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Article
Publication date: 2 March 2015

S.V. Lee, A.N. Hadi, Z.H.Z. Zainal Abidin, N.A. Mazni, N.A. Halim, R. Usop, H.C. Hassan, S.R. Majid and A.K. Arof

The purpose of this paper is to observe the colour and thermal stability of natural red dye consisting of anthocyanin with addition of different aqueous acids and applied…

Abstract

Purpose

The purpose of this paper is to observe the colour and thermal stability of natural red dye consisting of anthocyanin with addition of different aqueous acids and applied as coating films.

Design/methodology/approach

The natural red dye was extracted from Hibiscus sabdariffa L. (roselle) flowers and mixed with 1 per cent hydrochloric acid, 5 per cent acetic acid, 5 per cent citric acid and 5 per cent oxalic acid. All the dye samples were exposed to heat and UV-B to observe the colour stability by calculating the half-life and rate of reaction. In coating film application, each of the dye samples was mixed with 25 wt% of poly(vinyl alcohol) (PVA) and applied on to a glass substrate. The coating samples’ colour stability was observed by using CIE L*a*b* colour space coordinates. The coating films’ weight loss stability against temperature was observed by using thermogravimetric analysis.

Findings

Addition of hydrochloric acid enhances the thermal and UV stability of the anthocyanin natural dye. This can be observed from the calculation of the half-life of the dye. The half-life values for the thermal and UV stability studies were 1,155 hours and 210 hours, respectively. In coating films, the sample with addition of acetic acid showed the highest colour stability with colour difference (ΔE*) value 8.95.

Research limitations/implications

The coating films developed in this work are not suitable to be applied on metal substrates due to the presence of water, which can contribute to the corrosion formation.

Practical implications

The coating films developed in this work are suitable for washable coating application. In other words, they are non-permanent coatings applied on a glass substrate.

Originality/value

Development of water-based coatings from PVA binder with anthocyanin colourant is introduced in this study.

Details

Pigment & Resin Technology, vol. 44 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 15 March 2013

S.V. Lee, B. Vengadaesvaran, A.K. Arof and Z.H.Z. Abidin

The purpose of this paper is to develop a new water based coating system composed of poly(acrylamide‐co‐acrylic acid) and anthocyanin colourant extracted from Hibiscus

Abstract

Purpose

The purpose of this paper is to develop a new water based coating system composed of poly(acrylamide‐co‐acrylic acid) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and characterise the system.

Design/methodology/approach

Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted using optimised water extraction method with ratio of calyxes to water being 1:2. UV‐Vis absorption spectroscopy was conducted on the anthocyanin extract to monitor its degradation. Poly(acrylamide‐co‐acrylic acid) was mixed with the extracted anthocyanin solution in two different weight ratios. The mixtures were coated on glass substrate and let to cure for approximately one day. FTIR spectroscopy was conducted on the samples to determine their functional groups and identify the compounds in the samples. Cross hatch test was performed on the samples to determine the adhesion properties. Thermal degradation of the samples was determined through thermogravimetric analysis. Surface roughness of the samples was studied by atomic force microscopy. Colour stability was determined before and after UV irradiation.

Findings

Anthocyanin pigment from roselle extracted with water was found to be stable with 6.0 per cent drop in absorbance value over the 15 day period. The reaction rate was found to be 0.000181 h−1, and the half life was calculated to be 3,850 hours. Better adhesion of the samples to the glass substrate was due to the higher concentration of poly(acrylamide‐co‐acrylic acid). Thermogravimetric analysis revealed similar thermal stability of the samples. Surface roughness study revealed that sample with higher anthocyanin content has higher surface roughness. Colour stability of the 20PBR was found to be better than 10PBR.

Research limitations/implications

Usage of poly(acrylamide‐co‐acrylic acid) as coating is limited by its weak water resistance property. Improvement could be made in this direction for future applications.

Practical implications

Mixture of water‐based polymer and anthocyanin colourant from roselle has been developed into coating for the first time. Commercialisation is possible if more research is conducted towards water resistance property of poly(acrylamide‐co‐acrylic acid), storage condition for the pigment and coating, and mass production of the pigment.

Originality/value

Incorporation of anthocyanin pigment into water based coating is the first of its kind.

Details

Pigment & Resin Technology, vol. 42 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 29 June 2012

N. Aziz, N.A. Mat Nor, A.F. Mohd‐Adnan, R.M. Taha and A.K. Arof

The purpose of this paper is to evaluate the stability of anthocyanin colorant with and without ferulic acid (FA) stabilising agent in a polyvinyl alcohol (PVA) binder…

Abstract

Purpose

The purpose of this paper is to evaluate the stability of anthocyanin colorant with and without ferulic acid (FA) stabilising agent in a polyvinyl alcohol (PVA) binder coating system.

Design/methodology/approach

The anthocyanin colorant was extracted using methanol acidified with 0.5% trifluoroacetic acid (TFA). FA was added to improve thermal stability of the colorant. The FA added colorant was mixed with PVA to develop a coating system. To test the ability of the coating mixture to withstand heat in the liquid state, spectroscopic studies were carried out in the visible region of the electromagnetic spectrum when the liquid samples had cooled down to room temperature after being heated at 80 and 90°C for 30 minutes. This procedure was repeated six times until a total heating time of 180 minutes has been accomplished. The liquid samples were also coated on glass slides, cured and then stored in different incubators at 30, 40 and 50°C. The visible spectrum was taken everyday for 30 days to study the effect of storage temperature. Spectroscopic results were analysed in terms of intensity rate percentage (IRP).

Findings

In the liquid state, the anthocyanin‐PVA mixture without FA showed lower absorbance compared to the mixture containing FA after heating at 80 and 90°C. This shows that FA can enhance the intensity of absorbance of the liquid coating mixture. The mixtures containing FA show increase in absorbance with increase in heating time. The same results are obtained for the coating on glass substrate where FA containing coatings show increase in IRP with time for all storage temperatures. Coating with 1% FA content showed better enhancement and stability.

Research limitations/implications

The colour of the untreated samples quickly faded during heating and storage at different temperatures. In this study, the addition of 0.5% and 1% FA stabilised and enhanced the colour intensity at 30, 40 and 50°C. Further improvements may find the mixture suitable as paint or coating materials and as nail varnish.

Practical implications

The results indicate the possibility of applying the FA stabilised anthocyanin‐PVA, colorant‐binder composition in a coating system.

Originality/value

The use of anthocyanin from M. Malabathricum as a colourant in a coating system or nail varnish is original. Anthocyanin pigments are normally used as colorant in foods.

Details

Pigment & Resin Technology, vol. 41 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 March 1981

J.B. Adams

Anthocyanins. The anthocyanin pigments impart the pleasing red and purple colours associated with many fruits and vegetables. They belong to the class of compounds…

Abstract

Anthocyanins. The anthocyanin pigments impart the pleasing red and purple colours associated with many fruits and vegetables. They belong to the class of compounds referred to as ‘flavonoids’ and, in chemical terms, they are flavylium salts differing in the number and position of free or methylated hydroxyl groups and with a sugar moiety linked through position 3 or positions 3 and 5 in the ring. A commonly occurring anthocyanin pigment, cyanidin‐3‐glucoside, is shown in figure 3. The anthocyanins are soluble in water and are unstable under a variety of enzymic and non‐enzymic conditions.

Details

Nutrition & Food Science, vol. 81 no. 3
Type: Research Article
ISSN: 0034-6659

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Article
Publication date: 8 August 2018

Noraini Mahmad and R.M. Taha

The purpose of this study is to investigate the effects of pH, UV-B radiation and NaCl on anthocyanin extracted from vivid blue petals of Clitoria ternatea L. (legume…

Abstract

Purpose

The purpose of this study is to investigate the effects of pH, UV-B radiation and NaCl on anthocyanin extracted from vivid blue petals of Clitoria ternatea L. (legume crop), as a potential natural colourant for food, dye or coating technology.

Design/methodology/approach

The anthocyanin from petals of Clitoria ternatea was extracted using 0.5 per cent trifluroacetic (TFA) in methanol solution. The liquid colourant was exposed to different pH (1, 4.5 and 5.5), UV-B radiation and sodium chloride (NaCl). The results were compared using UV-vis spectrophotometric analysis.

Findings

Anthocyanins are sensitive and quickly degrade in the presence of light. In the dry powder form, the anthocyanin is easier to maintain and preserve (storage).

Research limitations/implications

Anthocyanins extracted from vivid blue petals of Clitoria ternatea L. are sensitive and quickly degrade in the presence of light.

Practical implications

The anthocyanin pigments extracted from Clitoria ternatea L. petals with methanolic acid were successfully coated on glass slides. The combination of binders and pigments had produced environmental paint which added with stabilisers (additives) for better durability. Acrylic has been known for its high weathering and embrittlement resistance, good mechanical and electrochemical properties and gloss retention.

Social implications

This anthocyanin is suitable as natural colourant especially in baby products, cosmetics production or for coating and varnish application.

Originality/value

Till date, the natural colourant of Clitoria ternatea L. petals is widely used in food. However, this result is a new finding, as there is no report on the potential of applications of this natural colourant for coating technology. Therefore, the current study with appropriate extraction method was significantly based on the relevant literatures of coating production from pigment by using other plant species. The findings and conclusion highlight the practicality as the potential applications in coating technology.

Details

Pigment & Resin Technology, vol. 47 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 17 May 2013

N.A. Mat Nor, N. Aziz, A.F. Mohd‐Adnan, R.M. Taha and A.K. Arof

The purpose of this paper is to evaluate the potential of natural colourants from fruits of Ixora siamensis for coating applications, to study its glossiness and…

Abstract

Purpose

The purpose of this paper is to evaluate the potential of natural colourants from fruits of Ixora siamensis for coating applications, to study its glossiness and effectiveness against UV‐B irradiation.

Design/methodology/approach

In this study, natural colourants from the fruits of Ixora siamensis were extracted using trifluoroacetic acid‐methanol solution. Anthocyanins and organic acid variants were mixed together to form co‐pigments. Different concentrations of ferulic and gallic acid co‐pigments were added to a blended solution of poly (vinyl alcohol), PVA and anthocyanin (from Ixora siamensis) to form a coating system. The coatings were exposed to UV‐B irradiation at room temperature in air using a UV‐lamp which emitted radiation at 312 nm. The effects of UV‐B irradiation on the coating system were evaluated using glossiness test and UV‐visible spectroscopy.

Findings

Anthocyanins are unstable and can quickly lose their colour. One of the methods of preserving the stability of these pigments is by co‐pigmentation. Co‐pigmentation of anthocyanin with organic acid variants resulted in an increase in both hyperchromic effects (ΔA) and bathochromic shifts (Δλ). In this study, ferulic acids yielded better results compared to gallic acids.

Research limitations/implications

Samples with co‐pigmentation give better result compared to the untreated samples. The addition of 0.5 and 1.0 per cent ferulic acid improves the gloss properties and resistivity of the samples towards the UV irradiation. Thus, in order to study the effectiveness of ferulic acid as additive and improving the properties of the samples, the percentage of ferulic acid added and exposure time could be increased.

Practical implications

The method developed provided a simple and efficient solution for improving the UV resistance of anthocyanin blend with poly (vinyl alcohol), PVA UV absorber. Effect of ferulic acid as UV absorber, if added in more concentration, can be further studied for optimization.

Social implications

The social implication is the use of local plant species as a low cost source of natural pigments in coating system.

Originality/value

The method for improving the resistance towards UV irradiation of anthocyanin blend with poly (vinyl alcohol), PVA was novel and could find numerous applications for natural product based on plant pigment.

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Article
Publication date: 30 October 2018

Tanya L. Swer, Komal Chauhan, Prodyut K. Paul, C. Mukhim, Khalid Bashir and Rachna Sehrawat

An upsurge in health and environmental concerns over the use of synthetic color has made the development of color from cheap and easily available natural sources, namely…

Abstract

Purpose

An upsurge in health and environmental concerns over the use of synthetic color has made the development of color from cheap and easily available natural sources, namely, plants, animals, micro-organisms and algae as indispensable. This study aims to extract anthocyanins, an important natural plant pigments, from Sohiong (Prunus nepalensis). This study demonstrated that Sohiong have high anthocyanins content and antioxidant property, indicating an immense potential for the fruit producers and food processors.

Design/methodology/approach

Response surface methodology was used to optimize the conditions for extraction of anthocyanins from Sohiong using conventional solvent extraction.

Findings

The optimum conditions for extraction were found to be 36.75°C temperature, 60.32 per cent ethanol concentration and 2.39 per cent citric acid concentration with recovery of 45 per cent total extract yield, 858.84 mg C3G/100g DM anthocyanin content and 824.91 mg GAE/100g DM phenolic content with in-vitro antioxidant activity of 31.40 mmol AEAC/100g DM for FRAP and 84.66 per cent DPPH scavenging capacity (20mg/ml). The F-values and high values of adjusted determination coefficient for each response imply high level of significance of the fitted models.

Practical implications

Extracted color can be used in food and pharmaceutical industries.

Social implications

Pigment extracted is from a natural source and possesses high antioxidative activity and potential health benefits. With increasing demand for natural colors and other additives, there is a wide range of applications of the pigment as natural colorant in the food and pharmaceutical sector.

Originality/value

Selected plant source, i.e. Sohiong, was not used earlier by any researcher to extract anthocyanins for potential applications as food colorant.

Details

Pigment & Resin Technology, vol. 47 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 27 January 2020

Hossein Barani and Homa Maleki

Finding blue colorants from natural sources is extremely difficult and, usually, the anthocyanin compounds are used for producing the blue color. This study aims to apply…

Abstract

Purpose

Finding blue colorants from natural sources is extremely difficult and, usually, the anthocyanin compounds are used for producing the blue color. This study aims to apply the Red Cabbage as a natural colorant to obtain different colors on wool yarn, as well as specify the optimum dyeing condition by response surface methodology for obtaining a blue color.

Design/methodology/approach

The effect of dyeing process parameters such as mordant concentration, dyeing time, pH of dyeing bath and dyeing temperature examined in the color characteristics of the dyed wool samples.

Findings

The obtained results indicated that the diverse colors achieve by varying the dyeing process parameters, which is in the range of 26° up to 271°. The non-mordanted dyed wool samples showed a red and red brownish color (Hue angle = 26° up to 70°), and the mordanted dyed wool samples showed a blue and blue-greenish color (Hue angle = 230° up to 271°). The obtained blue color with the optimized dyeing condition presented a considerable good wash and lightfastness.

Originality/value

This study provides a promising application of Red Cabbage as a natural colorant for obtaining different colors by varying the dyeing process parameters such as pH and stannous ion concentrations. The stannous ions yielded a co-pigmentation and presented a blue color on wool fibers, which is extremely difficult to obtain with natural colorant.

Details

Pigment & Resin Technology, vol. 49 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 6 July 2015

S.V. Lee, R. Usop, A.N. Hadi, N.A. Mazni, S.R. Majid, A.K. Arof, N.A. Halim and Z.H.Z. Abidin

The purpose of this paper is to observe the thermal and colour stabilities of coating films consisting of natural dye anthocyanin colourant with acid and nitrate salt as…

Abstract

Purpose

The purpose of this paper is to observe the thermal and colour stabilities of coating films consisting of natural dye anthocyanin colourant with acid and nitrate salt as additives.

Design/methodology/approach

The natural dye was extracted from Hibiscus sabdariffa L. (Roselle) by using distilled water as solvent. The extracted dye was mixed with 1 weight per cent hydrochloric acid and 5 weight per cent calcium nitrate to conduct the comparison study. The dye samples were than mixed with poly (vinyl alcohol) (PVA). The mixtures were applied on glass panels to form coating films. The coating films were left to dry for 24 hours. The thermal stability of coating films was investigated by using thermogravimetric analysis (TGA). The amorphousness coating films molecular structures were observed by using x-ray diffraction (XRD). CIE L*a*b* colour coordinate space technique was used to investigate the coating films colour stability against ultraviolet (UV).

Findings

The results show that addition of hydrochloric acid (HCl acid) enhanced thermal stability of PVA-anthocyanin coating and shifted the degradation temperature to higher temperature at 300°C. HCl acid also improved UV stability of the coating system significantly with the reduced ΔE from 26.67 to 16.89. Addition of calcium nitrate (Ca(NO3)2) salt promotes good interaction with PVA-anthocyanin system that caused structural changes, improved thermal stability and increased Tg from 61.5 to 83.1°C.

Research limitations/implications

The potential of using natural dye extracted from plant as renewable material.

Practical implications

The coating films developed in this works are suitable for glass substrate application.

Originality/value

Development of water-based coating from PVA binder with anthocyanin colourant is introduced in this study.

Details

Pigment & Resin Technology, vol. 44 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 15 March 2013

S.V. Lee, N.A. Halim, A.K. Arof and Z.H.Z. Abidin

The purpose of this paper is to develop a new water‐based coating system composed of poly(vinyl alcohol) and anthocyanin colourant extracted from Hibiscus sabdariffa L…

Abstract

Purpose

The purpose of this paper is to develop a new water‐based coating system composed of poly(vinyl alcohol) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and to characterise the system.

Design/methodology/approach

Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted by using distilled water and filtered to remove insoluble particle. Salts introduced into the extract were 5wt percent calcium nitrate, 5wt percent magnesium nitrate, and 5wt percent zinc nitrate. The solution was mixed with poly(vinyl alcohol) in ratio of 3:1. The mixtures were coated on glass substrate and allowed to cure for approximately one day. Colour of the extract systems was determined by CIELab colourimetry. FTIR spectroscopy was conducted on the samples to identify their functional groups and changes upon addition of salt. Thermal stability was assessed by thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) was employed to measure the glass transition temperature Tg of the samples. XRD was employed to determine the amorphous properties of the coating samples.

Findings

From FTIR spectroscopy, shifting in the OH stretching and CH2 bending bands was attributed to hydrogen bonds formation between PVA and nitrate salt. Shifting in the main decomposition step in samples with addition of nitrate salts in TGA was due to interaction of PVA and nitrate. Increase in glass transition temperature of samples with salts was attributed to the formation of hydrogen bonding. From XRD study, increase in the amorphous properties was due to the incorporation of nitrate salts into PVA coating.

Research limitations/implications

Limitation of implementating poly(vinyl alcohol) as coating is caused by its weak water resistance and hydrophilic properties. This study could bring about research towards incorporation of different natural colourant with different binder materials to form coatings which are environmental‐friendly and low cost.

Practical implications

Mixture of PVA and anthocyanin colourant from roselle for use as coating has been developed. The coating can find usage in various applications such as coloured coating for furniture and wooden materials for decorative purposes, biodegradable design materials for interior purposes. It can be practically applied on a variety of substrates such as glass and wood.

Originality/value

Development of water‐based coating from PVA binder with anthocyanin colourant is introduced in this study.

Details

Pigment & Resin Technology, vol. 42 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 10 of 185