Natural Colorants:Historical,Processing and Sustainable Prospects

With the public’s mature demand in recent times pressurized the textile industry for use of natural colorants,without any harmful effects on environment and aquatic ecosystem,and with more developed functionalities simultaneously.Advanced developments for the natural bio-resources and their sustainable use for multifunctional clothing are gaining pace now.Present review highlights historical overview of natural colorants,classification and predominantly processing of colorants from sources,application on textiles surfaces with the functionalities provided by them.Chemistry of natural colorants on textiles also discussed with relevance to adsorption isotherms and kinetic models for dyeing of textiles.

The feasibility study of natural pigments as food colorants and seasonings pigments safety on dried tofu coloring

In order to improve appetite,attract consumers and even conform to the food culture,food coloring has become one of the necessary links in modern food processing.For example,dried-tofu will be colored by adding artificial food colors(AFCs)such as sunset yellow,cochineal red A or other seasonings like soy sauce.However,the dispute persists about whether AFCs are harmful to health.Some studies indicate AFCs affect children’s intelligence and attention,cause hyperactivity,and allergy when children consumed≥50 mg.In addition,researches showed that chemical soy sauce produces a trace of methylglyoxal(MGO)in the manufacturing process,which is related to diseases such as oxidative stress,diabetes,and cognitive deterioration.Therefore,natural pigments are relatively new and promising strategy for replacing high-risk AFCs.Thus,the objective of this study was to use dried-tofu as a natural colorants coloring screening platform,through the concept of three primary colors to discuss the coloring effects of natural colorants in Taiwan in double–phase(liquid phase to solid phase)food coloring system and assess the effects of MGO on PC12 neuron cellular morphology and cell cycle at the dietary exposure in soy sauce.Our results showed that formula G:R=0.2:0.8 and C:R=0.08:0.92 were coloring by combined natural colorants had the same eye sensory quality acceptance of consumer and had the intention to purchase.Furthermore,the results from the PC12 cell suggested that dietary exposure of methylglyoxal(<50M)in soy sauce did not affect neuron cellular morphology and cell cycle significantly.Overall,Gardenia Yellow,Curcumin,and Radish Red could overcome the application restrictions in multiplephase food coloring system and simultaneously soy sauce as a coloring agent was safety.It showed the possibility of them as food colorants on dried-tofu.

Genotoxicity of Synthetic Food Colorants

A study was conducted to evaluate the genotoxicity, if any, of the permitted synthetic food colorants used in India. Eight synthetic food colorants namely Erythrosine （E 127）, Tartrazine （E 102）, Ponceau 4R （E 124）, Sunset Yellow FCF （E 110）, Brilliant Blue FCF （E133）, Fast Green FCF （E143）, Carmoisine （E122） and Indigo Carmine （E132） and their combination are used in sweets namely Ladu, Jilebi and Halwa in Calicut and suburban areas of Kerala, in India. The genotoxicity of the colorants alone and in combinations at different concentrations were evaluated by Cytokinesis Block Micronucleus （CBMN） Assay. It was observed that all the above colorants and their combinations could cause genotoxicity to human lymphocytes even at the permissible concentration of 100 ppm as per PFA （Prevention of Food Adulteration） Act of India. The toxicity varied from dye to dye and was proportional to their concentration. Combination of colors showed more toxicity than the individual components. Toxicity could be reduced drastically by reducing the concentration of the dyes at least 50% below the permissible limit. Permitted synthetic food colorants even at the permissible limit should be used with caution. This study demonstrated the need for redefining the permissible limit of the food colorants based on Admissible Daily Intake （ADI） as being practiced in developed countries.

Encapsulation of phenolic compounds by spray drying of Ancellotta and Aspirant Bouchet wines to produce powders with potential use as natural food colorants

Ancellotta and Aspirant Bouchet,Vitis vinifera L.,are wines with a high anthocyanin concentration that have been used to increase color in high-quality red wines.This work was focused on the encapsulation of Ancellotta(ANCE)and Aspirant Bouchet(AB)wines by spray drying and obtaining wine powders(WP)with a high concentration of phenolic compounds.Spray drying conditions were optimized and the phenolic compounds in the WP were characterized.All WP were evaluated for moisture content,water activity,color parameters,anthocyanins,and flavan-3-ols composition.There was no significant difference in total anthocyanins content of ANCE and AB WP when inlet air temperature increased from 135 to 145°C with a fixed carrier concentration of 8%(w/w)but a decrease in the total anthocyanins was observed when carrier concentration increased to 10%(w/w).Regarding color evaluation,ANCE and AB WP corresponded to the fourth quadrant of color space CIELAB indicating blue-red color(348–357°),characteristic of anthocyanins and wine.In general,the values of hue angle were not affected at higher percentages of carrier agent,consequently,an increase in the ratio carrier-wine did not lead to a dilution of material.These results indicate that inlet air temperature(in the selected range)did not influence the anthocyanin profile in the WP and has allowed for optimization of the conditions to obtain phenolic-rich colored powders with potential use as natural antioxidants and food colorants.

Natural hydroxyanthraquinoid pigments as potent food grade colorants:an overview

Natural pigments and colorants are widely used in the world in many industries such as textile dying,food processing or cosmetic manufacturing.Among the natural products of interest are various compounds belonging to carotenoids,anthocyanins,chlorophylls,melanins,betalains...The review emphasizes pigments with anthraquinoid skeleton and gives an overview on hydroxyanthraquinoids described in Nature,the first one ever published.Trends in consumption,production and regulation of natural food grade colorants are given,in the current global market.The second part focuses on the description of the chemical structures of the main anthraquinoid colouring compounds,their properties and their biosynthetic pathways.Main natural sources of such pigments are summarized,followed by discussion about toxicity and carcinogenicity observed in some cases.As a conclusion,current industrial applications of natural hydroxyanthraquinoids are described with two examples,carminic acid from an insect and Arpink red^(™)from a filamentous fungus.

EFFECTS OF ORGANIC COLORANTS ON PHOTO-INITIATED CROSSLINKING AND PHOTO-OXIDATION DEGRADATION OF POLYETHYLENE AND RELATED MECHANISM

The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations,X-ray photoelectron spectroscopy (XPS),mechanical property tests,UV spectroscopy,and light microscope.The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) sample...

Natural pigments: Anthocyanins, carotenoids, chlorophylls, and betalains as colorants in food products

Natural pigments are widely utilized as food additives nowadays to impart color or improve the taste of the food products.These pigments are significant food compounds used in the food industry due to their diverse nutritional and functional attributes.Color is the essential part of any food as it affects the consumer acceptability of the products.Recently consumer interest has shifted towards natural pigments as food colorants due to their high safety margins.Food industries prefer the use of natural pigments for foods and drinks owing to the harmful and undesirable effects of artificial pigments.These pigments include betalains-betaxanthin,betacyanin,flavonoids-anthocyanins,carotenoids-lutein,zeaxanthin,β-carotene,and chlorophylls-chlorophyllins,etc.There are some restrictions associated with the use of natural pigments based on the source of the pigment,quantity,and product nature.This review illustrates applications of permitted pigments in diversified food models and highlights their advantages as food ingredients.

Identification of Natural and Artificial Colorants in Industrial Products Marketed in Senegal

Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated with their consumption. This analysis requires, among other things, obtaining sufficient data on the presence of these colorants in foods, as well as their level of consumption. However, data on these colorants is often virtually non-existent in developing countries. The aim of this study was to determine the colorant profile of industrial products marketed in Senegal. Information on food additives was collected on 399 labels of different food product categories in shops located in Dakar. Data is recorded and processed using Excel software. Based on the Codex classification, analysis of the profile of additives identified on the labels of food samples revealed the presence of 31 colorants. The natural colorants identified are dominated by beta-carotene, widely present in beverages and dairy products, and paprika extract identified on cookies and industrial sauces. Artificial colors are dominated caramels present in several foods including bouillons, vinegars, sauces and hard candies. Secondly, there was a strong presence of the azo dye Sunset yellow FCF, widely found in samples of beverages, confectionery and cookies. The results of this case study enable us to appreciate the wide presence and diversity of colorants on the Senegalese market, and the importance of controlling them to guarantee consumer safety.

Rare earth colorants to start production

Nontoxic colorant from rare earths is expected to be put into full production in the current year in Baotou, the biggest city in the Inner Mongolia autonomous region, following a decision by the local government to upgrade the rare earths industry to value-added processes against previously mining the raw materials. "Due to its perfect coloring and nontoxic properties the coloring agent, mainly for plastics and leathers, can replace most existing dyes in the market," said Zhang Hongjie, inventor of the colorant and member of the Chinese Academy of Sciences.

Facile preparation of nano-g-C_(3)N_(4)/UiO-66-NH_(2) composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine,amaranth,carmine,sunset yellow,allura red and bright blue.The experiment parameters including the amount of sorbent,adsorption time,the p H of adsorption solution,desorption time,desorption solvent,the p H of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated.Under the optimized conditions,the limits of detection(S/N=3) and limits of quantitation (S/N=10) were determined in the ranges of 0.08-0.8 and 0.2-2.0 ng/m L,respectively.With the developed sample pretreatment method,carmine and brilliant blue were determined from blueberry juice by HPLC-DAD.The contents were calculated as 1.53μg/m L and0.17μg/mL,respectively.

Nanograting‑Based Dynamic Structural Colors Using Heterogeneous Materials

Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.

The pseudo-type response regulator gene Clsc regulates rind stripe coloration in watermelon

The color and pattern of watermelon rind are crucial external traits that directly affect consumer preferences.Watermelons with stripes having a stronger color than the background rind are ideal for studying stripe patterns in plants,while there is still limited knowledge about the genetic mechanisms underlying stripe coloration due to the lack of germplasm resources.In this study,we focused on a watermelon germplasm with colorless stripes,and genetic analysis revealed that the trait is controlled by a single recessive gene.The gene Clsc(Citrullus lanatus stripe coloration),which is responsible for the colorless stripe,was localized into a 147.6 kb region on Chr9 by linkage analysis in a large F2 mapping population.Further analysis revealed that the Cla97C09G175170 gene encodes the APRR2 transcription factor,plays a crucial role in determining the watermelon colorless stripe phenotype and was deduced to be related to chlorophyll synthesis and chloroplast development.Physiological experiments indicated that Cla97C09G175170 may significantly influence chloroplast development and chlorophyll synthesis in watermelon.The results of this study provide a better understanding of the molecular mechanism of stripe coloration in watermelon and can be useful in the development of marker-assisted selection(MAS)for new watermelon cultivars.

Fine mapping and identification of CaTTG1,a candidate gene that regulates the hypocotyl anthocyanin accumulation in Capsicum annuum

Pepper(Capsicum annuum L.)is a typical self-pollinating crop with obvious heterosis in hybrids.Consequently,the use of morphological markers during the pepper seedling stage is crucial for pepper breeding.The color of hypocotyl is widely used as a phenotypic marker in crossing studies of pepper.Pepper accessions generally have purple hypocotyls,which are mainly due to the anthocyanin accumulation in seedlings,and green hypocotyls are rarely observed in pepper.Here we reported the characterization of a green hypocotyl mutant of pepper,Cha1,which was identified from a pepper ethyl methanesulfonate(EMS)mutant library.Fine mapping revealed that the causal gene,CaTTG1,belonging to the WD40 repeat family,controlled the green hypocotyl phenotype of the mutant.Virus-induced gene silencing(VIGS)confirmed that CaTTG1 regulated anthocyanin accumulation.RNA-seq data showed that expression of structural genes CaDFR,CaANS,and CaUF3GT in the anthocyanin biosynthetic pathway was significantly decreased in Cha1 compared to the wild type.Yeast two-hybrid(Y2H)experiments also confirmed that CaTTG1 activated the synthesis of anthocyanin structural genes by forming a MBW complex with CaAN1 and CaGL3.In summary,this study provided a green hypocotyl mutant of pepper,and the Kompetitive Allele Specific PCR(KASP)marker developed based on the mutation site of the underlying gene would be helpful for pepper breeding.

Compiling molecular evidence from a tetraploid rose genome into a near-saturated map for the identification of pigment-related genes

With their high economic value and cultural significance,modern roses are one of the most important ornamental plants.Because of their complicated genetic background and tetraploid nature,the creation of high-density genetic maps of roses has been a challenge that has slowed the pace of molecular breeding for modern roses.The current construction of tetraploid genetic maps based on existing diploid rose genomes could lead to inaccurate marker information and genotyping results.Therefore,we generated the first high-quality tetraploid genome of Rosa chinensis‘Yunzheng Xiawei.'Utilizing Illumina,PacBio,and Hi-C sequencing technologies,we assembled a genome of 858.59 Mb with 14pseudo-chromosomes.Mode of inheritance analysis using PolyOrigin indicated that modern roses show both quadrivalent and bivalent pairing.Based on this reference genome,high-density genetic maps were constructed using MSTmap with nearly saturated markers.Quantitative trait locus(QTL)analysis was conducted using WinQTLCart and R/qtl for flavonoids and carotenoids,and 11 QTL clusters were identified.By combining the genome annotation,phylogenetic analyses,and gene expression analyses,we were able to identify several key genes related to flavonoid and carotenoid biosynthesis.This study provides the basis for further genetic analyses of highly heterozygous tetraploid roses and could facilitate the progress of marker-assisted selection in modern roses.

OptoGPT: A foundation model for inverse design in optical multilayer thin film structures

Optical multilayer thin film structures have been widely used in numerous photonic applications.However,existing inverse design methods have many drawbacks because they either fail to quickly adapt to different design targets,or are difficult to suit for different types of structures,e.g.,designing for different materials at each layer.These methods also cannot accommodate versatile design situations under different angles and polarizations.In addition,how to benefit practical fabrications and manufacturing has not been extensively considered yet.In this work,we introduce OptoGPT(Opto Generative Pretrained Transformer),a decoder-only transformer,to solve all these drawbacks and issues simultaneously.

Non-volatile dynamically switchable color display via chalcogenide stepwise cavity resonators

High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching.Antimony trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying devices.Herein,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity lengths.The device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost technique.As switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively changed.The color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase transition.Moreover,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far field.The minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) film.Ultrafast switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,etc.Importantly,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Colored rice is a type of high-quality,high-added-value rice that has attracted increasing attention in recent years.The use of large amounts of inorganic nitrogen fertilizer in rice fields results in low fertilizer use efficiency and high environmental pollution.Organic fertilizer is a promising way to improve soil quality and sustain high yields.However,most studies focus on the effect of animal-based organic fertilizers.The effects of different ratios of plantbased organic fertilizer and inorganic fertilizer on the grain yield and quality of colored rice have rarely been reported.Therefore,a two-year field experiment was conducted in 2020 and 2021 to study the effects of replacing inorganic N fertilizers with plant-based organic fertilizers on the yield,nitrogen use efficiency(NUE),and anthocyanin content of two colored rice varieties in a tropical region in China.The experimental treatments included no nitrogen fertilization(T1),100% inorganic nitrogen fertilizer(T2),30%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T3),60%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T4),and 100% plantbased organic fertilizer(T5).The total nitrogen provided to all the treatments except T1 was the same at 120 kg ha-1.Our results showed that the T3 treatment enhanced the grain yield and anthocyanin content of colored rice by increasing nitrogen use efficiency compared with T2.On average,grain yields were increased by 9 and 8%,while the anthocyanin content increased by 16 and 10% in the two colored rice varieties under T3 across the two years,respectively,as compared with T2.Further study of the residual effect of partial substitution of inorganic fertilizers showed that the substitution of inorganic fertilizer with plant-based organic fertilizer improved the soil physiochemical properties,and thus increased the rice grain yield,in the subsequent seasons.The highest grain yield of the subsequent rice crop was observed under the T5 treatment.Our results suggested that the application of plantbased organic fertilizers can sustain the production of colored rice with high anthocyanin content in tropical regions,which is beneficial in reconciling the relationship between rice production and environmental protection.

Self‑Healing Dynamic Hydrogel Microparticles with Structural Color for Wound Management

Chronic diabetic wounds confront a significant medical challenge because of increasing prevalence and difficult-healing circumstances.It is vital to develop multifunctional hydrogel dressings,with well-designed morphology and structure to enhance flexibility and effectiveness in wound management.To achieve these,we propose a self-healing hydrogel dressing based on structural color microspheres for wound management.The microsphere comprised a photothermal-responsive inverse opal framework,which was constructed by hyaluronic acid methacryloyl,silk fibroin methacryloyl and black phosphorus quantum dots(BPQDs),and was further re-filled with a dynamic hydrogel.The dynamic hydrogel filler was formed by Knoevenagel condensation reaction between cyanoacetate and benzaldehyde-functionalized dextran(DEX-CA and DEX-BA).Notably,the composite microspheres can be applied arbitrarily,and they can adhere together upon near-infrared irradiation by leveraging the BPQDs-mediated photothermal effect and the thermoreversible stiffness change of dynamic hydrogel.Additionally,eumenitin and vascular endothelial growth factor were co-loaded in the microspheres and their release behavior can be regulated by the same mechanism.Moreover,effective monitoring of the drug release process can be achieved through visual color variations.The microsphere system has demonstrated desired capabilities of controllable drug release and efficient wound management.These characteristics suggest broad prospects for the proposed composite microspheres in clinical applications.

A chromosome-level genome assembly for Chinese plum‘Wushancuili'reveals the molecular basis of its fruit color and susceptibility to rain-cracking

Chinese plum(Prunus salicina Lindl.)originates from China and makes a large contribution to the global production of plums.The P.salicina‘Wushancuili'has a green coloration and high fruit quality and is economically important in eliminating poverty and protecting ecology in the Yangtze River Three Gorges Reservoir.However,rain-induced cracking(rain-cracking,literally skin cracking caused by rain)is a limitation to‘Wushancuili'fruit production and causes severe losses.This study reported a high-quality‘Wushancuili'genome assembly consisting of a 302.17-Mb sequence with eight pseudo-chromosomes and a contig N50 of 23.59 Mb through the combination of Illumina sequencing,Pacific Biosciences HiFiⅢsequencing,and high-throughput chromosome conformation capture technology.A total of 25109 protein-coding genes are predicted and 54.17%of the genome is composed of repetitive sequences.‘Wushancuili'underwent a remarkable orthoselection during evolution.Gene identification revealed that loss-of-function in four core MYB10 genes results in the anthocyanin deficiency and absence of red color,revealing the green coloration due to the residual high chlorophyll in fruit skin.Besides,the occurrence of cracking is assumed to be closely associated with cell wall modification and frequently rain-induced pathogen enrichment through transcriptomic analysis.The loss of MYB10 genes might render fruit more susceptible to pathogen-mediated cracking by weakening the epidermal strength and reactive oxygen species(ROS)scavenging.Our findings provided fundamental knowledge regarding fruit coloration and rain-cracking and will facilitate genetic improvement and cultivation management in Chinese plums.

The protective effect of cyclodextrin on the color quality and stability of Cabernet Sauvignon red wine

The impact of cyclodextrins(CDs)on wine quality and stability remains largely unknown.This study systematically assessed the protective effect of the post-fermentation addition of CDs on color stability of red wine from the viewpoints of color characteristics,copigmentation and phenolic profiles.The grey relational analysis(GRA)and principal component analysis(PCA)methods were employed to dissect the key effective determinants related to color quality.The addition of CDs induced a significant hyperchromic effect of 8.19-25.40%,a significant bathochromic effect and an enhancement of the color intensity.Furthermore,the evolution of anthocyanin forms and the content of monomeric anthocyanins revealed that β-CD is a superior favorable cofactor during wine aging,but for long-term aging,2-HP-β-CD and 2-HP-γ-CD are more beneficial in promoting the formation of polymerized anthocyanins and color stability.This work provides an important reference for the use of CDs to enhance the color quality and stability of red wines.