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This study aims to develop a green, economical and efficient ultrasonic-/microwave assisted extraction (UMAE) process for the extraction of anthocyanins.

After optimizing the extraction conditions by response surface methodology, three assays including DPPH, ABTS·+, FRAP were applied to analyze the antioxidant activity of the extracted anthocyanins. The stability under different temperatures, reductant concentrations and pHs was also discussed. The components of anthocyanins in blueberry were analyzed by HPLC-QTOF-MS2.

The optimal extraction parameters were ultrasonic power of 300 W, microwave power of 365.28 W and solid–liquid ratio of 30 (g/mL). The possible structures can be speculated as Delphinidin-3-O-galactoside, Delphinidin, Petunidin, Delphinidin-3-O-glucoside, Petunidin-3-O-glucoside, Cyanidin-3-O-glucoside. The results demonstrated that the UMAE can improve the yield of anthocyanins in shorter extraction time with higher activity.

The present study may provide a promising and feasible route for extracting anthocyanins from blueberries and studying their physicochemical properties, ultimately promoting the utilization of blueberry anthocyanins.

The purpose of this research is to identify and investigate some natural dyes with halochromic properties for potential use as food spoilage indicators to reduce waste and curve the negative effects of food borne diseases.

Exactly 10 potential dye-yielding plants were selected based on their colour (mostly purple, red, maroon and pink). Solvent extraction was used to extract the dyes and pH differential method was used to determine the concentrations of anthocyanin in the extracted dyes. Different concentrations of hydrochloric acid and sodium hydroxide (0.1 M, 1 M and 2 M) in drops and in excess as acidic and basic solution, respectively, were used to test the halochromicity of the extracted dyes. Methyl red (a synthetic dye) was used as a reference standard/control. The pH of the dyes was recorded before and after addition of both NaOH and HCl solutions.

Five out of the 10 dyes extracted (labelled as dye A–E for Ti plant (green Cordyline fruticosa), coleus (Coleus blumei), paper flower (Bougainvillea glabra), painted nettle (Palisandra coleus) and purple heart (Setcresea purpurea), respectively, were found to be halochromic (even at low doses) by changing its colour when exposed to both acidic and basic solutions. While other dyes labelled F–J for red acalypha (Acalypha wilkesiana), golden shower (Cassia fistula), golden dew drop (Duranta repens), wild sage (Lantana camara var Aculeata) and pink oleander (Apocynaceae Nerium oleander), respectively, were either completely insensitive to the solutions in drops, slightly sensitive at high doses or the colour change is insignificant. Although some dyes were found to be more sensitive than others but in most cases, the colour changes in halochromic dyes were more stable in acidic conditions than in basic making it more sensitive to the basic than the acidic solution with the exception of dye A and E (to some extent) which was sensitive to both acidic and basic solution. The anthocyanin contents of dye A–J were found to be between the range of 2.28–10.35 mg/l with dye E having the lowest and dye J with the highest anthocyanin concentration, respectively. The initial pH of all the dyes falls within the range of 4.8–7.3 with most found within the acidic range.

Halochromic dye research studies are still at the infancy stage in developing world despite the vast available and abundant potential natural halochromic dye-yielding plants. The study explored this area of research and gives an opportunity for the development of smart packaging for pH-sensitive foods using natural dyes as an alternative to conventional synthetic dyes to reduce cost and also curve the negative effect of synthetic dyes as well as food borne diseases.

This paper aims to critically review the isolation and chemistry of plant pigments.

A literature survey from 1974 to 2022 was carried out and studied thoroughly. The authors reviewed literature in various areas such as isolation methods and catalytic properties of pigments.

With vast growing research in the field of catalytic activities of various pigments like chlorophyll, anthocyanin and flavonoids, there is still scope for further research for the pigments such as Lycopene, carotenoids and xanthophyll as there has not been any significant work in this area.

Plant pigments may be used as an ecofriendly catalyst for chemical reactions.

One can get the direction of pigment research.

Plant pigments are natural and ecofriendly catalyst which can reduce the pollution.

This is an original work. This paper precisely depicts the advantages as well as disadvantages of the isolation techniques of pigments. This study also presents the chemistry of plant pigments.

The purpose of this study was to review the information on the scientific efforts and achievements in sustainable industrial textile applications of natural colourants. Then the paper suggests the ways of improving the industrial textile applications of plant-based colourants.

The literature on the chemistry, sources and extraction of plant-based natural colourants was reviewed. The reviewed information was analysed and synthesised to provide techniques for selecting sustainable extraction methods, possible sustainable textile applications of natural colourants and the challenges which hinder industrial textile applications of plant-based natural colourants. The ways of overcoming the challenges of the industrial textile applications of plant natural colourants were suggested. Lastly, the current situation of industrial application of natural dyes in textiles is presented.

Despite the scientific achievement to overcome the challenges of natural colourants for textiles, the global industrial application of natural colourants is still low. Inadequate knowledge of the dyers results into poor performance of the natural dyed textile. The natural dyed textiles are expensive due to the scarcity of raw materials for manufacturing of natural colourants. The selection of suitable extraction, application methods and type of substrate should consider the chemistry of the particular colourant. The society should be educated about the benefits of natural dyed textiles. Cultivation of colourant-bearing plants should be promoted to meet the industrial material demand.

The paper provides a synthesized collection of information about the source, chemistry, extraction, textile application and challenges of plant-based natural colourants. The reviewed information was analysed and synthesised to provide techniques for selecting sustainable extraction methods, possible sustainable textile applications of natural colourants and the challenges which hinder industrial textile applications of plant-based natural colourants. The ways of overcoming the challenges of the industrial textile applications of plant natural colourants were suggested.

This study aims to investigate the potential use of potato peel extracts as antibacterial finishes for cotton fabrics against Staphylococcus aureus and Escherichia coli. Potato peels are abundant as waste and provide a natural, cheaper and sustainable alternative means of preventing the spread of bacterial infections on cotton fabric.

This research included the characterization of potato peel extracts, application of the extract onto cotton fabric and efficacy testing of the treated cotton fabric against bacteria. Phytochemical screening, agar well diffusion antibacterial test, minimum inhibitory concentration and Fourier transform infrared (FTIR) tests were used to characterize the extract. Antibacterial efficacy of the treated fabric was determined qualitatively using the disc diffusion assay and quantitatively using the bacteria reduction test.

Phytochemical screening confirmed the presence of several secondary metabolites including phenols and flavonoids. Antibacterial tests revealed a positive response in Escherichia coli and Staphylococcus aureus with a zone of inhibition of 6.50 mm and 5.60 mm, respectively. Additional peaks on the FTIR spectroscopy confirmed the presence of potato peel extract on the treated cotton fabric. The treated cotton fabrics showed efficacy against Staphylococcus aureus and Escherichia coli up to 20 washes.

This study introduced the application of potato peel extracts onto cotton fabrics and assessment of the antibacterial properties before and after washing. Results of this study suggest that potato peel extracts can be used as an organic eco-friendly antibacterial finish for cotton fabrics.

Natural dyeing has existed in human life from past to present. Although it lost its importance after the industrial revolution, it has started to make again a name for itself today with the increase in environmental awareness. The purpose of this study is to investigate whether the Hibiscus sabdariffa L. can be used in the coloring of woolen fabrics and as a natural antibacterial agent for these fabrics.

Within the scope of the study, it was investigated whether the antibacterial activity of the Hibiscus sabdariffa L. can be transferred to woolen fabrics. In the study, woolen fabric samples were dyed with and without mordant with the help of Hibiscus sabdariffa L. extract. After the dyed fabric samples were washed and dried, their color values were measured, and antibacterial effect tests (against Staphylococcus aureus – Escherichia coli), washing and rubbing fastness tests were carried out. In addition to these, scanning electron microscopy images of dyed fabric samples were taken and Fourier transform infrared microspectroscopy analyzes were also performed.

As a result of the study, it has been determined that the antibacterial activity of the Hibiscus sabdariffa L. can be transferred to woolen fabrics without the use of any chemicals.

Natural antibacterial agent for woolen fabrics was obtained within the scope of the study without the use of chemicals.

The purpose of this research is to develop an environmentally friendly antimicrobial dyeing of cotton fabric from the root of Euclea racemosa. Textile phytochemical finishing is in high demand worldwide because of its low toxicity, low pollution, ease of availability, renewability, pharmacological effects and non-carcinogenic properties, as well as its multifunctionality, rapid process stages and potential health benefit.

The cotton fabric was dyed with aqueous extracts of Euclea racemosa root dyes. Dyes were extracted for 20 min at pH 7.43 at room and boiling temperatures with material-to-liquor ratios (MLRs) of 1:5, 1:10, 1:15 and 1:20, altering one variable at a time, and the cotton fabric was colored using a post-mordanting procedure at 50°C with an MLR of 1:20. Using a properly cleaned Petri plate, the colored samples were tested in vitro for antibacterial activity. A spectrophotometer was used to assess color strength and shade depth, as well as wash fastness and annual rubbing fastness tests for both wet and dry.

L* = 36.29, a* = 58.56, b* = 32.46 and K/S = 0.51 were the CIELAB values for dye extracted at boiling temperature. L* = 47.14, a* = 42.23, b* = 49.61 and K/S = 0.38 were the CIELAB values for dye extracted at room temperature. The wash and rubbing fastness of the dyed samples were outstanding and the dyed cotton fabrics were found antibacterial against Gram-negative bacteria Escherichia coli.

Dyes derived from the E. racemosa root could be used to develop a new antibacterial cotton fabric dye.

This study aims to dye silk with natural pigments extract of Coreopsis tinctoria, by treating the fabrics with appropriate mordant under suitable dyeing conditions, to achieve good dyeing depth, fastness and ultraviolet (UV) protection.

Firstly, single factor experiments were used to determine the basic dyeing conditions of Coreopsis tinctoria. The optimal process conditions for direct dyeing were determined through orthogonal experiments. After that, the dyeing with mordant was used. Based on the previously determined optimal process conditions, silk fabrics were dyed with different mordanting methods, with different mordants and mordant dosages. The dyeing results were compared, in terms of the K/S values of the dyed fabrics, to determine the most appropriate dyeing conditions with mordant.

The extract of Coreopsis tinctoria can dye silk fabrics satisfactorily. Good dyeing depth and fastness can be obtained by using suitable dyeing methods and dyeing conditions, especially when using the natural mordant pomegranate rind and the rare earth mordant neodymium oxide. The silk fabrics dyed with Coreopsis tinctoria have good UV resistance, which allows a desirable finishing effect to be achieved while dyeing, using a safe and environmentally friendly method.

The composition of Coreopsis tinctoria is complex, and the specific composition of colouring the silk fibre has not been determined. There are many factors that affect the dyeing experiment, which have an impact on the experimental results.

The results of this study may help expand the application of Coreopsis tinctoria beyond medicine.

To the best of the authors’ knowledge, this paper is the first report on dyeing silk with the extract of Coreopsis tinctoria achieving good dyeing results. Its depth of staining and staining fastness were satisfactory. Optimum dyeing method and dyeing conditions have been identified. The fabric dyed with Coreopsis tinctoria has good UV protection effect, which is conducive to improving the application value of the dyeing fabric. The findings help offer a new direction for the application of medicinal plants in the eco-friendly dyeing of silk.

The purpose of this article is to investigate on changes of the microbial load and the chemical and physical properties of date fruits stored for 6 months under two different temperatures.

A composite sample of 100 kg date fruits from the Khalas variety, season 2019, was collected from the local market in Al Ahsa Province, Saudi Arabia, packaged in 1 kg lots, stored at room and refrigerator temperatures and the microbial contamination and the chemical and physical properties monitored over a period of six months of storage. Total bacteria, lactic acid bacteria, Enterobacteriaceae, yeasts and molds were counted and representatives of yeast and mold contaminants were identified using morphological, physiological and molecular typing techniques. Changes in the color and texture of the samples were also monitored during storage.

The yeasts detected were two strains of each of Lachancea thermotolerans and Rhodosporidiobolus fluvialis and one strain of Cystofilobasidium lacus-mascardii. For molds, one strain of each of Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Aspergillus caespitosus have been detected. No significant growth of these microorganisms was observed, but enough load persisted during storage that makes the samples not meeting the microbiological standards. There were significant changes in the color and texture of the fruits during storage.

These findings add important information that can help producers and processors to improve quality and promote marketing of date fruits, especially to international markets.

The purpose of this paper was to study the color change kinetics of lac dye in response to aldehydes, carbon dioxide and other food spoilage metabolites for its potential application in intelligent food packaging.

UV–Vis spectroscopy was used to study the color change of dye solution. Ratio of absorbance of dye solution at 528 nm (peak of ionized form) to absorbance at 488 nm (peak of unionized form) was used to study the color change. Color change kinetics was studied in terms of change in absorbance ratio (A₅₂₈/A₄₈₈) with time using zero and first-order reaction kinetics. Lac dye-based indicator was prepared to validate the result of study for monitoring quality of strawberries.

Lac dye was orange-red in acidic medium and purple in alkaline medium. Color change of dye in response to benzaldehyde followed zero-order reaction kinetics, whereas for carbon dioxide first-order model was found best. No color change of dye solution was observed for alcohols, ketones and sulfur compounds. In the validation part, the color of the indicator label changed from purple to orange when the strawberries spoiled.

The study expands application area for lac dye as sensing reagent in intelligent food packaging for spoilage or ripeness detection of fruits and vegetables.