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This paper aims to study the colour stability of chlorophyll and the effect of copper (II) nitrate – Cu(NO₃)₂ – as an additive in natural dye coating films after being exposed to ultraviolet-A (UV-A).

The natural dye was extracted from the leaves of Cassia alata L. using absolute ethanol as the solvent. The extract was divided into two parts and, one of it was added with 3 wt.% Cu(NO₃)₂ as an additive. The polymer blend of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. Both parts of the dye with and without additive were mixed with the blended polymer in a specific ratio. The resulted mixtures were applied as coating films on glass substrates. The colour stability of the coating films on exposure to UV-A with the time of exposure was observed with Commission internationale de l’éclairage (CIE) L*a*b* colour coordinates. The hidden power by the means of reflectivity and glossiness of the coatings was also studied. Statistical standard deviation (STD) was used to analyse the data.

The test showed that the coating films containing Cu(NO₃)₂ had smaller colour differences, (ΔE*) indicating higher colour stability. The analysis on hidden power also showed that the coating film with Cu(NO₃)₂ was 1.6 times more stable than the film without additive. All the measurements in this study were observed within 35 days of duration.

This paper implies the potential of using natural dye extracted from Cassia alata L. leaves as a stable dye colourant for coating applications.

The coating film developed in this study is suitable for glass substrate applications.

A new method of preparing solvent-based coating film from PMMA–acrylic polyol with chlorophyll colourant is introduced in this study.

The purpose of this study is to contribute with experimental study of the effects of binary and ternary combinations of river sand (RS), crushed sand (CS) and dune sand (DS) on the physical and mechanical performances of self-compacting concrete (SCC) subjected to acidic curing environments, HCl and H₂SO₄ solutions.

Five SCCs were prepared with the combinations 100% RS, 0.8RS + 0.2CS, 0.6RS + 0.2CS + 0.2DS, 0.6RS + 0.4DS and 0.6CS + 0.4DS. The porosity of sand, fluidity, deformability, stability, compressive strength and sorptivity coefficient were tested. SCCs cubic specimens with a side length of 10 cm were submerged in HCl and H₂SO₄ acids, wherein the concentration was 5%, for periods of 28, 90 and 180 days. The resistance to acid attack was evaluated by visual examination, mass loss and compressive strength loss.

The results showed that it is possible to partially substitute the RS with CS and DS in the SCC, without strongly affecting the fluidity, deformability, stability, compressive strength and durability against HCl and H₂SO₄ attack. The two combinations, 0.8RS + 0.2CS and 0.6RS + 0.2CS + 0.2DS, improved the compactness and the resistance to acid attacks of SCC. Consequently, the improvement in SCC compactness, by the combination of RS, CS and DS, decreased the sorptivity coefficient of SCC and increased its resistance to acid attacks, in comparison with that made only by RS.

The use of RS is experiencing a considerable increase in line with the development of the country. To satisfy this demand, it is necessary to substitute this sand with other materials more abundant. The use of locally available materials is a very effective way to protect the environment, improve the physico-mechanical properties and durability of SCC and it can be a beneficial economical alternative. Few studies have addressed the effect of the binary and ternary combination of RS, CS and DS on the resistance to acid attacks of SCC.

The purpose of this paper is to investigate the tensile strength, Young’s modulus, dimensional stability and porosity of acrylonitrile butadiene styrene (ABS)–oil palm fiber composite filament for fused deposition modeling (FDM).

A new feedstock material for FDM comprising oil palm fiber and ABS as a matrix was developed by a twin screw extruder. The composite filament contains 0, 3, 5 and 7 Wt.% of oil palm fiber in the ABS matrix. The tensile test is then performed on the fiber composite filament, and the wire diameter is measured. In this study, the Archimedes method was used to determine the density and the porosity of the filament. The outer surface of the wire composite was examined using an optical microscope, and the analysis of variance was used to assess the significance and the relative relevance of the primary factor.

The results showed that increasing the fiber loading from 0.15 to 0.4 MPa enhanced tensile strength by 60%. Then, from 16.1 to 18.3 MPa, the Young’s modulus rose by 22.8%. The density of extruded filament decreased and the percentage of porosity increased when the fiber loading was increased from 3 to 7 Wt.%. The diameter deviation of the extruded filaments varied from −0.21 to 0.04 mm.

This paper highlights a novel natural resource-based feedstock material for FDM. Its mechanical and physical properties were also discovered.

The purpose of the paper is to study the effect of color stability on introducing chenodeoxycholic acid (CDCA) into a colored liquid extract from saffron and determine the color quality of the extract over a nine-month period.

Six colored liquid samples with different CDCA contents ranging from 0 to 45 Wt.% have been successfully prepared. Chromaticity (C*), color saturation (s), UV-Vis spectroscopy and coloring strength studies have been assessed to determine how CDCA influences the color properties and to study the color quality over time. The color quality was analyzed using the Commission Internationale de l’Eclairage (CIE) system.

All results obtained revealed that the addition of CDCA significantly influenced the overall color performance of the saffron extraction. However, the most pronounced improvement was recorded with the use of 45 Wt.% CDCA. The sample exhibited the highest color quality at the end of nine months of storage with highest absorbance: C* value = 91.38, color saturation = 0.96 and coloring strength = 687.

This preliminary study offers significant findings for further research focused on stability of natural colorants extracted from Spanish saffron that can provide benefits for future applications especially in coating industry, food, agriculture, medicine and others.

The values of this work can be observed from the information and evidence provided by CIE color stability in terms of chromaticity and saturation, as well as UV-Vis spectrophotometric measurement. It showed that the addition of CDCA additive can help to prolong and enhance the natural colorant properties from Spanish saffron (Crocus sativus L.) for nine month of storage. This proved that by adding additives such as CDCA the saffron colorant can be maintained. To the best of the authors’ concern, this is the first time CDCA is used to prevent color degradation of natural colorant from saffron.

The aim of the present study is to gain correlation between saffron colours, their antioxidant capacity and the constituents of the secondary metabolites of three different saffron samples commonly available in the Malaysian market.

In this study, saffron samples imported from Iran, Spain and Kashmir were extracted using methanol and the total antioxidant capacity were analysed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. Ultra-high performance liquid chromatography (UHPLC) and electrospray ionization coupled with mass spectrometry (ESI-MS/MS) were then used to identify secondary metabolites present in the saffron crude extracts. The colour variation of the saffron extract was expressed by the CIELAB colorimeter in terms of lightness (L*), greenness (a*), yellowness (b*), chroma (C) and hue angle (H°). Principle component analysis (PCA) was carried out to analyse the similarities and correlation between variables.

This study reveals that antioxidant has a positive correlation with flavanols, especially quercetin and kaempferol. In addition, colour appearance is not necessarily an indicator for the antioxidant level.

The major classes of polyphenolics identified in saffron methanolic crude extract are flavonoids and phenolic acids. Further improvements in the extraction and identification methods may find other compounds that could attribute to the visual factors and antioxidant capacity as a complement for this preliminary study.

This analysis provides comparison basis and valuable information for saffron consumers in Malaysia depending on the consumers’ purpose of whether to have a certain desired colour or health benefits.

A comparative study about saffron product available in Malaysian market is original. To the best of the authors’ knowledge, this is the first attempt of evaluation on a saffron product that has been carried out in Malaysia.

The purpose of this paper is to validate the antimicrobial activity (both antibacterial and antifungal) of in vivo and in vitro ethanolic anthocyanin extracts of Clitoria ternatea L. (vivid blue flower butterfly-pea) and Dioscorea alata L. (purple yam) against selected bacteria (Bacillus subtilis, Staphylococcus aureus and Escherichia coli) and fungi (Fusarium sp., Aspergillus niger and Trichoderma sp.).

The freeze-dried samples (0.2 g) from in vivo vivid blue flowers of C. ternatea L. were extracted using 10 mL ethanol (produced ethanolic red extraction) and 10 mL distilled water (produced aqueous blue extraction) separately. Two-month-old in vitro callus samples (0.2 g) were only extracted using 10 mL ethanol. The anthocyanin extractions were separated with the addition (several times) of ethyl acetate and distilled water (1:2:3) to remove stilbenoids, chlorophyll, less polar flavonoids and other non-polar compounds. Furthermore, the antimicrobial properties were determined using agar diffusion technique. Three bacteria (B. subtilis, S. aureus and E. coli) and fungi (F. sp., A. niger and T. sp.) were streaked on bacteria agar and dextrose agar, respectively, using “hockey stick”. Then, the sterile paper discs (6 mm diameter) were pipetted with 20 µL of 1,010 CFU/mL chloramphenicol (as control for antibacterial) and carbendazim (as control for antifungal) in vivo and in vitro extracts. The plates were incubated at room temperature for 48 h, and the inhibition zones were measured.

Based on the results, both in vivo and in vitro ethanolic extracts from vivid blue flowers of C. ternatea L. showed the best antibacterial activity against the same bacteria (B. subtilis), 11 and 10 mm inhibition zones, respectively. However, different antifungal activity was detected in in vitro ethanolic callus extract (12 mm), which was against T. sp., contrary to in vivo ethanolic extract (10 mm), which was against F. sp.; antibacterial activity of D. alata L. was seen against the same bacteria (E. coli) with the highest inhibition zone for in vivo extract (8.8 mm), followed by in vitro extract (7.8 mm).

Anthocyanins are responsible for the water soluble and vacuolar, pink, red, purple and blue pigments present in coloured plant pigments. These pigments (pink, red, purple and blue) are of important agronomic value in many crops and ornamental plants. However, anthocyanins are not stable and are easy to degrade and fade whenever exposed to light.

Plant extracts containing bioactive agents with antimicrobial properties have been found to be useful in treating bacterial and fungal infections, as well as showed multiple antibiotic resistance.

Both in vivo and in vitro extracts from vivid blue flower petals (C. ternatea L.) and purple yam (D. alata L.) have important applications as natural antimicrobial (antibacterial and antifungal) agents in the coating industry, instead of natural pharmaceutical products.

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.

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.

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).

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

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.

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

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.

The purpose of this work is to investigate the influence of curcumin dye natural colorant on adhesion, mechanical, thermal and electrochemical properties of blend poly (methyl methacrylate) (PMMA) – acrylic polyol.

Extracted curcumin yellow dye colorant from Curcuma Demostica was mixed with PMMA‐acrylic polyol blended polymer in the volume ratios of 9:1, 8:2 and 7:3. The mixtures were applied on pre‐treated cold‐roll mild steel panels. All of the paint coating samples were subjected to potential time measurement (PTM), rapid impact deformation, differential scanning calorimetry (DSC), cross hatch and Fourier transform infrared spectroscopy (FTIR) tests.

The addition of curcumin dye colorant was able to improve the adhesion, flexibilities and resistance against electrolytes penetration of the blended poly (methyl methacrylate) (PMMA) – acrylic polyol polymer paint system. Cross hatch test studies showed that high amount of curcumin dye colorant (AP30 paint system) had the lowest peel‐off coating area from the substrate. The FTIR test had confirmed the high concentration of hydroxyl group in the AP30 sample. The hydroxyl group was able to promote hydrogen bonding between coating substrate interface. The AP30 sample had the highest coating flexibilities when tested with rapid impact test. This was due to the lowest glass transition value T_g which indicated lowest cross linking density in the coating molecules structure. In the PTM test, AP30 paint system had shown the highest rate electrolytes penetration within the AP sample.

The composition of curcumin dye colorant in the polymer blend is limited from 10 percent to 30 percent pigment volume concentration. Increasing the amount of lawsone pigment will result inhomogeneous mixtures.

The AP paint system is suitable for interior applications. This paint system has to be mixed with suitable additive materials to improve its performance for exterior purpose.

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.