Color Pigments Research Articles

Phase evolution of nanocrystalline Mn-based oxides screened under different calcination temperatures using different precursors for proficient application in near infrared pigmentation

We examined how different calcination temperatures and precursors affect the formation of Mn-based oxides. The formation of these oxides was influenced by both the temperature (400–––1000 °C) and the type of precursors used (MnCl2·4H2O, MnCO3, MnO2, and KMnO4). When MnCl2·4H2O was calcined at 800 and 1000 °C/3h, we obtained pure tetragonal Mn3O4 phase materials. Calcining MnCO3 at 600 and 1000 °C resulted in cubic Mn2O3 and tetragonal Mn3O4 phase materials, respectively. Heating commercial MnO2 powder at 600 and 800 °C transformed it into cubic Mn2O3 phase materials. At 400 °C, the tetragonal MnO2 phase remained, but at 1000 °C, mixed Mn3O4 and Mn2O3 phases formed. Calcining KMnO4 at 1000 °C/3h led to the formation of δ-MnO2 materials. The morphological features of Mn2O3 and Mn3O4 materials exhibited different sizes and shapes, including nanostone-like, nanorod-like, and nanoflakes morphologies. The thermal analysis revealed significant differences in weight loss and thermal events, including exo and endothermic peaks. The Raman spectra and UV–Vis DRS measurements data support the formation of Mn-based oxides. The highest NIR reflectance for the various synthesized materials of Mn3O4 phase indicates a reflectance of 68 % in the solar region and 91 % in the color pigment region.

Highly Stable Hybrid Pigments Prepared from Organic Chromophores and Fluorinated Hydrotalcites

Structural hydroxide groups in layered magnesium–aluminum double hydroxides were partially replaced by fluoride ions. Fluorinated and fluorine-free materials were used as hosts for two dyes, carminic acid and hydroxyl naphthol blue, resulting in a hybrid pigment color palette. The pigments were produced by two ways, either incorporating chromophore during the synthesis of the layered double hydroxide or in a post-synthesis step through the memory effect of the LDHs. Additionally, the pigments were protected with a magnesium hydroxide phase to prevent the color from fading over time. The pigments were stable for periods as long as 10 years. The color properties of the pigments were significantly influenced by the host of dye since the presence of fluorine directly influences the acid–base properties of the layered double hydroxides. The pigments conferred their color to white cream in the preparation of colored creams. The colored creams acquired the color of the layered pigment.

Mesoporous silica aerogels for sunflower oil refining and investigation of their adsorption performance

AbstractInvolving a succession of oil refining stages for edible oil production, a notable constraint lies in the necessity to employ diverse adsorbents at various steps within these processes. This study investigates the synthesis of mesoporous silica aerogels from rice husk ash, comparing their efficacy in physical sunflower oil refining with earth clay (Bentonite) and commercial silica (Trisyl). Tetraethyl orthosilicate (TEOS) impact during aging was analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption-desorption analyzer to examine alterations in the structure of silica aerogels. The surface areas of TEOS-doped silica aerogel (TSA) and non-TEOS-doped silica aerogel (NTSA) were 296.18 and 267.06 m²/g. Mesoporous silica aerogels were evaluated for their ability to reduce free fatty acids (FFA), peroxide value (PV), phosphorus, and color pigments in sunflower oil. TSA and NTSA demonstrated significant FFA removal, with TSA at 3 wt.% achieving the highest performance of 32.2%. TSA also effectively reduced PV and phosphorus compared to NTSA, Bentonite and Trisyl, exhibiting performance similar to Bentonite in the bleaching process. TEOS-doped silica aerogels have shown promise as adsorbents for impurity removal in sunflower oil and has emerged as the potential adsorbent that can comprehensively and effectively meet the requirements of many edible oil physical refining applications in a singular step. Graphical Abstract

The pattern of genetic variability in a core collection of 2,021 cowpea accessions.

Cowpea is a highly drought-adapted leguminous crop with great promise for improving agricultural sustainability and food security. Here, we report analyses derived from array-based genotyping of 2,021 accessions constituting a core subset of the world's largest cowpea collection, held at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria. We used this dataset to examine genetic variation and population structure in worldwide cowpea. We confirm that the primary pattern of population structure is two geographically defined subpopulations originating in West and East Africa, respectively, and that population structure is associated with shifts in phenotypic distribution. Furthermore, we establish the cowpea core collection as a resource for genome-wide association studies by mapping the genetic basis of several phenotypes, with a focus on seed coat pigmentation patterning and color. We anticipate that the genotyped IITA Cowpea Core Collection will serve as a powerful tool for mapping complex traits, facilitating the acceleration of breeding programs to enhance the resilience of this crop in the face of rapid global climate change.

Hair Evaluation in Orthodontic Patients with Oligodontia.

Oligodontia can be isolated or syndromic, associated with other ectodermal abnormalities. The aim of the study was to perform hair examination in orthodontic patients diagnosed with oligodontia with a low clinical expression of symptoms of ectodermal origin. All available orthodontic patients diagnosed with oligodontia in the permanent dentition were enrolled. Hair examination included clinical evaluation of the patients' hair, trichoscopy, trichogram and evaluation of the hair shafts under a polarized light microscope. In total, 25 patients, 18 males and 7 females, aged 6 to 24 years were evaluated for the presence of dental and hair abnormalities. The number of congenitally absent teeth ranged from 6 to 24 teeth and diastemas, microdontia, taurodontism and altered tooth shape were found in 23 patients. Hair disorders were found in 68% of the subjects. Hypotrichosis, the heterogeneity of shaft color and loss of pigment, androgenetic alopecia, telogen effluvium, trichoschisis, pili canaliculi, trichorrhexis nodosa and pseudomoniletrix were observed. Trichoscopy and trichogram are valid non-invasive diagnostic tests which could be used to differentiate between isolated and syndromic oligodontia in patients with a low clinical expression of ectodermal symptoms.

The Effect of Home Bleaching on Color Match with Anterior Single Shade Composite Restoration

Background: Aim of this study is to assess the color matching in class III restorations made with single-shade resin composite after bleaching with different carbamide peroxide concentrations. Methods: In this study, 20 human incisors that were free of caries or enamel abnormalities and freshly extracted for periodontal or orthodontic reasons were cleaned of blood, debris, and calculus. Mesial and distal surfaces were restored with single-shade composite (Omnichroma, Tokuyama, Japan). All samples were randomly divided into two groups, all of the mesial surfaces were isolated, and distal surfaces were coated with %10 and %15 carbamide peroxide (Opalescence PF; Ultradent Products, Inc, USA). Polishing discs (Zenit Flex, President Dental, Germany) were used the composite restoration. Color matching was evaluated on photographs with a digital colorimeter. SPSS software program was used to perform statistical analysis (IBM Corp., Armonk, NY, USA). Results: Statistically significant difference was found between the color matching of the restorations after the 5th treatment with 15% carbamide peroxide (p = 0.004), and at the end of 10th treatment with 10% carbamide peroxide (p = 0.028). Depending on the carbamide peroxide concentration, after the 5th treatment a statistically significant difference was found between 15% and 10% carbamide peroxide (p = 0.000), but no statistically significant difference after the 10th treatment (p > 0.05). Conclusions: After carbamide peroxide bleaching, hard tissue color became lighter. Since there is no color pigment in single-shade composites, color might be lighter after bleaching. Therefore, these composites may be considered safer in bleaching. Keywords: Bleaching, Color Match, Composite

Identifying a novel Listeria innocua subgroup and enhancing Listeria detection in grain: A duplex real-time PCR approach informed by comparative genomic analysis

This study focuses on enhancing the detection accuracy of Listeria species in the food industry, particularly addressing the challenges posed by closely related strains that complicate pathogen identification. Detecting Listeria monocytogenes, a key psychrotolerant foodborne pathogen, is crucial in the food industry. Although real-time PCR-based methods targeting the iap gene are commonly employed for identification, our investigation of L. innocua strains isolated from wheat in South Korea revealed false positives, indicating an imperative for more accurate detection approaches. We used comparative genomic analysis to identify a novel subgroup of L. innocua with closer genomic affiliations to L. monocytogenes. Consequently, we developed new primer and probe sets for more accurate detection of both L. monocytogenes and L. innocua, demonstrating high specificity and selectivity. Additionally, we revealed the importance of food matrix effects, particularly color pigments, in the design of diagnostic assays. These advances provide insight into genomic differences between L. monocytogenes and L. innocua, and pioneer new detection techniques for Listeria species.

Empirical BRDF model for goniochromatic materials and soft proofing with reflective inks.

The commonly used analytic bidirectional reflectance distribution functions (BRDFs) do not model goniochromatism, that is, angle-dependent material color. The material color is usually defined by a diffuse reflectance spectrum or RGB vector and a specular part based on a spectral complex index of refraction. Extension of the commonly used BRDFs based on wave theory can help model goniochromatism, but this comes at the cost of significant added model complexity. We measured the goniochromatism of structual color pigments used for additive color printing and found that we can fit the observed spectral angular dependence of the bidirectional reflectance using a simple modification of the standard microfacet BRDF model. All we need to describe the goniochromatism is an empirically-based spectral parameter, which we use in our model together with a specular reflectance spectrum instead of the spectral complex index of refraction. We demonstrate the ability of our model to fit the measured reflectance of red, green, and blue commercial structural color pigments. Our BRDF model enables straightforward implementation of a shader for interactive preview of 3D objects with printed spatially and angularly varying texture.

Insights into the mechanism of color formation of the freshwater prawn (Macrobrachium rosenbergii) revealed by de novo assembly transcriptome analysis

Body color is an important visual indicator of crustacean quality and plays a major role in consumer acceptability, perceived quality, and the market price of crustaceans. The freshwater prawn (Macrobrachium rosenbergii) has two distinct phenotypic variations, characterized by dark blue and light yellow body colors. However, the underlying mechanisms regulating the body color of M. rosenbergii remain unclear. In this study, the composition of shell color parameters and pigment cells of raw and cooked dark blue and light yellow M. rosenbergii was investigated and the mechanisms associated with body color were elucidated by transcriptome analysis. The results showed significant differences in the raw shells of the dark blue and light yellow M. rosenbergii (L: 26.20 ± 0.53 vs. 29.25 ± 0.45; a: −0.88 ± 0.19 vs. 0.35 ± 0.18; b: 1.73 ± 0.20 vs. 3.46 ± 0.37; dE: 70.33 ± 0.53 vs. 67.34 ± 0.45, respectively, p = 0.000) as well as the cooked shells (L: 58.14 ± 0.81 vs. 55.78 ± 0.55; a: 19.30 ± 0.56 vs. 16.42 ± 0.40; b: 23.60 ± 0.66 vs. 20.30 ± 0.40, respectively, p < 0.05). Transcriptome differential gene analysis obtained 39.02 Gb of raw data and 158,026 unigenes. Comprehensive searches of the SwissProt, Nr, KEGG, Pfam, and KOG databases resulted in successful annotations of 23,902 (33 %), 40,436 (25.59 %), 32,015 (20.26 %), 26,139 (16.54 %), and 22,155 (14.02 %) proteins, respectively. By KEGG pathway analysis, numerous differentially expressed genes were related to pigmentation-related pathways (MAPK signaling pathway, Wnt signaling pathway, melanin production, tyrosine metabolism, and cell-cell communication process). Candidate DEGs that may be involved in body color included apolipoprotein D, crustacyanin, cytochrome P450, and tyrosinase, as verified by quantitative real-time PCR. The results of this study provide useful references to further elucidate the molecular mechanisms of color formation of M. rosenbergii and other crustaceans.

Relationship of skin complexion with gingival tissue color and hyperpigmentation. A multi-ethnic comparative study

Background and ObjectiveThe most frequently seen intra-oral soft tissue is the gingiva. Most often, it is seen as coral-pink tissue that surrounds the neck of the teeth. Gingiva that encircles the tooth necks and covers the alveolar processes of the jaws is an intra-oral tissue that exhibits biomimetic features. The wide range of colors of the gingiva depends on the configuration of gingival vascularity, the degree of epithelial cornification, level of melanogenesis, and the depth of epithelialization. However, the color of the gingiva varies depending on the degree of melanin pigmentation. The current study aimed to identify the different distribution patterns of gingival color and determine the correlation between skin color, gender, and geographical area of origin.Materials and methodsA total of 839 subjects were involved in the study where the gingival color and skin tone were measured using the Dummett-Gupta Oral pigmentation Index (DOPI) combined with VITA VMK MASTER and skin shade method developed by Revlon (USA) and L’Oreal (France) for makeup foundation shades. One investigator was calibrated for the examination of the colors after being tested for normal color vision and color aptitude using the line test.ResultsA significant association was found between skin color and gingival pigmentation (χ2 value (6) = 114.48; P = 0.001). It was also found that females (67.1%) significantly had darker gingiva than males (58.3%). The study statistics display that location of the individual was also statistically associated with melanin pigmentation of the gingiva (χ2 value (57) = 559.33; P = 0.001).ConclusionThe study concluded that gender, skin color, and individual location are significantly associated with gingival melanin pigmentation.

An Insight into the Hormonal Interplay Regulating Pigment Changes and Colour Development in the Peel of ‘Granny Smith’, ‘OPAL®’ and ‘Royal Gala’ Apples

AbstractThree apple cultivars with different peel colour and known ripening dynamics were examined throughout development and on-tree ripening to unravel how the hormonal crosstalk may influence colour changes. Our results indicate that the colour of ripe apples in ‘Granny Smith’ and ‘Opal®’ cultivars was primarily influenced by chlorophyll levels masking the contribution of other pigments, whilst the development of red colour in the ‘Royal Gala’ was not only due to an important loss of chlorophyll during ripening but also to anthocyanins accumulation. The interplay amongst indole-3-acetic acid (IAA), ethylene and abscisic acid (ABA) seemed to control pigment content during the later stages of development, indicating that variations in the hormonal profile contribute to colour differences in ripe apples. In ‘Granny Smith’ apples, basal levels of IAA, ethylene and ABA were associated with the inhibition of chlorophyll loss, which was responsible for its green colour, despite the presence of high carotenoid levels. In contrast, the peel of ‘Opal®’ and ‘Royal Gala’ apples underwent a degreening process facilitated by the IAA-mediated activation of ethylene metabolism, in a crosstalk facilitated by MdARF5. The accumulation of anthocyanins in the peel of ‘Royal Gala’ apples seemed to be regulated in an ethylene-dependent manner, with MdMYB1 acting as the mediator between ethylene signalling and the anthocyanins biosynthesis and vacuolar transport pathways. On the other hand, the decline in carotenoid content during fruit development in the three cultivars appeared to be regulated at the catabolic level through ABA and its derivatives and possibly also facilitated by ethylene-mediated mechanisms. Notably, chlorophyll levels, crucial for the observed colour changes, were likely controlled by MdGLK1, a transcription factor involved in chloroplast biogenesis, working in coordination with ethylene-dependent catabolic enzymes. Overall, understanding the cultivar-specific hormonal regulation of apple colour provides valuable insights for developing preharvest and postharvest strategies to ensure an optimal fruit colour aligned with consumer preferences.

Non-iridescent magnetite photonic crystal films and pigments with enhanced magnetic coupling effect

Non-iridescent structural color films and pigments with novel enhanced microwave absorption characteristics are successfully fabricated at room temperature for the first time. The quasi-uniform magnetite nanoparticles (CV = 0.10 ∼ 0.20) with high refractive index (n = 2.42) and broad light absorption provide evident low-angle-independent property for the structural color pigments. More importantly, a universal technical protocol is developed for preparation of photonic crystals with inorganic nanoparticles, i.e., through designing of the binding strength between nanoparticles and mediated molecules, the slurry modulus is increased to 105 Pa, which effectively drives the nanoparticles to rapidly assemble into closely packed ordered arrays by our-designed powerful assembly technique. Additionally, the structural color materials are subjected as photonic crystal pigments (∼20 wt%) embedding in a transparent polymer matrix to form color coatings. Remarkably, the photonic crystal pigments exhibit strong magnetic coupling effect and enhanced microwave absorption performance due to the regular arrangement, with superior reflection loss (RLmin) values of −14.97 dB (increase by 65.8 % compared with randomized magnetic nanoparticles), and the effective absorption bandwidth (EAB) of 2.15 GHz. This new kind of photonic crystal pigment, combining visual color and radar wave absorption, provides a novel idea for developing of multi-wave-band high-performance stealth materials.

Valorization of waste seashells as bioadsorbent for sunflower oil bleaching

AbstractIn this study, the performance of waste seashells (SS) in adsorbing color and oxidation parameters during the bleaching process of sunflower oil was evaluated and compared with that of commercial clay. Seashell activation methods included microwave treatment (900 W for 30 min), acid treatment (7 N H2SO4), and a combination of both. Interestingly, the unactivated SS demonstrated superior adsorption performance compared with the activated SS. SS, which have the ability to eliminate color pigments like chlorophyll and carotenoid, were found to be effective in this regard. However, their effectiveness in reducing the peroxide and p‐anisidine value was not as successful as that of commercial clay. Free acidity content remained constant across all treatments. SS emerged as a cost‐effective alternative adsorbent, promising in preventing environmental pollution. Their use signifies a valuable contribution to sustainability. This study sheds light on SS potential as an eco‐friendly solution in industrial processes, warranting further exploration and application.Practical applicationsBiowaste valorization is a process that involves converting organic waste materials into valuable products, energy, or resources, instead of simply disposing of them in landfills or incinerating them. This approach has gained significance owing to its potential to address environmental, economic, and social challenges. In this respect, this study presents that bioadsorbent obtained from waste SS can be utilized for bleaching of sunflower oil.

Tyrosinase Inhibitory Activity of n-Hexane, Ethyl Acetate and Methanol Extracts of Padina sp

Melanin is a color pigment in the skin, if produced in excess will cause browning of the skin. The formation of melanin (melanogenesis) is assisted by tyrosinase through two reactions, namely monophenolase and diphenolase. Melanogenesis can be reduced through the tyrosinase enzyme inhibition mechanism. Seaweed can be used as a tyrosinase inhibitor (brightening agent), such as Padina sp containing secondary metabolites such as alkaloids, flavonoids, terpenoids, phenolics, and saponins. This study aimed to determine the tyrosinase inhibitory activity of Padina sp. The extraction method used was graded maceration with n-hexane (n-Hx), ethyl acetate (Et-OAc), and methanol (Me-OH) solvents, then carried out phytochemical screening, antioxidant test using the DPPH method, and tyrosinase inhibitory test by measuring the enzymatic reaction using L-tyrosine (monophenolase) and L-DOPA (diphenolase). Phytochemical analysis of extracts by GC-MS and in silico analysis by molecular docking were also carried out. The results showed that the total yield of the three extracts was 5.50%. The three extracts had moderate category of antioxidants. The IC50 values monophenolase of n-Hx, Et-OAc, Me-OH extracts, and Kojic acid were 937.68; 132, 92; 268.68; and 20.99μg/mL, respectively. The IC50 values diphenolase of n-Hx, Et-OAc, Me-OH extracts, and Kojic acid were 989.74; 178.33; 356, 87; and 31.76 μg/mL, respectively. The phytochemical of Et-OAc extract based on GC-MS data showed a variety of compounds that have been shown to have pharmacological effects. This data is supported by the results of molecular docking analysis, where compound Spiro(tetrahydrofuryl)2.1'(decalin), 5',5',8'a-trimethyl (1) is able to show a relatively low binding energy, namely -6.86 kcal/mol. The binding energy is even lower than the standard compound (Kojic acid) interaction which only has binding energy of -3.73 kcal/mol. Based on the study carried out, extract from Padina sp has the potential to be developed as a a skin brightening agent.

The effect of pH and extraction time on total phenolic content and antioxidant properties of coloured water extracts from Brassica Oleracea

Red cabbage (Brassica oleracea) is a rich source of phenolic content including colour pigments and have also high antioxidant capacities. The amounts of their phenolic substances and antioxidant activities change depending on the extraction conditions (pH, time, solvent, etc.). In this work, the coloured water extract was obtained from red cabbage at different pH values (pH 4-10) for both an hour and 24 hours. The extracts were evaluated regarding total phenolic contents and antioxidant activities. The results showed that the total phenolic content of red cabbage extracts in all extraction conditions ranged from 4.93±0.20 to 7.59±1.22 mg GAE/g fw. The highest total phenolic contents (7.59±1.22 mg GAE/g fw) were obtained from red cabbage at 24 h and pH=6. On the other hand, the red cabbage extracts have high DPPH (IC50 values ranged from 0.21±0.06 to 0.94±0.03 mg/mL) and ABTS (IC50 values ranged from 0.29±0.01 to 0.46±0.05 mg/mL) activities at all pH values and times. The extract obtained from red cabbage at 1 h and pH=7 exhibited the strongest DPPH activity with the IC50 values of 0.21±0.06 mg/mL, it showed the best ABTS activity with the IC50 values of 0.29±0.01 mg/mL at 1 h and pH=5 and 8.

Ensemble machine learning as a mathematical approach to predict high-voltage electric field-assisted removal of color and oxidative indices from soybean oil using the activated porous electrodes

Porous electrode materials provide a large surface area for electrochemical reactions and facilitate ion transport efficiently. By optimizing the design and properties of porous electrodes, it is possible to enhance the bleaching performance. In this research, three machine learning (ML) algorithms, namely Support Vector Regression, Ridge Regression, and Decision Tree Regression were utilized for predicting the bleaching efficiency under different conditions of HVEF-assisted bleaching (HVEFAB). Subsequently, the outcomes of these models were compared to ensemble models created by combining the algorithms as mentioned earlier using three techniques including bagging, boosting, and stacking. The levels of chlorophyll and carotenoids were reduced as a result of increased voltage, modification in the electrode surface, number of cathode-anode, and the presence of an inert electrolyte. Meanwhile, the reduction of red color and chlorophyll pigments was more significant than yellow color and carotenoid pigments. Moreover, the application of HVEFAB can potentially decrease the levels of polar compounds, such as oxidative compounds on the electrode surface. Based on the MSE, MAE, and R2 metrics, the algorithms' efficacy in forecasting outputs 1 (color index) and 2 (oxidative index) can be ordered as follows: Stacking > Boosting > Bagging > Decision Tree (DT) > Ridge > Support Vector Regression (SVR). The findings demonstrate that integrating these three models, mainly through the stacking technique, substantially improves the accuracy of the predicting model. Particle swarm optimization (PSO) and polynomial regression rather than RSM represented a superior model to predict red color removal.

Utilizing Xanthan Gum Coatings as Probiotic Bacteria Carriers to Enhance Postharvest Quality and Antioxidants in Fresh-Cut Cantaloupe and Honeydew (Cucumis melo L.) Melons.

Due to spoilage microflora and browning, minimally processed fresh-cut fruits have a short shelf life, and over the years, studies have shown the potential of using edible coatings to extend the shelf life and improve the safety of fresh-cut fruits. Recently, there has been a rise in research on the incorporation of probiotics in edible coatings due to the bespoke health and biopreservation benefits they impart. Therefore, in this study, lactobacillus strains (Lactiplantibacillus plantarum 75 and Bifidobacterium longum) were incorporated into a xanthan edible coating to enhance color retention, sensory properties, antioxidant retention (ascorbic acid, carotenoids, total phenols), and antioxidant activity (FRAP antioxidant power, ABTS scavenger activity) of fresh-cut cantaloupes and honeydew cucumis melo L. melons during cold storage at 5 C and 85% RH for five days. The edible coating was prepared by mixing 0.5% xanthan gum, 1% glycerol, and 2% citric acid solution with L. plantarum 75 (LAB 75) and Bifidobacterium longum bacteria separately, and the final lab count for each strain was made to be 8.0 log CFU/mL. Stable probiotic coatings with ζ-potential of between -39.7 and -51.4 mV and a PdI of 1 were developed, and the incorporation of the probiotic bacteria into the coating was justified using FTIR analysis. The probiotic coatings showed a typical pseudoplastic behavior, in which the viscosity curves fall as the shear rate increases. Thermal stability analysis showed a continuous and multi-step weight reduction in this work, illustrating how the edible coating components interact. The survival of both Lactobacillus strains was recorded on day 5. Both freshly cut melons coated with xanthan and loaded with Lactobacillus strains retained a sufficient quantity of probiotics at the end of storage, while L. plantarum 75 (7 log CFU/g for cantaloupe and 8 log CFU/g for honeydew) retained the highest viability compared to B. longum (6 log CFU/g for cantaloupe and 7 log CFU/g for honeydew). In comparison to the coated and uncoated control samples, the inclusion of L. plantarum 75 in xanthan coatings significantly retained the color properties, pigments (total chlorophyll and carotenoids), ascorbic acid, total phenols, and antioxidant activity (FRAP, DPPH, and ABTS). The overall acceptability of fresh cuts of cantaloupe and honeydew melons coated with xanthan gum loaded with L. plantarum 75 was higher than that of other treatments. Thus, xanthan gum loaded with L. plantarum 75 coating is most suitable for reducing postharvest losses in fresh cuts of honeydew melons and cantaloupe, which will help preserve antioxidant and bioactive properties. The xanthan gum loaded with L. plantarum 75 coatings exhibited the highest preservation impact; therefore, it can be recommended for the fresh-cut industry.

Antimicrobial Activities and Painting Application of Pigmented-Producing Actinobacteria Isolated from Rhizospheric Soils of Mosses (Taxithelium nepalense (Schwägr.) Broth. and Barbula indica (Hook.) Spreng.)

In the survey of biodiversity of actinobacteria associated with mosses (Taxithelium nepalense (Schwägr.) Broth. and Barbula indica (Hook.) Spreng.), certain strains of pigment producing actinobacteria were isolated and purified on SCA and incubated at 30°C for 1 week. Based on deep-shade color of actinobacterial pigments, 4 strains were collected and used for painting color preparation. To evaluate the antimicrobial activities, the crude extracts were prepared from 4 actinobacterial strains and tested with Escherichia coli PSRU-01 and Staphylococcus aureus PSRU-01. The results indicated that the crude extracts of C7, C13, C15 and D13 could not inhibit growth of E. coli PSRU-01, but S. aureus PSRU-01 was inhibited. Two fungal testers, including Colletotrichum sp. PSRU-01 and Fusarium sp. PSRU-01, were completely inhibited by the crude pigment extracts of C13, C15 and D13. Based on phylogenetic results, the actinobacterial strains were closely related to Streptomyces californicus (C7, 100% identity), Streptomyces bungoensis (C13, 99.8% similarity), Streptomyces humi (C15, 99.9% similarity), and Streptomyces rectiverticillatus (D13, 99.8% similarity). They also shared phenotypic characteristics with Streptomyces. The cultivated cells of actinobacteria on broken-milled rice were used for pigment extraction and followed by determination of the extracted pigments for mixing with acrylic color in the shade violet, green, orange and pink colors. Application of actinobacterial pigments in painting is the first report and it is an innovative utilization of actinobacterial pigments in non-scientific field in Thailand.

Transcriptomic and Physiological Analysis Reveal Melanin Synthesis-Related Genes and Pathways in Pacific Oysters (Crassostrea gigas).

Shell color is one of the shell traits of molluscs, which has been regarded as an economic trait in some bivalves. Pacific oysters (Crassostrea gigas) are important aquaculture shellfish worldwide. In the past decade, several shell color strains of C. gigas were developed through selective breeding, which provides valuable materials for research on the inheritance pattern and regulation mechanisms of shell color. The inheritance patterns of different shell colors in C. gigas have been identified in certain research; however, the regulation mechanism of oyster pigmentation and shell color formation remains unclear. In this study, we performed transcriptomic and physiological analyses using black and white shell oysters to investigate the molecular mechanism of melanin synthesis in C. gigas. Several pigmentation-related pathways, such as cytochrome P450, melanogenesis, tyrosine metabolism, and the cAMP signaling pathway were found. The majority of differentially expressed genes and some signaling molecules from these pathways exhibited a higher level in the black shell oysters than in the white, especially after L-tyrosine feeding, suggesting that those differences may cause a variation of tyrosine metabolism and melanin synthesis. In addition, the in vitro assay using primary cells from mantle tissue showed that L-tyrosine incubation increased cAMP level, gene and protein expression, and melanin content. This study reveals the difference in tyrosine metabolism and melanin synthesis in black and white shell oysters and provides evidence for the potential regulatory mechanism of shell color in oysters.

Microwave disinfection of facial silicone prostheses, Part 1: Color stability

The choice of cleaning method is an important consideration for lengthening the serviceable time of facial prostheses as microbial organisms and biofilms could degrade facial prostheses and cause skin irritation. Whether microwave disinfection is a suitable cleaning method without degradation of the properties of a prosthesis is unclear. The purpose of this in vitro study was to measure the color stability of 6 commonly used facial silicone elastomers after microwave disinfection over a simulated 1.5-year period. Six different facial silicone elastomers: MDX4-4210, MDX4-4210/Type A, M511, A-2186, VST-50, and A-2000 were mixed with intrinsic silicone white opacifier (except for the control group) and subsequently combined with 4 silicone intrinsic pigment color groups: red (R), yellow (Y), burnt sienna (B), and a mixture of R+Y+B (M). The control group was a silicone elastomer without opacifier or pigment. Each of the 30 experimental groups consisted of 5 specimens (N=150). Five specimens were placed in a 250-mL Erlenmeyer flask filled with 160mL of tap water. Seven flasks were then placed in a 660-W microwave oven. An exposure of 6 minutes was used according to the antimicrobial efficacy of microwave disinfection protocol on facial silicone prostheses with a final water temperature of 60°C for 18 times (simulating 1.5 years of microwave disinfection with one 6-minute exposure monthly). A spectrophotometer was used to measure reflectance color change values (∆E). Color differences were calculated following CIELab (∆E*ab) and CIEDE2000 (∆E00) formulae. ∆E*ab and ∆E00 were statistically analyzed by a linear mixed effects model with 3 factors (silicone type, color shade, and time) using the R Statistical software program (α=.05). Both ∆E*ab and ∆E00 of all silicone elastomers studied were less than the visual perceptibility thresholds (∆E*ab<1.1 and E00<0.7) and were considered clinically acceptable (∆E*ab<3.0 and E00<2.1) after the 1.5-year simulation of microwave disinfection. Yellow and blue pigments had more effect on MDX4-4210 and M511, while red pigment had more effect on MDX4-4210, MDX4-4210/Type A, and M511 (P<.05). Nevertheless, the values were still below the perceptibility threshold (∆E*ab≤1.0 and E00<0.6). All 6 facial silicone elastomers maintained clinically acceptable color after 18 months of exposure to microwave disinfection.