Codonopsis pilosula (WCP). Results showed that HAD and HPD were effective in retaining the alcohol -soluble leachate content, with the retention rates of 91.76 % and 91.32 %, respectively. The most attractive appearance was observed in VFD-WCP. There was no significant difference between the polysaccharide content of VFD-WCP and HPD-WCP, which were 202.62 mg/g and 201.71 mg/g, respectively. MD and SD were detrimental to the retention of color, physicochemical indicators, and atractylenolide III. The content of lobetyolin was increased significantly (P < 0.05) after drying, following this trend: HPD > HAD > VFD > MD > SD > Fresh. The aroma characteristics of WCP were altered by the drying process. However, the principal component analysis (PCA) showed that HAD and HPD produce similar aromatic characteristics with traditional SD. Overall, HPD shows promise as a replacement for SD, not only for increasing drying efficiency but also for improving the quality of WCP.

Anisotropic, free-standing anodic films with aligned anatase-bronze TiO2-integrated graphene for high-capacity lithium-ion batteries

The composition modification and structure manipulation of carbon-based battery electrodes is becoming an increasingly urgent need for safer, more reliable, and effective electric vehicles. Herein, we fabricate a free-standing hybrid anatase-bronze TiO2-grafted reduced graphene oxide (TiO2-rGO) through a one-pot solvothermal procedure. The TiO2-rGO composite was transformed into a film with an anisotropic alignment and assembled as an anode into lithium-ion batteries (LIBs) to enhance its performance. Our previously developed “Pulse Freezing” process, with modifications including: (1) dimensional and structural optimization for larger and faster film production and (2) optimal microfluidic condition for vertical porous alignment, is utilized for assembling this nanocomposite anodic film. During the microfluidic assembly process, we achieved the desirable flowrate, flow patterns, and alignments of the integrated TiO2-rGO layers while forming porous microstructures through freeze drying. The porous and aligned TiO2-integrated rGO film exhibits a significantly enhanced specific capacity of 400 mAh/g at 0.2 A/g, which is a drastic increase compared to traditional TiO2 and carbon black electrodes possessing <50 mAh/g capacity, attributed to the anisotropic alignment and porous microstructure of rGO in combination with TiO2 grafting. The developed TiO2-rGO composite film provides a promising application of Ti-based electrodes in LIBs for commercial battery industries.

Importance of Kv Distribution in Freeze Drying: Part II: Use in Lyo Simulation Modeling

This article is the second of a series of two articles. In the first article of the series, a new Kv distribution model and an experimental methodology to measure the Kv distribution were introduced. In this second part, the Kv distribution is integrated into a lyo-simulation tool, to more accurately predict the variability of the product temperature, primary drying time, total sublimation mass flow and Pirani signal. The Kv distribution is also integrated into the graphical design space. The impact of incorporating the Rp distribution is briefly discussed. The comparison of the simulation tool with actual product temperature monitoring, Pirani signal or overall sublimation flow shows very good agreement in the case studies presented. Overall, the lyo-simulation incorporating the Kv distribution is a very useful tool to support industrial development, i.e. process optimization, scale assessment, technology transfer, and troubleshooting of the lyophilization process.

Effect of distinct drying approach on bioactive compounds and nutritional profiling of Ulva intestinalis and Padina tetrastromatica from the Bay of Bengal, Bangladesh

Marine algae have been visualized as fostering a prevalent actuation of bioactive substances that have noteworthy therapeutic effects. The current investigations deployed a trio of separate drying methods, i.e., oven drying, freeze drying, and sun drying, to quantify the total phenolic content (TPC), total flavonoid content (TFC), and dietary vitality of Ulva intestinalis and Padina tetrastromatica. By mining and scrutinizing it to the quercetin and gallic acid standards, TPC and TFC were derived. Among three drying techniques, freeze drying asserted higher TPC (12.59 ± 1.07 in U. intestinalis and 68.74 ± 1.95 mg of GA/g in P. tetrastromatica) and TFC (7.92 ± 0.97 in U. intestinalis and 58.15 ± 2.05 mg of quercetin/g in P. tetrastromatica) values. Ulva intestinalis and P. tetrastromatica also contain a high amount of protein (18.34% and 8.7%, respectively). The findings demonstrated that green seaweed possessed higher levels of potassium (2.20%) and molybdenum (2.41%) and brown seaweed showed higher amounts of potassium (2.41%) and calcium (1.11%). Where rapid drying methods are recommended to enhance constituent levels, freeze-drying could be an attractive alternative to oven and sun drying, as it addresses the drawbacks associated with prolonged drying periods.

Evaluation of functional extrudates enriched with essential oils for enhanced stability

This study evaluates the performance and storage stability of functional extrudates enriched with natural additives, utilizing advanced food engineering and processing techniques. Essential oils from oregano, rosemary, hypericum, and chamomile were incorporated in both free and encapsulated forms using electrohydrodynamic processing, spray drying, and freeze drying, and added to the food matrix through extrusion processing. The encapsulated additives demonstrated superior retention and controlled release of bioactive compounds, with spray-dried agents achieving the highest total phenolic content (1.66 mg GAE/g) post-extrusion. During storage, these extrudates exhibited enhanced stability with low degradation rate constants (1.90×10⁻³ days⁻¹ at aw=0.33, 25°C, over 240 days). The bioactive extrudates maintained remarkable stability in terms of hardness and colour change, with hardness inversely correlated to moisture content. These findings highlight the potential of using encapsulation and extrusion processing to create stable, naturally bioactive food products, reducing dependence on synthetic additives. The research underscores the integration of emerging technologies in food science to enhance the stability and delivery of essential oils, supporting the development of sustainable and health-promoting food systems.

Structural modification of CNT-C xerogel through synthesis parameters

This study focuses on the synthesis of porous carbonaceous structures by drying resorcinol-formaldehyde (RF) gels under ambient conditions and then carbonizing them in an inert atmosphere. This avoids the expensive drying processes like supercritical drying or freeze drying. However, drying under ambient conditions does cause structural shrinkage and a reduction in porosity and specific surface area. Therefore, the goal of this study was to compensate for these structural degradations by adjusting other synthesis and process parameters, such as solvent exchange, drying condition, content of water, catalyst, and CNT in the gel. In the present study, different organic solvents such as t-butanol, ethanol, and acetone were used to replace the water in the hydrogels at a certain R/F molar ratio (1:2). The experimental results showed that t-butanol, with its low surface tension, resulted in a structure with a high specific surface area and pore volume. Regarding the catalyst dosage, by changing the R/C molar ratio between 71 and 849, the best structural properties were obtained using R/C∼200. Increasing the water content from 15 to 30 mL led to a decrease in specific surface area and pore volume. Drying the gel at an oven temperature of 85 °C resulted in the highest specific surface area, pore volume, and mean pore diameter. Increasing the dosage of carbon nanotubes (CNTs) in the range of 20–150 mg led to an increase in total pore volume and mean pore diameter. The results of this work can be a step forward towards the industrialization of these materials in various applications.

Effect of freezing temperature on rate of survival of lactococcus cultures during lyophilization

The important component in the activities of the collection of starter microorganisms is the preservation of the pool of the strains valuable for industrial production. Lyophilization (also known as freeze drying) is a widely used method for the long-term storage of the collection cultures. The critical parameter of the process of lyophilization is the pre-freezing temperature. This article brings forward the results of researches of the rate of survival of lactococcus strain cultures during their lyophilization with pre-freezing at the temperatures of minus 20 °C, minus 30 °C and minus 55 °C. Reconstituted 10% skim milk was used as the medium for strain culturing and lyophilization. Different reactions were detected among the microorganisms of Lactococcus lactis subsp. lactis, Lactococcus cremoris and Lactococcus lactis subsp. lactis biovar. diacetylactis for their freezing and lyophilization under the tested conditions. The highest rate of survival of lactococcus strains was observed at the freezing temperature of minus 20 °C. The most resistant cultures appeared to be Lactococcus lactis subsp. lactis biovar. diacetylactis — their rate of survival after lyophilization at minus 20 °C amounted to 42.6-57.9%. The lowest survival rate was recorded for Lactococcus cremoris in all freezing modes (from 3.1 to 15.7%). Lyophilization of lactococcus collection cultures ensures high survival rate of the cells.

Comparison of drying methods for biochemical composition, energy aspects, and color properties of alfalfa hay

AbstractAlfalfa is a crucial feed source for livestock, necessitating proper drying to achieve optimal moisture levels before consumption. This study aims to reveal alfalfa's drying characteristics and quality properties, defined as the queen of feed, by drying it under different drying conditions. Alfalfa samples were dried using different drying techniques: Open-sun, shade, greenhouse, hybrid (microwave-air-convective), air-convective, microwave, and freeze-drying. The influence of drying techniques on the drying kinetics, energy aspects, biochemical properties, mineral composition, fatty acids, carotene, and color attributes of alfalfa were investigated. Present findings revealed that shade and high-temperature drying conditions increased the crude fiber content (23.18%) of alfalfa samples. The highest protein values were found in open-sun drying (22.01%) and 60 °C air-convective drying (22.10%). The highest values for mineral composition were determined in freeze drying, and the greatest Zn (33.68 ppm) and Fe (135.45 ppm) contents were determined in 100 °C air-convective drying. The highest saturated fatty acids open-sun (21.27%) and freeze dryer (21.07%), unsaturated fatty acids at 60 °C (84.51%) and 80 °C (84.26%), poly unsaturated fatty acids at 60 °C (78.36%), 80 °C (78.14%) and 100 °C (77.74%) were obtained. The drying kinetics of alfalfa were best modeled with the Jena&amp;Das, and in terms of a* (greenness) values, the hybrid drying yielded the best results. The lowest total energy consumption (54.00 kWh) was seen in 200W + 80 °C hybrid drying and the highest (324.72 kWh) in 100 °C air-convective drying. The color attributes and energy consumption findings showed that hybrid drying could efficiently be used for alfalfa drying. In addition, freeze drying was determined to be the best drying method in terms of nutrient preservation.

Effect of Preparation and Drying Techniques on the Physicochemical, Functional and Nutritional Properties of products from Beetroot (Beta Vulgaris L.) varieties

Beetroot (Beta vulgaris L.) is rich in biologically active compounds. This study aimed to assess how different methods of preparation and drying affect the physical, chemical, functional, and nutritional properties of iron-rich beetroot powder. Two beetroot varieties, Detroit Dark Red (DetR) and Crimson Globe (CrimG), were processed using three drying techniques: sun drying (SD), oven drying (OD), and freeze drying (FD), with both boiled and fresh beetroots. The properties evaluated in the study included water activity, color, total phenolics and flavonoids, oxalate content, and mineral content. The results showed significant (p&lt;0.05) differences in these properties between the dried and fresh samples. Notably, drying increased calcium, zinc, and phosphorus levels while decreasing the iron content. Boiling followed by sun drying was the best method for retaining iron, particularly for the CrimG variety. The study suggests that drying can help preserve or even enhance the physicochemical properties and micronutrient content, especially iron while reducing phytochemical levels affecting iron absorption. These findings are important for developing iron-rich beetroot products to improve dietary iron intake, especially for adolescent children.

A Comparison Analysis of Quality and Metabolic Compounds in Lilies with Different Drying Treatments.

The present study aimed to investigate the variations in the nutritional composition, antioxidant capacity, and metabolite profile of lilies subjected to different drying treatments, including vacuum freeze drying (VFD), hot air drying (HAD), vacuum drying (VD), and infrared drying (ID). The results show that VFD provided better preservation of the original coloration and displayed the highest levels of total amino acid content, total phenolic content, total flavonoid content, and polysaccharide and alkaloid content. Our results reveal that VFD treatment can be employed to obtain high-quality lilies with desirable appearance characteristics and nutrient compositions. Metabolomics analysis identified a total of 464 metabolites from various dried lilies. Differential metabolite screening found 150 differential metabolites across all pairwise comparisons. Hierarchical clustering analysis (HCA) indicated that lilies subjected to VFD treatment exhibited a higher abundance of steroids, saponin, flavonoids, and phenolic glycoside, whereas those subjected to HAD, VD, or ID treatments showed relatively elevated levels of specific amino acids or derivatives. This study elucidates the significant impact of various drying treatments on the quality and metabolic profile of lilies, thereby providing valuable insights for enhancing the nutritional quality of processed lilies.

Quality Assessment of Greek-Style Set Yoghurt Fortified with Extracted and Dried Australian Native Fruit, Illawarra Plum.

The Illawarra plum (IP) is native to Australia and has been used as a bush food for centuries. With rich phytochemicals and natural pigments, IP has the potential to be an added ingredient to improve the physicochemical properties of food, including yoghurt. This study prepared dried IP powders through vacuum drying (VD) and freeze drying (FD), produced extracts from these dried powders, and fortified them into Greek-style set yoghurt. The changes in colour, pH, titratable acidity (TA), syneresis, total soluble solids (TS), and phytochemicals were measured throughout a chilled storage period of 28 days. The results showed that FD and FD extract could provide a stable, distinct pink colour to yoghurt. IP powders and their extracts improved TS content and, thus, the consistency of yoghurt. Compared to the control, VD, FD, and FD extract of IP did not significantly affect the level of acidity or syneresis after 28 days of chilled storage. Yoghurt fortified with FD and FD extract had the greatest level of phenolics, anthocyanins, and radical scavenging antioxidant activities. This study revealed that IP powders and their extracts can positively improve the physicochemical properties of Greek-style set yoghurt. FD powder is recommended over its extract to fortify this yoghurt, as it can be cost-effectively prepared by freeze drying and then grinding the fresh fruit into powder. Future studies are needed to evaluate other variables in yoghurt preparation, including the concentration of IP and strains of yoghurt culture. Further, the consumer perception of sensory quality and acceptability of yoghurt fortified with FD IP powder should be investigated.

Evaluation of Different Drying Treatments with Respect to Essential Oil Components, Phenolic and Flavonoid Compounds, and Antioxidant Capacity of Ajowan (Trachyspermum ammi L.).

Ajowan (Trachyspermum ammi L.) is considered a valuable spice and medicinal herb. In this study, the essential oil content and composition of the aerial parts of ajowan were investigated under different drying treatments (sun, shade, oven at 45 °C, oven at 65 °C, microwave, and freeze drying). Moreover, the phenolic content, flavonoid content, and antioxidant capacity of samples were also assessed. Fresh samples produced the highest essential oil content (1.05%), followed by those treated under sun (0.7%) and shade drying (0.95%). Based on gas chromatography-mass spectrometry (GC-MS), thirty compounds were determined in which thymol (34.84-83.1%), carvacrol (0.15-32.36%), p-cymene (0.09-13.66%), and γ-terpinene (3.12-22.58%) were the most abundant. Among the drying methods, freeze drying revealed the highest thymol content, followed by drying in a 45 °C oven. The highest TPC (total phenolic content) and TFC (total flavonoid content) were obtained in the fresh sample (38.23 mg TAE g-1 dry weight (DW)) and in the sample oven-dried at 45 °C (7.3 mg QE g-1 DW), respectively. Based on the HPLC results, caffeic acid (18.04-21.32 mg/100 gDW) and ferulic acid (13.102-19.436 mg/100 g DW) were the most abundant phenolic acids, while among flavonoids, rutin constituted the highest amount (10.26-19.88 mg/100 gDW). Overall, freeze drying was the most promising method of drying for preserving the phenolic (TPC) and flavonoid (TFC) compounds and oil components.

Extraction Optimization of Phenolic Compounds from Triadica sebifera Leaves: Identification, Characterization and Antioxidant Activity.

Triadica sebifera (T. sebifera) has attracted much attention because of the high oil content in its seeds, but there are few systematic studies on the phenolic compounds of T. sebifera leaves (TSP). In this study, the extraction process of TSP was optimized by response surface methodology. The phenolic components of these extracts were analyzed by high-performance liquid chromatography (HPLC). Moreover, the effects of hot air drying (HD), vacuum drying (VD) and freeze drying (FD) on the antioxidant activity and characterization of T. sebifera leaf extract (TSLE) were evaluated. Under the conditions of ethanol concentration 39.8%, liquid-solid ratio (LSR) 52.1, extraction time 20.2 min and extraction temperature 50.6 °C, the maximum TSP yield was 111.46 mg GAE/g dw. The quantitative analysis and correlation analysis of eight compounds in TSP showed that the type and content of phenolic compounds had significant correlations with antioxidant activity, indicating that tannic acid, isoquercitrin and ellagic acid were the main components of antioxidant activities. In addition, through DPPH and ABTS determination, VD-TSLE and FD-TSLE showed strong scavenging ability, with IC50 values of 138.2 μg/mL and 135.5 μg/mL and 73.5 μg/mL and 74.3 μg/mL, respectively. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) infrared spectroscopy revealed small differences in the extracts of the three drying methods. This study lays a foundation for the effective extraction process and drying methods of phenolic antioxidants from T. sebifera leaves, and is of great significance for the utilization of T. sebifera leaves.

Development of 3D Printable Gelatin Methacryloyl/Chondroitin Sulfate/Hyaluronic Acid Hydrogels as Implantable Scaffolds.

The development of biomaterials tailored for various tissue engineering applications has been increasingly researched in recent years; however, stimulating cells to synthesise the extracellular matrix (ECM) is still a significant challenge. In this study, we investigate the use of ECM-like hydrogel materials composed of Gelatin methacryloyl (GelMA) and glycosaminoglycans (GAG), such as hyaluronic acid (HA) and chondroitin sulphate (CS), to provide a biomimetic environment for tissue repair. These hydrogels are fully characterised in terms of physico-chemical properties, including compression, swelling behaviour, rheological behaviour and via 3D printing trials. Furthermore, porous scaffolds were developed through freeze drying, producing a scaffold morphology that better promotes cell proliferation, as shown by in vitro analysis with fibroblast cells. We show that after cell seeding, freeze-dried hydrogels resulted in significantly greater amounts of DNA by day 7 compared to the GelMA hydrogel. Furthermore, freeze-dried constructs containing HA or HA/CS were found to have a significantly higher metabolic activity than GelMA alone.

Superwetting PVA/cellulose aerogel with asymmetric structure for oil/water separation and solar-driven seawater desalination

Extracting clean water from oily wastewater and seawater is one of the effective strategies to alleviate the freshwater crisis. However, achieving both high separation efficiency and excellent salt resistance remain challenges for materials. Herein, a novel methyltrichlorosilane-modified polyvinyl alcohol/cellulose aerogel (MPCA) was prepared by freeze drying, chemical cross-linking, and chemical vapor deposition (CVD) methods. The superwetting MPCA presented an asymmetric structure, in which the small dense pores at the top surface facilitated the efficient separation of water-in-oil (W/O) emulsions and the large pores on the bottom surface were beneficial for brine exchange. The as-prepared superwetting aerogel was suitable for the separation of various W/O emulsions with excellent separation flux (631.9–2368.7 L·m−2·h−1) and outstanding separation efficiency (99.5 %). In addition, MPCA achieved a high evaporation efficiency of 1.39 kg·m−2·h−1 and a satisfactory energy conversion efficiency of 89.7 %. Moreover, the unique asymmetric structure endowed the evaporator excellent salt resistance and could self-dissolve the accumulated salt in 20 min. The as-prepared MPCA could achieve efficient W/O emulsion separation as well as produce freshwater in seawater, providing a new strategy for oily waste seawater purification.

Chitosan-Gelatin Scaffolds Loaded with Different Antibiotic Formulations for Regenerative Endodontic Procedures Promote Biocompatibility and Antibacterial Activity.

This study investigated the biocompatibility and antibacterial efficacy of chitosan-gelatin (CH-G) scaffolds loaded with slow-releasing antibiotic formulations used in regeneration endodontic procedures (REPs). Scaffolds were fabricated using freeze drying and loaded with varying concentrations of augmentin or modified triple antibiotic paste (mTAP). High-resolution scanning electron microscopy (SEM) was used to characterize the scaffold, while drug release was monitored via UV-Vis spectrophotometry. Immortalized human mesenchymal stem cells (hMSCs) were cultured on CH-G scaffolds alone (control), either 0.1 mg/mL or 1 mg/mL of augmentin or mTAP, and 10 mg/mL calcium hydroxide (Ca(OH)2). Cell viability and proliferation were assessed using the Alamar Blue assay and SEM, respectively, and live/dead staining further corroborated cell viability. Antibacterial activity against Enterococcus faecalis was evaluated using the MTT assay and confocal laser scanning microscopy (CLSM). Augmentin at 0.1 mg/mL appeared to promote better cell growth and attachment within the scaffolds than all other formulations, exhibiting acceptable viability. SEM revealed improved cell attachment in augmentin and mTAP groups compared to the Ca(OH)2 group. Augmentin at 1 mg/mL and mTAP groups significantly reduced viable bacteria compared to controls. Augmentin groups and mTAP at 1 mg/mL were highly effective in eliminating E. faecalis biofilms, with mTAP potentially causing more cell death within the remaining biofilm structures. This study suggests that CH-G scaffolds loaded with augmentin and mTAP, particularly at a concentration of 1 mg/mL, offer promising advantages for REPs due to their biocompatibility, antibacterial efficacy, and ability to promote cell attachment. Further research may explore the long-term effects in clinical settings.

Effect of Ultrasound and Freeze‐Drying to Enhance the Extraction of Phenolic Compounds in Dragon Fruit Peels and Apply Them in Edible Starch‐Based Films

ABSTRACTIn this study, dragon fruit peels were subjected to different times (5, 10, 15, 20 and 25 min) of ultrasound pretreatment (4.870 W m−2/25°C) and then freeze‐drying (FD) (−56°C/48 h) to obtain powder particles, which underwent physical–chemical, functional and structural characterisation. Additionally, the extraction of total phenolic compound (TPC) was evaluated through ultrasound‐assisted kinetics and mechanical agitation. Finally, films based on black rice starch were developed with the addition (0.5, 1.5 and 2.5%) of dragon fruit peel powder particles, and their physical, barrier, antioxidant, structural and mechanical properties were evaluated. The results obtained showed that all particles had low water content (4.21%–6.58%) and high solubility (84.62%–88.73%) with a reduction in particle size (23.21–39.32 μm). In the extraction of TPC, the synergistic effect of the tested conditions increased efficiency, reaching 686.66 mg GAE/100 g for pretreated dragon fruit peel powder particles (25 min) in 180 min of extraction. Furthermore, the type ‘A’ crystallinity structure did not change significantly with pretreatment, but there was a reduction in peak area, reflecting on relative crystallinity, with a maximum decrease of 29.04%. The starch‐based films produced with 2.5% dragon fruit peel powder particles showed low solubility (28.72%) and low water vapour permeability (5.03 × 10−8 g mm s−1 m2 Pa), however, they contained higher levels of TPC (31.78 mg GAE/100 g film) and antioxidant activity (8.17 μmol TE/g film) that were easily migrated in aqueous medium. Furthermore, they also presented low values of tensile strength at break (3.41 MPa) and Young's modulus (4.18 MPa), as well as a high value of elongation at break (45.82%). Finally, our results highlight the potential of ultrasound as a pretreatment for FD of dragon fruit peels, paving the way for the development of rice starch‐based food packaging.

V2O3/VO2@NC@GO ultrathin nanosheets as a high-performance cathode for aqueous zinc-ion batteries

Recently, vanadium oxides have attracted much attention as advanced cathodes for aqueous zinc-ion batteries on account of their high theoretical specific capacity, multi-electron transfer and easy synthesis; however, structural instability and poor conductivity of the materials limit their practical application. Herein, N-doped carbon-coated V2O3/VO2 hybrid nanosheets were encapsulated into graphene oxide (V2O3/VO2@NC@GO) as an advanced cathode for aqueous zinc-ion batteries by the combined process of hydrothermal treatment, high-temperature annealing and freeze drying. The multi-valence of vanadium element activates diverse redox reactions and thus results in high specific capacity, while graphene oxide and N-doped carbon layer derived from polyvinyl pyrrolidone establish an efficient conductive network for electronic transfer and provide a rigid skeleton for enhancing the structural stability of the hybrid nanosheets. Benefiting from the above unique advantages of composition and micromorphology, the V2O3/VO2@NC@GO cathode exhibits excellent reaction dynamics and rapid electron transfer, generating high specific capacities of 493.0 mAh g−1 at 0.5 A g−1 and 411.9 mAh g−1 at 5 A g−1 and outstanding long-term cycling performance with a retention of 92.4 % after 1000 cycles at 5 A g−1. This work offers a viable approach for developing high-performance vanadium oxide-based cathodes for aqueous zinc-ion batteries by enriching the valence states of vanadium and encapsulating active materials into highly conductive carbon materials.

Effects of different pretreatment on the drying characteristics and pectin properties of jujube by microwave coupled with pulsed vacuum drying

AbstractThe effects of ultrasound (US), ultrahigh pressure (UP), cold plasma (CP), and high pressure and pulsed electric fields (PEF) pretreatments were evaluated for drying characteristics, bioactive components, and pectin properties of jujube slices during microwave coupled with pulsed vacuum drying (MPVD). US, CP, and PEF reduced drying time by 18.75%, while UP reduced it by 6.25%. Samples treated with US and PEF showed improved color and rehydration (345.11%, 319.24%), with SEM revealing larger pores post‐pretreatment. PEF‐treated jujube had highest phenol (16.95 mg GAE/g DW) and water‐soluble pectin(WSP) (43.71 mg/g AIR), correlating positively with rehydration (r = 0.67). CP had highest flavonoid content (17.01 mg RE/g DW) and US showed highest antioxidant activity (DPPH 80.57%, ABTS 89.65%). Chelate‐soluble pectin (CSP) Sodium carbonate‐soluble pectin (NSP) was positively correlated with hardness (r = 0.71, 0.69). These findings suggest pretreatments improve drying efficiency, nutrient retention, and pectin functionality in jujube products. Practical ApplicationsDrying for jujube (Ziziphus jujuba Mill.) is the most common method of processing and ensure the sale. Three kinds of non‐thermal processing pretreatment method (ultrasound, ultrahigh pressure, and cold plasma) combined with novel drying method, microwave coupled pulsed vacuum drying (MPVD) was studied in the application on the dehydration of jujube slice in this paper. The drying characteristics and pectin properties of winter jujube were analyzed and treated by MPVD compared with freeze drying and hot air drying, for both technological research and processing practice. The drying kinetics, bioactive compounds, antioxidant capacity, sensory attributes, and pectin properties were also used as descriptors in order to promising dehydration method for obtaining high value‐added jujube products. Moreover, the relationship between the cell wall pectin and the phenols, hardness and crispness were analyzed, which give a new insight to study the changing scheme in the nutrients and the texture during the dehydration for fruits and vegetables.

Exploring thermal and in-situ mechanical properties of flexible 2D tungsten disulfide foam-polymer composite for thermal management

In the realm of thermal management applications, there is a growing need for flexible materials that can efficiently dissipate heat. Polymer composites incorporating two-dimensional (2D) materials offer promising solutions due to their superior thermal and mechanical properties. Tungsten disulfide (WS2) is an excellent filler candidate for polymer composites due to its superior thermal conductivity, mechanical strength, and electrical properties. Unlike graphene, WS2 has a tunable bandgap, exhibits higher thermal resistance in inert atmospheres, is an effective lubricant over a wide temperature range of −190°C to over 800°C, and offers superior gamma radiation shielding. However, high-density 2D material polymer composite fabrication faces challenges due to the agglomeration tendency and sedimentation of heavy nanomaterials within the polymer matrix. This poor dispersion stability negatively impacts the performance and reliability of the composite. We developed a flexible WS2 foam-polydimethylsiloxane (PDMS) composite via freeze drying and vacuum-assisted infiltration, which not only overcomes fabrication challenges but also enables unique filler reinforcement foam designs. The thermal conductivity of WS2-PDMS foam was 1.57 times higher than that of neat PDMS. These thermal properties were modeled using the Lewis-Nielsen model. In-situ tensile tests were conducted to understand the mechanical reinforcing behavior and failure mechanisms of WS2 foam, which were further studied using the Gibson and Ashby model. The addition of WS2 into PDMS resulted in an elastic modulus 1.56 times higher than that of neat PDMS. The composite's mechanical properties were analyzed using the Halpin-Tsai model. These findings highlight the potential of WS2-PDMS composites for flexible thermal management applications.