Natural dyes and their IR-spectra – supplementary data

A recent (2009–2021) perspective on sustainable color and textile coloration using natural plant resources

Color matching is critical in textile conservation for loss compensation and stabilization of historic textiles. Conservators rely primarily on visual assessments, making color evaluations vulnerable to variations in lighting conditions and metamerism, where perceived colors shift under different lights. This study compares the color-matching accuracy and color stability of natural (madder, fustic/logwood green blend) and synthetic dyes (direct, reactive) through controlled artificial fading, proposing a structured approach to color training for conservators. To simulate real conservation scenarios, 100% cotton woven fabrics were first dyed using historical natural recipes. Next, other cotton fabrics were dyed using contemporary synthetic dyes to achieve color matches with those dyed using natural dyes. Dyed fabrics underwent controlled artificial fading via xenon arc exposure in a Q-Sun chamber, simulating the long-term color degradation of textiles. Colors were objectively measured using an X-Rite SP62 V spectrophotometer and referenced to the CIE L*a* b* color space, both before and after artificial fading. Illuminant-dependent color differences (metamerism) were observed for all dyed samples across the tested lighting conditions (cool white, D65/daylight, and horizon). Results indicated that natural dyes exhibited unpredictable color shifts post-fading. Synthetic dyes initially offered more consistent coloration but failed to replicate the nuanced patina of naturally dyed and artificially faded fabrics. This study highlights the complexities of precise color matching and underscores synthetic dyes’ limitations in emulating natural dye aging behaviors. It emphasizes standardized dye training, integrating traditional dye techniques with modern analytical tools, and advancing reliable, data-driven methods in textile conservation.

A colour influences our moods and emotions and generally enhances the way in which we enjoy our surround-ings. Colour is introduced into these materials using substances known as dyes and pigments. Natural dyes are colours having several applications in textiles, inks, cosmetics, etc. Nature has gifted us more than 500 dye-yielding plant species. The natural dyes offered any imaginable shade of colour, in great brilliance and with ex-act reproducibility. Natural dyes are less toxic, less polluting, less health hazardous, non-carcinogenic and non-poisonous. This paper explains the information regarding the natural colours and dyes so that they are more uti-lized by the industries for the well being of society. Keywords: Natural colours; dyes; pigments

Maintaining color fastness and endow functionality of the fabrics dyed with natural colorants had been the major constraint of natural dye in modern textile practices. In this work, a natural dye was extracted from wall nut tree wood. The dye solution extracted from wall nut tree wood showed excellent thermal stability until 100°C. The structure and functional groups of the extracted dye were investigated by FTIR. The optimum dyeing process was performed at a pH about 4.5 at 90°C for 60 min. In this experiment, three different mordants were used to make silk fabrics show different colors and can improve the color fastness of wall nut tree wood. Finally, the color fastness of wall nut tree wood dye can be further improved by using a dye-fixing agent, and solve the problem of poor color fastness of natural dyes. The dye-fixing agent formed a protective film on the surface of the dyed silk fabrics. The protective film reduced the water solubility of the wall nut tree wood dye, thereby improving the color fastness of the dyed silk fabrics. The best washing fastness reached grade 3–4, and the sunlight fastness reached grade 4. The natural wall nut tree wood dye also showed excellent UV protection properties, and the UPF value of the dyed fabric was 50 + . The wall nut tree wood was expected to become a functional natural dye in the future.

This paper offers a broad overview on several natural dyes from plant origin. By this it is the fifth part in a series of review papers on natural dyes, their properties and infrared spectra. Basic information on origin of natural materials and dyes and their fields of application – especially in the field of textiles – is supported. The chemical structures of dyes are presented together with the measured infrared spectra (IR spectra) of 28 different dye products from various origin. A structure related discussion of the spectra is performed. Main aim of this overview is to offer a broad overview for people interesting in natural plant dyes. Further, the support of IR spectra is a helpful tool for material identification and quality control.

Natural dyes are one of the popular choices for textile dyes today. One part of the plant that has the potential to produce natural dyes is cocoa pod husk (Theobroma cacao L.) because it contains several secondary metabolite compounds, such as tannin which produces a brown color. The extraction method used in this research is Ultrasonic Assisted Extraction (UAE). This study aims to obtain the highest yield of natural dye extracts from cocoa pod husk by varying solvent types, extraction time, and material-to-solvent ratios using the UAE method. In addition, the types of compounds contained in extracts of natural dyes and color results on cotton fabrics were also obtained. The extraction process was carried out using several types of solvents, namely methanol, ethanol, acetone, and distilled water with varying extraction times of 30, 60, and 90 minutes. The research results show that the solvent that can extract the best natural dyes was ethanol with a yield of 11.43% and an extraction time of 90 minutes. Variable ratios of material to 96% ethanol solvent were also observed, namely at ratios of 1:5, 1:6, 1:7, and 1:8 for extraction times of 30, 60, 90, and 120 minutes. The research results were obtained for the ratio of material to ethanol solvent; 1:8 (w/v) and extraction time 120 minutes with a dye yield of 12.29%. The results of the UV-visible spectrophotometry analysis were obtained that the maximum wavelength of cocoa pod husk extract was 656.5 nm with an absorbance of 0.532. The results of the Gas Chromatography-Mass Spectrometry (GC-MS) analysis were obtained that the dye compound in the cocoa pod husk was tannin. Tannin compounds are natural dyes that can be applied to fabrics and will reduce the use of synthetic dyes. The application of dye extracts to cotton fabrics produced a brown color.

All modern lifestyles such as unhealthy eating patterns and lack of exercise can trigger the accumulation of free radicals in the human body, where the human body cannot neutralize these free radicals fast enough because of the large number of free radicals that have accumulated in it. Therefore, antioxidant compounds need to be consumed to suppress free radicals. In this study, mulberry is promoted as a natural, functional, and dye source that has been explored for further applications in food and beverages. This research aims to develop natural coloring products from mulberry fruit through extraction and encapsulation processes. Furthermore, hedonic testing was also carried out to determine the panelist's preference level for jelly products using mulberry fruit dyes. Mulberry fruit is extracted, encapsulated by freeze drying method, and processed into a natural dye in jelly products. Mulberry fruit extract contains vitamin C 4.1 g/ml, anthocyanin content of 215.16 mg/L, and antioxidant activity of 73.25. Mulberry encapsulates can be used as a natural dye in jelly products. Based on hedonic testing, jelly products made from natural dyes have superior taste and texture. Further development of natural mulberry fruit encapsulated dyes needs to be done to increase solubility, color sharpness, aroma and color stability

Along with the growing public awareness of personal and environmental health, lipa sabbe products with natural colors are increasingly popular. Natural dyes are advantageous because they do not need to be imported, are safe for human health during the manufacturing process, do not pollute the environment, and are safe. Although synthetic dyes are easier to use, they are harmful to health, produce hazardous waste, pollute the environment, and are made from imported materials. This study aims to determine the types of plants that can be used as natural dyes for lipa sabbe. Qualitative methods with literature studies sourced from journals, books, or other related scientific articles are used in this research. The results showed that natural dyes in lipa sabbe became one of the Science Learning Resources with natural dyes including extracts from cocoa shell waste, coconut fiber waste, oil palm shell waste, rambutan peel waste, mangosteen peel waste, guava leaf waste, mango leaf waste and avocado leaf waste is plantation waste that can be used as a natural lipa sabbe dye. The pigments in this material produce yellow, reddish brown, gray, and black colors.
 
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Handbook of Natural Colorants

Chapter 13 - Natural dyes and pigments in functional finishing

Natural dyes have been used for dyeing, painting, printing, and decoration since the dawn of time. However, with the manufacturing of synthetic dyes in the nineteenth century, it was revolutionised due to its extremely lasting properties and economic effectiveness. However, a new research highlights the negative implications of synthetic dyes, prompting people all over the world to reduce their use of synthetic dyes and focus on natural source colours, which have numerous advantages over synthetic dyes. These colours might be derived from animals, plants, minerals, or microorganisms. In this brief study, we will talk about natural colorants from an animal source and how to extract them using ancient and new methods that allow their counterparts to achieve equivalent properties.

Natural dye raw material is obtained from potential plants grown around the industry and then extracted by the industry itself. The uncertainty of the supply of natural dyes in the textile industry causes delayed fulfillment of consumer needs. The principle of sustainable production consists of economic, social and environmental aspects. The purpose of this paper is to examine the economic, social and environmental aspects of the production of natural textile dye industry. This study is conducted to determine consumer preferences for the natural dye textile products and the added value of the natural textile dye industry. Consumer preferences is acquired using cross-tab and value-added analysis using the Hayami method. Consumer preferences indicators were dye selection, willingness to pay, awareness, and market access. The natural textile dye industry has the potential to be developed because it can provide added value to agricultural materials that have not been used optimally and support sustainable development.

Natural materials, especially natural colorants, have achieved global prominence and might be regarded as an environmentally beneficial alternative to hazardous synthetic dyes. The color limitation of natural dyes hinders their application in textiles. The present work aims to prepare more color shades of wool yarns via dyeing with ternary natural dye mixtures without adding mordants. In this study, a sustainable dyeing approach for wool yarn was evaluated with three natural dyes, madder red (MR), gardenia blue (GB), and gardenia yellow (GY), by following an industrial dyeing procedure in the absence of a mordant. In the beginning, a preliminary assessment of dye stabilities was carried out, and it was found that the three natural dyes were sensitive to temperature and acid (degradation tendency). Then, the dyeing behavior was systematically evaluated, including a single natural dye, a binary natural dye mixture, and a ternary natural dye mixture. The results of wool yarn dyeing with a single natural dye show that the dye exhaustion percentage (E%) of MR, GY, and GB was in the ranges of 78.7–94.1%, 13.4–44.1%, and 54.8–68.5%, respectively. The dyeing results of wool yarns dyed with binary and ternary natural dye mixtures (a color triangle framework of dyed wool yarn) were characterized by colorimetric values (L*, a*, b*, C*, h, and K/S), and are presented to enlighten various colorful shades. Finally, color uniformity and colorfastness tests confirmed the vital contribution of natural dyes toward wool yarn coloration. Particularly, colorfastness to washing confirmed the stability of natural dyes with reference to the lower amount of dyes released into the effluent, which is beneficial for the environment. Overall, this study provides a good background for enhancing the industrialization trend of natural dyes by modulating their dyeing scheme.

Fast foods and variety food items are populating among the food lovers. To improve the appearance of the food product in surviving gigantic competitive environment synthetic or natural food dyes are added to food items and beverages. Although regulatory bodies permit addition of natural colorants due to its safe and nontoxic nature in food, synthetic dyes are stringently controlled in all food products due to their toxicity by regulatory bodies. Artificial colors are need certification from the regulatory bodies for human consumption. To analyze food dyes in different food samples many analytical techniques are available like high pressure liquid chromatography (HPLC), thin layer chromatography (TLC), spectroscopic and gas chromatographic methods. However all these reported methods analyzed only synthetic dyes or natural dyes. Not a single method has analyzed both synthetic and natural dyes in a single run. In this study a robust ultra-performance liquid chromatographic method for simultaneous identification of 6 synthetic dyes (Tartrazine, Indigo carmine, Briliant blue, Fast green, malachite green, sunset yellow) and one natural dye (Na-Cu-Chlorophyllin) was developed using acquitic UPLC system equipped with Mass detector and acquity UPLC HSS T3 column (1.8 μm, 2.1 × 50 mm, 100Å). All the dyes were separated and their masses were determined through fragments’ masses analyses.

The order of the reaction is the number of concentration factors that affect the speed of a chemical reaction. The reaction order can be used to determine how the adsorption process is in the colouring process based on determining the linear regression equation of the R square value. This study aims to compare the gravimetric method with the UV-Vis spectrophotometric method in determining the reaction order in chlorophyll samples of the natural dye papaya leaves. This study used a quantitative method to determine the value of the reaction order of the papaya leaf natural dye, with data analysis techniques including gravimetric method analysis to determine chlorophyll content, UV-Vis spectrophotometry to determine the value of chlorophyll absorbance and linear regression to determine the order of the reaction. The results showed that the two methods followed first order with an R-value of 0.951 for the gravimetric method and 0.994 for the UV-Vis spectrophotometric method. REFERENCESAisy, G. A. R. (2018). Analysis of the Chlorophyll Content of Papaya Leaf Extract (Upload Papaya L.) Against Extraction Time Variations Using a Hodothermal Extractor. Diponegoro University, (1969), 4–27.Azizah, H. P., & Utami, B. (2016). Utilization of Green Dyes from Papaya Leaves (Carica papaya L.) As a Natural Textile Dyes. UNY National Chemistry Seminar, (October 2016).Fauziah, L., & Wakidah, M. (2019). Extraction of Papaya Leaves (Carica papaya L.) Using Ultrasonic Cleaner. EKSAKTA: Journal of Sciences and Data Analysis, 19(1), 35–45.Khofya, A., & Aji, M. P. (2018). Papaya Leaf Extract (Upload Papaya L.) as a natural dye in batik cloth. Indonesian Journal of Natural Science Education (IJNSE), 1(1), 13–17.Manurung, M. (2012). Mangosteen Peel Application (Garcinia Mangostana L.) As a Natural Dyes on Cotton Fabrics by Pre-Mordanting. Journal of Chemistry, 6(2): 183-190.Matitaputty, J. K., Ufie, A., Ima, W., & Pattipeilohy, P. (2022). Implementation of Education for Sustainable Development (ESD) Through Ecopedagogy in Learning at SMP Negeri 8 Ambon. BUDIMAS Journal, 04(1). http://journal.um-surabaya.ac.id/index.php/JKM/article/view/2203Namirah, I., Affifah, I., Wijayanti, I. E., & Langitasari, I. (2019). Study of Natural Coloring Plants in the Outer Baduy Community. EduChemia (Journal of Chemistry and Education), 4(2), 204.Pujilestari, T. (2015). Review: Sources and Utilization of Natural Dyes for Industrial Purposes Dynamics of Crafts and Batik, 32(2), 93–106. Retrieved from https://media.neliti.com/media/publications/61575-ID-review-sumber-dan-pemanfaatan-zat-warna.pdfRibeiro, M. G. T. C., Costa, D. A., & Machado, A. A. S. C. (2010). “Green Star”: A holistic green chemistry metric for evaluation of teaching laboratory experiments. Green Chemistry Letters and Reviews, 3(2), 149–159.Saputra, B. W. (2008). Adsorption System. 6–21. Tugas Akhir Sarjana. Jurusan Teknik Elektro Universitas Indonesia, Jakarta.Sugiyono. (2011). Quantitative Research Methods, Qualitative and R&D. Bandung: Alphabet.