Natural Color Research Articles

Aloe Vera as a Printed Coating to Mitigate the Wear of Textiles

Aloe vera is well known for its biological properties as a bioflavonoid anti-inflammatory and antibacterial agent. It has been used frequently in the food sector as a food coating due to its hygroscopic properties and as an ingredient in the lucrative cosmetic industry. Studies have also included aloe vera as an eco-friendly green solution based on these properties. The current research focuses on the use of aloe vera gel in printing pastes as an alternative sustainable solution to synthetic thickeners, evaluating its wet performance and ease of fabric stitching, and has been inspired by studies that similarly used this substance and measured its effect on the fabric’s coefficient of friction and antimicrobial action. In the current study, printing pastes with natural colourants, such as saffron, curcumin, and annatto, and aloe vera gel thickener derived from natural leaves from Crete increased the fabric’s mechanical resistance to abrasion compared to the untreated pastes. The measured performance did not differ substantially from prints with traditional synthetic pastes, hence tolerating the substitution with the non-contaminant variant. The enhanced resistance to abrasion and wear extends the fabric’s serviceable life and resulting garments, decreasing the need for high industry processing volumes and, as a result, reducing pollution. The resistance to wear was evaluated using the dominant method in textile testing of the Martindale apparatus, which measured the cycles to failure, weight loss, and general appearance deterioration using the official photographic standards.

Weeds: A Vibrant Source for Eco-dyeing

The concept of color has consistently played a significant role in developing various human societies globally. It impacts all aspects of our lives, including the clothes we wear. As a result, the synthetic textile colouring industry has grown significantly. On the contrary, there has been a resurgence in the attention towards natural dyes due to the environmental apprehensions of synthetic dyes and their harmful health effects, as natural dyes are perceived to be more sustainable. Weeds are plants that are out of place and undesirable in a particular environment. Converting these plants into valorized products will be an efficient way of managing them. Many weeds have been identified as potential sources of natural plant pigments like anthocyanins, betalains, carotenoids, and other natural pigments. Using weed plants for dye extraction not only provides an alternative dye source but also helps to reduce weed plant invasion. A variety of natural colours can be extracted from weeds. Furthermore, several invasive species, including wire weed, siam weed, common purslane, etc., can be used to extract different hues and tints.

COMPARATIVE ASSESSMENT OF VISUAL COLOR MATCHING FOR ARTIFICIAL AND NATURAL TEETH BY STUDENT OF DENTAL FACULTY AT KHARKIV NATIONAL MEDICAL UNIVERSITY

The purpose of this study was to conduct a comparative assessment of dental students’ ability to match the color of patients’ teeth with aesthetic restorations. Materials and Methods. The study was conducted from 2021 to 2024 with participation of 2nd- and 3rd-year students at the Faculty of Dentistry, Kharkiv National Medical University, Kharkiv, Ukraine. Results. Accurate determination and reproduction of natural tooth color is a challenging task in aesthetic dentistry, as color plays a crucial aesthetic role. This process depends heavily on the experience and perception of dentists and can be approached subjectively (visual analysis) or objectively (special devices). Although shade determination is a routine task for dentists, errors are still common. The study revealed that 2nd-year students struggled significantly with color matching, especially for natural teeth, with error rates of 66.6% for artificial teeth and 80.8% for natural teeth, indicating a need for more training. Students performed better using the VITA Classic shade guide, which is simplified, but matching the color of natural teeth requires additional practice. The results confirm that clinical training improves students’ color-matching skills. After training, 3rd-year students showed a marked decrease in error rates: 35.8% for artificial teeth and 53.3% for natural teeth. The Vita 3D Master scale proved more accurate due to its broader color-matching capabilities. Overall, the accuracy levels improved significantly, highlighting the effectiveness of the training program. Conclusion. The results of the study demonstrate that training significantly improves students' ability to accurately determine tooth color. The 3rd year students who underwent clinical training showed better results in matching the color of both artificial and natural teeth, reducing the number of errors by 35.8% and 53.3%, respectively. The Vita 3D Master scale proved to be more accurate due to a wider selection of colors and more evaluation parameters. The 81.5% increase in the overall score confirms the effectiveness of the training in improving the accuracy of tooth color determination in the educational process.

Development and stability evaluation of double emulsions enriched with Anthocyanins from Juçara

This study aimed to develop double emulsions enriched with anthocyanins extracted from juçara, a fruit rich in bioactive compounds with antioxidant properties. Anthocyanins are promising natural colorants but present instability to pH and temperature variations, limiting their application. Encapsulation in double emulsions (W/O/W) is an effective solution to increase the stability and retention of these compounds. The main objective was to develop and evaluate the stability of the double emulsions, aiming to protect the anthocyanins during processing. The methodology included the anthocyanins extraction from juçara and the formation of primary emulsions, followed by incorporation into external aqueous phases, testing different (W/O)/W proportions and concentrations of Arabic gum. The most stable double emulsion showed higher anthocyanin retention, with an encapsulation efficiency of 98.04%. The double emulsion system proved effective in protecting anthocyanins against different pHs, temperatures, and storage times, highlighting its potential for application as natural colorants in foods.

Enhancing Image Dehazing Efficiency with Dual Colour Space Attentional Deep Networks

Aims and Background: Image dehazing is an essential task in computer-vision, aimed at enhancing the clarity and visibility of images degraded by fog and haze. Traditional methods often struggle with handling the complex scattering effects of haze and maintaining the natural colours of the scene. Objectives and Methodology: To address these challenges, we propose a novel approach termed Dual Colour Space Attentional Deep Network (DCSADN) for efficient image dehazing. Our method leverages the advantages of two-colour spaces: RGB and YCbCr, to boost the network's skill to capture both the luminance and chrominance information, thereby improving the dehazing performance. We employ a multi-stage training strategy to optimize the performance of the DCSADN. This multi-stage approach ensures that the network generalizes well across different types of haze conditions. Extensive experiments demonstrate the superiority of our method over state-of-the-art dehazing techniques. Results: The results indicate that our approach not only achieves higher quantitative scores in terms of Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM) but also produces dehazed images with more natural colours and details. Conclusion: The findings reveal that the dual colour space processing and attentional modules are crucial for the enhanced performance of our method and providing a valuable tool for improving image quality in hazy conditions.

Optimization of ultrasound-assisted anthocyanin extraction from agricultural waste purple corn silk for multifunctional hemp finishes

The utilization of agricultural wastes for textile dyeing has gained popularity due to their safe and environmentally friendly properties, as well as the resource sustainability. Natural dye extraction is usually achieved through solvent extraction, which is time-consuming, requires a lot of solvent, and degrades desired compounds at high temperatures. Thus, this study investigated ultrasound-assisted anthocyanin extraction from agricultural waste purple corn silk as natural functional colorants for hemp finishes, given the numerous health benefits associated with anthocyanin. In order to optimize the extraction processes and evaluate the synergistic impact of these conditions, response surface methodology was implemented. The optimum conditions were 1:15 material-liquid ratio, 47% ethanol concentration, 60°C, and 20 min, yielding 240.25 mg·L‒1 anthocyanin. The extracted anthocyanin was used for dyeing hemp fabrics and demonstrated satisfactory colorfastness, antibacterial action on both S.aureus and E.coli, with E.coli being more effective, and strong antioxidant (>80%). The dyed fabrics also exhibited their great UV shield (UPF value > 40+). Anthocyanin derived from purple corn silk could therefore be utilized as a natural functional color for medical and health products. Also, purple corn silk contains more anthocyanin than other natural sources, making it a promising natural anthocyanin resource in textile industry.

Optimization of Vacuum Freeze-Drying Process and Quality Evaluation of Stropharia rugosoannulata

Stropharia rugosoannulata is a valuable medicinal and food fungus with high nutritive value. Freeze-drying addresses the storage and transportation challenges of fresh Stropharia rugosoannulata, expanding its market while preserving its flavor and quality more effectively than other drying methods. This study optimizes the vacuum freeze-drying process for Stropharia rugosoannulata using an orthogonal experiment method. The process parameters were optimized to determine their effects on the quality of the vacuum freeze-dried product, including pre-freezing temperature, pre-freezing time, and freeze-drying time. The optimal conditions were identified as a pre-freezing time of 60 h, a pre-freezing temperature of −80 °C, and a freeze-drying time of 72 h. The optimal product exhibited a bright color close to its natural state, with minimal browning and its natural white color maintained post-drying. During the drying process, the internal structure of the raw materials remained intact. After drying, the finished product retained its natural form, making it suitable for sale on the market. The soluble protein content of the vacuum freeze-dried Stropharia rugosoannulata reached 68 mg/g. Optimizing the freeze-drying process can better preserve the tissue structure and bioactive substances of Stropharia rugosoannulata, providing a reference for high-quality food processing and showing potential for sustainable development.

Eco-friendly utilization of microwaves for extraction of dye from logwood and Its application onto silk

For minimizing the pollution associated with synthetic colorants, the world again is going to realize the benefits of natural colorants in applied fields such as textiles, food flavors, etc. As part of the ongoing research project, hematein is being investigated as a potential natural colorant derived from logwood chips, and its implementation on silk fabric is being investigated under the effect of microwave radiations. A number of dyeing variables, including pH, dyeing duration, temperature of the dye bath, volume of extraction, and salt concentration, have been investigated, and the effect of isolation medium has also been evaluated. For new shades with improved fastness ratings, extracts of various sustainable bio-mordants and chemical mordant such as salts of aluminum and copper, and tannic acid were also used. An experiment revealed that treating un-irradiated silk with 40 mL of methanolic extract with a pH of 2, irradiated for 6 min, produced outstanding outcomes when dyed at 90°C for 60 min. The dyeing process included the addition of 9 g of salt per 100 mL of solution as an exhausting agent. In these circumstances, the utilization of sustainable mordants has not only enhanced the ratings of color fastness but has also rendered the procedure more environmentally friendly and less polluting. Therefore, microwave radiation has great potential for extracting colorants from plants and effectively applying them to natural materials under decreased conditions.

Fabrication and optimization of ultra-long stable microencapsulated chlorophyll using combinations of wall material via response surface methodology

Nowadays, the need to use natural pigments instead of artificial colorants in food has increased due to health risks. Chlorophyll is a natural colorant with antioxidant properties. Chlorophyll is a natural pigment with superior antioxidant properties. However, this pigment is unstable in the different conditions of food processing. To increase the stability of chlorophyll extracted from Ulva intestinalis algae, encapsulation of chlorophyll with maltodextrin (MD) and whey protein isolate (WPI) carriers by two drying methods including spray drying and freeze drying was achieved. The optimum combination of wall and core materials to achieve the highest response including encapsulation efficiency (EE) and chlorophyll content (CC) was obtained by response surface methodology and central composite design. The optimal chlorophyll microcapsule (Chl-M) obtained was chosen for subsequent tests containing solubility, moisture content, and antioxidant properties. The results showed that the highest EE and CC were 90.27 ± 0.21%, 55.36 ± 0.36 μg/mL, and 90.46 ± 0.62%, 85.85 ± 0.43 μg/mL, respectively in SD and FD. The microcapsules produced by the freeze dryer (FD) had higher antioxidant activity (79.1 ± 0.24) than the microcapsules produced by the spray dryer (SD) (67.5 ± 0.16). The highest solubility (95.32%) and the lowest moisture content (3.7 ± 0.05) were related to the SD. Freeze drying method (FDM) had the highest EE (91.2%), CC (89.67 μg/mL), and antioxidant properties (79.1%). It is hoped that the encapsulated chlorophyll can be used as a health-promoting food color additive in the food industry.

[formula omitted]-norm regularized quaternion matrix completion using sparse representation and approximate QSVD

Color image completion is a challenging problem in computer vision. Despite the effectiveness of low-rank quaternion matrix completion (LRQMC) methods, their reliance on quaternion singular value decompositions (QSVD) makes them computationally expensive. We propose a novel method based on quaternion Qatar Riyal decomposition (QQR) and quaternion L2,1-norm, named QLNM-QQR, which reduces computational complexity by avoiding the need for calculating the QSVD of large quaternion matrices. Furthermore, we introduce two improvements: IRQLNM-QQR, which utilizes iteratively reweighted quaternion L2,1-norm minimization, and QLNM-QQR-SR, which integrates sparse regularization. Additionally, an analysis of the convergence of the proposed algorithms is conducted. Our experiments show that IRQLNM-QQR outperforms QLNM-QQR on both natural and medical color images. The QLNM-QQR-SR method achieves higher PSNR and SSIM values than state-of-the-art methods, with PSNR averaging 4-8 dB higher than non-sparse methods and 0.4 dB higher than the sparse-based TNN-SR method.

Digitized Identification of Indigo Natural Dyeing on Batik and Non-Batik Fabrics

Natural coloring in textiles has regained favor as the sustainable fashion movement grows. Fabric colour digitisation can help with data inventory of natural dyed textiles because digital data could endure longer than physical sample artifacts. In this research, digitization was performed on standardized fabric samples: cotton fabric dyed with indigo natural dyestuff and processed with batik and non-batik treatment. Indigo dye is made from the indigo plant (Indigofera tinctoria) and is fixed with quicklime (Calcium Oxide), which serves as both the initial and final mordant. Fabric dyeing was repeated three, six and nine times until the desired hue is reached. The final fabric samples were then scanned to produce discrete color values in RGB format. Color digitization of batik and non-batik fabrics produces content which can be used in digital mediums.

Utilization Of Butterfly Pea Flowers (Clioria ternate L.) In Gram Staining Of Staphylococcus aureus and Escherichia coli Bacteria

Introduction : Butterfly pea flower (Clitoria ternatea L.) is one of the most commonly found plants. Butterfly pea flowers contain anthocyanins which are abundant in the flowers and play a role in giving red, violet-blue color to the flowers. Anthocyanins are the main molecules of plant colorants. The potential of anthocyanins in butterfly pea flowers can be used as a natural coloring reagent. Objective : The purpose of this study was to determine whether telang flower extract can be used as a substitute for gentian violet in Gram staining. Method : The research method used is experimental. Result : The results of Gram staining research using original pH butterfly pea flower extract at concentrations of 1:10, 2:10, 3:10, 4:10, and pH 5 butterfly pea flower extract at concentrations of 1:10, 2:10, 3:10, 4:10, 5:10 on Staphylococcus aureus bacteria showed poor bacterial staining results because the bacteria were not purple while the original pH butterfly pea flower extract at a concentration of 5:10 showed good staining results because the bacteria were purple. While in Escherichia coli bacteria, butterfly pea flower extract shows good staining results because the bacteria are red. Conclusion : Data analysis using the Kruskal Wallis test obtained Asymp. Sig (0.000) <0.05, it can be concluded that there is a significant difference in Gram staining using gentian violet and telang flower extract with variations in pH and composition as a substitute for gentian violet.

Optimization of Production Process of Alcohol Vinegar Macerated With Acai (Euterpe Precatoria) Using RSM to Add Colour and Functional Compounds to Vinegar

In Brazil, the alcohol vinegar is the cheapest vinegar found in the market and it has the lowest nutritional quality. The acai, a native Amazon fruit, is globally recognized as a super fruit and it is highly perishable. Research has been performed to deliver bioactive compounds and to substitute synthetic by the natural colourants in finished foods.

A colorimetric paper based on curcumin-loaded CD-MOFs and CNFs for visual monitoring of strawberry freshness

Curcumin is a natural yellow colorant, but the color variation occurs only under alkaline conditions, limiting the monitoring range for food freshness. In this study, curcumin obtained the property of acid-responsive color transition from red to yellow by encapsulating in alkaline CD-MOFs. Then, the curcumin-loaded CD-MOFs (CD-MOFs-Cur) with red color was incorporated in cellulose nanofibrils (CNFs)/ethanol suspensions forming a colorimetric paper through the wet-forming process. Results showed that the cubic CD-MOFs-Cur was evenly distributed in the network of CNFs. With the increase amount of CD-MOFs-Cur, the paper exhibited a redder color, but all exhibited high color stability. In pH 5–10 buffer solutions, the paper showed obvious color change from red to yellow with the pH decreased, but the pH that induced the color of the paper turn to yellow was lower with the increase of CD-MOFs-Cur amount. Similar color alteration also occurred when CD-MOFs-Cur was exposed to CO2. Based on this, the CNFs/CD-MOFs-Cur composite paper was successfully used for visual monitoring of strawberry freshness. This work provides the possibility for curcumin to detect the freshness of foods that release acid gases during spoilage.

Development of Endek Innovation in Encouraging Digitalization of MSMEs

Endek cloth is a cultural heritage on the island of Bali and even an icon of Bali, which was first introduced in Gelgel, Klungkung Regency but is currently experiencing a decline in interest in producing it. This makes this service carried out in order to be able to provide encouragement for innovation to green products, care for the green environment, the use of natural dyes with the utilization of environmental waste, and concern for the environment related to pollution, with the aim of encouraging promotional strategies so that businesses will be sustainable. The method in this service is qualitative observation, involving owners as business actors, workers, and users in obtaining information. The results of this study provide encouragement to innovate more varied products by using environmentally friendly colors from nature, then utilizing organic waste that can produce natural colors so that it will reduce environmental pollution. Green product innovation is also balanced with STP (Segmentation, targeting, and promotion), Tini Zhop after getting support in product innovation into green products also promoted to millennials by promoting to students by conducting online promotions and exhibitions to campuses.

Recent Advances in Purple Sweet Potato Anthocyanins: Extraction, Isolation, Functional Properties and Applications in Biopolymer-Based Smart Packaging.

Petroleum-based plastic packaging materials have negative impacts on the environment and food safety. Natural biopolymer-based food packaging materials are the proper substitutes for plastic-based ones, which is because biopolymers are nontoxic, biodegradable and even edible. The incorporation of bioactive and functional substances into a biopolymer-based film matrix can produce novel smart packaging materials. Anthocyanins, one class of natural colorants with potent antioxidant activity and pH-response color-changing ability, are suitable for producing biopolymer-based smart packaging films. The purple sweet potato is a functional food rich in anthocyanins. In the past decade, numerous studies have reported the extraction of anthocyanins from purple sweet potato and the utilization of purple sweet potato anthocyanins (PSPAs) in biopolymer-based smart packaging film production. However, no specific review has summarized the recent advances on biopolymer-based smart packaging films containing PSPAs. Therefore, in this review, we aim to systematically summarize the progress on the extraction, isolation, characterization, purification and functional properties of PSPAs. Moreover, we thoroughly introduce the preparation methods, physical properties, antioxidant and antimicrobial activity, pH sensitivity, stability and applications of biopolymer-based smart packaging films containing PSPAs. Factors affecting the extraction and functional properties of PSPAs as well as the properties of biopolymer-based films containing PSPAs are discussed.

The Profile of Phenolic Compounds Identified in Pitaya Fruits, Health Effects, and Food Applications: An Integrative Review.

This integrative review aimed to identify the phenolic compounds present in pitayas (dragon fruit). We employed a comprehensive search strategy, encompassing full-text articles published between 2013 and 2023 in Portuguese, English, and Spanish from databases indexed in ScienceDirect, Capes Periodics, Scielo, and PubMed. The study's selection was guided by the question, "What are the main phenolic compounds found in pitaya fruits?". After screening 601 papers, 57 met the inclusion criteria. The identified phytochemicals have been associated with a range of health benefits, including antioxidant, anti-inflammatory, and anxiolytic properties. Additionally, they exhibit promising applications in the management of cancer, diabetes, and obesity. These 57 studies encompassed various genera, including Hylocereus, Selenicereus, and Stenocereus. Notably, Hylocereus undatus and Hylocereus polyrhizus emerged as the most extensively characterized species regarding polyphenol content. Analysis revealed that flavonoids, particularly kaempferol and rutin, were the predominant phenolic class within the pulp and peel of these fruits. Additionally, hydroxycinnamic and benzoic acid derivatives, especially chlorogenic acid, caffeic, protocatechuic, synaptic, and ellagic acid, were frequently reported. Furthermore, betalains, specifically betacyanins, were identified, contributing to the characteristic purplish-red color of the pitaya peel and pulp. These betalains hold significant potential as natural colorants in the food industry. Therefore, the different pitayas have promising sources for the extraction of pigments for incorporation in the food industry. We recommend further studies investigate their potential as nutraceuticals.

Pengaruh Penambahan Ekstrak Lemon (Citrus limon) terhadap Karakteristik Minuman Bunga Telang (Clitoria ternatea)

With its distinctive flower color, the butterfly pea flower has excellent potential as a functional beverage ingredient. Its anthocyanin content provides natural color and high antioxidant activity. This study aims to improve the quality of butterfly pea flower drink by adding lemon extract, which is rich in vitamin C. Using a Completely Randomized Design (CRD) with five treatment levels (10%, 20%, 30%, 40%, and 50% lemon extract), this study evaluated the effect of adding lemon extract on the physicochemical and organoleptic characteristics of butterfly pea flower drink. Antioxidant, pH, color, and sensory evaluations of taste, color, and scent were all included in the analysis. The outcomes demonstrated that adding lemon extract considerably impacted the butterfly pea flower drink's qualities. The best treatment was obtained at a concentration of 10% lemon extract (L1) with an antioxidant value of 0.28 ppm, pH 2.78, L*a*b* color value of 37.87, and received a good assessment in the organoleptic test, namely taste 3.48 (like), color 2.92 (like), and aroma 2.92 (like). * The combination of the natural blue color of butterfly pea flowers with the acidity of lemon produces a drink with an attractive appearance and fresh taste. In addition, adding lemon extract to butterfly pea flower drinks can improve product quality, especially at a concentration of 10%. With the addition of lemon extract, Butterfly pea flower drinks have great potential as functional drinks that are healthy and attractive to consumers.

Integration of mathematical and experimental modeling for sustainable phycobiliprotein production via fed-batch cultures

The production of phycobiliproteins, such as cyanobacterial phycocyanins, is a growing interest due to their diverse industrial and biotechnological applications. This study focuses on optimizing phycocyanin production using the strain Potamosiphon sp. through experimental techniques and mathematical modeling in fed-batch cultures. The methodology applied includes determining the kinetic constants by linearizing the Monod equation evaluating the concentrations of biomass, C-phycocyanin (C-PC), nitrates (NO3), and phosphates (PO4). A mathematical model of periodic fed-batch feeding was subsequently established, applying mass conservation principles and evaluating the accuracy of the Monod, Contois, Moser, and Tessier models. The results indicate that phycocyanin production is highly dependent on phosphorus and nitrogen concentrations, with optimal conversion observed at specific levels of these elements (0.832 for phosphorus and 0.805 for nitrogen in terms of C-PC and biomass, respectively). The Tessier model demonstrated the highest accuracy in predicting production and optimizing operational conditions, with a Mean Squared Error (MSE) of 0.005000 for biomass production, 0.200000 for C-PC production, and 0.000010 for substrate consumption. It also achieved high R² values of 0.980 for biomass, 0.999 for C-PC production, and 0.997 for substrate consumption. It presented the lowest Akaike Information Criterion (AIC) scores, indicating its robustness and reliability in modeling these processes and manipulating cultivation conditions and providing adequate nutrition allowed for achieving growth rates of 1.23 g/L and a C-PC concentration of 37 mg/L, which are essential for industrial applications such as natural colorants and antioxidants, among others.

Comprehensive analysis of antioxidant and antibacterial activities of water and methanol extracts of Hibiscus flower

This study provides a comprehensive investigation into the antioxidant and antibacterial properties of Hibiscus flower extracts, highlighting their potential for future applications in functional foods. The research addressed key challenges by employing a multi-faceted approach, including four distinct methods for evaluating antioxidant potential: DPPH and FRAP assays, reducing power, and chelating ability of Fe ions. Total phenolic content was quantified using the Folin–Ciocalteu method, while tannins and flavonoids were assessed via vanillin–HCl and aluminum chloride assays. Additional analyses included spectrophotometric measurement of total flavonols and anthocyanins. Antibacterial activity was determined using a modified agar disk diffusion method, with results indicating significant inhibition of Salmonella typhimurium and Staphylococcus aureus by both aqueous and methanolic extracts. Colorimetric analysis revealed a reduction in chroma and hue angles, while FTIR spectroscopy identified key functional groups, such as suberin, lipids, and polysaccharides. Notably, the antioxidant efficacy varied depending on the solvent used, with aqueous extracts showing higher total phenolic content (4325.12 mg GAE/100 g) compared to methanolic extracts (3487.05 mg GAE/100 g). The study concludes that Hibiscus flower extracts, rich in antioxidants like tannins and anthocyanins, possess significant potential for use as natural preservatives and colorants in food products, supporting their role in developing novel functional foods.