Tomas Bata University in Zlín
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Effect of technological processing and recipe formulation on the physico-chemical properties of ganaches and chocolate pralines
No full textThis study investigates the impact of structural modifications of chocolate ganaches by changes in technological processing and by addition of emulsifier, milk fat, milk protein, and guar gum. Ganaches were evaluated by textural analysis, differential scanning calorimetry, frequency sweep rheology, and optical microscopy. Chocolate pralines were manufactured from studied ganaches, followed by sensory and microbial tests for consumer acceptability and shelf-life stability, respectively. Ganache subjected to a 3-min emulsification process exhibited optimal properties and was sensorially rated as the most preferred. Notably, neither the emulsifier application nor extended 6-min emulsification had significant effect on the measured properties. The addition of milk proteins and guar gum resulted in a firm and complex water-binding structure, confirmed by higher viscoelasticity and lower water activity, and resulted in a better shelf-life stability. The preparation process minimally affected melting profiles measured by DSC, however, sample with guar gum exhibited a slight shift to higher temperatures.Tomas Bata University in Zlín, TBU, (IGA/FT/2024/005); Tomas Bata University in Zlín, TBUTomas Bata University in Zlin [IGA/FT/2024/005
The effect of inulin addition on rice dough and bread characteristics
Get PDFFeatured Application: The obtained results may be applied in gluten-free bread production. Inulin may be widely used in in the food industry due to its many health benefits. It has the potential to increase the insufficient nutritional quality of gluten-free bread. Therefore, the aim of this study was to test the applicability of inulin in rice baking. The impact of added inulin (5%, 10%, 20%, 30%, and 40%) on the dough’s rheological, bread’s textural and sensory characteristics was evaluated. The extensibility of rice dough during uniaxial deformation tests (8.5 mm) was improved by the added inulin (10.2–12.3 mm). The presence of inulin softened the dough and shifted the gelatinization temperature toward higher values. The added inulin also increased the loaf’s specific volume (1.16–1.48 mL/g), tenderized the breadcrumbs, increased the crumb porosity (36–58%), and generally improved the crumb structure. The panelists favored the sensory characteristics of breads with inulin. However, baking losses were increased in these breads as well (15.1–18.5%). The effect of the added inulin on the dough and bread characteristics generally rose with an increasing addition of inulin, reaching the maximum in samples with 30% inulin. The presence of 40% inulin deteriorated some characteristics of the bread. Therefore, the addition of up to 30% of inulin seemed to be optimal for rice bread.International Glaucoma Association, IGA, (IGA/FT/2024/009, IGA/FT/2024/006); International Glaucoma Association, IGAIGA [IGA/FT/2024/009, IGA/FT/2024/006
Grasping the behavior of magnetorheological fluids in gradient pinch mode via microscopic imaging
Get PDFMagnetorheological (MR) fluids are suspensions of micrometer-sized ferromagnetic particles in a carrier fluid, which react to magnetic fields. The fluids can be operated in several fundamental modes. Contrary to the other modes, the rheology and microstructure formation of the MR fluid in the gradient pinch mode have been studied to a far lesser extent. The magnetic field distribution in the flow channel is intentionally made non-uniform. It is hypothesized that the Venturi-like contraction is achieved via fluid property changes, leading to a unique behavior and the presence of a pseudo-orifice. The main goal is to investigate the presence of the Venturi-like contraction effect in the fluid by means of optical imaging and hydraulic measurements. To accomplish the goal, a unique test rig has been developed including a fluorescence microscope and MR valve prototype. The Venturi-like contraction hypothesis was confirmed. The results indicate that the effective flow channel size decreases by 92% at the maximum magnetic flux applied. This has a direct impact on the flow characteristics of the MR valve. The variation of the pressure-flow rate curve slope with magnetic field was demonstrated. The results provide valuable information for understanding the rheology and microstructure formation mechanism in MR fluids in the pinch mode.Grantová Agentura České Republiky, GA ČR; Narodowe Centrum Nauki, NCN, (GACR 21-45236L, 2020/39/I/ST8/02916)National Science Centre (Narodowe Centrum Nauki-NCN, Poland) [GACR 21-45236L]; [2020/39/I/ST8/02916
Carbonized leather waste with deposited polypyrrole nanotubes: Conductivity and dye adsorption
Get PDFThis paper reports the conversion of a waste to a conducting material, exploiting the ability to adsorb pollutant organic dyes. Leather waste was carbonized at 800 °C in an inert nitrogen atmosphere. The resulting biochar was used for in-situ deposition of polypyrrole nanotubes produced by the oxidative polymerization of pyrrole in the presence of methyl orange. The composites of carbonized leather with deposited polypyrrole nanotubes of various composition were compared with similar composites based on globular polypyrrole. Their molecular structure was characterized by infrared and Raman spectra. Both conducting components formed a bicontinuous structure. The resistivity was newly determined by a four-point van der Pauw method and monitored as a function of pressure applied up to 10 MPa. The typical conductivity of composites was of the order of 0.1 to 1 S cm−1 and it was always higher for polypyrrole nanotubes than for globular polypyrrole. The method also allows for the assessment of mechanical features, such as powder fluffiness. The conductivity decreased by 1–2 orders of magnitude after treatment with ammonia but still maintained a level acceptable for applications operating under non-acidic conditions. The composites were tested for dye adsorption, specifically cationic methylene blue and anionic methyl orange, using UV-vis spectroscopy. The composites were designed for future use as functional adsorbents controlled by the electrical potential or organic electrode materials.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (RP/CPS/2022/005)Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/005
Two squares in a barrel: An axially disubstituted conformationally rigid aliphatic binding motif for cucurbit[6]uril
Get PDFNovel binding motifs suitable for the construction of multitopic guest-based molecular devices (e.g., switches, sensors, data storage, and catalysts) are needed in supramolecular chemistry. No rigid, aliphatic binding motif that allows for axial disubstitution has been described for cucurbit[6]uril (CB6) so far. We prepared three model guests combining spiro[3.3]heptane and bicyclo[1.1.1]pentane centerpieces with imidazolium and ammonium termini. We described their binding properties toward CB6/7 and α-/β-CD using NMR, titration calorimetry, mass spectrometry, and single-crystal X-ray diffraction. We found that a bisimidazolio spiro[3.3]heptane guest forms inclusion complexes with CB6, CB7, and β-CD with respective association constants of 4.0 × 104, 1.2 × 1012, and 1.4 × 102. Due to less hindering terminal groups, the diammonio analogue forms more stable complexes with CB6 (K = 1.4 × 106) and CB7 (K = 3.8 × 1012). The bisimidazolio bicyclo[1.1.1]pentane guest forms a highly stable complex only with CB7 with a K value of 1.1 × 1011. The high selectivity of the new binding motifs implies promising potential in the construction of multitopic supramolecular components.Internal Funding Agency of Tomas Bata University, (IGA/FT/2023/001); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LM2023042, LUAUS23144); Ústav organické chemie a biochemie Akademie věd České republiky, ÚOCHB AV ČR, (RVO: 61388963)Internal Funding Agency of Tomas Bata University in Zlin [IGA/FT/2023/001]; MEYS CR [LM2023042]; Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences [RVO: 61388963]; Ministry of Education, Youth and Sports [LUAUS23144
Critical entities resilience failure indication
Get PDFThe adoption of the new Directive (EU) 2022/2557 on the resilience of critical entities has raised the question of how to assess the level of resilience of these entities in relation to current security threats. Until now, approaches have focused only on assessing the resilience of critical infrastructure elements. However, the new Directive exemplifies the need to pay attention not only to the element resilience, but also and more importantly to the resilience of their owners and operators, i.e., critical entities. Based on this fact, the authors of the article created a tool for Critical Entities Resilience Failure Indication (CERFI Tool). The essence of this tool is a probabilistic algorithm that predicts the relationship between the threat intensity and the protective part of critical entity resilience through indicators (to be created by the assessors themselves). The result of this prediction is an indication of the critical point of failure of the critical entity's resilience in phases of prevention and absorption of impacts. The CERFI Tool thus contributes to increasing the safety of technically oriented infrastructures, especially those of an energy and transport nature. The paper concludes with an example of the practical application of the developed tool on a selected critical entity in the energy sector.Ministerstvo Vnitra České Republiky, (SP2023/086, VK01030014)Ministry of the Interior of the Czech Republic [VK01030014]; VSB - Technical University in Ostrava [SP2023/086
Study on surface roughness, morphology, and wettability of laser-modified powder metallurgy-processed Ti-graphite composite intended for dental application
Get PDFIn this study, the surface laser treatment of a new type of dental biomaterial, a Ti-graphite composite, prepared by low-temperature powder metallurgy, was investigated. Different levels of output laser power and the scanning speed of the fiber nanosecond laser with a wavelength of 1064 nm and argon as a shielding gas were used in this experiment. The surface integrity of the machined surfaces was evaluated to identify the potential for the dental implant’s early osseointegration process, including surface roughness parameter documentation by contact and non-contact methods, surface morphology assessment by scanning electron microscopy, and surface wettability estimation using the sessile drop technique. The obtained results showed that the surface roughness parameters attributed to high osseointegration relevance (Rsk, Rku, and Rsm) were not significantly influenced by laser power, and on the other hand, the scanning speed seems to have the most prevalent effect on surface roughness when exhibiting statistical differences in all evaluated profile roughness parameters except Rvk. The obtained laser-modified surfaces were hydrophilic, with a contact angle in the range of 62.3° to 83.2°.KOMPLAS; Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA, (026STU-4/2023); Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, VEGA, (2/0054/23)VEGA [2/0054/23]; KEGA [026STU-4/2023]; STU Grand Scheme for Support of Young Researcher
Conducting and magnetic hybrid polypyrrole/nickel composites and their application in magnetorheology
Get PDFHybrid organic/inorganic conducting and magnetic composites of core–shell type have been prepared by in-situ coating of nickel microparticles with polypyrrole. Three series of syntheses have been made. In the first, pyrrole was oxidised with ammonium peroxydisulfate in water in the presence of various amounts of nickel and the composites contained up to 83 wt% of this metal. The second series used 0.1 M sulfuric acid as a reaction medium. Finally, the composites with polypyrrole nanotubes were prepared in water in the presence of structure-guiding methyl orange dye. The nanotubes have always been accompanied by the globular morphology. FTIR and Raman spectroscopies confirmed the formation of polypyrrole. The resistivity of composite powders of the order of tens to hundreds Ω cm was monitored as a function of pressure up to 10 MPa. The resistivity of composites slightly increased with increasing content of nickel. This apparent paradox is explained by the coating of nickel particles with polypyrrole, which prevents their contact and subsequent generation of metallic conducting pathways. Electrical properties were practically independent of the way of composite preparation or nickel content and were controlled by the polypyrrole phase. On the contrary, magnetic properties were determined exclusively by nickel content. The composites were used as a solid phase to prepare a magnetorheological fluid. The test showed better performance when compared with a different nickel system reported earlier.Grantová Agentura České Republiky, GA ČR, (22-25734S, 23-07244S)Czech Science Foundatio
Chitosan/dialdehyde cellulose hydrogels with covalently anchored polypyrrole: Novel conductive, antibacterial, antioxidant, immunomodulatory, and anti-inflammatory materials
Get PDFIn this work, conductive composite hydrogels with covalently attached polypyrrole (PPy) nanoparticles are prepared. Hydrogels are based on partially re-acetylated chitosan soluble at physiological pH without any artificial structural modifications or need for an acidic environment, which simplifies synthesis and purification. Low-toxic and sustainable dialdehyde cellulose (DAC) was used for crosslinking chitosan and covalent anchoring of PPy colloidal particles. The condensation reaction between DAC and PPy is reported for the first time and improves not only the anchoring of PPy particles but also control over the properties of the final composite. The soluble chitosan and PPy particles are shown to act in synergy, which improves the biological properties of the materials. Prepared composite hydrogels are non-cytotoxic, non-irritating, antibacterial, can capture reactive oxygen species often related to excessive inflammation, have conductivity similar to human tissues, enhance in vitro cell growth (migration assay), and have immunomodulatory effects related to the stimulation of neutrophils and macrophages. The covalent attachment of PPy also strengthens the hydrogel network. The aldol condensation as a method for PPy covalent anchoring thus presents an interesting possibility for the development of advanced biomaterials in the future.DKRVO, (RP/CPS/2022/001, RP/CPS/2022/007); Tomas Bata University in Zlín, TBU, (IGA/CPS/2023/001); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR, (23-07425S)Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/001]; DKRVO [RP/CPS/2022/007]; Internal Grants of Tomas Bata University in Zlin [IGA/CPS/2023/001]; Czech Science Foundation [23-07425S
Valorization of grape (Vitis vinifera) leaves for bioactive compounds: novel green extraction technologies and food-pharma applications
Get PDFGrape leaves, scientifically known as Vitis vinifera, the primary by-product obtained after the processing of grapes, are gathered in enormous amounts and disposed of as agricultural waste. For more sustainable agriculture and better food systems, it is crucial to investigate these byproducts’ nutritional values. The primary bioactive compounds present in grape leaves are quercetin, resveratrol, caffeic acid, kaempferol, and gallic acid, which favour pharmacological effects on human health such as antioxidant, anti-inflammatory, anti-obesity, anti-diabetic, and hepatoprotective. Furthermore, grape leaves extract has been used as a functional ingredient for creating both food and non-food products. The aim of the current review is to review the nutritional and phytochemical composition of various varieties of grape leaves, their health-promoting characteristics and their applications. The study also highlights the various extraction techniques including conventional and non-conventional methods for extracting the various bioactive compounds present in grape leaves. Grape leaves bioactives can be extracted using environmentally safe and sustainable processes, which are in line with the rising demand for eco-friendly and healthful products worldwide. These methods are perfectly suited to the changing needs of both customers and industries since they lessen environmental effect, enhance product quality, and offer financial advantages