Color Difference Research Articles

A pH-responsive dual-emission composite for fast detection of BAs and visual monitoring seafood freshness with large luminescence color difference

Sensing biogenic amine (BAs) content is very important for assessing food freshness. To address the limitations such as small color difference values (ΔE) and complex preparation of probes for visualizing the freshness of seafood, a pH-responsive ratiometric fluorescent probe (EnEB) was prepared by Eu(NO3)3, trimeric acid (BTC), and hydrochloric acid norepinephrine (Enr). EnEB emitted blue (446 nm) and red fluorescence (616 nm) originating from Enr and Eu3+, respectively, and exhibiting a fluorescence wavelength difference up to 170 nm. The ratiometric fluorescent signals of EnEB showed a linear correlation with pH in the range of 5.5–8.0. Thus, EnEB can rapidly and precisely detect BAs, such as histamine, tyramine, and spermine, with detection limits and response times of 1.14 μmol/L (3 s), 1.04 μmol/L (8 s), and 0.41 μmol/L (2 s), respectively. Furthermore, an EnEB aerogel was prepared by loading EnEB in a matrix formed by polyvinyl alcohol (PVA) and agarose (AG). EnEB aerogel exhibited excellent acid-base gas-sensing properties. The fluorescence color of EnEB aerogel can change significantly with the deterioration of seafood. When seafood changed from fresh to decayed, the ΔE value of EnEB aerogel was as high as 80.9. Importantly, the results of seafood freshness by naked eye using EnEB aerogel was consistent well with the TVB-N content and the freshness standard stipulated by national food standard, indicating EnEB aerogel can accurately visually and real-time monitor seafood freshness. Furthermore, the strategy for sensing food freshness based on EnEB aerogel also offered multiple color variations to indicate fine freshness levels of seafood. This work provided a convenient, efficient, and accurate approach to assessing the freshness of seafood. Additionally, EnEB also has promising applications in security and anti-counterfeiting.

VOC removal from automotive waste by supercritical CO2 extraction

This study investigated the reduction of volatile organic compounds (VOCs) from waste polypropylene (PP) from automobile bumpers by supercritical carbon dioxide (scCO2) extraction. The scCO2 extraction was performed with varying temperatures, pressures, and times in the range of 313–353 K, 10–25 MPa, and 1–6 h, respectively. At 333 K, 25 MPa, and 6 h, highly efficient removal of xylene, styrene, and total VOCs were observed, with removal percentages of >98 %. Optimal condition for VOC removal using scCO2 based on response surface methodology was determined to be 313 K, 10 MPa, and 2.17 h. No differences in size and color were observed in the scCO2-treated PP pellets. Moreover, VOC removal using scCO2 did not induce noticeable changes in the chemical and thermal properties of the treated PP samples. This result demonstrated that scCO2 extraction is a promising method for the VOC removal from automobile plastic waste.

Development of functional foods: Consumer acceptance of resveratrol-loaded crackers and cookies

Micro-nano encapsulation can be impactful in flavour masking of bioactives, and it has the potential to be used in the development of functional food ingredients.This work aimed to develop functional foods using emulsified resveratrol, assessing the impact of resveratrol addition and its consumer acceptance. Resveratrol-loaded emulsions were produced through high-speed homogenization/ultrasonication. Functional snacks (crackers and cookies) loading 4 mg resveratrol/g were developed using resveratrol-loaded emulsions and free resveratrol. Results showed that the incorporation of emulsified resveratrol in the dough led to an increase in its elasticity and a decrease in its consistency. Slight color differences were noticed between non-encapsulated resveratrol and reference samples. The texture of baked crackers and cookies showed a decrease in hardness for the emulsified cookies and an increase in the crackers.Sensory analysis was conducted with over one-hundred volunteers. For both products, the reference sample was the highest-rated sample in overall liking, followed by the emulsion-loaded sample and the unencapsulated resveratrol-loaded sample. Unencapsulated resveratrol-loaded and emulsion-loaded samples displayed an increase in bitterness when compared to the reference. The sensory analysis revealed a slight positive impact of the encapsulation of resveratrol versus the unencapsulated resveratrol. Nonetheless, further progress needs to be achieved to reduce resveratrol's impact.

MOF-818 nanoparticles as radical scavengers to improve the aging resistance of silk fabric

Silk fabrics hold immense historical value as precious legacies left by our ancestors, yet they face significant damage during archaeological excavations, necessitating urgent protective measures. However, The current protective materials can’t effectively prevent the degradation of silk fabrics. Nanotechnology has emerged as a promising avenue for the consolidation and preservation of silk fabrics, offering novel concepts and materials. In this study, we propose an innovative and cost-effective method that uses the MOF-818 with a radical scavenging ability to enhance the protection of silk fabrics. The resulting demonstrates that the MOF-818 was the large surface area and porous properties, which exhibited excellent superoxide dismutase (SOD)-like activity at 10 ug/mL. The silk fabrics treated by MOF-818 displays small color difference, reduced the oxidation of functional group and prevents the degradation of silk fabrics. The successful development of this nanocomposite marks a significant advancement in silk protection, opening new horizons for the preservation of silk cultural relics.

Novel color vision assessment tool: AIM Color Detection and Discrimination.

Color vision assessment is essential in clinical practice, yet different tests exhibit distinct strengths and limitations. Here we apply a psychophysical paradigm, Angular Indication Measurement (AIM) for color detection and discrimination. AIM is designed to address some of the shortcomings of existing tests, such as prolonged testing time, limited accuracy and sensitivity, and the necessity for clinician oversight. AIM presents adaptively generated charts, each a N×M (here 4×4) grid of stimuli, and participants are instructed to indicate either the orientation of the gap in a cone-isolating Landolt C optotype or the orientation of the edge between two colors in an equiluminant color space. The contrasts or color differences of the stimuli are adaptively selected for each chart based on performance of prior AIM charts. In a group of 23 color-normal and 15 people with color vision deficiency (CVD), we validate AIM color against Hardy-Rand-Rittler (HRR), Farnsworth-Munsell 100 hue test (FM100), and anomaloscope color matching diagnosis and use machine learning techniques to classify the type and severity of CVD. The results show that AIM has classification accuracies comparable to that of the anomaloscope, and while HRR and FM100 are less accurate than AIM and an anomaloscope, HRR is very rapid. We conclude that AIM is a computer-based, self-administered, response-adaptive and rapid tool with high test-retest repeatability that has the potential to be suitable for both clinical and research applications.

Chemostratigraphy and mineralogical characterization of Piacenzian sapropels cluster A (2.75–2.57 Ma) in the Gelasian GSSP type-section of Monte San Nicola (Sicily, Italy): Paleoenvironmental and paleogeographic implications

Mineralogical, geochemical and stable isotope (δ18O, δ13C) data from Marine Isotope Stages (MIS) G4 to 103 are here presented. The studied interval includes the sapropelic cluster A (A2-A5) from the Gelasian GSSP type-section, outcropping at Monte San Nicola (Sicily, Italy). The studied section exhibits a good response of the δ18O measured on the bulk carbonate to the Earth's astronomical parameters. The sapropelic red/brown layers (A2- A5) are alternated to grey marls and this cyclicity is clearly evident by the difference in colour, organic matter content, redox-sensitive elements and runoff indicators, tied to the precession/insolation cycles. Further, the obliquity signal is well evident in paleoproductivity indicators and mineralogical composition, driven by glacial-interglacial cycles. The obtained dataset has allowed the reconstruction of the paleoenvironmental conditions during marls/sapropels deposition, which appears to be influenced by the precessional forcing that induced strong changes in the marine water circulation. This scenario is also integrated by an original paleogeographic model including the presence of a high topographic structure in SE Sicily that limited water exchanges between the Ionian and Central Mediterranean Seas during sea level drawdowns, caused by glacial phases, triggered by obliquity minima.

Role of anthocyanin metabolic diversity in bract coloration of Curcuma alismatifolia varieties

Anthocyanins are one of the key metabolites influencing the coloration of ornamental bracts in plants. Curcuma alismatifolia is an emerging ornamental plant, known for the rich diversity in the coloration of its bracts and the variety of anthocyanins present. However, the specific anthocyanin metabolites contributing to this diversity are not entirely clear. This study examines the bract color variation across 19 C. alismatifolia varieties using colorimetric analysis and spectrophotometric determination of total anthocyanin content. The 19 accessions were categorized into four color groups: white, light pink, pink, and purple. Further analysis using anthocyanin metabolomics and transcriptomics was conducted on five C. alismatifolia varieties with significant differences in coloration and total anthocyanin content. In addition to previously reported anthocyanins, delphinidin-3-O-glucoside and peonidin-3-O-rutinoside were identified for the first time as important contributors to the diverse bract coloration in C. alismatifolia. Fifty-three differentially expressed genes (DEGs) were identified in the anthocyanin biosynthesis pathway, and two significant gene modules were determined through WGCNA analysis. Correlation network analysis revealed two BZ1 genes that may be key terminal enzyme genes affecting anthocyanin synthesis in C. alismatifolia bracts. Multiple transcription factors, including MYB, NAC, WRKY, ERF, and bHLH, may be involved in regulating the accumulation of different anthocyanin contents in the bracts. This research sheds light on the genetic and metabolic factors that influence bract coloration in C. alismatifolia.

Optical properties of advanced lithium disilicate.

A variety of firing protocols are available for the IPS e.max lithium disilicate (LD) and can be used for new, 'advanced' LD (ALD). However, the impact of firing protocols on the optical properties of ALD is still unknown. The aim of the present study was to evaluate the color difference (ΔE00), the translucency parameter (TP00) and the whiteness index for dentistry (WID) for both LD glass ceramics after the processes of firing/glazing. Fifty disk-shaped specimens, with a diameter of 10 mm and a thickness of 1.2 mm, were fabricated from IPS e.max CAD (LD; Ivoclar) and another 50 from CEREC Tessera™ (ALD; Dentsply Sirona). The specimens from each group were further divided into 5 subgroups (n = 10) according to the firing/glazing protocol applied: crystallization (c); one-step crystallization and glazing (cg); crystallization and refiring (c-r); two-step crystallization and glazing (c-g); or long-firing crystallization (lfc). The ΔE00, TP00 and WID were assessed. The statistical analysis of ΔE00 was performed using the one-way analysis of variance (ANOVA) and Tukey's post hoc test, while TP00 and WID were analyzed with the two-way ANOVA and Tukey's post hoc test at a statistical significance level of 0.05. The cg groups were designated as the reference. The ANOVA showed that the firing procedures had no effect on ΔE00, TP00 and WID in the case of LD. In addition, LD exhibited greater translucency and brightness as compared to ALD. For ALD, all color changes observed in relation to the reference firing protocol were clinically unacceptable. The ALD specimens which underwent 1 standard firing cycle showed higher TP00 and WID values than other ALD groups. The choice of the firing protocol has no impact on the color, TP00 or WID of LD. Additionally, LD presents higher WID values than ALD, irrespective of the firing protocol used. Alternative firing protocols result in clinically unacceptable color variations when compared to the manufacturer-recommended protocol for ALD. Advanced LD is more sensitive to different firing protocols with regard to its optical properties, which makes the workflow less predictable in comparison with LD.

Leveraging multi-output modelling for CIELAB using colour difference formula towards sustainable textile dyeing

Textile dyeing requires optimizing combinations of ingredients and process parameters to achieve target colour properties. Modelling the complex relationships between these factors and the resulting colour is challenging. In this case, a physics-informed approach for multi-output regression to model CIELAB colour values from dyeing ingredient and process inputs is proposed. Leveraging attention mechanisms and multi-task learning, the model outperforms baseline methods at predicting multiple colour outputs jointly. Specifically, the Transformer model’s attention mechanism captures the complex interactions between dyeing ingredients and process parameters, while the multi-task learning framework exploits the intrinsic correlations among the L*, a*, and b* dimensions of the CIELAB colour space. In addition, the incorporation of physical knowledge through a physics-informed loss function integrates the CMC colour difference formula. This loss function, along with the attention mechanisms, enables the model to learn the nuanced relationships between the dyeing process variables and the final colour output, thereby improving the overall prediction accuracy. This reduces trial-and-error costs and resource waste, contributing to environmental sustainability by minimizing water and energy consumption and chemical emissions.

Repeatability of different mobile phone applications for color measurement in dentistry.

To assess the repeatability of various color-measuring mobile phone applications (MPAs) on dental materials in clinically relevant shades in 1-mm thickness. A benchtop spectrophotometer was used as a reference instrument. Seven MPAs were used: Color Analysis, Color Analyzer-Iro Shirabe, Color Grab, and Colorimeter from Android, and Color Analyzer-Iro Shirabe, ColorMeter RGB, and Optishade from iOS. Color measurements were performed on 1-mm thickness slices of CAD-CAM materials, Vita Enamic shades 1M2, 2M2, 3M2, 4M2, and Vitablocs Mark II shades A1C, A2C, A3C, A4C (n=10, for a total 80 specimens). The specimens were measured at three time periods, Day 0, Day 1, and Day 7, and three measurements were made on each day, to mimic short-, medium-, and long-term repeatability. The color differences were analyzed using the CIEDE2000 formula, with the corresponding color difference (ΔE00), and mean color difference from the mean (MCDM00). One-way ANOVA, Repeated measures ANOVA, and Paired sample t-tests were used for statistical analysis. Optishade from iOS showed the lowest mean color difference among the MPAs (ΔE00=0.2 (SD 0.1), 0.3 (SD 0.2), and 0.2 (SD 0.1) at Day 0, 1, and 7, respectively, and ΔE00=0.5 (SD 0.3) for all three periods Days 0-1, 0-7, and 1-7). Material-dependent variations in the repeatability of color measurements were observed. There was a statistically significant difference among color measurements using MPAs and a spectrophotometer, among the MPAs, and materials. The spectrophotometer exhibited the highest repeatability across the tested time periods. The iOS Optishade showed the highest repeatability among the MPAs.

Cocoa bean metabolomics reveals polyphenols as potential markers relating to fine dark chocolate color shades.

This study aimed to evaluate the color and the discriminating compounds for two types of cocoa beans (black and brown beans) related to 70% dark chocolates of black and brown colors from a previous work of our group. Color analysis and untargeted high-resolution mass spectrometry-based metabolomic analysis were performed on eight beans of each type. Mass spectral data processing, univariate and multivariate statistical methods were conducted for classification of beans and selection of discriminant features. The results showed that the color difference already observed for black and brown chocolates preexists in the beans. Black and brown beans had 45 and 50 discriminant features, respectively, of which 16 and 41 were phenolic compounds. Most of them were also previously identified as discriminating compounds for black and brown chocolates. Black beans predominantly contained glycosylated flavanols, ranging from monomers to trimers, with dimers and trimers being A-type procyanidins, along with a phenolic acid (protocatechuic acid), and an O-glycosylated flavonol (quercetin-3-O-glucoside). In contrast, brown beans mostly contained non-glycosylated B-type procyanidins ranging from dimers to decamers, but also dimers and trimers of A-type procyanidins, and a glycosylated and sulfated flavanol ((epi) catechin hexoside-sulfate). These markers may be useful for quality control purposes and may contribute to the selection of beans that yield black or brown dark chocolates.

Reinforcement of 3D-printed resins for denture base by adding aramid fibers: Effect on mechanical, surface, and optical properties.

The present study evaluated the mechanical, surface, and optical properties of 3D-printed resins for removable prostheses reinforced by the addition of aramid fibers. According to ISO 20795-1:2013 standards, specimens were printed using a digital light processing 3D printer and divided into two groups (n=06/group): 3D-printed resin for denture base as the control group, and a group with the same 3D-printed resin in addition of 5% aramid fibers as the experimental group. Red aramid fibers were chosen for aesthetic characterization. The specimens were evaluated for their mechanical properties, such as elastic modulus (GPa), flexural strength (MPa), and superficial properties by their surface microhardness (KHN), surface roughness (μm), and surface free energy (mJ/m2). Optical properties were evaluated by the color difference (∆E00) between groups. The statistical test chosen after the exploratory analysis of the data was One-way ANOVA followed by Tukey's HSD (α=0.05). The results showed statistical differences in elastic modulus (p<0.0001), flexural strength (p<0.0001), surface free energy polar variable (p=0.0322), total surface free energy (p=0.0344), with higher values for the experimental. Surface hardness and surface roughness showed no statistical difference (p≥0.05). The color difference (∆E00) obtained through the CIEDE2000 calculus was below the perceptibility threshold (≤1.1). Adding aramid fibers to 3D-printed resin for denture bases resulted in better mechanical properties, without major alterations in surface properties. In addition, it is an easy-to-apply choice for mechanical reinforcement and aesthetic characterization, with the expression of small blood vessels in the 3D-printed resin for removable denture bases.

Active packaging coating based on Ocimum basilicum seed mucilage and Hypericum perforatum extract: Preparation, characterization, application and modeling the preservation of ostrich meat

Fresh meat is prone to spoilage, resulting in health risks and financial losses. Research has explored various edible coatings infused with antioxidants and antibacterial agents to preserve meat freshness. The purpose of this research was therefore to create an innovative edible coating for ostrich meat slices using Ocimum basilicum seed mucilage (OBSM) infused with Hypericum perforatum extract (HPE). The phenolic profile, antioxidant, and antimicrobial properties of HPE were investigated. The HPE contained significant levels of phenolic (34.48 mg gallic acid/g) and flavonoids (15.44 mg quercetin/g) compounds, which included hyperforin, protopseudohypericin, and hypericin as the primary extract compounds. The HPE also demonstrated potent antimicrobial and antioxidant activities. The HPE (0, 0.5, 1.5, and 2.5 %) was combined with OBSM to coat the ostrich meat slices and stabilize their physicochemical, microbial, and sensory properties during storage (4 °C, 9 days). The samples coated with OBSM+2.5 %HPE showed lower counts of total viable count (6.20 vs. 7.46 log colony forming unit (CFU)/g), psychrotrophic (4.09 vs. 5.37 log CFU/g), coliform (3.08 vs. 3.62 log CFU/g), and fungi (2.33 vs. 3.36 log CFU/g). Additionally, the coated samples exhibited a lower total color difference and higher moisture content, hardness, and overall acceptance during storage. The comparative analysis revealed that Gaussian Process Regression (GPR) outperformed the Multilayer Perceptron (MLP) in terms of precision, demonstrating a superior ability to estimate the experimental data with minimal deviation. The findings of this study indicate that the OBSM+HPE-based edible coating was highly effective in improving the shelf-life of ostrich meat.

Activated carbon derived from Mahachanok mango seeds as a potential material to delay the ripening of mangoes

The mango processing industry in Thailand generates significant waste, with over 60 % consisting of mango seed. Mahachanok mango seeds, a by-product of mango processing, can be processed into highly porous activated carbon with potential application in agricultural and food preservation. This study investigated the potential of activated carbon derived from Mahachanok mango seeds on delaying the ripening of Nam Dok Mai mangoes. The activated carbon was prepared through a two steps process: biochar preparation followed by activation using KMnO4. The morphology of activated carbon was characterized by Fourier transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area, and Scanning electron microscopy (SEM). The optimal carbonization temperature was determined, and the activated carbon was applied to mango storage. The mango ripening was assessed by measuring weight loss, total color difference (ΔE), firmness, total soluble solids (TSS), titratable acidity (TA), and TSS/TA ratio as a ripening level indicator. The optimal carbonization temperature was found to be 500 °C, yielding 25.47 % activated carbon with iodine number of 361.77 mg I2/g AC. The activated surface carbon contained hydroxyl and manganyl groups, with a BET-surface area of 0.649 m2/g. Mangoes stored with 10 g of synthesized activated carbon exhibited the best delay in ripening, extending the ripening process by five days compared to the control. On the 8th day of storage, mangoes became early ripe with firmness and TSS/TA values for 10 g of synthesized activated carbon were 0.467 N/mm and 22.35, respectively (p < 0.05). The TSS/TA ratio indicated that this treatment effectively maintained mango quality for up to 14 days of storage. Activated carbon derived from Mahachanok mango seed shows promising results in delaying mango ripening, especially when used at 10 g dosage. This approach utilized food processing waste to create a valuable product for post-harvest handling, potentially improving the freshness of exported fruit.

Effect of Physical Separation with Ultrasound Application on Brewers' Spent Grain to Obtain Powders for Potential Application in Foodstuffs.

Brewers' spent grain (BSG) is the primary by-product of beer production, and its potential use in food products is largely dependent on its processing, given its moisture content of up to 80%. This study aimed to evaluate the effects of physical separation with ultrasound application on the color, total phenolic content (TPC), antioxidant activity, proximate composition, total dietary fibers, and particle size distribution of BSG powders. Wet BSG (W) was subjected to two processes: one without ultrasound (A) and one with ultrasound (B). Both processes included pressing, convective air-drying, sieving, fraction separation (A1 and B1 as coarse with particles ≥ 2.36 mm; A2 and B2 as fine with particles < 2.36 mm), and milling. The total color difference compared to W increased through both processes, ranging from 1.1 (B1 vs. A1) to 5.7 (B1 vs. A2). There was no significant difference in TPC, but process B powders, particularly B2, showed lower antioxidant activity against ABTS•+, likely due to the release of antioxidant compounds into the liquid fraction during pressing after ultrasound treatment. Nonetheless, process B powders exhibited a higher content of soluble dietary fibers. In conclusion, ultrasound application shows potential for further extraction of soluble fibers. However, process A might be more practical for industrial and craft brewers. Further studies on the use of the resulting BSG powders as food ingredients are recommended.

Fabrication and characterization of novel biodegradable films based on tomato seed mucilage and gelatin plasticized with polyol mixtures

This research evaluates the potential of tomato seed mucilage (TSM) –gelatin (Ge) in producing edible films. Edible films were made using various ratios of TSM to Ge (1:0, 0.33:0.66, 0.66:0.33, and 0:1). Moreover, the effects of including three types of plasticizers, namely, glycerol (Gly), sorbitol (Sor), and polyethylene glycol (PEG) were investigated. The findings indicated that adding Ge did not affect the thickness of the films (p>0.05). However, it significantly increased the tensile strength (TS) and Young's modulus while reducing the elongation at break (EB) (p˂0.05). A higher TSM ratio significantly increased total color difference (ΔE) and yellowness index while decreasing film lightness and whiteness index (WI) (p˂0.05). The contact angle significantly decreased with the TSM ratio increases and Ge decreases (p˂0.05). Moreover, this led to higher opacity, solubility, moisture content, oxygen permeability, water vapor permeability (WVP), swelling, and moisture absorption (p˂0.05). Adding a plasticizer had no effect on the films' opacity, contact angle, and thickness. The Gly-containing film featured the highest EB, solubility, moisture content, swelling, WVP, oxygen permeability, and moisture absorption. The Sor-containing film had the highest TS. TSM concentration was directly correlated with increased film heterogeneity and surface roughness. X-ray diffraction peaks became sharper by increasing TSM concentration and including PEG, while Gly inclusion produced ordered broad peaks.

Integrating Microwave Heating with Foam-Mat Drying: Drying Kinetics and Optimization for Thick Foamed Mango Pulp

This study addresses the challenge of processing undersized or overripe mangoes by integrating microwave heating with traditional foam-mat drying technique. The study aims at investigating drying kinetics coupled with thin-layer drying modeling and influences of microwave power (300 - 600 W) and hot-air temperature (55 - 75 °C). Among ten drying models, the so-called Midilli equation fitted well with experimental data. Results showed enhanced drying process associated with microwave heating, providing reduced drying time from 600 - 700 min (for conventional hot-air mode) to 30 - 100 min (for microwave-assisted mode). Standard deviations of moisture content and dried foam thickness measured at various points revealed uneven heat distribution when using high microwave energy, evidenced by burnt spots at 600 W. Additionally, foam collapse was observed under the mild process with low microwave powers, possibly due to prolonged drying periods. Response surface methodology demonstrated that microwave power was more important factor, positively affecting effective diffusivity coefficient (Deff) while inversely influencing specific energy consumption (SEC) and color difference (DE). Deff value increased from 5.41´10-6 m²×s-1 at 300 W and 55 °C to 18.43´10-6 m²×s-1 at 600 W and 75 °C, confirming enhance drying performance. As assisted with microwave heating, drying foamed mango sample consumed less energy up to 92 %. Optimal drying parameters were determined based on balancing the enhancement of drying performance and color alteration, suggesting drying the thick foamed mango pulp at temperature of 55 °C combined with microwave heating at 520 W, which can be served as a basis for further industrial scale-up. HIGHLIGHTS Novel method for thick mango pulp snacks. Reduced drying time from 600 - 700 to 30 - 100 min. Lowered energy use to 5.83 kWh×kg-1. Optimal conditions at 520 W, 55 °C, desirability 0.669. Applied Midilli model with 99 % accuracy. GRAPHICAL ABSTRACT

Comparison of the Characteristics of Baekak(chalk) and Hobun(shell) Pigment for Dancheong based on Natural Raw Materials

Calcium carbonate white pigments were manufactured by classifying them into Baekak(chalk) and Hobun(Shell) according to the type of natural raw material, and their material characteristics were analyzed. Their performances were compared by evaluating their weather resistance, antifungal activity, and flame retardancy. The main components of Baekak pigments are calcite and dolomite, and those of Hobun pigments a re calcite and a ragonite. Depending on the raw material, the specific factors identified are Mg from the mineral composition of Baekak pigments, and P and S from the protein composition of Hobun pigments. The particle shape of the pigment shows a crystal structure unique to minerals in the case of Baekak pigments, but the Hobun pigments are classified into plate-shaped or columnar structures depending on the raw material and are in an aggregated state with a large specific surface area. While the absorption amount of Baekak pigments made from limestone and dolomite is similar, that of Hobun pigments shows differences depending on the raw material, with the absorption amount being high in the order of oyster &gt; cockle &gt; clam. As a result of the color analysis, both the Baekak and the Hobun pigments had L* values of over 90 and opacity of over 90, indicating good whiteness and painting workability. As a result of the accelerated weathering test, the final color difference value(ΔE) was less than 2.02, which was difficult to recognize with the naked eye, and the Hobun pigment showed superior color and film stability compared to the Baekak pigment. As a result of the antifungal test, all calcium carbonate-based white pigments showed high preventive effects against decay fungi, and among them, the pigment made from clams and cockles showed excellent antiseptic properties. In addition, the pigment made from clams and cockles has been shown to have flame retardant properties, and it is expected that it will contribute to enhancing the preservation of organic cultural heritage when applied to it.

The physicomechanical optimization and antimicrobial properties of the Ɛ-polylysine/ZnO nanoparticles loaded active packaging films

Response surface methodology (RSM) was used to evaluation the effects of Ɛ-polylysine (Ɛ-PL: 0–5 wt%) and zinc oxide nanoparticle (ZnO: 0–5 wt%) on the physico-mechanical properties of the gelatin/polyvinyl alcohol (G/PVA) based nanocomposite packaging films. Using Design-Expert 7.0.0 software, numerical and graphical improvements were also carried out. The optimization was focused on increasing the values of the ultimate tensile strength (UTS), strain at break (SAB), Young's modulus (YM), and lightness (L), and reducing the values of the water vapor permeability (WVP), yellowness index (YI), and overall color difference (∆E). The overall optimal concentrations of ZnO and Ɛ-PL were 1.00 (wt%) and 4.30 (wt%), respectively, with a maximum desirability of 75 %. Additionally, the microstructure, surface topography, interactions, and distribution quality of ZnO nanoparticles and Ɛ-PL in the biopolymer matrix were analyzed using Scanning Electron Microscopy, Atomic Force Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction measurements. The result of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved thermal stability of nanocomposite films containing ZnO nanoparticles and Ɛ-PL. MIC test showed that ZnO and Ɛ-PL were effective against E. coli, S. aureus, P. fluorescence, and S. typhimurium at the concentration of 2–3 and 10–12 mg/mL, respectively. The antimicrobial activity of G/PVA nanocomposites containing ZnO, Ɛ-PL, and ZnO/Ɛ-PL against E. coli was more than S. aureus.

In Vitro Effect of Anodization of Titanium Abutments on Color Parameters and Color Difference of Lithium Disilicate All-Ceramic Crowns.

This study assessed the effect of the anodization of titanium abutments on the color parameters and color difference of lithium disilicate (LDS) all-ceramic crowns. In this study, 19 straight abutments were divided into two groups: anodized (n = 9) and non-anodized control (n = 9), with one hybrid zirconia abutment as a reference. Anodization was achieved by applying 63 V energy using seven 9 V flat batteries in series, with an electrolyte solution comprising 1 g trisodium phosphate in 250 mL distilled water for 5 s, resulting in a gold-yellow color. Abutments were then scanned, and full-contour monolithic IPS e.max maxillary central incisor crowns were fabricated with 2 mm thickness and glazed. Reflectance was measured using a spectroradiometer, and color coordinates (L*, a*, b*, h*, and C*) were calculated using CS-10W software. Color differences of the crowns in both groups were quantified using the CIEDE2000 (ΔE00) color difference formula and analyzed by t-test (α = 0.05) compared to the standard sample. The L*, a*, b*, and c* parameters in anodized abutments were significantly higher than those in non-anodized abutments, while the h* parameter in anodized abutments was significantly lower than that in non-anodized abutments (p < 0.001 for all). There was a significant difference in ΔE00 of the two groups (p = 0.043). Anodization of titanium abutments improved the color parameters of LDS all-ceramic crowns and significantly decreased their ΔE compared with non-anodized abutments.