Color Measurements Research Articles

Effect of different thawing methods on the quality of goat liver

The experiment was conducted to find out the effect of different thawing methods like ambient temperature thawing, refrigerator thawing and tap water thawing on the quality of goat liver. Sensory evaluation, proximate components, physico-chemical quality, biochemical properties and microbiological tests. Six goat livers were collected from a local slaughterhouse. Liver samples were preserved under freezing condition (-20°C) for 3 months after fresh evaluation. After evaluation of thawed liver, color, odor, juiciness, and tenderness were significantly (P<0.05) different with maximum values of color and odor found in refrigerator thawing while maximum juiciness and tenderness value found in ambient temperature thawing. DM and Ash contents were not significantly differed (P>0.05); however, the highest value found in refrigerator thawing within the three thawing methods. CP content was significant (P<0.05) different among the different thawing methods. EE content differed significantly (P<0.05), although less amount of EE content was found in refrigerator thawing. There was no significant (P>0.05) variation of pH value on studied thawing methods. Thawing loss, WHC and colour measurement significantly (P<0.05) differed with the different thawing methods, while thawing loss of tap water thawing, WHC value of ambient temperature thawing and colour value of refrigerator thawing were found in maximum level. TBARS value was significantly varied among the different thawing methods where the minimum result found in tap water thawing but maximum result found in ambient temperature thawing. TVC, TCC and TYMC comparatively more number found in ambient temperature thawing but less number found in refrigerator thawing. The lowest number of microbial counts found in refrigerator thawing. It may conclude that refrigerator thawing is the best thawing method to determine the quality of goat liver than others in this experimental condition.

Imaging Based Techniques Combined with Color Measurements for the Enhancement of Medieval Wall Paintings in the Framework of EHEM Project.

(1) Background: This paper illustrates an innovative methodological approach chosen to study and map the colors of the medieval wall painting of Santa Maria Antiqua in the Roman Forum, one of the pilot sites of the EHEM project (Enhancement of Heritage Experiences: The Middle Ages). Digital Layered Models of Architecture and Mural Paintings over Time). (2) Methods: Two methods were employed to gather information about colors and mapping. Specifically, colorimetry was utilized for spot measurements, and hypercolorimetric multispectral imaging (HMI) was employed to map the same colors sampled through colorimetry. (3) Results: Chromatic data for all colors in the wall paintings were obtained in the CIELAB color space. Additionally, chromatic similarity maps were generated using the innovative HMI system, a multispectral imaging technique capable of obtaining color data information through advanced calibration software named SpectraPick® (Version 1.1). This comprehensive approach facilitates a thorough understanding of color characteristics and distribution. (4) Conclusions: The color measurements and mapping represent significant advancements in the interpretation of medieval wall paintings, which are often fragmentary and stratigraphically complex. This research sheds new light on the colors used and enhances our understanding of the original appearance of the iconographic patterns. Furthermore, it enables the reconstruction of colors that closely resemble the originals.

A New Approach in Part Design for Friction Stir Welding of 3D-Printed Parts with Different Infill Ratios and Colors.

Parts produced using a 3D printer are combined with friction stir welding (FSW). In the FSW processing of parts with a low infill ratio, welding errors occur due to a lack of material. In this study, plates were created using two different-colored PLA Plus filaments with different infill ratios in the weld area (20%, 60%, and 100%). Triangular pin geometry, different feed rates (20, 40, and 60 mm/min), and different tool rotation speeds (1250, 1750, and 2250 rpm) were used as FSW process parameters. Tensile testing was performed to determine weld strength and hardness measurements, and visual inspections were performed. Color measurements were made on the test samples before and after the welding process, and the relationship between welding performance and color was evaluated. The best welding strength was obtained as 17.83 ± 0.68 MPa at a feed rate of 20 mm/min, a tool rotation speed of 1750 rpm, and a part with a 60% infill ratio in the welding zone. In the sample with the best weld strength, the temperature was measured as 198.97 °C. Color changes in the weld area of parts with 60% and 100% infill ratios were measured between 78.9-82.2 and 79.1-84.5, respectively. It was determined that the color change decreases as the weld strength increases in these parts. The results show that with the proposed new part design, the FSW method can be used at low infill ratios, and the weld strength can be evaluated based on the color changes in the weld zone.

A comparative study on photodegradation of twenty-three wood species after UV irradiation

The study investigates the effect of UV irradiation on different native and exotic wood species which is an open subject of research. Thirteen native wood species and ten exotic wood species, totally twenty-three wood species, all important for wood industry in Turkey, were subjected to UVA-340nm irradiation with a constant irradiance of 0.89 W/m2/nm and a temperature of 60 °C for 2, 4, 8, 16, 24, 48, 72, 96, 120, 144, 168, 252 and 336 h to determine the critical degradation time for the wood species. A short exposure time (from 2h to 48h) was especially studied since the previous studies reported that important and rapid changes occurred within the initial exposure periods. The effect of UV irradiation on wood surfaces was investigated by color, surface roughness, and FTIR-ATR measurements. The results proved that UV radiation caused a rapid color change for extractive-rich wood species at the initial period of exposure (16h–48h) which decreases upon prolonged exposure. The overall color change and surface roughness were higher for native wood species in a long exposure period than for exotic ones. Elm, oak, plane, walnut, acacia and linden as native wood species, iroko, tiama, acajou, okoume, garapa, sapelli, dibetou and teak as exotic wood species were found to be more resistant to color changes in prolonged irradiation periods, probably due to content of their components especially extractives and lignin. Similar to greater color change found within the beginning of the irradiation period (16h–48h), the first 8h–24h seemed to cause a greater increase in roughness for exotic species and 16h–24h for native wood species probably due to the changes in surface chemistry. Acacia, elm, cherry, beech, tiama, teak and okoume had the highest RI whilst S. pine, ash, poplar, plane, sapelli, limba and iroko had the lowest RI among the wood species. FTIR–ATR analysis demonstrated that UV light ended up with photodegradation of lignin and photooxidation of hemicelluloses which leads carbonyl-containing chromophores, even after short-time exposures (8h–24h).

Structure, Microbiology and Sensorial Evaluation of Bologna-Style Sausages in a Kilohertz Ohmic Heating Process

Ohmic heating (OH) is a sustainable heating technology with a high potential in terms of energy and time efficiency. However, its industrial application for solid or semi-solid foods is not widespread yet. This study evaluates the pilot-scale production of Bologna-style sausages (2.3 kg weight) via conventional heating (COV) and OH at an electrical frequency of 10 kHz. Sausages with a diameter of 110 mm heated via OH were produced in approximately 5% of the time (i.e., 10 min) needed to produce sausages heated via COV. OH-treated samples showed a higher moisture content and an increased water holding capacity. A texture profile analysis revealed OH sausages as possessing a lower hardness, springiness, and chewiness. The microbiological load of the samples was identical, regardless of the heating technology. Color measurements (L*a*b* values) showed OH-treated samples to be less red. However, this difference could not be confirmed during sensorial evaluation. Temporal sensation of dominance and descriptive sensory analyses were conducted and revealed a decreased solid consistency but an increased meat taste when sausages were heated via OH. The gel network structures obtained via scanning microscopic analysis showed an increased size of fat globules within OH-treated samples. The results indicated that OH can be used as an alternative heating method to produce Bologna-style sausages.

Novel Beeswax-neat’s-foot oil formulation and its impact on leather finishing

Leather finishing provides an esthetic look to the leather. Oil in combination with wax emulsion in the form of oleogel when applied to leather finishing produces a special class of leather known as crunch leather. Using an optimized ratio of Beeswax emulsion blended with Neat’s-foot oil in the form of oleogel for the making of crunch leather was investigated in this study. The chemical characterizations such as FTIR, dynamic light scattering, and particle size analysis, of the experimental emulsion were carried out. The experimental leathers undergo various tests such as contact angle measurements, optical microscopy imaging, color measurement, light fastness, fastness to dry and wet rub, tensile, tear strength, and elongation at break. The experimental leathers were showing better results than the control leathers. The present work focuses on the finishing of leather, and the interaction of oil and wax oleogel with leather which approaches a sustainable and eco-friendly process.

CO2-equivalent emissions and quality evaluation of chilled and frozen Atlantic salmon transported from Norway to Japan

Atlantic salmon (Salmo salar) is the top imported fish in Japan. It is usually shipped in chilled form by air cargo to preserve its freshness but posts a high environmental impact. As a sustainable alternative, ocean freight can be implemented if the salmon is frozen. However, the question arises as to whether the quality of the frozen and thawed salmon is comparable. Therefore, the aim of this study is to evaluate the environmental impact and quality of Norwegian Atlantic salmon in chilled and frozen form. The CO2 equivalent emissions of the key life-cycle stages were calculated, and the quality assessment was carried out by colorimetry and sensory evaluation with careful preparation and execution. The results showed that the CO2 equivalent emissions of the packaging, transport, and overall cycle of the frozen salmon were 35 %, 90 %, and 60 % lower than those of the chilled salmon. Color measurements using digital imaging show that the frozen salmon is slightly redder, with a higher a* value and a lower b* value. Panelist ratings indicated that there was no statistically significant difference in perceived color, glossiness, fishy smell, texture, umami, and juiciness between chilled and frozen salmon. The study provides preliminary results that demonstrate the potential of frozen seafood and ocean freight transportation as a sustainable cold chain solution.

Color Biomimetics in Textile Design: Reproduction of Natural Plant Colors through Instrumental Colorant Formulation.

This paper explores the intersection of colorimetry and biomimetics in textile design, focusing on mimicking natural plant colors in dyed textiles via instrumental colorant formulation. The experimental work was conducted with two polyester substrates dyed with disperse dyes using the exhaustion process. Textiles dyed with different dye colors and concentrations were measured in a spectrophotometer and a database was created in Datacolor Match Textile software version 2.4.1 (0) with the samples' colorimetric properties. Colorant recipe formulation encompassed the definition and measurement of the pattern colors (along four defined natural plants), the selection of the colorants, and the software calculation of the recipes. After textile dyeing with the lowest expected CIELAB color difference (ΔE*) value recipe for each pattern color, a comparative analysis was conducted by spectral reflectance and visual assessment. Scanning electron microscopy and white light interferometry were also used to characterize the surface of the natural elements. Samples dyed with the formulated recipe attained good chromatic similarity with the respective natural plants' colors, and the majority of the samples presented ΔE* between 1.5 and 4.0. Additionally, recipe optimization can also be conducted based on the colorimetric evaluation. This research contributes a design framework for biomimicking colors in textile design, establishing a systematic method based on colorimetry and color theory that enables the reproduction of nature's color palette through the effective use of colorants.

IMPACT OF DIFFERENT ORGANIC AND INORGANIC AMENDMENTS ON GROWTH AND YIELD OF MUNG BEAN IRRIGATED WITH TEXTILE EFFLUENTS

Water is an important substance for all life on earth, and it is essential for human beings, financial improvement, and the existence of ecological units. The quality and quantity of the water supply is very important, especially during irrigation. Due to the extensive measurement of water and colour associated with the manufacturing process, textile printing, and dyeing production lines around the world pose a major environmental risk. Textile wastewater contains a lot of pollutants including pH, temperature, shade, COD, BOD, TSS, TDS, EC, and heavy metals. This textile runoff continues to irrigate agricultural land, causing contamination of soils and plant systems with heavy metals. Therefore, adding organic and inorganic modifiers to soil is an effective technique for fixing heavy metals. Irrigate pots with textile wastewater of selected concentrations (10%, 25%, 50%, and 100%) collected in specific industrial sectors. The parameters of vegetative growth are reduced by increasing the concentration of textile effluent. Note the substantial reduction in the growth of plants applying wastewater at 100% concentration. In the case of T5, a significant increase in growth parameters was observed, where only tap water was used to pressurize the sludge, while dilute wastewater also enhanced growth at concentrations of 10% and 25%. For the chlorophyll content of mung bean plants, when the wastewater concentration is 100%, the recorded decrease is greater, followed by 10% and 25% respectively. The presence of heavy metals in wastewater reduces plant growth. In the experiment, all four treatments contained organic amendments (pressed sludge, poultry manure, biogas slurry, and farmyard manure). The other four treatment methods are pressure treatment of textile wastewater and the amount of organic modifier is 2%. By adding a correcting agent, the utilization rate of Cr is reduced, as the correcting agent will increase the pH of the soil, thus reducing the solubility of the metal. In addition, Cr can form insoluble complexes with organic materials, thus reducing its solubility.

Thermochromic materials in the paints and varnishes sector. Part I: perception and measurement of color

Thermochromic materials in the paints and varnishes sector. Part I: perception and measurement of color

The Highly Durable Antibacterial Gel-like Coatings for Textiles.

Hospital-acquired infections are considered a priority for public health systems since they pose a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper introduces a highly durable antibacterial gel-like solution, Silver Shell™ finish, which contains chitosan-bound silver chloride microparticles. The study investigates the coating's environmental impact, health risks, and durability during repeated washing. The structure of the Silver Shell™ finish was studied using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The TEM images showed a core-shell structure, with chitosan forming a protective shell around groupings of silver microparticles. The field-emission scanning electron microscopy (FESEM) demonstrated the uniform deposition of Silver Shell™ on the surfaces of the fabrics. AATCC Test Method 100 was employed to quantitatively analyze the antibacterial properties of the fabrics coated with silver microparticles. Two types of bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were used in this study. The antibacterial results showed that after 75 wash cycles, a 100% reduction for both S. aureus and E. coli in the coated samples using crosslinking agents was observed. The coated samples without a crosslinking agent exhibited 99.88% and 99.81% reductions for S. aureus and E. coli after 50 washing cycles. To compare the antibacterial properties toward non-pathogenic and pathogenic strains of the same species, MG1655 model E. coli strain (ATCC 29213) and a multidrug-resistant clinical isolate were used. The results showed the antibacterial efficiency of the Silver ShellTM solution (up to 99.99% reduction) coated on cotton fabric. AATCC-147 was performed to investigate the coated samples' leaching properties and the crosslinking agent's effects against S. aureus and E. coli. All coated samples demonstrated remarkable antibacterial efficacy, even after 75 wash cycles. The crosslinking agent facilitated durable attachment between the silver microparticles and cotton substrate, minimizing the release of particles from the fabrics. Color measurements were conducted to assess the color differences resulting from the coating process. The results indicated fixation values of 44%, 32%, and 28% following 25, 50, and 75 washing cycles, respectively.

Effect of air-abrasion pretreatment with three desensitizing agents on efficacy of in-office tooth bleaching.

To evaluate the influence of air-abrasion of enamel with three different desensitizing powders on the whitening effect of a bleaching gel containing 40% H2O2, which was used for in-office tooth bleaching. Forty human incisors, extracted and prepared, were acquired for this study and subsequently randomized into four groups (n = 10). The control group specimens underwent no pretreatment prior to the bleaching procedure, whereas the remaining three groups underwent air abrasion using distinct desensitizing powders; (a) Sylc, which contains bioglass 45S5; (b) BioMinF, which contains calcium phospho-fluoro-silicate glass; and (c) MI Pearls, which contains nano-hydroxyapatite, 1 h preceding the Opalescence Boost PF 40% bleaching procedure. Color measurements were conducted using a double-beam UV-Vis spectrophotometer at four distinct time points (prior to bleaching, 24 h, 15 days, and 30 days post-bleaching). Tooth color change outcomes revealed that there were no statistically significant results with respect to the interaction of the two criteria (treatments and time) (p = 0.990). Additionally, there were no statistically significant results with respect to the main effects of treatments (p = 0.385), while there were statistically significant effects with respect to the time criterion (p = 0.013). The use of the tested desensitizing powders prior the bleaching procedure did not affect the tooth color change induced by the tested bleaching agent. Tooth color change and whiteness are not affected by air-abrasion desensitizing treatments when applied prior to in-office bleaching procedures.

Comparative Analysis of the Color Stability of Machined Denture Base Materials: An In-Vitro Approach.

Color stability is a crucial aspect in the selection of denture base materials as it directly impacts the esthetic appeal and longevity of dental prostheses. This study aimed to compare the color stability of different denture base materials through an in vitro approach. Three machined denture base materials including polymethyl methacrylate (PMMA), Acetal (AC), and polyether ether ketone (PEEK) were subjected to artificial aging using a xenon-arc lamp. Color measurements were taken before and after aging using a spectrophotometer. Statistical analysis was performed to determine any significant differences among the materials. The color stability of the denture base materials was quantitatively assessed using parameters such as ΔE values. PEEK exhibited the least color change (ΔE = 2.1 ± 0.3), followed by AC (ΔE = 3.5 ± 0.4), while PMMA showed the highest color change (ΔE = 5.9 ± 0.7). In this in vitro study, PEEK demonstrated superior color stability compared to AC and PMMA denture base materials under artificial aging conditions. These findings emphasize the importance of material selection in achieving long-term esthetic outcomes in dental prostheses.

Chromatic Restoration of a Beech Marten Taxidermy Specimen to Resemble its Original Population: Analysing Painting Products and Colour Parameters

ABSTRACT Natural history collections preserve invaluable taxidermy specimens, which are prone to light-induced degradation, compromising their historical and educational significance. Restoration of these specimens to their original appearance through chromatic reintegration is imperative. The principle of reversibility mandates interventions that are modifiable or reversible without harming the original work, thereby preserving authenticity and enabling future conservation efforts. This study aims to identify the most suitable product for chromatic reintegration of a mammal taxidermy specimen, evaluate its fidelity to the original population, and assess its imperceptibility to the general public during exhibitions. Various products underwent rigorous evaluation for colouration, drying time, coverage, reversibility, safety, and resistance to light degradation. Accelerated aging tests using the Xenotest were conducted to simulate long-term light exposure. A beech marten taxidermy specimen was restored with the chosen dye, and its colour was compared against skins from the original population of the species. Public perception tests were conducted to gauge the ability of people to detect the chromatic restoration during exhibitions. Orasol® dye emerged as the optimal choice for chromatic reintegration, meeting criteria for colouration, reversibility, coverage, and resistance to light degradation. Despite its toxicity for aquatic organisms, it demonstrated promising results. Most colour measurements closely matched the original beech marten population, with minor hue deviations. Public perception tests confirmed the imperceptibility of the chromatic restoration, indicating its suitability for exhibition and educational purposes. This study highlights the importance of authenticity and imperceptibility in restoration processes, emphasizing the need for meticulous consideration of budget constraints in museum settings.

Improved UFIR Filter for Fusing Recent INS-assisted Visual Measurement under Colored Measurement Noise in UAV Landing

Improved UFIR Filter for Fusing Recent INS-assisted Visual Measurement under Colored Measurement Noise in UAV Landing

Advancements and 4E + Q performance analyses in solar drying for maize kernels preservation: A comprehensive review

AbstractThe world's population is projected to increase, impacting a 60% rise in food production demand by 2050, including the demand for maize. Currently, maize production is estimated to reach 1510 million tons in 2023, necessitating suitable methods for preserving maize kernels to maintain quality and reduce post‐harvest agricultural losses. Although drying methods present a viable solution to address this issue, the majority of farmers in Indonesia still use conventional drying methods, such as open sun drying, which has several drawbacks. Hence, solar drying systems aim to overcome these limitations by harnessing renewable, clean, sustainable, and eco‐friendly energy to support the sustainable development goals (SDGs). This research comprehensively reviews the progress of solar drying technology, providing insights into its working principles, innovative designs, and operational modes across various types of solar dryers. The 4E + Q analysis provides information regarding the performance of solar drying systems, including energy analysis to determine the quantity of energy utilized and exergy analysis to demonstrate irreversibility in thermodynamic processes. Additionally, this analysis highlights environmental impacts such as CO2 emissions and mitigation efforts, while considering economic aspects through lifecycle assessment and payback period methods. The quality assessment of dried maize kernels according to the standards set by the Indonesian National Standard (SNI) is conducted, including proximate analysis, aflatoxin levels, color measurements, and internal cracking analysis.Practical applicationsDrying technology is essential for the food preservation process, enabling the maintenance of product quality and extending storage life by reducing the moisture content to eliminate the activities of microbial agents. The application of solar drying technology harnesses solar radiation as the primary energy source, making it well‐suited for crops like paddy, maize, cassava, etc. The development of solar dryers continues through modifications and the addition of auxiliary systems to achieve more efficient, economical, and sustainable technologies. The hope is that in the future, these technologies can be adopted by farmers on an industrial scale due to low operational costs, ease of operation, and controllable operating conditions. The methodological approach is necessary to evaluate the performance of solar dryers and the quality of dried products through a 4E + Q analysis, it provides information on energy consumption, exergy flow, economic considerations, environmental aspects, and quality assessments against national quality standards (SNI).

Assessment of Tooth Shade Measurement Precision and Consistency with Digital Photography Calibration System.

To ascertain the degree of precision and repeatability inherent in the "capture to edit" digital imaging system, namely the ColorChecker Passport Photo (X-Rite, MI, USA), and to juxtapose its performance against spectrophotometric assessments utilizing the Vita Easyshade® (Vita Zahnfabrik, H Rauter GmbH & Co. KG., Bad Sackingen, Germany) for the same set of teeth. Eighty participants aged 19-25 were included in the study; all of them were Croatian students at the School of Dental Medicine, University of Zagreb. Color measurements of the maxillary right central incisors were performed in controlled, standardized laboratory conditions. The measurements were performed on calibrated digital photographs by an experienced clinician three times in a row, and L, a, and b of CIELAB color space values were recorded. The same procedure was performed using the Vita Easyshade 5.0 spectrophotometer (Vita Zahnfabrik, Bad Säckingen, Germany) in "Tooth single" mode. The Cronbach's alpha was used as a repeatability measurement, thus revealing high consistency for both methods (α=0.94-1). Correlations were moderate (Pearson r=0.44-0.66 p<0.05). Testing confirmed that digital photography is inaccurate as spectrophotometry (p<0.05). An analysis of errors of means and their standard deviations revealed consistent discrepancies with minor deviations. The "capture to edit" method showed high consistency (Cronbach's α=0.94-0.96), and it exhibits comparability in terms of variability, reliability, and repeatability when compared to spectrophotometric measurement (VitaShade 5, VitaZahnfabrik). Disparities between the methods are evident and anticipated, yet they do not follow a consistently linear pattern. The combination of repeatability and consistency renders the "capture to edit" method a valuable tool for enhanced color mapping, thus facilitating comparisons between digital images.

A Hubble Space Telescope Search for r-Process Nucleosynthesis in Gamma-Ray Burst Supernovae

The existence of a secondary (in addition to compact object mergers) source of heavy element (r-process) nucleosynthesis, the core-collapse of rapidly rotating and highly magnetized massive stars, has been suggested by both simulations and indirect observational evidence. Here, we probe a predicted signature of r-process enrichment, a late-time (≳40 days post-burst) distinct red color, in observations of gamma-ray burst supernovae (GRB-SNe), which are linked to these massive star progenitors. We present optical to near-IR color measurements of four GRB-SNe at z ≲ 0.4, extending out to >500 days post-burst, obtained with the Hubble Space Telescope and large-aperture ground-based telescopes. Comparison of our observations to models indicates that GRBs 030329, 100316D, and 130427A are consistent with both no enrichment and producing 0.01–0.15 M ⊙ of r-process material if there is a low amount of mixing between the inner r-process ejecta and outer supernova (SN) layers. GRB 190829A is not consistent with any models with r-process enrichment ≥0.01 M ⊙. Taken together the sample of GRB-SNe indicates color diversity at late times. Our derived yields from GRB-SNe may be underestimated due to r-process material hidden in the SN ejecta (potentially due to low mixing fractions) or the limits of current models in measuring r-process mass. We conclude with recommendations for future search strategies to observe and probe the full distribution of r-process produced by GRB-SNe.

Effect of Calcium Hydroxide and Antioxidant Agents Filling the Pulp Chamber after Internal Bleaching.

To evaluate the effect of calcium hydroxide (CH), sodium ascorbate (SA) and sodium thiosulfate (ST) filling the pulp chamber on color stability and longevity of teeth after internal bleaching. Crowns of bovine incisors were submitted to internal bleaching and divided into groups according the material used in the pulp chamber: Control, CH, SA, ST. Each group was divided into two subgroups according to the time to perform restorative procedures (7 or 15 days). Color measurement was performed with a spectrophotometer at nine periods. The darkening (ΔE) values were calculated. The Mann-Whitney test was used to statistically analyze the data (p ⟨ 0.05). After bleaching, ΔE values were higher than 3.5, showing that the procedure was effective. After 24 hours, no difference was observed between groups. After 7 days, SA showed higher ΔE than the control group (p ⟨ 0.05). CH and TS did not differ from the control group. In restorations performed after 7/15 days, SA group showed higher values of darkening after 1 and 4 months than the control group (p ⟨ 0.05). SA induced perceptible darkening after bleaching and should not be used to fill the pulp chamber. ST and CH show color stability and longevity after 12 months.

Changes in the Physicochemical and Bioactive Properties of Yerba Mate Depending on the Brewing Conditions.

Yerba Mate drink made from dried and crushed leaves and twigs of Paraguayan holly (Ilex paraguariensis A. St.-Hil.), which is a valuable source of bioactive substances, in particular antioxidants. The available literature lacks data on changes in the content and profile of bioactive compounds such as tannins, caffeine, the phenolic acid profile of flavonoids and carotenoids, as well as total polyphenol content and antioxidant activity in Yerba Mate infusions depending on different brewing conditions, and how different brewing conditions affect the physicochemical properties of these infusions. Therefore, this study evaluated the physicochemical properties of dried and Yerba Mate infusions prepared via single and double brewing processes at 70 °C and 100 °C. The organoleptic evaluation, as well as the instrumental color measurement, showed significant changes in the total color difference (ΔE) and the L*a*b* chromatic coordinates of dried Yerba Mate samples and their infusions. Moreover, the research showed higher contents of tannins (mean 1.36 ± 0.14 g/100 g d.m.), caffeine (mean 17.79 ± 3.49 mg/g d.m.), carotenoids (mean 12.90 ± 0.44 μg/g d.m.), phenolic acids (mean 69.97 ± 7.10 mg/g d.m.), flavonoids (mean 5.47 ± 1.78 mg/g d.m.), total polyphenols (mean 55.26 ± 8.51 mg GAE/g d.m.), and antioxidant activity (mean 2031.98 ± 146.47 μM TEAC/g d.m.) in single-brewed Yerba Mate infusions compared to double-brewed (0.77 ± 0.12 g/100 g d.m., 14.28 ± 5.80 mg/g d.m., 12.67 ± 0.62 μg/g d.m., 57.75 ± 8.73 mg/g d.m., 3.64 ± 0.76 mg/g d.m., 33.44 ± 6.48 mg GAE/g d.m. and 1683.09 ± 155.34 μM TEAC/g d.m., respectively). In addition, infusions prepared at a lower temperature (70 °C) were characterized by a higher content of total polyphenols and higher antioxidant activity, in contrast to the tannin and carotenoid contents, the levels of which were higher at 100 °C than at 70 °C. Considering the high amount of bioactive ingredients, in particular antioxidants, and a wide range of health benefits, it is worth including Yerba Mate in the daily diet.