Coloration Mechanism Research Articles

Nanosecond laser coloration of Ti-based metallic glass under various laser parameters and irradiation atmospheres

Laser coloration is an emerging technique for surface functionalization of metallic glasses (MGs). Understanding the influence of laser parameters on surface color of MGs will accelerate their commercialization. Herein, surface coloration was conducted on a Ti-based MG, and the hue–saturation–intensity (HSI) color space was employed to evaluate color variation. Various colors were achieved by varying the average power and scanning speed in an ambient atmosphere. The results indicated that the overlap rate and number of repetitive scans had a negligible effect on the color and significantly changed the microscopic morphology. The irradiated surfaces were yellowish and colorless in nitrogen and argon atmospheres. Furthermore, the effect of morphology on the surface color and the mechanism of surface coloration were examined. This study demonstrates that nanosecond laser irradiation is an effective method for achieving surface coloration of MGs, which is expected to enrich the surface functionality of MG products.

Transcriptome analysis reveals the mechanism of ‘ZhongShan-HongYu’ grape anthocyanin accumulation

During the biosynthesis of anthocyanin, the protein encoding GST transports anthocyanins synthesized in the endoplasmic reticulum to the vesicle, resulting in plant coloration. ‘ZhongShan-HongYu’ (ZS-HY) is a new teinturier germplasm which accumulates anthocyanin in the skin and flesh of the fruit. However, the molecular mechanisms of the flesh coloration in ‘ZS-HY’ remains unclear. We analyzed the transcriptomic profiles of ‘ZS-HY’ and ‘Zico’ flesh (‘ZS-HY’ and ‘Zico’ have similar phenological periods) at 5, 6 and 7 days after anthesis (DAA) using RNA-sequencing technology. A total of 76.27 G of clean data were obtained from our RNA-seq. By analyzing the differentially expressed genes (DEGs) in the flesh, 212 genes potentially involved in anthocyanin biosynthesis were screened. Through further analysis of DEGs, the genes related to anthocyanin accumulation in grape flesh, including VvMYBA1 and VvGST4, were selected for gene function verification. Subcellular localization analysis revealed that VvMYBA1 and VvGST4 were located in cytoplasm and nucleus. The interaction between VvMYBA1 and VvGST4 was analyzed by yeast two-hybrid analysis and BiFC assay. Meanwhile, we found that VvMYBA1 can regulate the activity of VvGST4 promoter by binding with it. Our study provides a basis for the molecular mechanism of anthocyanin transport in grape.

Weighted Gene Co-Expression Network Analysis of red body color formation of crimson snapper, Lutjanus erythropterus

Crimson snapper (Lutjanus erythropterus) is a highly valued economic fish species, with its red body color being a crucial economic characteristic. A systematic study of skin pigmentation could offer insights into the mechanism of red coloration. In this study, we conducted the first network analysis of snapper transcriptomes during key developmental stages of pigmentation, identifying a cascade of cellular development and responsive gene modules and key genes, including eight developmental-specific modules. Among the four candidate hub genes (TNNT2, ROBO2, APBA2, and APOD), APOD was involved in pigmentation development. The network further revealed some key genes, such as TYRP1a, TYRP1b, PMEL, BCO1, BCO2, CYP2J2, CYP2J6, CYP3A4, PNPLA2, FABP6, ENPP7, and FFAR3, associated with melanin synthesis, carotenoids, and lipid metabolism. Our findings showed that pteridine and carotenoids were involved in yellow coloration after initial feeding, while yellow pigmentation-related genes (e.g., GCH1, PTS, SPR, CBR1, SCARB1, CD36, ABCA1, NpC1L1, etc.) had the same expression pattern at three days post-hatching (3 dph). At the red coloration emergence stage (45 dph), we observed an RNA level signal indicating the conversion of coloring substances from pteridine to carotenoids. These results substantially enhance understanding of the molecular mechanisms underlying pigmentation and skin color variation in L. erythropterus, providing a theoretical basis for improving of body coloration in economically cultured fish and genetic breeding of ornamental fish.

A Review of Environmental Impact of Azo Dyes

Green plants are one of nature’s factories, fixing inorganic chemicals into organic compounds through photosynthesis and other reactions. Microbes are one of the nature’s most effective tools, converting organic materials—dead plants and animals—into inorganic forms through decomposition and mineralization. Together, green plants and microbes are responsible for maintaining a balance between the organic and inorganic worlds, but pollutants, such as synthetic dyes, can upset this balance. Compared with synthetic dyes, natural dyes are safer and more environmentally friendly, but they are also costlier and more difficult to apply, so they are not viable in most commercial applications. Azo dyes are low cost and have high intensity and color fastness, so they are the most frequently used class of synthetic dyes. The main threats related to the dumping of untreated azo dyes into the environment come from their primary byproducts––aromatic amines––which result from the cleavage of the central azo bonds, and which have been classified as significant carcinogenic compounds, representing a great risk to humans as well as the environment. To address this threat, the degradation of synthetic azo dyes is showing promise as an approach to treating azo-dye wastewater. In this review, the classification of azo dyes and their color mechanism is presented first, and then an overview of the research on their environmental impacts is provided, including their effects on biochemical and chemical oxygen demand, water ecosystems, plants, and crops. Finally, the legislation and guidelines on azo dyes and their byproducts are discussed. Keywords: azo dyes; climate change; biochemical oxygen demand; chemical oxygen demand; aromatic amines

The domestication-associated L1 gene encodes a eucomic acid synthase pleiotropically modulating pod pigmentation and shattering in soybean

Pod coloration is a domestication-related trait in soybean, with modern cultivars typically displaying brown or tan pods, while their wild relative, Glycine soja, possesses black pods. However, the factors regulating this color variation remain unknown. In this study, we cloned and characterized L1, the classical locus responsible for black pods in soybean. By using map-based cloning and genetic analyses, we identified the causal gene of L1 and revealed that it encodes a hydroxymethylglutaryl-coenzyme A (CoA) lyase-like (HMGL-like) domain protein. Biochemical assays showed that L1 functions as a eucomic acid synthase and facilitates the synthesis of eucomic acid and piscidic acid, both of which contribute to coloration of pods and seed coats in soybean. Interestingly, we found that L1 plants are more prone to pod shattering under light exposure than l1 null mutants because dark pigmentation increases photothermal efficiency. Hence, pleiotropic effects of L1 on pod color and shattering, as well as seed pigmentation, likely contributed to the preference for l1 alleles during soybean domestication and improvement. Collectively, our study provides new insights into the mechanism of pod coloration and identifies a new target for future de novo domestication of legume crops.

Identification of ApbHLH1 as a Partner Interacting with ApMYB1 to Promote Anthocyanin Biosynthesis during Autumnal Leaf Coloration in Acer palmatum

Anthocyanin biosynthesis determines the leaf color of Acer palmatum as a widely-planted landscape tree. Previously, ApMYB1 has been characterized as a positive regulator of anthocyanin biosynthesis. To further elucidate the mechanism of leaf coloration, the present study identified a basic helix-loop-helix (bHLH) transcription factor (ApbHLH1) through the phylogenetic analysis of 156 putative bHLH proteins in Acer palmatum and eight reference bHLHs which were known to be involved in the anthocyanin biosynthesis of selected plants. Protein structure comparison showed that ApbHLH1 has a conserved bHLH domain, and its N-terminal contains an MYB-interacting region. The expression of ApbHLH1 in leaves was found to not be correlated with anthocyanin contents either in green, semi-red leaves or during leaf autumnal senescence when anthocyanin content increased. ApbHLH1 expression in detached leaves was induced by exogenous senescence-promoting chemicals, including H2O2, SA, MeJA, ACC and ABA, with certain durations. In particular, either high light or low temperature induced ApbHLH1 expression significantly, and combination of high light and low temperatures seemed more effective in inducing ApbHLH1 expression. Luciferase complementation imaging assays confirmed the physical interaction between ApbHLH1 and ApMYB1, which could be abolished by either the truncating MYB-interacting region of ApbHLH1 or the deleting bHLH interacting domain of ApMYB1. The transient expression of ApbHLH1 could not induce anthocyanin production, while the co-expression of ApbHLH1 and ApMYB1 resulted in a higher accumulation of anthocyanins compared to the expression of ApMYB1 alone in tobacco leaves. Collectively, our results revealed that ApbHLH1 participated in leaf coloration through binding with ApMYB1 and enhancing the ApMYB1 function of promoting anthocyanin biosynthesis during leaf autumnal reddening in Acer palmatum. ApbHLH1 could have the potential for breeding color-leafed plants through co-transformation with ApMYB1.

Coupling coloration of meta‐aramid fabric utilising diazonium salts from weakly basic aromatic amines

AbstractMeta‐aramid fibre exhibits poor dyeing performance when treated using conventional dyeing methods. In this study, coloration of meta‐aramid fabrics was performed at room temperature utilising diazonium salts from weakly basic aromatic amines and was achieved via in situ construction of azo chromophores on the meta‐phenylenediamine moiety. To promote diazonium‐salt penetration into the meta‐aramid fibre, the pretreatment of meta‐aramid fabrics with dimethyl sulfoxide at 55°C for 30 min and the utilisation of methanol were involved during the coloration process. As a result, the fabrics could be coloured with deep, levelled and firm shades of brown series. The azo chromophore is derived from the skeleton of the polyamide chain. Therefore, the coloured fabrics exhibit good resistance to organic solvents as well as good to excellent colour fastness to soaping, rubbing and sublimation. A study of the coloration mechanism revealed that the terminal and middle meta‐phenylenediamine moieties serve as the main coupling reaction sites. When treated with a diazonium salt, the highly reactive terminal meta‐phenylenediamine moiety reacted first and generated chromophores with an absorption peak in the long‐wavelength region. However, such chromophores only contributed a limited colour depth owing to the limited number of the terminals. If excess diazonium salts were used, the main hue can be attributed to the azo chromophores based on the massive middle meta‐phenylenediamine moieties, although these moieties are less reactive than the terminal meta‐phenylenediamine moieties.

Emission color tuning based on core-shell microcrystals through modulation of laser power for anti-counterfeiting

Manipulating color with lanthanide doped upconversion luminescence materials is an excellent approach for anti-counterfeiting, thanks to their abundant energy levels and convenient NIR-to-VIS luminescence property. However, most of the materials are limited by the single-color emission and low photoluminescence efficiency. Herein, pumping-dependent multicolor upconversion luminescence core-shell microcrystals have been obtained through a facile hydrothermal method. In comparison to nanomaterials, core-shell microcrystals possess a smaller surface area-to-volume ratio and fewer surface defects, leading to enhancing the luminescence. A naked-eye recognizable color can be switched from green to blue with increasing the laser power. Furthermore, the mechanism of tunable color with laser power varying has been systematically studied. Due to emission colors of the core-shell materials with excitation power sensitivity and being distinguished by naked-eye easily, core-shell microcrystals reveal promising applications for anti-counterfeiting.

Transcriptomic and metabolomic analysis of autumn leaf color change in Fraxinus angustifolia.

Fraxinus angustifolia is a type of street tree and shade tree with ornamental value. It has a beautiful shape and yellow or reddish purple autumn leaves, but its leaf color formation mechanism and molecular regulation network need to be studied. In this study, we integrated the metabolomes and transcriptomes of stage 1 (green leaf) and stage 2 (red-purple leaf) leaves at two different developmental stages to screen differential candidate genes and metabolites related to leaf color variation. The results of stage 1 and stage 2 transcriptome analysis showed that a total of 5,827 genes were differentially expressed, including 2,249 upregulated genes and 3,578 downregulated genes. Through functional enrichment analysis of differentially expressed genes, we found that they were involved in flavonoid biosynthesis, phenylpropanoid biosynthesis, pigment metabolism, carotene metabolism, terpenoid biosynthesis, secondary metabolite biosynthesis, pigment accumulation, and other biological processes. By measuring the metabolites of Fraxinus angustifolia leaves, we found the metabolites closely related to the differentially expressed genes in two different periods of Fraxinus angustifolia, among which flavonoid compounds were the main differential metabolites. Through transcriptome and metabolomics data association analysis, we screened nine differentially expressed genes related to anthocyanins. Transcriptome and qRT-PCR results showed that these nine genes showed significant expression differences in different stages of the sample, and we speculate that they are likely to be the main regulatory factors in the molecular mechanism of leaf coloration. This is the first time that we have analyzed the transcriptome combination metabolome in the process of leaf coloration of Fraxinus angustifolia, which has important guiding significance for directional breeding of colored-leaf Fraxinus species and will also give new insights for enriching the landscape.

New insight into the coloration mechanism and synthesis of ultrafine Pr‐ZrSiO4 yellow pigments

AbstractIt is of particular significance to unveil the authentic coloration mechanism of the multivalent praseodymium colored ZrSiO4 yellow pigments for advanced decoration applications. We herein adopted a facile strategy to modulate the fluorine‐assisted zircon crystallization and thereby obtained ultrafine Pr‐ZrSiO4 yellow pigments, which have a remarkably narrow size distribution and average diameters within 250–400 nm. By virtue of some cogent combinative spectra of reflection, absorption, excitation, and emission from three types of elaborately‐designed H2‐, air‐, and O2‐based pigments, the coloration mechanism for the Pr‐colored zircon was systematically unveiled: both Pr4+ and Pr3+ coexist invariably in the pigments, while the former contributes primarily to the ligand‐to‐metal charge transfer from O2p to Pr(IV)4f for the blue–violet absorption to generate the yellow hue, and the latter is inclined to discolor the pigments. Therefore, an oxidizing atmosphere is preferable to produce brilliant Pr‐ZrSiO4 pigments with enhanced chromatic properties. The stark spectroscopic distinctions between the wide‐band absorption from the nonluminescent tetravalency and the narrow‐band absorption from the luminescent trivalency can expand our understanding to the rare‐earth‐based inorganic pigments.

Comparative transcriptome sequencing analysis to postulate the scheme of regulated leaf coloration in Perilla frutescens.

Perilla as herb, ornamental, oil and edible plant is widely used in East Asia. Until now, the mechanism of regulated leaf coloration is still unclear. In this study, four different kinds of leaf colors were used to measure pigment contents and do transcriptome sequence to postulate the mechanism of leaf coloration. The measurements of chlorophyll, carotenoid, flavonoid, and anthocyanin showed that higher contents of all the aforementioned four pigments were in full purple leaf 'M357', and they may be determined front and back leaf color formation with purple. Meanwhile, the content of anthocyanin was controlled back leaf coloration. The chromatic aberration analysis and correlative analysis between different pigments and L*a*b* values analysis also suggested front and back leaf color change was correlated with the above four pigments. The genes involved in leaf coloration were identified through transcriptome sequence. The expression levels of chlorophyll synthesis and degradation related genes, carotenoid synthesis related genes and anthocyanin synthesis genes showed up-/down-regulated expression in different color leaves and were consistent of accumulation of these pigments. It was suggested that they were the candidate genes regulated perilla leaf color formation, and genes including F3'H, F3H, F3',5'H, DFR, and ANS are probably important for regulating both front and back leaf purple formation. Transcription factors involved in anthocyanin accumulation, and regulating leaf coloration were also identified. Finally, the probable scheme of regulated both full green and full purple leaf coloration and back leaf coloration was postulated.

Phenotype of White Sika Deer Due to SCF Gene Structural Variation.

Breeding ornamental white sika deer is a new notion that can be used to broaden the sika deer industry However, it is very rare for other coat phenotypes to occur, especially white (apart from albinism), due to the genetic stability and homogeneity of its coat color phenotype, making it difficult to breed white sika deer between species. We found a white sika deer and sequenced its whole genome. Then, the clean data obtained were analyzed on the basis of gene frequency, and a cluster of coat color candidate genes containing 92 coat color genes, one SV (structure variation), and five nonsynonymous SNPs (single nucleotide polymorphisms) was located. We also discovered a lack of melanocytes in the skin tissue of the white sika deer through histological examination, initially proving that the white phenotype of sika deer is caused by a 10.099 kb fragment deletion of the SCF gene(stem cell factor). By designing SCF-specific primers to detect genotypes of family members of the white sika deer, and then combining them with their phenotypes, we found that the genotype of the white sika deer is SCF789/SCF789, whereas that of individuals with white patches on their faces is SCF789/SCF1-9. All these results showed that the SCF gene plays an important role in the development of melanocytes in sika deer and is responsible for the appearance of the white coat color. This study reveals the genetic mechanism of the white coat color in sika deer and supplies data as a reference for breeding white ornamental sika deer.

Transcription factors TgbHLH42-1 and TgbHLH42-2 positively regulate anthocyanin biosynthesis in Tulip (Tulipa gesneriana L.).

The floral coloration of tulip flowers is one of the most prominent traits contributing to its high ornamental value. The molecular mechanisms of petal coloration remain elusive in tulip species. In this study, we performed comparative metabolome and transcriptome analyses using four tulip cultivars with distinguished petal colors. Four types of anthocyanins were identified, including cyanidin derivatives and pelargonidin derivatives. Comparative transcriptome analysis identified 22,303 differential expressed genes (DEGs) from the four cultivars, and 2589 DEGs were commonly regulated in three comparison groups (colored vs. white cultivar), including anthocyanins biosynthesis-related genes and regulatory transcription factors. Two basic helix-loop-helix (bHLH) transcription factors, TgbHLH42-1 and TgbHLH42-2, with differential expression levels among cultivars and petal developmental stages, have high homology to TRANSPARENT TESTA 8 (AtTT8) of Arabidopsis. The anthocyanins accumulation in TgbHLH42-1 overexpressing (OE) seedlings was markedly greater than that in wild-type seedlings in the presence of methyl jasmonate (MeJA), but not for TgbHLH42-2 OE seedlings. Both TgbHLH42-1 and TgbHLH42-2 restored pigmentation defects in tt8 mutant seeds after complementation assay. TgbHLH42-1 could interact with MYB protein AtPAP1 to synergistically activate the transcription of AtDFR, whereas TgbHLH42-2 failed to. Silencing TgbHLH42-1 or TgbHLH42-2 individually could not, but simultaneously silencing both TgbHLH42 could reduce the anthocyanin in tulip petals. These results indicate that TgbHLH42-1 and TgbHLH42-2 function partially redundantly to positively regulate anthocyanin biosynthesis during tulip petal coloration.

Genome-wide screening of AP2/ERF transcription factors involved in Citrus maxima ‘Sanhongmiyou’ exocarp coloring

Pummelo (Citrus maxima) belong to subfamily Aurantioideae of Rutaceae. In production, ‘Sanhongmiyou’ exocarp turned out red after bagging but remained yellow green without bagging. Carotenoids were the main color in pummelo exocarp. The AP2/ERF family has been confirmed to be associated with fruit coloring by regulating genes related to carotenoid metabolism in multiple species. To better understand the molecular mechanisms of exocarp coloration and carotenoid accumulation, a total of 126 AP2/ERF transcription factor family members distributed on 9 chromosomes were screened from pummelo genome database and divided into 3 subfamilies including 110 ERF subfamilies, 13 AP2 subfamilies and 3 RAV subfamilies. 26 pairs of genes from the AP2/ERF transcription factor family were colinear. 18 pairs of genes were evolutionarily conserved and functionally different after tandem repetition events. Multi-species collinearity analysis showed close evolutionary relationship between pummelo, Actinidia chinensis and Eriobotrya japonica. Cis-acting elements prediction in the promoter region revealed that members of AP2/ERF family are rich in cis-acting elements which respond to light and plant hormones. Color parameters L*, a*, b* and CCI values were measured. Chlorophyll a,chlorophyll b, carotenoid content in fruit exocarp were determined. Eight ERF genes related to the carotenoid metabolism were screened out and tested by qRT-PCR. The expression pattern of structure genes in carotenoid metabolism were also measured with qRT-PCR. The expression patterns of CitERF23, CitERF27 and CitERF32 appeared correlation with pigment content and color indexes. Meanwhile, CitERF23 showed significant positively correlation with ZDS and CDD4. CitERF27 showed significant positively correlation with CDD1. CitERF32 showed significant positively correlation with PDS. CitERF120 showed significant positively correlation with CDD1. CitERF23, CitERF27 and CitERF32 were proposed as a candidate gene regulating carotenoid metabolism in the AP2/ERF family.

The Prediction of Evolutionary Trend for Coloration of Mammals under the Influence of Climate Change

Like humans getting tanned after sunbath, mammals around the world may also change their coloration according to the dynamic environment. Such changes primarily aim for better camouflage, but it also comes with some linked physiological changes for mammals to potentially have better fitness. The article predicts the overall evolutionary trend of mammal coloration using case studies across different species in distinct geographical locations. The article focuses on the explanation of animal coloration mechanism and the comparison between the potential fitness of the same species of mammals with different colorations. As demonstrated by most case studies, the evolutionary trend of mammal coloration is to become darker. Such an evolutionary trend is promoted in which darker coloration brings better fitness for the mammal for the purpose of better camouflage and more adapted physiology to the environment under the influence of climate change.

Gemology, Mineralogy, and Spectroscopy of Gem-Quality Diopside from Pakistan and Russia: New Insights for the Chromogenic Mechanism and Possible Origin

Green diopside is currently popular in the jewelry market due to its attractive color and excellent transparency. Gem-quality diopsides are mainly sourced from Pakistan, Italy, Russia, and other places. The color, geographic origin, and formation mechanism are the main factors affecting the value of gemstones, which can be determined by examining their gemology and composition characteristics. This study systematically characterizes the standard gemology of green diopsides from Pakistan and Russia and compares them with the blue diopsides produced within the skarn process and the diopsides from the nearby region in Russia from previous studies by gemological microscopy, spectral testing (infrared, Raman and ultraviolet-visible spectroscopy), and chemical analyses (electron probe and laser ablation inductively coupled plasma mass spectrometry). The results show that the spectral characteristics and phase composition of the green diopside samples from Pakistan and Russia have excellent uniformity and similarity. The high Cr, Fe, V, and Ni contents are the reasons why they appear as green. Meanwhile, the elemental characteristics of the diopside are effective tools for distinguishing different origins of different diopsides. The Russian green diopsides have higher contents of Sr, Sc, Zr, and rare earth elements (REE), indicating that they are related to alkaline ultrabasic rocks, and the source of the diopside sample from Pakistan is metamorphic rock.

Rational design and coloration mechanism of soluble intrinsic black polyimide with high comprehensive performance for black flexible copper clad laminates

With the development of flexible printed circuit boards (FPCBs) and photoelectric devices, the demand for black polyimide (BPI) is increasing, but the existing BPIs have some problems, such as poor electrical properties, mechanical performance, masking ability and solubility. To solve these problems, a novel diamine monomer (TPCPOHPDA) containing tetraphenylcyclopentadienone (TPCP) grafted with hydroxyl groups and benzene rings was customized, and then TPCPOHPDA was polymerized with 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) to obtain polyimide (TPCPOHPPI). TPCP had a broad UV–visible light absorption range (250–600 nm). Appending benzene rings and auxochrome (hydroxyl groups) on the TPCP skeleton extended the conjugated π-electron system and enhanced the mobility of electrons in the large π bonds, respectively. These structural modifications further extended its light absorption range, and the resulting TPCPOHPPI was dark black with a cutoff wavelength (λcut) of 680 nm and Commission International Eclairage (CIE) lab color parameter L* of 0.7. Simulation calculations indicated that the visible-light absorption that caused the black appearance of TPCPOHPPI was mainly due to the electron transition from HOMO to LUMO occurring within the TPCP-containing diamine moieties, in which the charge mainly transferred from the aryl moieties in positions 2 and 5 to the central cyclopentadienone core. Further investigation showed that TPCPOHPPI had excellent thermal, electrical and mechanical performances and high solubility. The TPCPOHPPI-based two-layer black flexible copper clad laminate (2L-FCCL) possessed good dip soldering resistance and peeling strength. This work provides a new idea for the design and synthesis of soluble intrinsic black polyimide with excellent comprehensive performance.

Metabolomics and transcriptomics strategies to reveal the mechanism of diversity of maize kernel color and quality

BackgroundMaize has many kernel colors, from white to dark black. However, research on the color and nutritional quality of the different varieties is limited. The color of the maize grain is an important characteristic. Colored maize is rich in nutrients, which have received attention for their role in diet-related chronic diseases and have different degrees of anti-stress protection for animal and human health.MethodsA comprehensive metabolome (LC-MS/MS) and transcriptome analysis was performed in this study to compare different colored maize varieties from the perspective of multiple recombination in order to study the nutritional value of maize with different colors and the molecular mechanism of color formation.ResultsMaize kernels with diverse colors contain different types of health-promoting compounds, highlighting that different maize varieties can be used as functional foods according to human needs. Among them, red-purple and purple-black maize contain more flavonoids than white and yellow kernels. Purple-black kernels have a high content of amino acids and nucleotides, while red-purple kernels significantly accumulate sugar alcohols and lipids.ConclusionOur study can provide insights for improving people’s diets and provide a theoretical basis for the study of food structure for chronic diseases.

Proteomic approaches to characterize biochemistry of fresh beef color

Color of retail fresh beef is the most important quality influencing the consumers' purchase decisions at the point of sale. Discolored fresh beef cuts are either discarded or converted to low-value products, before the microbial quality is compromised, resulting in huge economic loss to meat industry. The interinfluential interactions between myoglobin, small biomolecules, proteome, and cellular components in postmortem skeletal muscles govern the color stability of fresh beef. This review examines the novel applications of high-throughput tools in mass spectrometry and proteomics to elucidate the fundamental basis of these interactions and to explain the underpinning mechanisms of fresh beef color. Advanced proteomic research indicates that a multitude of factors endogenous to skeletal muscles critically influence the biochemistry of myoglobin and color stability in fresh beef. Additionally, this review highlights the potential of muscle proteome components and myoglobin modifications as novel biomarkers for fresh beef color. SignificanceThis review highlights the important role of muscle proteome in fresh beef color, which is the major trait impacting consumers’ purchase decisions. In recent years, innovative approaches in proteomics have been exploited for an in-depth understanding of the biochemical mechanisms influencing color development and color stability in fresh beef. The review suggests that a wide range of factors, including endogenous skeletal muscle components, can affect myoglobin biochemistry and color stability in beef. Furthermore, the potential use of muscle proteome components and myoglobin post-translational modifications as biomarkers for fresh beef color is discussed. The currently available body of evidence presented in this review can have important implications in meat industry as it provides novel insights into the factors influencing fresh beef color and an up-to-date list of biomarkers that can be used to predict beef color quality.

Effects of tannic acid on film formation process of colored Ti/Zr-based conversion coatings

Corrosion of aluminum (Al) alloys represents a major issue in industrial applications, giving rise to safety concerns and enormous economic loss. Chromate conversion coatings (CCCs) have been widely used in industry over the past decades, providing exceptional corrosion protection for aluminum alloys at a relatively low cost. However, new environmental regulations prohibiting the use of chromium (VI) (Cr6+) have raised a growing interest in the development of alternative technologies to CCCs, but only titanium (Ti)/zirconium (Zr) conversion coatings have been used in industrial applications thus far. However, there remain some disadvantages to these coatings, such as colorless appearance and poor corrosion resistance, which affect their wide application. Here, a colored titanium/zirconium-based conversion coating, formed on aluminum alloy 6063 using a solution containing tannic acid (TA; C76H52O46), hexafluorozirconic acid (H2ZrF6), hexafluorotitanic acid (H2TiF6) and sodium metavanadate (NaVO3), was developed recently by the authors, enabling rapid film formation at room temperature and improved corrosion resistance. The influence of TA on the film-forming process of colored titanium/zirconium-based conversion coatings was investigated using the ultraviolet–visible spectrophotometry, X-ray photoelectron spectroscopy and infrared spectroscopy techniques, and the possible reaction process after adding TA, as well as the mechanism of rapid film formation and color rendering, was also explored. The results showed that the large number of organic complexes formed by TA with metal ions during the aging process of conversion solution and film formation was the main reason for the rapid film formation and color rendering of the coating.