Search results

The purpose of this study is to address consumer’s preference of natural pigments over synthetic ones and their use in various product developments rather than using synthetic colours. A budding interest of using natural pigments has made researchers to explore several techniques for their stabilization and application in different food products.

In this review, four major natural pigments with potential health benefits have been studied. Betalins, carotenoids, anthocyanins and chlorophylls, in spite of having excellent bio-functional and therapeutic profile, are found to be unstable. Therefore, various nanoencapsulation techniques are used to increase their stability along with their therapeutic properties.

Nanoencapsulation of natural pigments improves their stability, their effect on therapeutic properties and their application in different food products. These findings could be attributed to the encapsulating material as it acts as a barrier and ushers changes in the matrix of natural pigments. Also, nanoencapsulation not only increases stability but also provides several health benefits such as anti-inflammation, anti-cancer, anti-allergic and anti-thrombotic properties.

This paper highlights the openings for the use of nanoencapsulation of natural pigments to stabilize them and use them as a potential colourant and functional ingredient in different food products. Phenols, carotenoids and antioxidant activity are the major factors that are responsible for promoting several health benefits.

Whey is a by-product of paneer, cheese and casein industry and considered as a dairy waste. Worldwide, approximately 180–1,900 million tons of whey is produced annually. Whey is classified as a high pollutant due to its organic matter level. Owing to its high chemical oxygen demand and biological oxygen demand, it is a big threat to the environment. Whey contains 4.5%–5.0% lactose, 0.6%–0.7% protein, 0.4%–0.5% lipids, vitamins and minerals. Due to its high nutritional profile, it is a good substrate for the microorganisms for production of natural pigments. The purpose of this paper is to review the utilization of low cost substrate (whey) for production of various types of pigments and their applications in different sectors.

The databases for the search included: Scopus, PubMed, Science Direct, Web of Science, Research gate and Google. The main search was directed towards different types of natural pigments, stability, technologies for enhancing their production and contribution towards circular economy. Approximately 100 research papers were initially screened. A global search was conducted about natural pigments. Research articles, review papers, books, articles in press and book chapters were the type of search for writing this review paper.

Production of natural pigments using whey and their addition in food products not only improves the colour of food but also enhances the antioxidant properties of food products, helping the health benefits by chelating free radicals from the body. The sustainable use of whey for production of natural pigments can improve the bio-based economy of different industries and thereof the national economy.

Efficient utilization of whey can bring a lot more opportunities for production of natural pigments in a sustainable manner. The sustainable approach and circular economy concepts will benefit the dependent industries and health conscious consumers. The potential uses of whey for the production of natural pigments using diverse organisms are highlighted in this paper.

In this study, it was aimed to investigate the antibacterial properties of natural pigments prepared from Thymus serpyllum.

Al (III), Fe (II), Sn (II) and Cu (II) complexed natural pigments were obtained by using a precipitation method and the main constituents in the pigments were identified with HPLC-DAD. Also FTIR analysis was performed for further structural characterization. Moreover, the thermal stability and thermal degradation properties of the pigments were analyzed by thermogravimetric analyses (TGA). The antimicrobial activity of the thyme plant-extracted pigments was evaluated by measuring the minimal inhibitory concentration.

Apigenin and luteolin flavones were detected as the main components of the natural dyes. Thermal degradation behaviour of the pigments was determined by means of TGA. All pigments showed high char yields and it was attributed to the high complexation between the metal and the ligand species. The antimicrobial activity of the thyme plant-extracted pigments was measured and it was found that all pigments had high antimicrobial activity. Aluminum-thymus pigments showed the highest antimicrobial efficiency among other pigments used in this study.

The obtained pigments have high antimicrobial activities, and therefore, they can be used for the production of antimicrobial textiles. Furthermore, Thymus-based natural pigments might have potential applications in coating, paint, plastic industries, etc.

The purpose of this paper is to prepare, analyse and measure the colour values of the lake pigments obtained from the reaction of Al3+, Fe2+ and Sn2+ metal salts with the natural dyes present in European buckthorn (Rhamnus cathartica L.).

A reversed‐phase high performance liquid chromatography (HPLC) with diode‐array detection method was utilised for the identification of buckthorn lake pigments. The extraction of dyes from the lake pigments was carried out with 37% hydrochloric acid/methanol/water (2:1:1; v/v/v) solution.

According to the results of the HPLC analysis of the lake pigments, it was determined that rhamnetin, kaempferol, and emodin were present in the acid hydrolysed plant extract and in the lake pigment that was precipitated by Sn(II), quercetin‐3‐arabinosid, rhamnetin, and emodin were present in the non‐hydrolysed plant extract, and kaempferol, rhamnetin, isorhamnetin, and emodin were found in the lake pigment that was precipitated by Al(III). Rhamnetin and emodin were present in the lake pigment that was precipitated by Fe(II).

In the present context for the preparation of buckthorn lake pigments, a simple and practical method is presented. In addition, the analysis of the lake pigments was performed by reversed phase HPLC (RP‐HPLC) with diode array detector (DAD).

The paper describes the preparation of lake pigments and their qualitative analysis. This method can be used to determine the origins of the dyestuffs used in historical art pieces.

The paper describes the development of methods for the analysis and the preparation of European buckthorn lake pigments.

This paper aims to isolate fungal strains producing natural colours, explore their application as colourant in paints and develop cost-effective durable natural paints.

Fungal strains producing natural colours of different shades were isolated. Colourant production was carried out by fermentation method. Natural lime, milk, oil-in-water emulsion paints using natural microbial colours and eco-friendly ingredients were prepared. Bio-paint applications were carried out and evaluated.

Our results indicate that microbes in general and fungi in specific represent dependable source of variety of natural colours, and cost-effective durable natural paints can be prepared with commonly available natural ingredients using scientific information based on history of paints.

Natural colours are gaining importance because of their use in health, nutrition, pharmaceutical, textile and environmental applications. Nature is quite rich in several types of colourants. Chemical synthesis of synthetic dyes is complex and not environmental friendly. Microbial dyes manufactured can evade inherent environmental problems of synthetic dyes and offer significant opportunity as a colourant in paints. However, only generally regarded as safe microbial strains are to be considered for colour production.

Choosing natural alternatives to protect the health and environment is the need of hour. Fungal colourants are relatively more stable and robust and offer significant opportunity as a colourant in paints. Cost-effective durable natural paints can be prepared using selected stable fungal colourants with commonly available natural ingredients. High diversity of rich and complex natural colourants can be obtained from microorganisms. With the available techniques of fermentation, natural colours can be produced in large quantities of on an economically viable scale and explored for their applications.

Bio-paints are eco-friendly natural paints, low volatile organic compounds (VOC) paints or organic paints alternate to conventional paints. Most of these natural paints are durable, breathable, prevent moisture problems, contribute to a positive room climate, use safer technology and are less energy-intensive than conventional latex paints to produce. These paints improve indoor air quality and reduce urban smog and offer beneficial characteristics such as low odour, excellent durability and a washable finish.

Many of the old art works that still survive today are a tangible proof and evidence of beauty and durability of natural paints. Organic materials used in these paints include natural pigments of mineral, plant and animal origin and other raw biodegradable ingredients. Successful commercialisation of many microbial pigments for food and textile applications is reported in literature. Therefore, present research work aims at developing natural paints using microbial pigments and recipes that have been successfully used by people for years.

The purpose of this paper is to evaluate the potential of betacyanin pigment extracted from Hylocereus polyrhizus fruit pulp and peel as a natural colorant and to observe the effects of pH and light on betacyanin contents.

In this study, pigment from the pulp and peel of H. polyrhizus fruits was extracted using 80 per cent methanol and 80 per cent acetone. Effects of pH and light exposure during storage on betacyanin content were evaluated. The betacyanin extract, mixed with 20 per cent poly(methyl methacrylate) and coated onto glass slides, was tested with different concentrations of sodium hydroxide (NaCl) to determine its durability. An ultraviolet (UV)–visible spectrophotometer was used for analyzing the betacyanin content.

Betacyanin pigment extracted from pulp using 80 per cent acetone as the solvent at pH 1.0 had the highest betacyanin content. Betacyanin content decreased when stored under exposure of light compared to storage in dark. In this study, increasing concentration of NaCl decreased the absorbance values at faster rates for betacyanin-coated glass slides.

Acetone is volatile and evaporates rapidly. Pigments extracted with acetone were stored in glass vials which were closed tightly to prevent evaporation.

The social implication is the use of natural pigments from cactus species as a valuable and eco-friendly source in a coating system without adverse effects for human health.

The method for detection of stability and effectiveness of betacyanin pigment used as a natural colorant for coating application was beneficial and recent for environment-friendly and natural plant-based product development.

This paper aims to study the effect of different organic solvents on the extraction of pigments present in callus cultures of E. cinerascens.

Attempts have been made to extract pigments from callus cultures through tissue culture system as an alternative replacement for conventional plant cultivation as tissue culture provides unlimited supplies of plant samples. Callus of E. cinerascens was induced from stem explant cultured in Murashige and Skoog medium supplemented with combination of 0.5 mg/L 6-benzylaminopurine and 0.5 mg/L α-naphthaleneacetic acid maintained under photoperiod of 16 h light and 8 h dark. Fresh samples of the callus were harvested and dissolved in various types and concentrations of solvents such as 100 per cent acetone, 80 per cent acetone, 95 per cent ethanol, 100 per cent methanol and 90 per cent methanol. Each of the mixtures was directly centrifuged to get clear supernatant containing pigments of interest. The pigments were detected and subsequently quantified via two simple techniques, ultraviolet-visible (UV-Vis) spectrophotometer and thin layer chromatography (TLC).

UV-Vis spectrophotometer detected two families of pigments present in the callus cultures, namely, carotenoids (carotene and xanthophyll) and tetrapyrroles (chlorophyll a and b). Pigment contents in various solvent extractions were estimated using spectroscopic quantification equations established. Through TLC, spots were seen on the plates, and Rf values of each spots were assessed to indicate the possible existence of carotenoids and tetrapyrroles.

This preliminary study offers significant finding for further advance research related on natural pigments extracted from E. cinerascens that would provide profits in the future applications, especially in food industry, medicine, agriculture, etc.

The purpose of this study is to evaluate the content of bioactive pigments in coloured callus of Azadirachta indica and to understand the correlation between the callus colours with their bioactive constituents, antioxidant properties and cytotoxicity. These assessments will yield valuable insight into the use of in vitro-derived pigments for possible use as functional natural colourants.

In this study, the authors have successfully developed a protocol to produce leaf-derived callus of various colours with enhanced content of bioactive pigments in A. indica through plant tissue culture. Comparative analysis of the pigments content (chlorophyll, carotenoid, phenolics and anthocyanins) in the coloured callus was conducted, followed by evaluation of its bioactive properties. The antioxidant properties against 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, ferric reducing antioxidant power and cytotox activities of the coloured callus extracts were also reported.

Callus of various colours were successfully produced in A. indica through plant tissue culture, and their valuable pigment content and bioactivity were evaluated. The green callus contained the highest amount of anthocyanin, followed by brown and cream callus. The total anthocyanin contents in both the green and brown callus was more than two-fold higher than that in cream callus. Contrasting observation was obtained for total phenolic content (TPC), where the TPC of cream callus was significantly higher than that in brown callus. Nevertheless, the green callus also exhibited the highest TPC. Green callus also contained the highest amount of total chlorophyll and carotenoid, as well as exhibited the highest antioxidant potential, and was found to be the only extract with active cytotox activity against SKOV-3 cells. Correlation analysis revealed that the excellent bioactivity exhibited by the coloured extracts was strongly correlated with the bioactive pigments present in the callus.

The major bioactive compounds identified in the methanolic extracts of A. indica coloured callus are anthocyanins, phenolics, chlorophylls and carotenoids. Future research work should include improvements in the extraction and identification methods, which may lead to detection and determination of other compounds that could attribute to its bioactivity, to complement the findings of the current study.

This analysis provides valuable information on the application of plant tissue culture as an alternative source for sustainable production of major pigments with medicinal benefits in A. indica for possible use as functional natural colourants.

A comparative study on bioactive pigment production in coloured callus from A. indica leaves and its antioxidant potential and cytotoxicity is original. To the best of the authors’ knowledge, this is the first report detailing a comparative evaluation on the production of coloured callus in A. indica and its relative biochemical composition and bioactive properties.

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 is to isolate yellow pigment producing fungal strain and to determine the media requirement for growth and secondary metabolite production.

Fifteen soil samples were collected and studied for a pigment producing fungal sources. Selection of a fungus was based on pigment produced and further conditions, such as effect of media composition and light wavelength on pigment production and growth parameters were optimised.

Out of the isolates analysed, Epicoccum nigrum was selected for further study as this strain has the potential for pigment production. Among all the media evaluated, potato dextrose agar (PDA) was found to be the best media for growth and sporulation, whilst sabouraud dextrose agar (SDA) was only 29 per cent as capable as the best medium. The radial growth rate in case of PDA was 3 ± 0.02 mm/day, while in case of SDA, it was only 1.09 mm/day. Whilst starch as a carbon source was found to increase the radial growth to 5.15 ± 0.02 mm/day, sucrose significantly (p < 0.05) influenced the sporulation (224,000 ± 1,550 spores/ml) of Epicoccum nigrum. Amongst the various nitrogen sources analysed, peptone significantly increased (p < 0.05) the radial growth (6.55 ± 0.02 mm/day) as well as sporulation (220,000 ± 2,100 spores/ml). The observations also indicated that E. nigrum is able to sense and differentiate between light in different wavelength ranges and respond differently in growth and sporulation. The light passing through a red colour sheet resulted in better radial growth (8.5 ± 0.02 mm/day) in comparison to unfiltered light (3 ± 0.02 mm/day). Yellow pigment production in terms of hue values was significantly influenced by the presence of dextrose, peptone and darkness.

The isolated strain could be studied for variable conditions and stress factors for optimal production of the pigment. Recovery and purification studies could be carried out at pilot and industrial scale.

The isolation of a strain producing valuable microbial pigment will increase the alternatives of natural food colours and enhance the its commercial applications

This study identifies Epicoccum nigrum as a potential source of microbial pigment and facilitates its growth and production for possible applications in industrial pigment production.