Extraction of natural colorant from purple sweet potato and dyeing of fabrics with silver nanoparticles for augmented antibacterial activity against skin pathogens

Fabrication of pH-sensitive silk and wool fabrics treated with pectin for multichromic sensor dyes with biochromic butterfly pea flowers (Clitoria ternatea L.) extract

The Butterfly pea flowers (BPFs) edible blooms are plentiful in blue-colored anthocyanins (73.85 %). Known as ternatins, they demonstrated a wide spectrum of color change and good thermal stability at varied pH values. This investigation is meant to generate a new generation of intelligent silk and wool fabrics that are dyed with the acidic aqueous extract of BPFs, a natural chromic dye. These fabrics' biochromic performance depends on the BPFs extract's thermochromic and halochromic properties. Smart thermochromic dyed fabrics exhibit colorimetric characteristics and overall color change at a variety of pH levels. The hue of the halochromic dyed fabrics' acid-base sensitivity was studied and showed a reversible transformation to pink when exposed to HCl gas and to green when it was subjected to ammonia vapor. The study reveals that BPFs extract can effectively function as a thermochromic and halochromic sensor dye for proteinic fabrics, exhibiting strong fastness properties at various pH values. The self-cleaning activity (SC) and the tensile strength (TS) of colored treated proteinic fabrics are superior in the range of 74.55-73.95 % and 49.99-55.04 KgF respectively than untreated fabrics. The unique fabrication of multichromic dyed fabrics using BPFs extract could facilitate the creation of multifunctional smart textiles or clothing.

Recent Advances in Purple Sweet Potato Anthocyanins: Extraction, Isolation, Functional Properties and Applications in Biopolymer-Based Smart Packaging

Petroleum-based plastic packaging materials have negative impacts on the environment and food safety. Natural biopolymer-based food packaging materials are the proper substitutes for plastic-based ones, which is because biopolymers are nontoxic, biodegradable and even edible. The incorporation of bioactive and functional substances into a biopolymer-based film matrix can produce novel smart packaging materials. Anthocyanins, one class of natural colorants with potent antioxidant activity and pH-response color-changing ability, are suitable for producing biopolymer-based smart packaging films. The purple sweet potato is a functional food rich in anthocyanins. In the past decade, numerous studies have reported the extraction of anthocyanins from purple sweet potato and the utilization of purple sweet potato anthocyanins (PSPAs) in biopolymer-based smart packaging film production. However, no specific review has summarized the recent advances on biopolymer-based smart packaging films containing PSPAs. Therefore, in this review, we aim to systematically summarize the progress on the extraction, isolation, characterization, purification and functional properties of PSPAs. Moreover, we thoroughly introduce the preparation methods, physical properties, antioxidant and antimicrobial activity, pH sensitivity, stability and applications of biopolymer-based smart packaging films containing PSPAs. Factors affecting the extraction and functional properties of PSPAs as well as the properties of biopolymer-based films containing PSPAs are discussed.

IbMYC2 Contributes to Salt and Drought Stress Tolerance via Modulating Anthocyanin Accumulation and ROS-Scavenging System in Sweet Potato

Basic helix-loop-helix (bHLH) transcription factors extensively affect various physiological processes in plant metabolism, growth, and abiotic stress. However, the regulation mechanism of bHLH transcription factors in balancing anthocyanin biosynthesis and abiotic stress in sweet potato (Ipomoea batata (L.) Lam.) remains unclear. Previously, transcriptome analysis revealed the genes that were differentially expressed among the purple-fleshed sweet potato cultivar 'Jingshu 6' and its anthocyanin-rich mutant 'JS6-5'. Here, we selected one of these potential genes, IbMYC2, which belongs to the bHLH transcription factor family, for subsequent analyses. The expression of IbMYC2 in the JS6-5 storage roots is almost four-fold higher than Jingshu 6 and significantly induced by hydrogen peroxide (H2O2), methyl jasmonate (MeJA), NaCl, and polyethylene glycol (PEG)6000. Overexpression of IbMYC2 significantly enhances anthocyanin production and exhibits a certain antioxidant capacity, thereby improving salt and drought tolerance. In contrast, reducing IbMYC2 expression increases its susceptibility. Our data showed that IbMYC2 could elevate the expression of anthocyanin synthesis pathway genes by binding to IbCHI and IbDFR promoters. Additionally, overexpressing IbMYC2 activates genes encoding reactive oxygen species (ROS)-scavenging and proline synthesis enzymes under salt and drought conditions. Taken together, these results demonstrate that the IbMYC2 gene exercises a significant impact on crop quality and stress resistance.

An eco-friendly ultrasound approach to extracting yellow dye from Cassia alata flower petals: Characterization, dyeing, and antibacterial properties

Using natural dyes in dyeing industries becomes an alternative to synthetic dyes, which are known to contain harmful chemicals that can pose risks to the environment and human health. This study involves the extraction of yellow dye from Cassia alata flower petals, optimization of the extraction process using an ultrasonic bath (40 KHz and an input power of 500), ultrasonic probe (390 W, 455 W, 520 W, 585 W, and 650 W), and conventional heating (heating mantle with 30 °C, 40 °C, 50 °C, 60 °C, and 70 °C), characterization of the dye, as well as dyeing (cotton, silk, and leather) without using a mordant. The extracted yellow dye was further evaluated to determine its antibacterial activity against skin bacteria. Dye extraction optimization using UV-Visible spectrophotometric analysis revealed that the maximum yellow color in methanol extract (287 and 479 nm) was obtained at 50 °C for 45 min using ultrasonic water bath extraction, followed by the ultrasonic probe and direct heating. Based on the FTIR spectra, it is evident that OH is present at approximately 3300 cm^-1, while CH stretches at around 2900 cm^-1. A characteristic peak at 1608 cm^-1 bears a striking similarity to anthraquinonoid-based compounds. Also, using the ultrasonic water bath dyeing technique at 50 °C for 45 min, the yellow color of cotton, silk, and leather was dyed optimally. Due to effective color removal after two washings with boiling soap liquid, the dyed cotton and silk fabric displayed good washing and rubbing fastness. Regarding antibacterial activity, the dye was highly active against all pathogens after extraction in methanol. The maximum inhibition was observed against Pseudomonas sp. with a MIC value of 1.56 mg/ml.

Functional silver nanoparticles synthesis from sustainable point of view: 2000 to 2023 ‒ A review on game changing materials

The green and facile synthesis of metallic silver nanoparticles (AgNPs) is getting tremendous attention for exploring superior applications because of their small dimensions and shape. AgNPs are already proven materials for superior coloration, biocidal, thermal, UV-protection, and mechanical performance. Originally, some conventional chemical-based reducing agents were used to synthesize AgNPs, but these posed potential risks, especially for enhanced toxicity. This became a driving force to innovate plant-based sustainable and green metallic nanoparticles (NPs). Moreover, the synthesized NPs using plant-based derivatives could be tuned and regulated to achieve the required shape and size of the AgNPs. AgNPs synthesized from naturally derived materials are safe, economical, eco-friendly, facile, and convenient, which is also motivating researchers to find greener routes and viable options, utilizing various parts of plants like flowers, stems, heartwood, leaves and carbohydrates like chitosan to meet the demands. This article intends to provide a comprehensive review of all aspects of AgNP materials, including green synthesis methodology and mechanism, incorporation of advanced technologies, morphological and elemental study, functional properties (coloration, UV-protection, biocidal, thermal, and mechanical properties), marketing value, future prospects and application, especially for the last 20 years or more. The article also includes a SWOT (Strengths, weaknesses, opportunities, and threats) analysis regarding the use of AgNPs. This report would facilitate the industries and consumers associated with AgNP synthesis and application through fulfilling the demand for sustainable, feasible, and low-cost product manufacturing protocols and their future prospects.

Leather Dyeing by Plant-Derived Colorants in the Presence of Natural Additives

This research aimed to dye leather fabric samples with the application of plant-derived colorants and natural additives. Two grades of chitosan were used as additives, in addition to caffeine, nettle extract, and shellac solution. The ability of colorants to dye leather fabric and the impact of additives on leather fabric properties such as structure, color intensity, color stability under exposure to UVC irradiation, and mechanical properties were examined. For this purpose, dyed samples were tested by a colorimeter, ATR-FTIR spectrophotometer, mechanical testing machine, and X-ray diffractometer. The results indicated that the applied colorants of plant origin have the potential to dye leather fabrics without affecting their structure and without a negative impact on the environment. Applied natural additives can, therefore, beneficially influence the effects of the dyeing process, such as color intensity, colorfastness after exposure to UV irradiation, or tensile strength of the material.

Application of Achillea millefolium extract as a reducing agent for synthesis of silver nanoparticles (AgNPs) on the cotton: antibacterial, antioxidant and dyeing studies

The phyto-synthesis of silver nanoparticles and cotton dyeing with natural colorants can reduce the environmental impact of the process considerably. In this study, the extraction of natural colorants from Achillea millefolium petals was optimized by ultrasound technique. The AMP extract was applied for synthesis of silver nanoparticles (Ag NPs) on the cotton fabrics. The dyeing, antibacterial and antioxidant characteristics of cotton samples were investigated to optimize the process and evaluate its efficiency. The AMP extract had good substantivity towards cotton fabrics and the presence of tannic acid, as an environmentally-friendly mordant, further improved the absorption of AMP dye. The antibacterial and antioxidant activities of the dyed samples with AMP extract of were 50%and 60%, respectively. The addition of TA and Ag enhanced the antibacterial and antioxidant activities on the cotton samples to over 99%.

Effect of nonthermal treatments on selected natural food pigments and color changes in plant material

In recent years, traditional high-temperature food processing is continuously being replaced by nonthermal processes. Nonthermal processes have a positive effect on food quality, including color and maintaining natural food pigments. Thus, this article describes the influence of nonthermal, new, and traditional treatments on natural food pigments and color changes in plant materials. Characteristics of natural pigments, such as anthocyanins, betalains, carotenoids, chlorophylls, and so forth available in the plant tissue, are shortly presented. Also, the characteristics and mechanism of nonthermal processes such as pulsed electric field, ultrasound, high hydrostatic pressure, pulsed light, cold plasma, supercritical fluid extraction, and lactic acid fermentation are described. Furthermore, the disadvantages of these processes are mentioned. Each treatment is evaluated in terms of its effects on all types of natural food pigments, and the possible applications are discussed. Analysis of the latest literature showed that the use of nonthermal technologies resulted in better preservation of pigments contained in the plant tissue and improved yield of extraction. However, it is important to select the appropriate processing parameters and to optimize this process in relation to a specific type of raw material.

Phytofabrication of Silver Nanoparticles Using Three Flower Extracts and Their Antibacterial Activities Against Pathogen Ralstonia solanacearum Strain YY06 of Bacterial Wilt

Bacterial wilt caused by the phytopathogen Ralstonia solanacearum (R. solanacearum) is a devastating plant disease worldwide. The use of bactericides and antibiotics for controlling bacterial wilt has shown low efficiency and posed environmental risks. This study was to phytofabricate silver nanoparticles (AgNPs) mediated by canna lily flower (Canna indica L.), Cosmos flower (Cosmos bipinnata Cav.), and Lantana flower (Lantana camara L.). The biosynthesized AgNPs were confirmed and characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscopy (SEM). UV-visible spectra showed absorption peak bands at 448, 440, and 428 nm of AgNPs synthesized by C. indica L., C. bipinnata Cav., and L. camara L. flowers, respectively. FTIR spectra confirmed that biofunctional groups of flower extract were involved in the synthesis of AgNPs as capping and stabilizing agents. The spherical AgNPs synthesized by C. indica L., C. bipinnata Cav., and L. camara L. flowers had average diameters of 43.1, 36.1, and 24.5 nm, respectively. The AgNPs (10.0 μg/ml) synthesized by L. camara L. flower had a maximum suppression zone of 18 mm against R. solanacearum strain YY06 compared with AgNPs synthesized by C. indica L. and C. bipinnata Cav. flowers. Bacterial growth, biofilm formation, swimming motility, efflux of nucleic acid, cell death, cell membrane damage, and reactive oxygen species (ROS) generation of R. solanacearum were also negatively affected by AgNPs with high concentration and small size. In summary, the biosynthesized AgNPs can be used as an efficient and environmentally friendly antibacterial agent to reasonably inhibit R. solanacearum.

Impact of adding glucose-coated water-soluble silver nanoparticles to the silkworm larval diet on silk protein synthesis and related properties

Biological modifications of the silk fibroin (silk) material have broad applications in textiles, biomedical materials and other industrial materials. It is economical to incorporate nanoparticles to the biosynthesis of silk fibroin by adding them to silkworm larval diets. This strategy may result in the rapid stable production of modified silk. Glucose-coated silver nanoparticles (AgNPs) were used to improve the AgNPs' biocompatibility, and the AgNPs were efficiently incorporated into silk by feeding. Larvae fed with AgNPs produced silk with significantly improved antibacterial properties and altered silk secondary structures. Both positive and negative effects on the growth and synthesis of silk proteins were observed after different AgNPs doses. Larvae feeding with low concentration of 0.02% and medium 0.20% AgNPs have greater transfer efficiencies of AgNPs to silk compared with feeding high concentration of 2.00% AgNPs. In addition, the elongation and tensile strength of the produced silk fibers were also significantly increased, with greater mammalian cell compatibility. The appropriate AgNPs concentration in the diet of silkworms can promote the synthesis of silk proteins, enhance their mechanical properties, improve their antibacterial property and inhibit the presence of Gram-negative bacteria.

Photo-fermentation of purple sweet potato (Ipomoea batatas L.) using probiotic bacteria and LED lights to yield functionalized bioactive compounds

The purpose of this study was to examine if fermentation of purple sweet potato (Ipomoea batatas L.) powder (PSP) by Lactobacillus brevis under green, red, blue, white light-emitting diode (LED) illumination or sunlight might yield functionalized products with good antibacterial, antioxidant activity, and/or cytotoxic activity. The Purple sweet potato (PSP) powder fermented with probiotic bacteria L. brevis under white LED light (1.9 ± 1.80/1.6 ± 0.52), blue LED light (1.4 ± 1.32/1.8 ± 0.83), or sunlight (1.2 ± 1.26/1.5 ± 1.83) for Propionibacterium acne and Staphylococcus epidermidis displayed good to moderate antibacterial activity based on minimum inhibitory concentration (MIC) red, blue, white LED lights and sunlight (80 µg/mL) for P. acne and S. epidermidis, minimum bactericidal concentration red, blue LED lights and sunlight shows (46/48, 61/70, 50/48 µg/mL) for P. acne and S. epidermidis. Antioxidant activity for dark, white, blue and green LED lights for ABTS and white, blue and green Led for DPPH assay resulted in lower activity. Fourier transform infrared spectroscopy was performed to determine the functional groups in the non-fermented (control) and fermented products of PSP powders obtained using different light sources. Sunlight, white, and blue LED light-fermented extracts contained alcohol, acid, and phenol groups, as well as aliphatic amines. The results of this study clearly indicate that fermentation of purple sweet potato with probiotic bacteria under various LED light sources can yield compounds that can be used in cosmetic and value-added food products.