Search Results (375)

Papaver rhoeas L. has four strikingly red petals with a distinctly black area bordered by a thin white line at the petal base, thus creating a color pattern that makes the center of the flower, where the pollen is located, visually stand out. This paper aims to assess the intra-petal spatial variability in P. rhoeas petal color intensity and hue and associate it with corresponding differences in the amount and type of petal pigments. The distribution of pigments in the petal epidermis was investigated in different petal segments by column chromatography. Fresh petals were extracted with deionized water during blooming, between April and June 2023, in northwestern Greece. UV–visible absorption spectra of the eluted fractions revealed five pigments, with each pigment belonging to a different elution zone. In the black spots of the petals, anthocyanin coexists with a yellow flavonol with a maximum absorption peak at 340 nm. Red petal extract in 70:30 ethanol–water showed a distinct negative Cotton effect at 284 nm, distinct from black segment extract with a negative Cotton effect at 227 nm. The uneven distribution of floral pigments along the petal epidermis creates a unique color palette, enabling UV-reflection, which is key in attracting pollinators responsible for plant reproduction. Full article

Identifying the mineral pigments used in the decoration of prehistoric pottery is a significant step for understanding the evolution of the technological practices over time. On the Balkan Peninsula during late prehistory, the techniques used for red and dark-colored decorations underwent a significant transformation. In the Early Neolithic period, pottery was often decorated with dark-toned paints, ranging from deep red to brown. However, this approach declined noticeably during the Chalcolithic period, when red pigment pseudo-incrustation became the predominant decorative method. This study aims to identify the mineral pigments used in red and dark decorations on Neolithic and Chalcolithic pottery from Bulgaria and to trace possible technological, regional, or chronological variations in their composition. A total of 34 ceramic sherds, decorated in shades from red to brown and black, were analyzed using two complementary spectroscopic techniques: laser-induced breakdown spectroscopy (LIBS) and Fourier-transform infrared spectroscopy (FTIR). LIBS data were further evaluated using principal component analysis (PCA) to classify materials based on elemental composition. The results indicate that red decorations are consistently composed of hematite and remain compositionally stable regardless of the region, time period, or application technique. In contrast, dark decorations contain various combinations of iron oxides (magnetite and hematite) and manganese oxides, often including barium-rich manganese compounds—potentially indicating pigment provenance. Additionally, the dark decorations display regional differences. Full article

The Rubus genus includes numerous berry species known for their rich phytochemical content and antioxidant properties. However, comparative evaluations of wild and cultivated Rubus germplasms in East Asia remain limited. This study aimed to identify superior resources with potential for use in functional foods and breeding through integrated phytochemical and antioxidant profiling. Fifteen accessions collected across Korea were assessed for fruit coloration, total phenolic content (TPC), total flavonoid content (TFC), five antioxidant activities (DPPH, ABTS⁺, superoxide, ferric-reducing activity power, and Fe²⁺ chelation), and anthocyanin composition by high-performance liquid chromatography‒Mass spectrometry. The TPC ranged from 1.03 to 7.54 mg g⁻¹ of frozen fruit, and TFC ranged from 2.75 to 7.52 mg g⁻¹ of frozen fruit, with significant differences among accessions (p < 0.05). Black-colored fruits such as R. coreanus and R. ursinus varieties exhibited high anthocyanin levels (approximately total 471 and 316 mg g⁻¹ extracts, respectively), with cyanidin-O-hexoside and cyanidin-3-O-glucoside being the dominant pigments. However, the antioxidant performance of these accessions varied. A wild R. crataegifolius (no. 9, resource F) showed the highest TPC and ranked within the top five in multiple antioxidant assays, despite its moderate anthocyanin content. Correlation analysis revealed that TPC and TFC were significantly associated with antioxidant activity (p < 0.05) but not directly with anthocyanin content. These results suggest that antioxidant potential is influenced by a broader spectrum of phenolic compounds, rather than anthocyanins alone. These findings underscore the need to look beyond visual traits and focus on biochemical evidence when selecting elite Rubus accessions. Full article

Efficient and convenient intelligent online detection methods can provide important technical support for the standardization of processing flow in the tea industry. Hence, this study focuses on the key chemical indicators—tea pigments in the rolling process of black tea as the research object, and uses multi-source information fusion methods to predict the changes of tea pigments content. Firstly, the tea pigments content of the samples under different rolling time series of black tea is determined by system analysis methods. Secondly, the spectra and images of the corresponding samples under different rolling time series are simultaneously obtained through the portable near-infrared spectrometer and the machine vision system. Then, by extracting the principal components of the image feature information and screening characteristic wavelengths from the spectral information, low-level and middle-level data fusion strategies are chosen to effectively integrate sensor data from different sources. At last, the linear (PLSR) and nonlinear (SVR and LSSVR) models are established respectively based on the different characteristic data information. The research results show that the LSSVR based on middle-level data fusion strategy have the best effect. In the prediction results of theaflavins, thearubigins, and theabrownins, the correlation coefficients of the testing sets are all greater than 0.98, and the relative percentage deviations are all greater than 5. The complementary fusion of the spectrum and image information effectively compensates for the problems of information redundancy and feature missing in the quantitative analysis of tea pigments content using the single-modal data information. Full article

Background: Vitis vinifera L. exhibits diverse varietal traits influencing fruit quality and stress tolerance. The summer black grape (Xiahei), known for its superior tolerance to abiotic stress and intense pigmentation, was hypothesized to possess distinct metabolic and genetic profiles, particularly in flavonoid and anthocyanin biosynthesis. This study aimed to elucidate the metabolic and molecular basis underlying these phenotypic traits by comparing carbohydrate composition and metabolomic and transcriptomic profiles of four grape varieties (summer black, flame seedless, black grape, and red milk). Methods: Grapes were consistently sampled five days after full maturity, and metabolites were analyzed using UPLC-MS/MS and GC-MS, while transcriptome analysis employed RNA sequencing followed by qRT-PCR validation. Results: The results demonstrated that carbohydrate content was similar among all grape varieties, whereas the summer black grape showed significantly higher levels of flavonoids, particularly anthocyanins such as delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, and pelargonidin-3-O-glucoside. Metabolomic analyses revealed substantial enrichment of metabolites involved in flavonoid biosynthesis pathways, in agreement with transcriptomic data showing significant upregulation of key regulatory genes (CHS, DFR, and ANS) specific to anthocyanin biosynthesis. These findings suggest that the pronounced anthocyanin accumulation in summer black grape contributes to its distinctive dark pigmentation and enhanced resistance to abiotic stresses compared to other varieties. Conclusion: This study provides novel insights into the molecular and metabolic mechanisms driving anthocyanin accumulation in summer black grapes, which could inform future breeding programs aimed at improving grape resilience. Full article

Rice (Oryza sativa L.) plays a pivotal role in the Brazilian economy, serving as a staple food for more than half of the world’s population and thereby contributing to global food security. Projections of future climate change scenarios indicate an increase in extreme weather events. Among climate variables that impact the development and productivity of irrigated rice, solar radiation is one of the most important in defining productive potential. Understanding the risks imposed on agricultural production by the occurrence of days with reduced luminosity availability is crucial for guiding adequate responses that mitigate the negative impacts of climate variability. Therefore, this study aimed to investigate the effect of shade on the metabolism and productivity of irrigated rice plants, with a specific focus on the synthesis of photosynthetic pigments, carbohydrate accumulation, invertase activity, and the nutritional status and grain yield of rice. For this, the study was conducted on the field rice cultivars IRGA 424 RI, BRS PAMPA, and BRS PAMPEIRA, which were subjected to 35% shading using black nylon netting installed when the plants reached the reproductive stage (R0). The restriction was maintained until the R4 stage, and later, from the R4 stage until the R9 stage. After the imposition of treatments, evaluations took place at the phenological stages R2, R4, R6, and R8. In shaded plants, a higher content of photosynthetic pigments and a lower accumulation of carbohydrates were observed, which was reflected in an increase in the activity of invertase enzymes. These conditions were able to potentiate effects on the nutritional status of the plants, in addition to reducing productivity and 1000-grain weight and increasing spikelet sterility, due to changes in the source–sink relationship, with effects more pronounced in cultivars BRS PAMPA and BRS PAMPEIRA during the R4–R9 period. Full article

This paper presents the results of a study on the development of a processing technology for pyrite–cobalt concentrates to obtain iron oxide pigments (Fe₂O₃ and Fe₃O₄) via high-temperature hydrolysis. It was found that, in a single operation, the concentrate can be effectively purified from lead, zinc, and copper, yielding an iron–nickel–cobalt product suitable for further processing by standard technologies, such as smelting into ferronickel. The scientific originality of research concludes in a mechanism of stepwise selective chloride volatilization, which was established as follows: stage I (500–650 °C)—removal of lead; stage II (700–750 °C)—chlorination of copper and iron; stage III (850–900 °C)—volatilization of nickel and cobalt. Microprobe analysis of the powders obtained from high-temperature hydrolysis of FeCl₂·4H₂O and FeCl₃·6H₂O revealed the resulting Fe₃O₄ and Fe₂O₃ powders with particle sizes 50 μm and 100 μm. A visual color palette was created, corresponding to different Fe₃O₄/Fe₂O₃ ratios in the pigment composition—ranging from black (magnetite) to red (hematite)—and potential application areas. For the first time, the new technological scheme was proposed of pigments Fe₂O₃ and Fe₃O₄ production from pyrite–cobalt concentrates via combination of oxidized roasting with subsequent chlorination and high-temperature hydrolysis of the products. Full article

Black tea is widely consumed worldwide, and its characteristic taste and color result from fermentation, where polyphenols are enzymatically oxidized to generate major pigments, including theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs). This study investigated the effects of increased oxygen treatment during fermentation on the flavor attributes and chemical properties of Congou black tea. Fresh tea leaves (variety “Fuyun 6”) were subjected to four oxygen treatments: 0 h (CK), 1 h (TY-1h), 2 h (TY-2h), and 3 h (TY-3h), with oxygen supplied at 8.0 L/min. Sensory evaluation revealed that oxygen-treated samples exhibited tighter and deeper-colored leaves, a redder liquor, fuller taste, and a sweeter fragrance compared with CK. Chromatic analysis showed significant increases in redness (a*) and luminance (L*), alongside reduced yellowness (b*), indicating enhanced liquor color. Chemical analyses demonstrated elevated levels of TFs, TRs, and TBs in oxygen treatments, with TRs showing the most pronounced increase. Non-targeted metabolomics identified 2318 non-volatile and 761 volatile metabolites, highlighting upregulated flavonoids, phenolic acids, and lipids, and downregulated catechins and tannins, which collectively contributed to improved taste and aroma. Optimal results were achieved with 2–3 h of oxygen treatment, balancing pigment formation and sensory quality. These findings can provide a scientific basis for optimizing oxygen conditions in black tea fermentation to improve product quality. Full article

This study compares the nutritional and metabolic properties of unconventional cold-pressed vegetable oils available on the Polish market. Twelve oils—milk thistle, evening primrose, flaxseed, camelina sativa, black cumin, pumpkin seed, sesame, mustard seed, sea buckthorn, blue poppy seed, borage, and safflower—were examined. The chosen oils were investigated based on their fatty acids profiles, total phenolic compounds (TPC), tocopherols, and pigment contents. Despite the high polyunsaturated fatty acids (PUFAs) content raising concerns about oxidative stability, the significant tocopherol levels and polyphenols content contribute to antioxidative protection. These oils’ favorable hypocholesterolemic, antiatherogenic, and antithrombogenic properties were highlighted by key nutritional indices, showing potential benefits for cardiovascular health. These results suggest that these oils are a promising dietary supplement for promoting both cardiovascular health and sustainability, owing to their rich content of essential fatty acids and bioactive compounds. Moreover, high correlations were found between theoretical and experimental established oxidative stability of the tested oils at the ending stage of the thermostat test. Full article

The rapid evolution of deep learning (DL) has fundamentally transformed the paradigm for detecting special components in agricultural products, addressing critical challenges in food safety, quality control, and precision agriculture. This comprehensive review systematically analyzes many seminal studies to evaluate cutting-edge DL applications across three core domains: contaminant surveillance (heavy metals, pesticides, and mycotoxins), nutritional component quantification (soluble solids, polyphenols, and pigments), and structural/biomarker assessment (disease symptoms, gel properties, and physiological traits). Emerging hybrid architectures—including attention-enhanced convolutional neural networks (CNNs) for lesion localization, wavelet-coupled autoencoders for spectral denoising, and multi-task learning frameworks for joint parameter prediction—demonstrate unprecedented accuracy in decoding complex agricultural matrices. Particularly noteworthy are sensor fusion strategies integrating hyperspectral imaging (HSI), Raman spectroscopy, and microwave detection with deep feature extraction, achieving industrial-grade performance ($RPD$ > 3.0) while reducing detection time by 30–100× versus conventional methods. Nevertheless, persistent barriers in the “black-box” nature of complex models, severe lack of standardized data and protocols, computational inefficiency, and poor field robustness hinder the reliable deployment and adoption of DL for detecting special components in agricultural products. This review provides an essential foundation and roadmap for future research to bridge the gap between laboratory DL models and their effective, trusted application in real-world agricultural settings. Full article

Dyed wool samples and lake pigments prepared from the same dyestuffs were exposed to light over the course of 14 months. Brazilwood or sappanwood, cochineal, madder, and weld were used for both wools and pigments, with the addition of dyer’s broom, indigo, and tannin-containing black dyes for the wools and eosin for the pigments. The wools were dyed within the MODHT European project on historic tapestries (2002–2005), using recipes derived from fifteenth- to seventeenth-century sources. The pigments were prepared according to European recipes of the same period, or using late nineteenth-century French or English recipes. Colour measurements made throughout the experiment allowed for overall colour difference (ΔE₀₀) to be tracked and half-lives to be calculated for some of the colour changes. Alterations in the samples’ hue and chroma were also monitored, and spectral information was collected. The results showed that, for both textiles and pigments, madder is the most stable red dye, followed by cochineal, and then brazilwood. Eosin was the most fugitive sample examined. Comparisons of textile and lake samples derived from the same dyestuff, whether red or yellow, indicate that the colourants are more stable when used as textile dyes than in analogous lake pigments. Full article

The occurrence of anthocyanins in rice (Oryza sativa) and barley (Hordeum vulgare) varies among cultivars, with pigmented varieties (e.g., black rice and purple barley) accumulating higher concentrations due to genetic and environmental factors. The biosynthesis of anthocyanins is regulated by a complex network of structural and regulatory genes. Key enzymes in the pathway include chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT). These genes are tightly controlled by transcription factors (TFs) from the MYB, bHLH (basic helix–loop–helix), and WD40 repeat families, which form the MBW (MYB-bHLH-WD40) regulatory complex. In rice, OsMYB transcription factors such as OsMYB3, OsC1, and OsPL (Purple Leaf) interact with OsbHLH partners (e.g., OsB1, OsB2) to activate anthocyanin biosynthesis. Similarly, in barley, HvMYB genes (e.g., HvMYB10) coordinate with HvbHLH TFs to regulate pigment accumulation. Environmental cues, such as light, temperature, and nutrient availability, further modulate these TFs, influencing the production of anthocyanin. Understanding the genetic and molecular mechanisms behind the biosynthesis of anthocyanins in rice and barley provides opportunities for the development of biofortification strategies that enhance their nutritional value. Full article

This study analyzes a lacquered ear cup excavated from the Luobowan tomb complex in Guigang, Guangxi, attributed to the Nanyue Kingdom of the early Han dynasty. A range of analytical techniques, including optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), were employed to investigate the structural layers, material composition, and preservation state of the artifact. The lacquerware consists of four traditional layers: a wooden core, fabric reinforcement, lacquer ground, and lacquer film, reflecting Central Plains lacquerware techniques. The wooden core was identified as Phoebe sp., and the fabric layer is likely hemp, though fiber degradation limited exact identification. The lacquer ground layer contains natural lacquer mixed with SiO₂ from brick or tile powder. The lacquer film is a blend of Chinese and Vietnamese lacquer, with no synthetic additives or plant oils detected. The red lacquer layer contains cinnabar (HgS) as a pigment, while the black lacquer uses carbon black. Differences in moisture content between the red and black lacquer films are attributed to variations in surface porosity and pigment characteristics. This research provides valuable insights into Nanyue lacquer technology and preservation challenges. Full article

The local goat breeds of Chongqing represent the typical goat populations of Southwestern China and play a significant role in global goat research. However, studies on these goats remain limited. Chongqing goats exhibit diverse coat colors, a crucial economic trait essential for individual and breed identification. In this study, we performed genome-wide association analysis (GWAS) of Chongqing goats to identify candidate genes associated with coat color. The results of the GWAS revealed that the ASIP, AHCY, and ITCH genes on chromosome 13 are significantly associated with coat color variation in Chongqing goats. Furthermore, haplotype analysis, gene function annotation, and pathway analysis enrichment further confirmed that a significant region on chromosome 13 is associated with coat color in local Chongqing goats, and that ASIP and AHCY are related to black coat color, whereas ITCH is potentially associated with white coat expression. Additionally, we also identified TPK1 as being associated with coat color in goats, which has hardly been reported. The newly identified genes expand our understanding of the complex genetic architecture underlying pigmentation traits in livestock. Our study identifies the genes related to coat color in local goats, which enriches the genetic resource pool of goats and contributes to a deeper understanding of the genetic mechanisms underlying coat color in these breeds. Full article

Structural color is a kind of natural color that widely exists in nature. The ordered microstructure of nano materials can absorb or reflect light of specific wavelength, thus showing colorful colors. Structural color is an ideal choice for color contact lens pattern pigment due to its good tinting degree, stability, and nontoxicity. This paper explores a method for synthesis of zinc oxide (ZnO) nanoparticles with a high refractive index and enhancement of the brightness of the structured colors by introducing carbon black nanoparticles. This method is convenient and successful to prepare ZnO ink, which can produce bright structural colors, and to produce color patterns through rubber pad printing. It is worth mentioning that ZnO nanoparticles can be self-assembled and arranged in contact lens ink without subsequent complicated processing. At the same time, the color only comes from ZnO and carbon black. While there is no other organic matter, the presence of nanoparticles plays a certain role in sterilization. Blue contact lenses prepared by this method have bright structural color, high oxygen permeability, and high hydrophilicity. At the same time, a cell viability test showed that the contact lenses prepared by this method had low adsorption capacity for lipids and proteins, reflecting the photonic crystal’s high biocompatibility. In summary, a trend for future research is to use high-refractive-index zinc oxide nanoparticles to produce structural colors rather than employing conventional contact lens pigments. Full article