Orange-red Color Research Articles

Pityriasis rubra pilaris: A review

Pityriasis rubra pilaris (PRP, syn.: Devergie's disease) is a rare idiopathic papulo-squamous inflammatory skin disease characterized by follicular papules, palmar-plantar keratoderma, scaling plaques of orange-red color with characteristic foci of unaffected skin. Histologically, the alternating pattern of orthokeratosis and parakeratosis is considered a distinctive feature of PRP (staggered hyperkeratosis). A violation of the regulation of innate immunity is a component of the pathogenesis of PRP. Congenital mutations of CARD 14 or concomitant antigens, which can take the form of iatrogenic lesions, infections or malignant neoplasms, can be the initial triggers of the disease, although the etiology is often idiopathic. There are classically five subtypes of the disease, depending on the age of onset and clinical picture. Type VI PRP is associated with infection caused by the human immunodeficiency virus. CARD 14-associated papulosquamous rash and discoid dermatitis of the face represent new clinical phenotypes of PRP. Devergie's disease has a pronounced negative impact on the quality of life, and those who become ill are at increased risk of depression and suicide. Ixekizumab, methotrexate and secukinumab can be considered as systemic drugs of the first choice. If there is a contraindication to immunosuppressive therapy, high doses of isotretinoin are recommended. Topical agents, including calcipotriene, calcineurin inhibitors, emollients and topical corticosteroids, are used as additional therapy.

Synthesis, characterization and MAFLD prevention potential of Ganoderma lucidum spore polysaccharide-stabilized selenium nanoparticles

The unstability of selenium nanoparticles (SeNPs) results in decreased activity which limits its therapeutic potential. In this study, we utilized Ganoderma lucidum spore polysaccharide (GLP, Mw = 983.96 kDa) as a novel stabilizer to synthesize GLP-SeNPs. GLP-SeNPs (Se/GLP = 1/3) with an average diameter of 149 nm were successfully prepared and it was stable for at least 30 days at 4 °C. It exhibited an orange-red color, zero valence state, amorphous structure, selenium uniform distribution, a zeta potential of −29.73 mV, selenium content of 16.04 %. GLP-SeNPs pretreatment decreased lipid accumulation, reduced ROS content and enhanced SOD and CAT activity in HepG2 cells. Fe2+ and MDA contents were decreased, while GPX4 and GSH activities were increased. All these ameliorated effects could be abolished by NRF2 antagonist ML385. The expression of anti-oxidant genes and iron exporter was up-regulated, while that of pro-oxidant and lipid biosynthesis gene was down-regulated. The GPX4 activity could be reduced by ML385 addition. In conclusion, GLP-SeNPs was successfully constructed at the ratio of 1/3 (Se/GLP). It prevents MAFLD by targeting ferroptosis, including lowering iron overload, inhibiting lipid accumulation and attenuating oxidative stress. The improvement was conducted via activating SLC40A1-mediated iron pathway, ACSL4-mediated lipid metabolism and NRF2-mediated GSH-GPX4 pathway. Therefore, GLP-SeNPs can be used as potential selenium nutritional supplements or adjuvants for MAFLD prevention.

Sr2BiF7: A New Bismuth-Based Host Material for Lanthanide Ions Doping: Synthesis, Downshifting, and Upconversion Luminescence Properties for Multimode Anticounterfeiting.

A new bismuth-based host material, i.e., Sr2BiF7, is explored in this work. Undoped and lanthanide ion-doped Sr2BiF7 nanomaterials are prepared using a simple coprecipitation technique at 120 °C. The undoped nanomaterials exhibit a blue color under 365 nm excitation. The downshifting and upconversion photoluminescent properties of Er and Yb codoped Sr2BiF7 nanomaterials are investigated. The optimum up-conversion luminescence is produced by nanomaterials doped with 5% Yb3+ and 0.2% Er3+. These nanomaterials show blue and magenta colors upon excitation at 365 and 395 nm wavelengths, respectively. Sr2BiF7 material doped with Er3+ shows green emission, while the codoped Er3+, Yb3+ nanomaterials exhibit an orange-red color under 980 nm light. A specific amount of polyvinyl chloride (PVC) is used for producing luminescent ink with these nanoparticles for multimode anticounterfeiting applications. The letters and patterns written with luminescent ink based on Er3+, Yb3+ doped nanomaterials show blue, magenta, and orange-red colors under 365, 395, and 980 nm light, respectively. These results establish that this material can be effectively used as a multimode photoluminescent covert tag to combat counterfeiting.

ORANGE gene positively regulates chromoplast formation and carotenoid accumulation in Osmanthus fragrans

Sweet osmanthus (Osmanthus fragrans) cultivar from Aurantiacus Group shows orange or orange-red flower color due to the accumulation of abundant carotenoids in the petals. Orange (Or) gene has been functionally characterized in the formation of plant chromoplasts and carotenoid accumulation in several species. However, whether Or gene from sweet osmanthus plays essential role in the formation of plant chromoplasts is not clear. In this study, we isolated Or homologous gene OfOr from sweet osmanthus by transcriptome homology search. The protein encoded by the gene has two transmembrane domains and a zinc finger domain, and is co-localized with the chloroplasts. Transmission electron microscopy analysis of the petal tissues of sweet osmanthus showed that the chromoplast volume, the plastoglobule number and volume increased significantly with petal development, accompanied by an increase in the expression level of OfOr. Correlation analysis showed that the development of chromoplasts was significantly positively correlated with the expression pattern of OfOr. In addition, after stable overexpression of OfOr in tomato (Solanum lycopersicum), it was found that the transgenic tomato fruits exhibited significantly higher redness, yellowness and chroma, as well as an increased distribution of carotenoids in the pulp cells, with total carotenoid content significantly higher than that of wild type. In summary, our study indicate that OfOr positively regulates chromoplast formation and carotenoid accumulation. This study also further reveals that OfOr can be used as a novel genetic tool to increase the accumulation of carotenoids and improve the coloring of colored organs in crops and ornamental plants.

Non-destructive identification of iron oxide crystals in 15th century A.D. Chinese imperial red overglaze decoration

Red overglaze decoration is one of the earliest and most important colorful overglaze decorations in China, which had a remarkable influence on the successful firing and development of polychrome overglaze porcelains. The uncontrollability of red overglaze decoration led to a certain proportion of defective porcelain products in the Ming Dynasty (1368–1644 CE). To investigate and identify the coloring effect of iron oxide crystals in red overglaze decoration, three groups of samples with different color appearance were non-destructively analyzed and observed by OM, spectrophotometer, XRF, Raman spectroscopy, XRD and SEM. The results show that the hue of red overglaze decoration was caused by the different crystal forms of iron oxide. Hematite (α-Fe2O3) displays red color, while maghemite (γ-Fe2O3) and magnetite (Fe3O4) yield orange-red and dark red colors. With the similar raw materials and manufacturing processes, the presence of maghemite and magnetite are relatedto subtle differences in processing raw materials and firing them.

Investigation of isomerization and oxidation of astaxanthin in ready-to-eat Litopenaeus vannamei during accelerated storage

Astaxanthin (AST), the natural pigment in Litopenaeus vannamei, is susceptible to oxidation and isomerization, leading to the fading of the orange-red color in ready-to-eat (RTE) shrimps. This study specifically investigated the changes mechanism in AST content, including geometric and stereoisomers, as well as oxidation degradation, throughout the storage process of RTE shrimps. The results showed that the total amount of AST decreased by 46.76 % after 45 days of storage at 40 °C. The levels of geometric isomers (all-E, 9-Z, 13-Z) and stereoisomers (3S,3′S, 3S,3′R, 3R,3′R) gradually decreased over time. Notably, 9-Z and 3S,3′S isomers, known for their strong antioxidant activity, were reduced by 83.57 % and 61.64 % respectively. Additionally, AST underwent oxidative degradation, forming short-chain compounds (astaxanthinal or astaxanthinone), with the main products being Apo-14′-astaxanthinal and Apo-7-astaxanthinone DHA ester. These findings provide a theoretical foundation for further research on the degradation mechanism of AST, and offer valuable insights into the color protection of RTE shrimps.

Deciphering Rind Color Heterogeneity of Smear-Ripened Munster Cheese and Its Association with Microbiota.

Color is one of the first criteria to assess the quality of cheese. However, very limited data are available on the color heterogeneity of the rind and its relationship with microbial community structure. In this study, the color of a wide range of smear-ripened Munster cheeses from various origins was monitored during storage by photographic imaging and data analysis in the CIELAB color space using luminance, chroma, and hue angle as descriptors. Different levels of inter- and intra-cheese heterogeneity were observed. The most heterogeneous Munster cheeses were the darkest with orange-red colors. The most homogeneous were the brightest with yellow-orange. K-means clustering revealed three clusters distinguished by their color heterogeneity. Color analysis coupled with metabarcoding showed that rinds with heterogeneous color exhibited higher microbial diversity associated with important changes in their microbial community structure during storage. In addition, intra-cheese community structure fluctuations were associated with heterogeneity in rind color. The species Glutamicibacter arilaitensis and Psychrobacter nivimaris/piscatorii were found to be positively associated with the presence of undesirable brown patches. This study highlights the close relationship between the heterogeneity of the cheese rind and its microbiota.

Mechanism of discoloration of Antarctic krill oil upon storage: A study based on model systems

The reddish-orange color of Antarctic krill oil fades during storage, and the mechanism remains unclear. Model systems containing different combinations of astaxanthin (ASTA), phosphatidylethanolamine (PE), and tocopherol were subjected to accelerated storage. Among all groups containing ASTA, only the ones with added PE showed significant fading. Meanwhile, the specific UV–visible absorption (A470 and A495) showed a similar trend. Peroxide value and thiobarbituric acid reactive substances increased during storage, while ASTA and PE contents decreased. Correlation analysis suggested that oxidized PE promoted fading by accelerating the transformation of ASTA. PE content exceeded the critical micelle concentration (1μg/g) indicating the formation of reverse micelles. Molecular docking analysis indicated that PE also interacted with ASTA in an anchor-like manner. Therefore, it is speculated that amphiphilic ASTA is more readily distributed at the oil-water interface of reverse micelles and captured by oxidized PE, which facilitates oxidation transfer, leading to ASTA oxidation and color fading.

Pharmacognostical Studies on the Leaves of Caesalpinia sappan Linn (Fabaceae)

Botanical medicine, herbalism, and herbal medicine are all terms that describe the same practice. There are many different chemical compounds found in and produced by herb plants that have physiological effects. Traditional herbal medicine is an integral part of the medical systems of all indigenous peoples, including Ayurvedic, naturopathic, homeopathic, traditionally oriental, and native American Indian medicines. The amount and quality of medicinal components determine the medicinal plant’s therapeutic effectiveness. Misidentification is the first step in the unlawful use of plant-based materials or herbal remedies. Pharmacognostical studies of medicinal plants by proper standardization parameters ensures plant identification and authentication. Brazil, or Sappan wood, is a popular name for Caesalpinia sappan Linn., which belongs to the Fabaceae family. In Hindi, it is referred to as Bakam/Patang. The Malay Peninsula, Sri Lanka, India, Myanmar, and Vietnam all have a long history of using the medicinal herb C. sappan Linn. heartwood is beneficial for Pitta, burning feelings, injuries, ulcers, leprosy, dermatological ailments, dysentery, diabetes, loose stool, and more, according to Ayurveda. The tree’s huge, decorative panicles of yellow blossoms are the reason it’s grown in gardens. The plant grows rapidly after being produced from seed. Cultivated throughout every region of tropical Asia, this spreading shrub or tree may reach a height of 10 m. It is native to and exists in the wild in places like the southern part of India, the West Bengal region, Orissa, Madhya Pradesh, Malaya, as well as Sri Lanka. The wood has an especially smooth, uniform appearance, is somewhat massive, and has a strong, orange-red color. Its grain is straight. Branchlets, pubescent and rufous, equipped with tiny prickles. Pinnae are 9 to 14 pairs in number. Leaves are big, hairy to glabrous, and have little prickles at the base and leaflets are subsessile, oblong, membranous, and obliquely truncate, with 10 to 20 pairs per pinna. Primarily, it promotes blood flow and acts as an analgesic, emmenagogue, hemostatic, and anti-inflammatory in traditional Chinese medicine for traumatic diseases. One of the ingredients of the world-famous Indian toothpaste and powder Vicco-Vajradanti is the wood of the C. sappan Linn Tree. Some research suggests that C. sappan Linn. may have antidiabetic effects. The flavonoid of C. sappan Linn. wood extract is protosappanin, Brazilin, and gallic acid compounds. Brazilin has a mechanism of action to increase the production of fructose 2,6 bisphosphate and hexose six phosphate. Fructose 2,6 bisphosphate in the metabolic process has a role in regulating glycolysis and gluconeogenesis in the liver. Increased fructose 2,6 bisphosphate in a state of hyperglycemia will stimulate the process of glucose breakdown (glycolysis) by activating phosphofructokinase 1 intended for the purpose of can be a reduction in blood glucose levels in body. This paper deals with the morphological studies and microscopical studies carried out on the leaves of C. sappan Linn according to the World Health Organization (WHO) accepted parameter for the identification of medicinal plants. For a better understanding of structure, zooming in using a Zeiss Axio Cam Erc5s digital camera and a Nikon ECLIPSE-E200 trinocular microscope under strong field lighting also employed.

Removal of colour methylene red orange (MRO) by using commercial granular activated carbon (CGAC)

Abstract This study examined the effectiveness of granular activated carbon as an adsorbent for removing methylene red orange (MRO) colour from synthetic wastewater. The experiment involved using 250 mL conical flasks and maintaining the pH at an optimised value of 9. A concentration of 1.6 g of commercial granular activated carbon (CGAC) was mixed with 100 mL of MRO solution (200 mg/L) and agitated at room temperature. Samples were collected at specific time intervals to measure the MRO concentration. The collected data was analysed to describe the interaction between adsorbates and adsorbents. The Langmuir model showed a good fit for isotherm studies, supporting the efficacy of CGAC as an adsorbent for MRO dye removal. This study highlights the potential of CGAC for MRO dye removal and contributes to the understanding of the adsorption process.

First report of Nectria dematiosa causing European canker of apple in India

AbstractNectria dematiosa exhibiting orange red colour perithecia on stems and branches of young and old apple trees were reported under field conditions during 2020 and 2021. Reddish discoloration followed by papery appearance of stem and branches were the characteristic symptoms observed. Ascomata were non‐papillate, surface irregular comprising numerous cylindrical to narrowly clavate asci. Ascospores were ellipsoidal to fusiform, straight or slightly curved, hyaline with 0 to 1‐septa. Richard and Royal Delicious variety of apple were more susceptible with moderate to high severity of the European canker. Based on nucleotide homology and phylogenetic analysis, the pathogen was confirmed as N. dematiosa (accession no. OQ152022). To the best of our knowledge, this is the first report of N. dematiosa causing European canker of apple in India.

Formulation and evaluation of red fruit (Pandanus conoideus) oil-based nanoemulsion loaded thermosensitive gel combined with solid microneedle for topical delivery

Red fruit (Pandanus conoideus) is a fruit that has been well-known for its ability to treat various diseases because of its abundant active ingredients. One of them is β-carotene, an antioxidant compound that could maintain the skin's health with many benefits. In this study, we developed a thermosensitive nanoemulgel formulation from red fruit extract that delivers β-carotene topically in combination with solid microneedles (SMN) to increase the bioavailability of β-carotene in the skin. The preparation of thermosensitive nanoemulgel was carried out using red fruit oil nanoemulsion and thermosensitive gel based on Pluronic® F127 and F68. The best nanoemulsion formulation droplet size was 103.43 ± 9.74 nm, with a PDI value of 0.204 ± 0.02. The characterization results showed that this thermosensitive nanoemulgel prepared has a bright reddish-orange color. Moreover, it is a liquid at room temperature and turns into a gel at body temperature to allow longer contact time with the skin. The dermatokinetic profile of the combination of red fruit oil-based thermosensitive nanoemulgel with 1 mm SMN showed a significant increase in the concentration of β-carotene up to 5-fold in skin layers for ex vivo (129.98 ± 13.39 μg/cm2) and up to 3-fold in skin layers for in vivo (51.24 ± 5.53 μg/cm2). Importantly, no hemolytic activity or irritation in vivo was found in the skin tissue, proving the primary safety of this preparation. For the first time, developing red fruit extract into a thermosensitive nanoemulgel form has provided promising approaches with safety for improving the bioavailability of β-carotene in the skin.

Quantum yield and scintillation behaviors of lanthanum barium borate doped with Eu3+ ion scintillating glasses

Lanthanum barium borate glasses doped with Eu3+ ions were synthesized using a melt quenching method, with a nominal chemical composition of {10La2O3–20BaO-(70-x)B2O3-xEu2O3; 0.0 ≤ x ≥ 7.0} mol%. These glass samples were characterized, including assessments of their physical, structural, optical, and luminescent properties. The emission spectra, both of photoluminescence and radioluminescence studies were presented and found featuring five distinct peaks at 577 nm (5D0→7F0), 590 nm (5D0→7F1), 613 nm (5D0→7F2), 652 nm (5D0→7F3), and 701 nm (5D0→7F4). Interestingly, concentration quenching effects were observed at Eu3+ concentrations of 3.0 mol% and 5.0 mol% for photoluminescence and radioluminescence respectively. The decay time of LaBaBEu3.0 show 1.617 ms and the quantum yield reaching value of 14.16%. The CIE 1931 chromaticity coordinates of these glasses show reddish-orange color. This reddish-orange color was particularly observed when the samples were excited under a UV lamp.

Structure and photoluminescence of α-MoO3:Eu3+ microbelts

Phosphors of α-MoO3 with varying concentrations of Eu activator emitting an orange–red color were synthesized using a conventional solid-state reaction. The sintered pellets consisted of microbelts with a wide size distribution. The surface morphology became rough with an increase in the sintering temperature, which was attributed to a higher proportion of large and transparent nonluminous microbelts under ultraviolet light. Photoluminescence of 1 at.% Eu-doped α-MoO3 pellet sintered at 710 °C exhibited the strongest intensity. Ultrasonic vibrations caused the disruption of interlayer bonding and fragmentation in the horizontal direction of the α-MoO3 crystals, resulting in smaller belts with a thickness of 10–20 nm. The finely fragmented Eu-doped α-MoO3 microbelts dispersed in water retained luminescent properties under ultraviolet light with a wavelength of 254 nm. The report on the fabrication of emitting α-MoO3 micro/nanobelts through sintering and subsequent ultrasonication is promising for developing low-cost and large-area optical devices.

Exploration of Photoluminescence, Colorimetric, and Decay Performance of Sm-activated CaWO4 Ceramic.

This paper represents structure, photoluminescence, and colorimetric investigations of Sm-activated CaWO4 ceramic made with the help of a solid-state reaction process. Structures of the ceramics are examined through X-ray diffraction spectroscopy. It indicates that these materials have a tetragonal structure and I41/a space group without having any other secondary phase. Energy band gaps are increased with the higher concentrations of Sm dopants. Photoluminescence analyses show that concentration quenching is found at x = 0.02 Sm incorporated CaWO4. The critical distance of energy transfer is obtained as about 20Å. Q-value is observed approximately equal to 6 which denotes that dipole-dipole interactions occur in the materials that create the critical energy transfer distance in them. Chromaticity values are described in that the ceramics emit orange-red color as well as excellent colorimetric parameters. Quantum efficiency of x = 0.02 Sm composition in CaWO4 is measured under 405nm EX wavelength. Photoluminescence decay behaviors are observed and average lifetime values are evaluated.

Plant-based carotenoid supplementation: Growth, feed utilization efficiency, and coloration in false clownfish (Amphiprion ocellaris)

The false clownfish (Amphiprion ocellaris) is a prominent species in the marine ornamental trade, valued for its vibrant orange-red coloration. However, aquaculture-bred individuals often exhibit less intense coloration than their wild counterparts, presenting a challenge for both breeders and aquarists. This study evaluates the effects of carotenoid-enriched diets, sourced from natural ingredients such as pumpkin, bell pepper, carrot, and gac, as well as a synthetic source like astaxanthin, on the coloration and growth of false clownfish. In a controlled experiment, juvenile fish with an initial average length of 3.21 ± 0.03 cm and weight of 0.61 ± 0.02 g were allocated to 60-liter tanks and fed the experimental diets over a 75-day trial period. Carotenoid supplementation was standardized at 250 mg/kg across diets, with a control group receiving no added carotenoids. The experimental design was completely randomized, involving three replicates per dietary treatment. The results indicated that diets supplemented with gac and bell pepper significantly enhanced growth and feed efficiency (p < 0.05). Notably, the skin redness intensity (a* value) was increased by 75.73% in the gac-supplemented group, 89.20% in the bell pepper group, and 91.99% in the astaxanthin group, relative to the control (p < 0.05). Additionally, carotenoid deposition in the integument was significantly higher in all supplemented groups, with an increase of 83.74% in the astaxanthin group, 89.59% in the gac group, and 98.43% in the bell pepper group, compared to the control (p < 0.05). These findings suggest that natural carotenoids, particularly from gac and bell pepper, can be effective alternatives to synthetic astaxanthin, potentially improving the attractiveness and commercial value of captive-bred false clownfish and alleviating the exploitation of wild populations.

Sucrose-phosphate osmotic system improves the quality characteristics of reduced-salt salted egg yolk: Profiling from protein structure and lipid distribution perspective

This paper was dedicated to the study of the effect of sucrose-phosphate on aspects of physicochemical properties, lipid distribution and protein structure during the picklig of reduced‐salt salted egg yolk (SEY). This work constructed a reduced‐salt pickling system from a new perspective (promoting osmosis) by using a sucrose-phosphate-salt. Results showed that SEY-28d achieved a desirable salt content (1.07 %), hardness (573.46 g) and springiness (0.65 g). The matured SEY was in excellent quality with orange-red color and loose sandy texture. This was because the lipoprotein aggregated with each other through hydrophobic interaction to form a stable network structure. In addition, the hypertonic environment accelerated salt penetration. These also created good condition for lipid spillage. The results of confocal laser scanning microscope also verified this phenomenon. This work provides important guidance for new reduced‐salt curing of traditional pickled foods, deep processing of SEY, and industry development in the field of poultry egg.

Development of Assessment Criteria for Managing the Quality of Taishan Black Tea

In order to obtain the quality information of Taishan black tea and provide data support for the establishment of assessment criteria for quality control of Taishan black tea, in this study, 45 samples of Taishan black tea were collected during the summer to investigate their quality characteristics. The results showed that the Taishan black tea typically exhibited a dark-brown, curly appearance and a uniform texture. The tea soup displayed a bright orange-red color. The tea was mainly described as having a fruity aroma, followed by a caramel flavor, sweet aroma, flowery flavor, and clean aroma, with a strong and enduring fragrance. The taste profile was mostly heavy and mellow or heavy and strong, with fewer samples exhibiting slight bitterness and astringency. The tea leaves were characterized by a reddish-auburn color, a soft texture, and an even appearance. The main biochemical components of the Taishan black tea fell within the following ranges: water extracts (38.65–43.35%), free amino acids (1.41–3.45%), tea polyphenols (9.80–15.05%), catechins (6.11–9.03%), and caffeine (1.65–3.05%). The phenolic acid/amino acid ratio was 2.31–6.65%. Catechins and tea polyphenols emerged as critical indicators influencing taste quality, followed by amino acids, water extracts, and caffeine. The aroma analysis identified common compounds, such as 3-methyl-butanal, 2-methyl-butanal, decanal, 2-methyl-propanal, 1-octen-3-ol, and β-ionone, in most samples. These compounds exhibited relatively high contents and high odor activity values, making them the primary contributors to the tea’s aroma. This investigation into the quality of Taishan black tea offers valuable scientific insights, providing a foundation for the standardization of Taishan black tea’s quality.

Transcriptomic and metabolic analysis unveils the mechanism behind leaf color development in Disanthus cercidifolius var. longipes.

Introduction: Leaf coloration in Disanthus cercidifolius var. longipes results from the interplay of various pigments undergoing complex catalytic reactions. Methods: We aimed to elucidate the mechanisms of pigment biosynthesis affecting leaf color transition in D. cercidifolius var. longipes by analyzing variations in pigment accumulation and levels of gene expression. Results: We identified 468, 577, and 215 differential metabolites in green leaves (GL), gradual-color-changing leaves (GCCL), and red leaves (RL), respectively, with 94 metabolites shared across all comparisons. Metabolite accumulation patterns were similar among GL, GCCL, and RL, with flavonoids being the main differential metabolites. Delphinidin, malvidin, and petunidin derivatives were mostly accumulated in GCCL, whereas cyanidin, pelargonidin, and peonidin derivatives accumulated in RL. Transcriptome sequencing was used to identify differentially expressed genes. The expression of anthocyanin biosynthetic pathway genes was associated with anthocyanin accumulation patterns. Discussion: Our findings reveal that the content of delphinidin, malvidin, petunidin, and carotenoids collectively determines the gradual transition of leaf color from green in spring and summer to green, purple, and orange-yellow in early autumn, whereas the content of cyanidin, peonidin, pelargonidin, and carotenoids together causes the autumnal transition to red or orange-red colors as leaves of D. cercidifolius var. longipes age.

Pengaruh Jenis Mordan Dan Lama Waktu Pencelupan Terhadap Kualitas Warna Kain Batik Dengan Pewarnaan Alam Kulit Bawang Merah Menggunakan Proses Post-Mordanting

Red onion skin is one of the wastes that can be used as a natural dye because it contains anthocyanins which are one of the natural color pigments. The availability of red onion skin waste is very abundant, especially from household waste and industrial waste which has not been optimally utilized. The purpose of this study was to determine the effect of fixation type with different dyeing times on the color quality of batik fabric. This research method is an experiment by varying the fabric treatment in the pre-mordanting process, time variations of 30 and 60 minutes, and fixation variations, namely alum, arbor, and quicklime. The results of the study obtained that red onion skin extract is very good as a natural dye for dyeing batik fabric, the value of the color fastness test at 40 ℃ soap washing and cloth rubbing (wet) shows good quality with an average value of 4 and 4 - 5. The value of the L *, a *, b * color difference test and the results of visual observations on the pantone color produce an orange-red color that contains dominant color elements towards reddish and yellowish.