A comprehensive review on innovative and advanced stabilization approaches of anthocyanin by modifying structure and controlling environmental factors

Accelerating the conversion of black chokeberry anthocyanins toward vinylphenolic pyranoanthocyanins by displaying phenolic acid decarboxylase from Lactiplantibacillus plantarum on the surface of Pichia pastoris

In fermented chokeberry products, hydroxycinnamic acids are enzymatically converted into 4-vinyl derivatives by phenolic acid decarboxylase (PAD), which react with anthocyanins (ACNs) to form stable pyranoanthocyanins (PACNs) that enhance color stability and exhibit excellent bioactivity. However, the fermentation process is usually acidic, the level of PAD secreted by microorganisms is limited and PAD has poor acid stability, resulting in low PACN production. To overcome this, we engineered a whole-cell biocatalyst (WCB) by displaying PAD from Lactiplantibacillus plantarum on Pichia pastoris GS115 (dLPPAD). This WCB showed improved acid tolerance and thermal stability, efficiently converting Aronia melanocarpa anthocyanins (AMAs) into PACNs. Additionally, we examined the relationship between hydroxycinnamic acid structure and LPPAD catalytic efficiency. This work introduces a cost-effective, impurity-free biocatalytic strategy to enhance PACN yields, with potential applications in berry fermentation products and related industries.

The potential of red-fleshed apples for cider production

Cider quality is influenced by numerous factors relating to the apples used during production. While extensive research has been done to explore the phenolic content, sensory quality, and storage stability of various apple products, the domain of fermented apple products, such as ciders, remains underrepresented. Red-fleshed apples (RFAs) have naturally high concentrations of phenolic compounds, which indicate their potential in the production of novel cider products. However, a knowledge gap remains regarding the application of RFAs in cider production and how their physicochemical and sensory properties are changed during processing. This review is the first to comprehensively investigate whether and to what extent apple categories (dessert, cider, and RFAs) differ regarding their physicochemical and sensory properties from harvest throughout cider processing. Furthermore, it highlights the importance of a holistic understanding of apple characteristics, encompassing both traditional and RFA varieties in the context of cider production. The findings offer valuable insights for stakeholders aiming to enhance product quality, providing a foundation for future studies on optimizing processing methods for a diverse and appealing range of ciders.

Synthesis and Properties of Site-Specific Acetylated Anthocyanins: Focusing on Cyanidin-3-O-glucoside and Malvidin-3-O-glucoside

Anthocyanins are widely used water-soluble pigments with various activities, which are attributed to their flavylium salt and polyhydroxy structure. However, this also leads to low lipid solubility and stability. Acylation modification has always been an attempt by researchers to improve it. In this study, two site-specific acylated anthocyanins, cyanidin-3-O-(2″-acetyl)-glucoside (C3AG) and malvidin-3-O-(2″-acetyl)-glucoside (M3AG), were prepared by optimizing the removal conditions of the protecting group through the general anthocyanin total synthesis route established in the early stage. The accurate positioning of the acylation is determined by MS/MS and 2D NMR. By comparing the oil-water partition coefficient, antioxidant activity, color, and thermal stability of the two acylated anthocyanins, it was found that the 2″ acylated anthocyanin achieved better lipid solubility and stability, but the antioxidant activity showed variability. These results together prove that these acylated anthocyanins have been optimized in application scenarios with little impact on the original activity. Therefore, this work not only provides a reference method for the acylation modification of anthocyanins but also promotes their application in the food and cosmetics industries.

Updated insights into steady-modified anthocyanin food packaging: Novel strategies, characterization, application and future challenges

Rising attentions on food safety and quality as well as disadvantages of conventional plastic food packaging motivates extensive study in anthocyanin-based food packaging. However, anthocyanins are susceptible to environmental conditions, resulting in easily-degradable properties of anthocyanin-based food packaging. Therefore, steady-modified anthocyanin-based food packaging are highly demanded for further deeper application. Based on this, thorough insights into steady-modified anthocyanin-based food packaging are provided in the current review. The degradation phenomenon and factors affecting stability of anthocyanin-based film during long-term storage were investigated. Novel steady-modification strategies to improve film stability were systemically summarized. Also, their effects on film physical (structure/mechanical/hydrophobic) properties and functional (pH-responsive, antioxidant and antibacterial) properties were explored. Meanwhile, application cases of steady-modified anthocyanin-based film regarding freshness monitoring and quality maintenance were comprehensively discussed. Finally, major challenges and future prospects were also proposed for further development.

Impact of Hormone on Growth and GA3 Regulation of Anthocyanin Biosynthesis in Suspension-Culture Cells of Cyclocarya paliurus

Hormones are effective in regulating plant metabolism and, therefore, are often used in plant cell culture to increase the yield of target products. This study investigated the effects of hormones on the growth and anthocyanin biosynthesis of suspension-cultured red Cyclocarya paliurus cells. Additionally, the mechanism by which gibberellin induces anthocyanin biosynthesis was explored through multi-omics integrated analysis and the assay of the dynamic changes in signaling molecule concentration. The results showed that the total anthocyanin content and yield of suspension-cultured cells, when induced by 1.0 mg L⁻¹ Gibberellin A3 (GA3), experienced increases of 1.92- and 1.83-fold, respectively. The application of exogenous GA3 activated the synthesis and transduction of four signaling molecules, that is, nitric oxide (NO), hydrogen peroxide (H2O2), salicylic acid (SA), and jasmonic acid (JA), in the cells and altered the expression patterns of transcription factors. The altered expression of transcription factors upregulated the expression of anthocyanin biosynthetic genes such as anthocyanin-3-O-glucosyl transferase and leucoanthocyanidin dioxygenase, while downregulated the expression of anthocyanin reductase and flavonoid 3',5',-hydroxylase, which activated the anthocyanin biosynthesis pathway, ultimately leading to a significant increase in anthocyanin biosynthesis. This research work establishes a foundation for further research on the role of hormones in regulating anthocyanin biosynthesis in suspension-cultured plant cells.

Structural and functional properties of common natural organic cations

BACKGROUND

Natural products have emerged as a critical focus in modern scientific research due to their structural diversity and therapeutic potential. Among these are natural organic cations-a distinct class of nitrogen- and oxygen-containing compounds. Despite their pharmacological relevance, the literature lacks a systematic synthesis of structure-activity relationships for natural organic cations (NOC). This gap hinders the rational development of NOC-based therapies as sustainable alternatives to synthetic compounds.

METHODS

Literature was searched and collected using databases, including PubMed, Science Direct, and Web of Science. The search terms used included "natural organic cation", "alkaloid", "anthocyanin", "structure-activity relationship", "charge interaction", "π-cation interaction", "biological activity", "antimicrobial", "antioxidant", "anticancer", "neuroprotection", "anti-inflammatory", "berberine", "coptisine", "palmatine", "cyanidin", "delphinidin", "pelargonidin", "free radical scavenging", "gut microbiota metabolism", "NF-κB pathway", "G-quadruplex DNA", "isoquinoline alkaloid", "protoberberine", "benzophenanthridine", "planar conjugated system", "charge delocalization", "methylenedioxy group", and several combinations of these words.

RESULTS

The bioactivity of NOC is underestimated. This review uncovers the structure-activity relationships of NOC. Firstly, planar conjugated systems and substituents control target binding: N⁺ in alkaloids enhances DNA/protein affinity, while O⁺ in anthocyanins enables free radical scavenging and enzyme inhibition. Secondly, cationic species outperform neutral analogs in antimicrobial potency, antioxidant capacity, and target selectivity. NOC bind to biomolecules via π-cation/π-π stacking and electrostatic binding. Charge localization in conjugated systems enhances stability and bioactivity.

CONCLUSION

This review consolidates evidence that NOC represent promising candidates for replacing synthetic compounds in therapies for cancer, neurodegeneration, metabolic disorders, etc. Key findings highlight the superiority of cationic species in target engagement and bioactivity, driven by planar conjugated systems and substituent effects. However, clinical translation requires addressing gaps in bioavailability and long-term safety. Future research must prioritize structural optimization and mechanistic validation. By bridging these gaps, NOC could advance as sustainable, low-toxicity agents in precision medicine and functional nutrition.

Recent advances in improving anthocyanin stability in black carrots

This review focuses on the methods of enhancing the stability of black carrot anthocyanins, which are susceptible to degradation due to temperature, pH, light, and oxygen. These anthocyanins are valued for their health benefits and blue-violet color, but their instability limits their application in the food industry. It is hypothesized that implementing advanced stabilization techniques can significantly improve the stability and usability of black carrot anthocyanins. Key methods to improve anthocyanin stability, including encapsulation, co-pigmentation, and acylation, are comprehensively reviewed. Encapsulation techniques such as spray drying, freeze drying, and liposomes have shown effectiveness in protecting anthocyanins during food processing and storage. Co-pigmentation with non-anthocyanin phenolics and using whey proteins significantly enhance thermal and pH stability, thereby improving color retention. Additionally, innovative strategies like genetic modification and nanoencapsulation have demonstrated potential in further stabilizing anthocyanins by enhancing their structural resilience and bioavailability. These innovative approaches represent a significant advancement in the ability to maintain the integrity of black carrot anthocyanins. Advanced techniques for preserving the functional properties and nutritional benefits of black carrot anthocyanins facilitate broader use in health-oriented food products. Combining these modern methods is essential for optimal stability, and further research is needed to optimize these techniques.

Effect of bovine serum albumin and Copigments on the stability of Haskap berry anthocyanin extracts at neutral pH

Haskap berry anthocyanin extract (HAE), a high-value and high-potential natural pigment, is prone to degradation by external factors such as heat and light. To improve the chemical and color stability of HAE, the binary and ternary composite system of HAE, BSA and copigments was compared for the protection of anthocyanin in the heat and light treatments at neutral pH. Compared to the binary composite system of HAE with BSA and ferulic acid (FA), the select HAE-BSA-FA ternary composite system decreased the total anthocyanin degradation rate (TADR) to 65.26 % and 70.06 % after heat and light treatments, and the color difference value (ΔE) to 43.59 % and 71.64 %, the bioaccessibility index (BAI) at the conclusion of gastric digestion and intestinal digestion increased 17.52 % and 44.57 %, which had a better protective effect on the thermal, light and in vitro digestion stability of HAE. Results of fluorescence spectroscopy, circular binning, FTIR spectroscopy, SDS-PAGE, and particle size analysis indicated that the stability of HAE was promoted by non-covalent binding with BSA and FA, such as hydrogen bonding, electrostatic force. HAE, BSA, and FA are complexed by hydrophobic interactions, and the secondary structure of BSA was changed in the process.

A highly stable gellan gum/potato starch/anthocyanin smart film with ferulic acid co-pigmentation for monitoring fish freshness

A novel high stability pH-sensitive smart film (GGPS-R-FA) was prepared by using gellan gum (GG) and potato starch (PS) as the film-forming material, red cabbage anthocyanins extract (RCAE) as the indicator, and ferulic acid (FA) as the co-pigmentation agent. The enhancement effect of co-pigmentation on the stability of RCAE, as well as the performance and application of smart film were investigated. The RCAE co-pigmented with FA showed higher absorbance and greater thermal stability, as evidenced by the retention of anthocyanin content and thermodynamic parameters. The retention rates of anthocyanin content was increased from 24.59 % to 37.94 %. Structural characterization showed that molecular interactions protected the structure of anthocyanins and contributed to form a more stable film network. The EAB of the films was improved to 25.13 % and the opacity was increased to 5.02 A·mm-1. The co-pigmented films exhibited excellent color stability after co-pigmentation. The ∆E of GGPS-R-FA films was lower than 3 during 120 days of storage at 4 °C. The films exhibited a sensitive responsiveness to pH and ammonia. When the films were applied to monitor the fish's freshness, the color changes of GGPS-R-FA1 and GGPS-R-FA2 films represented a strong correlation with the spoilage indices of grass carp.

Interactions with peanut protein isolate regulate the bioaccessibility of cyanidin-3-O-glucoside: Multispectral analysis, simulated digestion, and molecular dynamic simulation

Anthocyanins are susceptible to degradation owing to environmental factors. Combining them with proteins can improve their stability; however, the interaction mechanism is difficult to elucidate. This study used multispectral and molecular dynamics simulations and molecular docking methods to investigate the interaction mechanism between peanut protein isolate (PPI) and cyanidin-3-O-glucoside (C3G). The UV absorption peak and PPI turbidity increased, while the fluorescence intensity decreased with greater C3G content. Protein secondary structure changes suggested that PPI and C3G coexisted in spontaneous covalent and non-covalent interactions via static quenching. The complex structures were stable over time and C3G stably bound to the peanut globulin Ara h 3 cavity through hydrogen bonding and hydrophobic interactions. Furthermore, PPI enhanced the C3G antioxidant activity and bioaccessibility by increasing its retention rate during in-vitro simulated digestion. This study elucidates the binding mechanism of PPI and C3G and provides insight into applications of the complex in food development.

Exploring the effects of whey protein components on the interaction and stability of cyanidin-3-O-glucoside

BACKGROUND

Anthocyanins are susceptible to degradation due to external factors. Despite the potential for improved anthocyanin stability with whey protein isolate (WPI), the specific effects of individual components within WPI on the stability of anthocyanins have yet to be studied extensively. This study investigated the interaction of WPI, β-lactoglobulin (β-Lg), bovine serum albumin (BSA), and lactoferrin (LF) with cyanidin-3-O-glucoside (C3G), and also considered their effects on stability.

RESULTS

Fluorescence analysis revealed static quenching effects between C3G and WPI, β-Lg, BSA, and LF. The binding constants were 1.923 × 103 L · mol⁻¹ for WPI, 24.55 × 103 L · mol⁻¹ for β-Lg, 57.25 × 103 L · mol⁻¹ for BSA, and 1.280 × 103 L · mol⁻¹ for LF. Hydrogen bonds, van der Waals forces, and electrostatic attraction were the predominant forces in the interactions between C3G and WPI and between C3G and BSA. Hydrophobic interaction was the main binding force in the interaction between C3G and β-Lg and between C3G and LF. The binding of C3G with WPI, β-Lg, BSA, and LF was driven by different thermodynamic parameters. Enthalpy changes (∆H) were -38.76 kJ · mol⁻¹ for WPI, -17.59 kJ · mol⁻¹ for β-Lg, -16.09 kJ · mol⁻¹ for BSA, and 39.50 kJ · mol⁻¹ for LF. Entropy changes (∆S) were -67.21 J · mol⁻¹·K⁻¹ for WPI, 3.72 J · mol⁻¹·K⁻¹ for β-Lg, 37.09 J · mol⁻¹·K⁻¹ for BSA, and 192.04 J · mol⁻¹·K⁻¹ for LF. The addition of C3G influenced the secondary structure of the proteins. The decrease in the α-helix content suggested a disruption and loosening of the hydrogen bond network structure. The presence of proteins enhanced the light stability and thermal stability (stability in the presence of light and heat) of C3G. In vitro simulated digestion experiments demonstrated that the addition of proteins led to a delayed degradation of C3G and to improved antioxidant capacity.

CONCLUSION

The presence of WPI and its components enhanced the thermal stability, light stability, and oxidation stability of C3G. Preheated proteins exhibited a more pronounced effect than unheated proteins. These findings highlight the potential of preheating protein at appropriate temperatures to preserve C3G stability and bioactivity during food processing. © 2024 Society of Chemical Industry.

Enhancing sensitivity and stability of natural pigments in pH-responsive freshness indicators: A review

Natural pigments are an indicator component in the freshness indicator, which is advantageous due to their safety, renewability, and low cost. However, freshness indicator with natural pigments as pH indicators has the problems of low stability and the color rendering domain could not effectively cover the shelf life of food. This paper describes the types and structures of natural pigments commonly used in freshness indicators and their color change mechanisms under different pH conditions. Also, the preparation methods of natural pigments freshness indicators are reviewed. Based on the current limitations and shortcomings faced by natural pigments freshness indicators, this paper highlights optimization strategies to enhance their sensitivity and stability, including modification, co-pigmentation, natural pigments mixing, encapsulation, and metal-ion complexation. The exploitation of these optimization strategies can help develop natural pigment-based intelligent packaging with superior performance to meet the food industry's needs for quality and safety monitoring.

Innovative approaches to harnessing natural pigments from food waste and by-products for eco-friendly food coloring

With unprecedented growth in the world population, the demand for food has risen drastically leading to increased agricultural production. One promising avenue is recovery of value-added pigments from food waste which has been gaining global attention. This review focuses on sustainable strategies for extracting pigments, examining the factors that influence extraction, their applications, and consumer acceptability. The significant findings of the study state the efficiency of pigment extraction through innovative extraction techniques rather than following conventional methods that are time-consuming, and unsustainable. In addition to their vibrant colors, these pigments provide functional benefits such as antioxidant properties, extended shelf life and improved food quality. Societal acceptance of pigments derived from food waste is positively driven by environmental awareness and sustainability. The study concludes by highlighting the stability challenges associated with various natural pigments, emphasizing the need for tailored stabilization methods to ensure long-term stability and effective utilization in food matrices.

Electron beam irradiation coupled ultrasound-assisted natural deep eutectic solvents extraction: A green and efficient extraction strategy for proanthocyanidin from walnut green husk

Proanthocyanidin (PAC) is recognized as a potent natural antioxidant that prevents various diseases. As societal awareness increases, eco-friendly and efficient natural product extraction technologies are gaining more attention. In this study, an electron beam irradiation (EBI) coupled with ultrasound-assisted natural deep eutectic solvents (NADES) extraction method was developed to enable the green and highly efficient extraction of PAC from walnut green husk (WGH). NADES, prepared with choline chloride and ethylene glycol, demonstrated excellent extraction capacity and storage stability for PAC. Molecular dynamics simulations elucidated the high compatibility between NADES and PAC, attributed mainly to a higher SASA value (207.85 nm2), a greater number of hydrogen bonds (330.99), an extended hydrogen bonding lifetime (4.54 ps), and lower inter-molecular interaction energy. Based on these findings, the optimal conditions (13 kGy EBI, 42 mL/g liquid-solid ratio, 38 °C extraction temperature, 70 min extraction time) resulted in a maximum PAC extraction yield of 56.34 mg/g. Notably, this yield was 32.93 % higher than that observed in samples not treated with EBI and ultrasound-assisted extraction (UAE). Analysis of tissue morphology, extract functional groups and thermal behavior suggested a possible mechanism for the synergistically enhanced PAC extraction by the EBI-NADES-UAE method. Additionally, the PAC extracted using the NADES by the EBI coupled with ultrasound-assisted method exhibited outstanding antioxidant activity (comparable to Vc), digestive enzyme inhibition (IC50: 17-0.61 mg/mL), and anti-glycation capacity (IC50: 86.49 μg/mL). Overall, this work provided a green and efficient strategy for PAC extraction from WGH, elucidated the extraction mechanism and bioactivities, and offered valuable insights for potential industrial applications.

Development of antioxidant films based on anthocyanin microcapsules extracted from purple corn cob and incorporated into a chitosan matrix

Biodegradable food packaging films were prepared from chitosan incorporated with microencapsulated anthocyanins powder (MAP) that was extracted from purple corn cob using the casting method. Anthocyanins extracts were microencapsulated with maltodextrin, gum arabic, and soy protein using a spray-drying method. The film based on chitosan and MAP (CHt@MAP) was prepared through citric acid cross-linking and plasticization with glycerol. The structural analysis of the CHt@MAP film revealed a semicrystalline structure by X-ray diffraction. The interactions were mainly via electrostatic and hydrogen bonding, as confirmed by Fourier-transform infrared. Based on scanning electron microscopy, the morphology of the films revealed evidence of the presence of MAP on the surface and cross-section. The microcapsules inside the films produced an increase in thickness (0.18-0.21 mm), lower water vapor permeability (12.4-8.5 × 10-10 g m-1s-1Pa-1), and reduced elongation at break (217 % to 165 %), as well as tensile strength (1.3 to 0.45 MPa) compared to the chitosan film. Furthermore, the antioxidant activity of CHt@MAP film was high, with a radical scavenging activity of 56 %. It also exhibited a strong barrier to UV and visible light. The results indicate that the CHt@MAP film preserves the shelf life of blueberries at room temperature and could be used as an active packaging film for foods.

A single nucleotide polymorphism affects protein translation and leads to post-anthesis color change variation in closely related Lotus species

Flower color change, a common phenomenon that is important in pollination ecology, has intrigued scientists for decades. While previous flower color studies have mainly focused on color diversity among different plant species, our focus is on unraveling the mechanism of post-anthesis color change (PACC) and the molecular basis for its presence and absence, respectively, in two closely related species of Lotus, Lotus filicaulis and Lotus japonicus MG20. Metabolomic analysis reveals anthocyanins as the key metabolites responsible for the observed PACC. Differential expression of anthocyanin biosynthetic and transport genes causes the variation in PACC between the two Lotus species. Crucially, the significant upregulation of a functionally characterized MYB regulator, LfPAP1, is linked to the accumulation of anthocyanins and visible color alterations in L. filicaulis flowers. Notably, we uncover a nucleotide polymorphism in the initiation codon of LjPAP1. Although this mutation does not affect transcription, we show that it has a major effect in attenuating protein translation, reducing its capacity to activate anthocyanin biosynthesis, and leading to a failure of PACC in L. japonicus MG20. Our study sheds light on mechanisms of PACC phenomenon and highlights the potential for mutations in initiation sequences to generate phenotypic differences between species in evolution.

Dynamic changes of anthocyanins during 'Ziyan' tea wine processing

In this study, the dynamic changes of different anthocyanins in the processing of 'Ziyan' tea wine were investigated quantitatively. Results showed that six types of anthocyanins, namely petunidin, malvidin, pelargonidin, delphinidin, cyanidin and peonidin, as well as two co-pigmented substances, procyanidins and flavonoids, were detected in 'Ziyan' tea wine. As fermentation proceeded, the contents of petunidin, pelargonidin, delphinidin, cyanidin and peonidin decreased. Among them, petunidin, peonidin and pelargonidin showed a tendency of decreasing first, then increasing and finally decreasing, whereas delphinidin and cyanidin continued to decrease during fermentation. Variation trend of procyanidins and flavonoids was consistent with those of petunidin. Furthermore, metabolism of delphinidin, cyanidin and pelargonidin were main pathways responsible for the anthocyanin changes during 'Ziyan' tea wine processing. These findings suggested that the color of 'Ziyan' tea wine was achieved by the combination of various anthocyanins in different ratios and the co-pigmentation of procyanidins and flavonoids.

Elevating anthocyanin extraction from mangosteen pericarp: A comparative exploration of conventional and emerging non-thermal technology

Mangosteen pericarp (MP) is abundant in bioactive compounds but is often discarded as waste, leading to environmental pollution. This study compared the extraction of dried MP using maceration and high-pressure processing (HPP). HPP at 10 min (500 MPa/20 °C) resulted in the highest ACNs, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities. It also significantly reduced residual enzyme activities (REA) of polyphenol oxidase (PPO) and peroxidase (POD) by 33.90 % and 8.27 %, respectively. Fourier-transform infrared spectroscopy (FT-IR) analysis revealed a new wavelength at 2665.25 cm-1, and scanning electron microscopy (SEM) showed significant pore formation in MP cells, indicating cell damage. HPP-10 min enhanced the extraction of bioactive compounds, which significantly elevated the thermal stability of ACNs at 60 °C. This suggests that HPP is a promising method for extracting and preserving ACNs and other bioactive compounds from dried MP, with potential applications as natural colorants.

Factors affecting the stability of anthocyanins and strategies for improving their stability: A review

Anthocyanins, as the most common and widely distributed flavonoid compounds, are widely present in fruits and vegetables. Anthocyanins show various biological activities including antioxidant, anticancer, anti-inflammatory, antibacterial, and immunomodulatory activities. Hence, anthocyanins are widely used in the fields of food and pharmaceuticals. However, anthocyanins are susceptible to environmental and processing factors due to their structural characteristics, which leads to poor storage and processing stability. Numerous studies have indicated that structural modification, co-pigmentation, and delivery systems could improve the stability and bioavailability of anthocyanins in the external environment. This article reviews the main factors affecting the stability of anthocyanins. Moreover, this review comprehensively introduces methods to improve the stability of anthocyanins. Finally, the current problems and future research advances of anthocyanins are also introduced. The findings can provide important references for deeper research on the stability, biological activities, and bioavailability of anthocyanins.

The mechanism of pectin in improving anthocyanin stability and the application progress of their complexes: A review

Improving anthocyanin stability is a major challenge for the food industry. Studies have revealed that the interaction with pectin through non-covalent bonds can improve the anthocyanin stability, thus showing the potential to alleviate the above challenges. However, the interactions are highly complex and diverse. Thus, analyzing the effect of this interaction on anthocyanin stability is essential to promote anthocyanin-pectin complexes application in functional foods. Pectin can interact with anthocyanins through covalent and non-covalent interactions, and these interactions are affected by their structure, the external environment, and the processing methods. Through their interaction with pectin, the thermal, color, and storage stability of anthocyanins are improved, enhancing their bioavailability in the gastrointestinal and facilitating their application range in food processing. This review provides a theoretical reference for improving anthocyanin stability and increasing the application range of anthocyanin-pectin complexes.

Recent insights into anthocyanin biosynthesis, gene involvement, distribution regulation, and domestication process in rice (Oryza sativa L.)

Anthocyanins are water-soluble natural pigments found broadly in plants. As members of the flavonoid family, they are widely distributed in various tissues and organs, including roots, leaves, and flowers, responsible for purple, red, blue, and orange colors. Beyond pigmentation, anthocyanins play a role in plant propagation, stress response, defense mechanisms, and human health benefits. Anthocyanin biosynthesis involves a series of conserved enzymes encoded by structural genes regulated by various transcription factors. In rice, anthocyanin-mediated pigmentation serves as an important morphological marker for varietal identification and purification, a critical nutrient source, and a key trait in studying rice domestication. Anthocyanin biosynthesis in rice is regulated by a ternary conserved MBW transcriptional complexes comprising MYB transcription factors (TFs), basic-helix-loop-helix (bHLH) TFs, and WD40 repeat protein, which activate the expression of structure genes. Wild rice (Oryza rufipogon) commonly has purple hull, purple stigma, purple apiculus, purple leaf, and red pericarp due to the accumulations of anthocyanin or proanthocyanin. However, most cultivated rice (Oryza sativa) varieties lose the anthocyanin phenotypes due to the function variations of some regulators including OsC1, OsRb, and Rc and the structure gene OsDFR. Over the past decades, significant progress has been made in understanding the molecular and genetic mechanisms of anthocyanin biosynthesis. This review summarizes research progress in rice anthocyanin biosynthetic pathways, genes involvements, distribution regulations, and domestication processes. Furthermore, it discusses future prospects for anthocyanin biosynthesis research in rice, aiming to provide a theoretical foundation for future investigations and applications, and to assist in breeding new rice varieties with organ-targeted anthocyanin deposition.

Nano techniques: an updated review focused on anthocyanin stability

Anthocyanins (ACNs) are one of the subgroups of flavonoids and getting intensive attraction due to the nutritional values. However, their application of ACNs is limited due to their poor stability and bioavailability. Accordingly, nanoencapsulation has been developed to enhance its stability and bio-efficacy. This review focuses on the nano-technique applications of delivery systems that be used for ACNs stabilization, with an emphasis on physicochemical stability and health benefits. ACNs incorporated with delivery systems in forms of nano-particles and fibrils can achieve advanced functions, such as improved stability, enhanced bioavailability, and controlled release. Also, the toxicological evaluation of nano delivery systems is summarized. Additionally, this review summarizes the challenges and suggests the further perspectives for the further application of ACNs delivery systems in food and medical fields.

Progress on molecular modification and functional applications of anthocyanins

Anthocyanins have attracted a lot of attention in the fields of natural pigments, food packaging, and functional foods due to their color, antioxidant, and nutraceutical properties. However, the poor chemical stability and low bioavailability of anthocyanins currently limit their application in the food industry. Various methods can be used to modify the structure of anthocyanins and thus improve their stability and bioavailability characteristics under food processing, storage, and gastrointestinal conditions. This paper aims to review in vitro modification methods for altering the molecular structure of anthocyanins, as well as their resulting improved properties such as color, stability, solubility, and antioxidant properties, and functional applications as pigments, sensors and functional foods. In industrial production, by mixing co-pigments with anthocyanins in food systems, the color and stability of anthocyanins can be improved by using non-covalent co-pigmentation. By acylation of fatty acids and aromatic acids with anthocyanins before incorporation into food systems, the surface activity of anthocyanins can be activated and their antioxidant and bioactivity can be improved. Various other chemical modification methods, such as methylation, glycosylation, and the formation of pyranoanthocyanins, can also be utilized to tailor the molecular properties of anthocyanins expanding their range of applications in the food industry.

Effect of high-pressure-homogenisation on the interaction between pomegranate peel pectin fractions and anthocyanins in acidic environment

In this study, changes in the basic composition and structural characterisation of water-soluble pectin (WSP), homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) from pomegranate peel were investigated after high-pressure-homogenisation (HPH) at 50 MPa and 300 MPa. The interactions between three pectin and anthocyanin (ACN) complex were also studied. The three pectin fractions were mainly composed of galacturonic acid (34.95%-87.69%), all with low degrees of methyl-esterification ≤41.20%. HPH at 300 MPa increased the binding ratios of ACN to three pectin fractions by 34.22%-34.59%. Changes in the structural characterisation results of pectin confirmed that the depolymerisation and breakdown of the side chains of pectin after HPH promoted electrostatic interactions, hydrogen bond and hydrophobic interaction between pectin and ACN. Correspondingly, the thermal and storage stabilities of ACN in the complex was boosted after HPH at 300 MPa. This study provides insights into the interaction between pectin and ACN under HPH.

Regulated anthocyanin release through novel pH-responsive peptide hydrogels in simulated digestive environment

The instability of anthocyanins significantly reduces their bioavailability as food nutrients. This proof-of-concept study aimed to develop efficient carriers for anthocyanins to overcome this challenge. Characterization of the hydrogels via SEM (scanning electron microscope) and rheological analysis revealed the formation of typical gel structures. MTT (methyl thiazolyl tetrazolium) and hemolysis assays confirmed that their high biocompatibility. Encapsulation efficiency analysis and fluorescence microscopy images demonstrated successful and efficient encapsulation of anthocyanins by pH-responsive hydrogels. Stability studies further validated the effect of peptide hydrogels in helping anthocyanin molecules withstand factors such as gastric acid, high temperatures, and heavy metals. Subsequently, responsive studies in simulated gastric (intestinal) fluid demonstrated that the pH-responsive peptide hydrogels could protect anthocyanin molecules from gastric acid while achieving rapid and complete release in intestinal fluid environments. These results indicate that these peptide hydrogels could stabilize anthocyanins and facilitate their controlled release, potentially leading to personalized delivery systems.

Design of a liposome casein hydrogel as an efficient front-end homeostatic anthocyanin loading system

Proteins have been studied and applied to improve the stability of anthocyanins (ACNs), but the changes in the pH microenvironment during the preparation of steady-state systems are often ignored, and more attention is given to the stability of the system after preparation. In this study, we propose the "anthocyanin front-end homeostasis strategy", which involves designing a system can protect anthocyanins under acidic conditions so that more anthocyanin prototypes can be loaded inside the protein. Anthocyanins are encapsulated in liposomes (Lip) at pH 3.0 and combined with casein methacrylate (CSMA) to form Anthocyanin-loaded liposomes/CSMA hydrogel (Lip@ACNs/CSMA), with good physical properties and good blood compatibility. The system increased the hydrogen peroxide scavenging capacity by 1.16 mg Vc equiv./mg ACNs and the cellular antioxidant activity by 17.55 μM quercetin/100 mg ACNs, the photo and thermal storage stability increased by 36.50 % and 30.71 %, the digestive rate increased by 17.50 %, and the biological availability increased by 0.0049 mg/mL. This study designed a liposome casein hydrogel as an efficient front-end homeostatic anthocyanin loading system and provided a new approach for improving the stability of anthocyanins.

Enhancing cotton fabric dyeing: Optimizing Mordanting with natural dyes and citric acid

This study investigates the optimization of fabric dyeing using natural dyes extracted from Clitoria ternatea, Cudrania javanensis, and Hibiscus sabdarifa by enhancing the mordanting process with citric acid. The principle of adding citric acid is as a crosslinker agent between cotton fabric and dye through an esterification reaction. A central composite design (CCD) of the response surface methodology (RSM) is employed to optimize parameters. Three mordanting variations and dyeing parameters, such as temperature and time, are considered. Results indicate that pre-mordanting yields superior outcomes, with optimal temperature and time at 65 °C and 82 min, respectively. Cotton fabric dyed with Cudrania javanensis and citric acid exhibits the highest color durability. This study successfully demonstrates the effectiveness of pre-mordanting, meta-mordanting, and post-mordanting methods with optimized conditions for achieving optimal coloring outcomes, particularly highlighting the efficacy of citric acid as a crosslinking agent.

Enzymatic acylation of cyanidin-3-O-glucoside with aromatic and aliphatic acid methyl ester: Structure-stability relationships of acylated derivatives

Anthocyanins are water-soluble pigments, but they tend to be unstable in aqueous solutions. Modification of their molecular structure offers a viable approach to alter their intrinsic properties and enhance stability. Aromatic and aliphatic acid methyl esters were used as acyl donors in the enzymatic acylation of cyanidin-3-O-glucoside (C3G), and their analysis was conducted using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The highest conversion rate achieved was 96.41 % for cyanidin-3-O-(6″-feruloyl) glucoside. Comparative evaluations of stability revealed that aromatic acyl group-conjugated C3G exhibited superior stability enhancement compared with aliphatic acyl group derivatives. The stability of aliphatic C3G decreased with increasing carbon chain length. The molecular geometries of different anthocyanins were optimized, and energy level calculations using density functional theory (DFT) identified their sites with antioxidant activities. Computational calculations aligned with the in vitro antioxidant assay results. This study provided theoretical support for stabilizing anthocyanins and broadened the application of acylated anthocyanins as food colorants and nutrient supplements.

Intermolecular copigmentation of anthocyanins with phenolic compounds improves color stability in the model and real blueberry fermented beverage

To improve the color stability of anthocyanins (ACNs) in blueberry fermented beverage, the intermolecular copigmentation between ACNs and 3 different phenolic compounds, including (-)-epigallocatechin gallate (EGCG), ferulic acid (FA), and gallic acid (GA) as copigments, was compared in the model and the real blueberry fermented beverage, respectively. The copigmented ACNs by EGCG presented a high absorbance (0.34 a.u.) and redness (27.09 ± 0.17) in the model blueberry fermented beverage. The copigmentation by the participation of the 3 different phenolic compounds showed all a spontaneous exothermic reaction, and the Gibbs free energy (ΔG°) of the system was lowest (-5.90 kJ/mol) using EGCG as copigment. Furthermore, the molecular docking model verified that binary complexes formed between ACNs and copigments by hydrogen bonds and π-π stacking. There was a high absorbance (1.02 a.u.), percentage polymeric color (PC%, 68.3 %), and good color saturation (C*ab, 43.28) in the real blueberry fermented beverage aged for 90 days, and more malvidin-3-O-glucoside had been preserved in the wine using EGCG as copigment. This finding may guide future industrial production of blueberry fermented beverage with improved color.

Chemical stability of carboxylpyranocyanidin-3-O-glucoside under β-glucosidase treatment and description of their interaction

Anthocyanins are susceptible to degradation by β-glycosidase, resulting in color loss. This study analyzed the impact of β-glycosidase on carboxylpyranocyanidin-3-O-glucoside (Carboxyl-pycy-3-gluc) and its precursor cyanidin-3-O-glucoside (Cy-3-gluc). Carboxyl-pycy-3-gluc exhibited enhanced stability upon treatment with β-glucosidase. Ultraviolet-visible and circular dichroism spectroscopy revealed slight changes in the microenvironment and secondary structure of β-glycosidase when carboxyl-pycy-3-gluc was present. The fluorescence experiment indicated that anthocyanins quench the fluorescence of β-glycosidase through static quenching via hydrophobic interactions. Molecular docking of six types of carboxylpyranoanthocyanins and their precursors with β-glycosidase revealed that carboxylpyranoanthocyanins exhibited lower binding affinity than their precursors, consistent with the enzyme kinetic experiment results. The incorporation carboxyl-pycy-3-gluc into Sanhua Plum Juice and Wine endowed them with vivid and stable coloration. The study illustrated that carboxyl-pycy-3-gluc exhibits low binding affinity with β-glycosidase, thereby maintaining stability and confirming its potential as a colorant.

Valorization and protection of anthocyanins from strawberries (Fragaria×ananassa Duch.) by acidified natural deep eutectic solvent based on intermolecular interaction

This study introduces an innovative approach for the valorization and protection of anthocyanins from 'Benihoppe' strawberry (Fragaria × ananassa Duch.) based on acidified natural deep eutectic solvent (NADES). Choline chloride-citric acid (ChCl-CA, 1:1) was selected and acidified to enhance the valorization and protection of anthocyanins through hydrogen bond. The optimal conditions (ultrasonic power of 318 W, extraction temperature of 61 °C, liquid-to-solid ratio of 33 mL/g, ultrasonic time of 19 min), yielded the highest anthocyanins of 1428.34 μg CGE/g DW. UPLC-Triple-TOF/MS identified six anthocyanins in acidified ChCl-CA extract. Stability tests indicated that acidified ChCl-CA significantly increased storage stability of anthocyanins in high temperature and light treatments. Molecular dynamics results showed that acidified ChCl-CA system possessed a larger diffusion coefficient (0.05 m2/s), hydrogen bond number (145) and hydrogen bond lifetime (4.38 ps) with a reduced intermolecular interaction energy (-1329.74 kcal/mol), thereby efficiently valorizing and protecting anthocyanins from strawberries.

Exploring the potential utilization of copigmented barberry anthocyanins in ice cream: Focusing on foaming aspects, and melting attributes

Anthocyanins have emerged as promising substitutes for synthetic dyes owing to their color profiles, and potential health-boosting properties. The primary aim of this investigation was to assess the impact of copigmented, and un-copigmented barberry anthocyanins, employed at different concentrations (1, 3, and 5% w/w) as colorants in ice cream. The secondary goal was to investigate the influence of barberry anthocyanins on ice cream foaming characteristics, and melting point. The samples' physicochemical, textural, and organoleptic characteristics, total phenolic, and anthocyanin content, and antioxidant activity were determined. By increasing barberry extract concentrations in the samples, the pH levels (5.81) decreased, and overrun increased(30.0 ± 1.15%), respectively. Furthermore, the textural analysis showed that increasing barberry anthocyanins within the ice cream formulation correlated with an increase in sample hardness (113.72 ± 1.34 N). The control sample (vanilla ice cream) had the highest value of melting rate (1.09 ± 0.03 g/min), whereas the specimen containing 5% of copigmented barberry anthocyanins exhibited the lowest rate of melting (0.50 ± 0.01 g/min). The start time of melting of control sample was 1098 s and by increasing the concentration of copigmented barberry anthocyanins from 1 to 5%, this time increased from 1405.2 s to 1831.2 s (P < 0.05). In conclusion, barberry anthocyanins reduced the melting rate as a crucial attribute for ice cream.

Combinatorial preparation and structural characterization of anthocyanins and aglycones from Purple-heart Radish for evaluation of physicochemical stability and pancreatic lipase inhibitory activity

In this study, an efficient approach to preparation of different anthocyanins from Purple-heart Radish was developed by combining microwave-assisted extraction (MAE), macroporous resin purification (MRP) and ultrasound-assisted acid hydrolysis (UAAH) for evaluation of physicochemical stability and pancreatic lipase (PL) inhibitory activity. By optimization of MAE, MRP and UAAH processes, the anthocyanins reached the yield of 6.081 ± 0.106 mg/g, the purity of 78.54 ± 0.62 % (w/w) and the content of 76.29 ± 1.31 % (w/w), respectively. With high-resolution UHPLC-Q-Orbitrap/MS, 15 anthocyanins were identified as pelargonins with diverse glucosides and confirmed by pelargonidin standard. By glycosylation, pelargonins exhibited higher stability in different pH, temperature, light, metal ions environments than that of pelargonidin. However, PL inhibitory assay, kinetic analysis and molecular docking demonstrated that pelargonidin had higher PL inhibitory activity than pelargonins even though with similar binding sites and a dose-effect relationship. The above results revealed that the effect of glycosylation and deglycosylation on PL inhibitory activity and physicochemical stability.

Unveiling the multifaceted world of anthocyanins: Biosynthesis pathway, natural sources, extraction methods, copigmentation, encapsulation techniques, and future food applications

Numerous datasets regarding anthocyanins have been noted elsewhere. These previous studies emphasized that all processes must be carried out meticulously from the source used to obtain anthocyanins to their inclusion in relevant applications. However, today, full standardization has not yet been achieved for these processes. For this, presenting the latest developments regarding anthocyanins under one roof would be a useful approach to guide the scientific literature. The current review was designed to serve the stated points. In this context, their biosynthesis pathway was elaborated. Superior potential of fruits and certain by-products in obtaining anthocyanins was revealed compared to their other counterparts. Health-promoting benefits of anthocyanins were detailed. Also, the situation of innovative techniques (ultrasound-assisted extraction, subcritical water extraction, pulse electrical field extraction, and so on) in the anthocyanin extraction was explained. The stability issues, which is one of the most important problems limiting the use of anthocyanins in applications were discussed. The role of copigmentation and various encapsulation techniques in solving these stability problems was summarized. This critical review is a map that provides detailed information about the processes from obtaining anthocyanins, which stand out with their functional properties, to their incorporation into various systems.

A review on improving the sensitivity and color stability of naturally sourced pH-sensitive indicator films

Naturally sourced pH-sensitive indicator films are of interest for real-time monitoring of food freshness through color changes because of their safety. Therefore, natural pigments for indicator films are required. However, pigment stability is affected by environmental factors, which can in turn affect the sensitivity and color stability of the pH-sensitive indicator film. First, natural pigments (anthocyanin, betalain, curcumin, alizarin, and shikonin) commonly used in pH-sensitive indicator films are presented. Subsequently, the mechanisms behind the change in pigment color under different pH environments and their applications in monitoring food freshness are also described. Third, influence factors, such as the sources, types, and pH sensitivity of pigments, as well as environmental parameters (light, temperature, humidity, and oxygen) of sensitivity and color stability, are analyzed. Finally, methods for improving the pH-sensitive indicator film are explored, encapsulation of natural pigments, incorporation of a hydrophobic film-forming matrix or function material, and protective layer have been shown to enhance the color stability of indicator films, the addition of copigments or mental ions, blending of different natural pigments, and the utilization of electrospinning have been proved to increase the color sensitivity of indicator films. This review could provide theoretical support for the development of naturally sourced pH-sensitive indicator films with high stability and sensitivity and facilitate the development in the field of monitoring food freshness.

Study of UV-Vis molar absorptivity variation and quantitation of anthocyanins using molar relative response factor

The effects of anthocyanin's substitution groups on the UV-Vis molar absorptivity were examined by analyzing a group of 31 anthocyanidin/anthocyanin reference standards with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD). The substitution groups on aglycones were found to associate with molar absorptivity variations, often neglected in anthocyanin quantitation, resulting in significant analytical errors. A simple yet comprehensive strategy based on the molar relative response factors (MRRFs) and a single master reference calibration (i.e., cyanidin-3-glucoside) was proposed to quantify anthocyanins in red cabbage, blueberry, and strawberry samples with improved analytical accuracy. The results indicate this approach provides an effective, inexpensive, and accurate analytical method for anthocyanins in food materials without using individual reference standards. MRRFs of 617 anthocyanins/anthocyanidins were calculated, and the information is freely available at https://BotanicalDC.online/anthocyanin/. This study could be critical to developing new reference methods for anthocyanin analysis and harmonizing results and data from various sources.

Pharmacokinetics of cyanidin-3-O-galactoside and cyanidin-3-O-arabinoside after intravenous administration in rats

Cyanidin-3-O-galactoside and cyanidin-3-O-arabinoside (purity >98%) were isolated from black chokeberry by preparative high-performance liquid chromatography, and an animal experiment was conducted to investigate the pharmacokinetics of two anthocyanin monomers after intravenous administration. The results showed that cyanidin-3-O-galactoside has preferable druggability than cyanidin-3-O-arabinoside in pharmacokinetic area.

Enhanced stability and bioavailability of mulberry anthocyanins through the development of sodium caseinate-konjac glucomannan nanoparticles

This study was carried out to improve the stability of anthocyanins (ACNs) by developing MA-SC-KGM nanoparticles using a self-assembly method that involved the combination of sodium caseinate (SC) and konjac glucomannan (KGM) with mulberry anthocyanin extract (MA). Atomic force microscopy (AFM) analysis showed SC encapsulated MA successfully. Multispectral techniques demonstrated the presence of hydrogen bonds and hydrophobic interactions in the nanoparticles. MA-SC-KGM ternary mixture improved storage stability, color stability and anthocyanin retention better compared to the MA-SC binary mixture. Notably, MA-SC-KGM nanoparticles significantly inhibited the thermal degradation of ACNs, improved pH stability, and showed stability and a slow-release effect in gastrointestinal digestion experiments. In addition, MA-SC-KGM nanoparticles were effective in scavenging DPPH· and ABTS+ free radicals, with enhanced stability and antioxidant capacity even during the heating process. This study successfully developed a novel MA-SC-KGM protein-polysaccharide composite material that effectively stabilized natural ACNs, expanding the application of ACNs in various industries.

Ion presence during thermal processing modulates the performance of rice albumin/anthocyanin binary system

Thermal processing with salt ions is widely used for the production of food products (such as whole grain food) containing protein and anthocyanin. To date, it is largely unexplored how salt ion presence during thermal processing regulates the practical performance of protein/anthocyanin binary system. Here, rice albumin (RA) and black rice anthocyanins (BRA) were used to prepare RA/BRA composite systems as a function of temperature (60-100 °C) and NaCl concentration (10-40 mM) or CaCl2 concentration (20 mM). It was revealed that the spontaneous complexing reaction between RA and BRA was driven by hydrophobic interactions and hydrogen bonds and becomes easier and more favorable at a higher temperature (≤90 °C), excessive temperature (100 °C), however, may result in the degradation of BRA. Moreover, the salt ion presence during thermal processing may bind with RA and BRA, respectively, which could restrict the interaction between BRA and RA. Additionally, the inclusion of Na+ or Ca2+ at 20 mM endowed the binary system with strengthened DPPH radical scavenging capacity (0.95 for Na+ and 0.99 for Ca2+). Notably, Ca2+ performed a greater impact on the stability of the system than Na+.

Dietary Sources, Stabilization, Health Benefits, and Industrial Application of Anthocyanins-A Review

Natural phytochemicals are well known to protect against numerous metabolic disorders. Anthocyanins are vacuolar pigments belonging to the parent class of flavonoids. They are well known for their potent antioxidant and gut microbiome-modulating properties, primarily responsible for minimizing the risk of cardiovascular diseases, diabetes, obesity, neurodegenerative diseases, cancer, and several other diseases associated with metabolic syndromes. Berries are the primary source of anthocyanin in the diet. The color and stability of anthocyanins are substantially influenced by external environmental conditions, constraining their applications in foods. Furthermore, the significantly low bioavailability of anthocyanins greatly diminishes the extent of the actual health benefits linked to these bioactive compounds. Multiple strategies have been successfully developed and utilized to enhance the stability and bioavailability of anthocyanins. This review provides a comprehensive view of the recent advancements in chemistry, biosynthesis, dietary sources, stabilization, bioavailability, industrial applications, and health benefits of anthocyanins. Finally, we summarize the prospects and challenges of applications of anthocyanin in foods.

RuBisCo can conjugate and stabilize peonidin-3-O-p-coumaroylrutinoside-5-O-glucoside in isotonic sport models: Mechanisms from kinetics, multispectral, and libDock assays

The co-pigmentation behaviour of RuBisCo proteins (with different concentrations) on peonidin-3-O-p-coumaroylrutinoside-5-O-glucoside (P3C5G, extracted from Rosetta potato's peels) conjugates in isotonic sport drinks (ISD) was examined using multispectral, thermal stability kinetics, and libDock-based molecular docking approaches. The colorant effects of RuBisCo on P3C5G were also studied in spray-dried microencapsulated ISD-models. RuBisCo, especially at a concentration of 10 mg/mL in ISD, showed a co-pigmentation effect on the color of P3C5G, mostly owing to its superior hyperchromicity, pKH-levels, and thermal stability. Results from multispectral approaches also revealed that RuBisCo could noncovalently interact with P3C5G as confirmed by libDock findings, where P3C5G strongly bound with RuBisCo via H-bonding and π-π forces, thereby altering its secondary structure. RuBisCo also preserved color of P3C5G in ISD-powdered models. These detailed results imply that RuBisCo could be utilized in ISD-liquid and powder models that might industrially be applied as potential food colorants in products under different conditions.

Enhancement of pyranoanthocyanin formation in blueberry wine with non-Saccharomyces yeasts

The development of blueberry wine provides an alternative method for maintaining the nutritional value and extending the shelf life of blueberries. However, anthocyanin loss and off-flavor compound generation during fermentation impair blueberry wine color and quality. Hydroxycinnamate decarboxylase from yeast can catalyze the conversion of hydroxycinnamic acids to vinylphenols, which later may condense with anthocyanins to form more stable vinylphenolic pyranoanthocyanins. In this study, 10 non-Saccharomyces yeasts from Daqu that showed hydroxycinnamate decarboxylase activity were screened. Among the 10 strains, Wickerhamomyces anomalus Y5 showed the highest consumption (34.59%) of the total tested phenolic acids and almost no H2S production. Furthermore, Y5 seemed to produce four vinylphenol pyranoanthocyanins (cyanidin-3-O-galactoside/glucoside-4-vinylcatechol, cyanidin-3-O-galactoside/glucoside-4-vinylsyringol, malvidin-4-vinylguaiacol, and malvidin-4-vinylcatechol) during blueberry wine fermentation, which may improve the color stability of blueberry wine. These findings provide new insights for improving the quality of blueberry wine using non-Saccharomyces yeasts.

Advancements in the promotion of pyranoanthocyanins formation in wine: A review of current research

Pyranoanthocyanin (PACN) is a class of anthocyanin (ACN)-derived pigments found in aged red wines, which has certain advantages over the prototype ACN in terms of stability, and biological activity. However, the efficiency and yield of PACNs in the natural fermentation system are low. This article summarizes five frequently employed physical processing techniques that can accelerate the formation of PACN. From a mechanistic standpoint, these techniques can produce large amounts of active substances, further promoting the extracellular release of phenolics and the formation of some cofactors and PACNs' pyran rings. Precursor substances and environmental factors affecting PACN yields are also pointed out. It mainly included the parent ring substitution in ACNs, the type and quantity of glycosides, the electron donating ability and concentration of cofactors, etc. Thus, this article aims to provide an overview of the advancements in processing techniques, thereby facilitating their wider utilization in the food and beverage industry.

Leptin pathway is a crucial target for anthocyanins to protect against metabolic syndrome

The high prevalence of metabolic syndrome is threatening the health of populations all over the world. Contemporary work demonstrates that high leptin concentration is directly related to the development of metabolic syndrome such as obesity, fatty liver diseases, type 2 diabetes mellitus and cardiovascular diseases. Anthocyanins are a widespread group of dietary polyphenols, which can ameliorate chronic diseases related to metabolic syndrome. In addition, anthocyanins can regulate the leptin pathway in chronic metabolic diseases, however the potential mechanism between anthocyanin and leptin is complex and elusive. In this review paper, we have evaluated the bioactivity of anthocyanins on the mediation of leptin level and the upstream and downstream pathways in chronic metabolic diseases. Anthocyanins could regulate the hypertrophy of adipose tissue, and the expression of leptin level via mediating TNF-α, C/EBP, PPAR, CREB and SREBP-1. Anthocyanins promoted the leptin sensitivity by increasing the level of leptin receptor, phosphorylation of JAK2/STAT3, PI3K/AKT, and additionally ameliorated metabolic disorder related outcome, including oxidative stress, inflammation, lipid accumulation, insulin resistance and the balance of gut microbiota. However, direct evidence of anthocyanins treatment on leptin signal transduction is still limited which calls for future molecular binding and gene regulation test.

Microencapsulation with fructooligosaccharides and whey protein enhances the antioxidant activity of anthocyanins and their ability to modulate gut microbiota in vitro

Anthocyanins are the primary functional pigments in the diet. However, anthocyanins exhibit instability during digestion, coupled with limited bioavailability. Microencapsulation offers anthocyanins a sheltered environment, enhancing their stability and bioactivity. Fructooligosaccharides (FOS) and whey protein (WP) commonly serve as wall materials in microencapsulation and represent a significant source of probiotic functionality. Our prior research successfully established a robust microencapsulation system for anthocyanins utilizing FOS and WP. This study investigates the antioxidative capacity, stability during in vitro digestion, modulation on gut microbiota, and short-chain fatty acids (SCFAs) production of black soybean skin anthocyanins microencapsulated with FOS and WP (anthocyanin-loaded microencapsule particles, ALM). The results demonstrate that ALM exhibits a superior antioxidant capacity compared to free anthocyanins (ANCs) and cyanidin-3-glucoside (C3G). During simulated digestion, ALM exhibits enhanced anthocyanin retention compared with ANC in both gastric and intestinal phases. In comparison with ANC and even non-loaded microcapsules (NLM), in vitro fermentation demonstrates that ALM exhibits the highest gas production and lowered pH, indicating excellent fermentation activity. Furthermore, in comparison with ANC or NLM, ALM exerts a positive influence on the diversity and composition of gut microbiota, with potentially beneficial genera such as Faecalibacterium and Akkermansia exhibiting higher relative abundance. Moreover, ALM stimulates the production of SCFAs, particularly acetic and propionic acids. In conclusion, microencapsulation of anthocyanins with FOS-WP enhances their antioxidative capacity and stability during in vitro digestion. Simultaneously, this microencapsulation illustrates a positive regulatory effect on the intestinal microbiota community and SCFA production, conferring potential health benefits.

Unlocking the health potential of anthocyanins: a structural insight into their varied biological effects

Anthocyanins have become increasingly important to the food industry due to their colorant features and many health-promoting activities. Numerous studies have linked anthocyanins to antioxidant, anti-inflammatory, anticarcinogenic properties, as well as protection against heart disease, certain types of cancer, and a reduced risk of diabetes and cognitive disorders. Anthocyanins from various foods may exhibit distinct biological and health-promoting activities owing to their structural diversity. In this review, we have collected and tabulated the key information from various recent published studies focusing on investigating the chemical structure effect of anthocyanins on their stability, antioxidant activities, in vivo fate, and changes in the gut microbiome. This information should be valuable in comprehending the connection between the molecular structure and biological function of anthocyanins, with the potential to enhance their application as both colorants and functional compounds in the food industry.

The promising stability of carboxylpyranocyanidin-3-O-glucoside during food processing and simulated digestion and its bioavailability research

BACKGROUND

Pyranoanthocyanins are stable anthocyanin derivatives. Carboxylpyranoanthocyanin is one of the simplest pyranoanthocyanin, among which the production of carboxylpyranocyanidin-3-O-glucoside (crboxyl-pycy-3-gluc) is most feasible as a result of the abundance of its reactant, cyanidin-3-O-glucoside (Cy-3-gluc).

RESULTS

In the present study, carboxyl-pycy-3-gluc was synthesized and its stability during processing and after ingestion as well as its bioavailability in vivo were comprehensively evaluated. Our results indicated that the color of carboxyl-pycy-3-gluc remained more stable compared to Cy-3-gluc when facing the large-span pH variation. The high retention of anthocyanin symbolized the superb stability under thermal processing, sulfur dioxide bleaching and ultrasonic treatment of carboxyl-pycy-3-gluc. Because of the stability under the alkaline condition, carboxyl-pycy-3-gluc is more stable after oral-gastrointestinal digestion. After in vitro gut microbiota fermentation, the retention of carboxyl-pycy-3-gluc was significantly higher than that of Cy-3-gluc. The larger molecular size made absorption of carboxyl-pycy-3-gluc into blood more difficult than its precursor.

CONCLUSION

The present study demonstrated the promising stability of carboxyl-pycy-3-gluc during food processing and after digestion, confirming the potential of carboxyl-pycy-3-gluc as a colorant. © 2023 Society of Chemical Industry.

A critical review on the stability of natural food pigments and stabilization techniques

This comprehensive review article delves into the complex world of natural edible pigments, with a primary focus on their stability and the factors that influence them. The study primarily explores four classes of pigments: anthocyanins, betalains, chlorophylls and carotenoids by investigating both their intrinsic and extrinsic stability factors. The review examines factors affecting the stability of anthocyanins which act as intrinsic factors like their structure, intermolecular and intramolecular interactions, copigmentation, and self-association as well as extrinsic factors such as temperature, light exposure, metal ions, and enzymatic activities. The scrutiny extends to betalains which are nitrogen-based pigments, and delves into intrinsic factors like chemical composition and glycosylation, as well as extrinsic factors like temperature, light exposure, and oxygen levels affecting for their stability. Carotenoids are analyzed concerning their intrinsic and extrinsic stability factors. The article emphasizes the role of chemical structure, isomerization, and copigmentation as intrinsic factors and discusses how light, temperature, oxygen, and moisture levels influence carotenoid stability. The impacts of food processing methods on carotenoid preservation are explored by offering guidance on maximizing retention and nutritional value. Chlorophyll is examined for its sensitivity to external factors like light, temperature, oxygen exposure, pH, metal ions, enzymatic actions, and the food matrix composition. In conclusion, this review article provides a comprehensive exploration of the stability of natural edible pigments, highlighting the intricate interplay of intrinsic and extrinsic factors. In addition, it is important to note that all the references cited in this review article are within the past five years, ensuring the most up-to-date and relevant sources have been considered in the analysis.

A Review of the Ethnobotany, Biological Activity, and Phytochemistry of the Plants in the Gundelia Genus

A comprehensive literature search was conducted in PubMed, Cochrane Library, Web of Science, Scopus, the National Library of Medicine (NLM) catalog, and Google Scholar from January 1980 up until October 2023 on plants in the Gundelia genus. Gundelia L. (Asteraceae) has been treated as a monospecific genus with Gundelia tournefortii L. (1753: 814) in most recent floras with wide variation in corolla color, but nowadays, the genus consists of 17 species. The unripe inflorescences of these species, especially G. tournefortii L., are consumed in many ways. 'Akkoub' or 'akko' in Arabic, "Kangar" in Persian, and "Silifa" in Greek are the common names of G. tournefortii L., also known as tumble thistle in English. They have been used in traditional medicine to treat bronchitis, kidney stones, diarrhea, stomach pain, inflammation, liver and blood diseases, bacterial and fungal infections, and mumps. Based on recent studies, their extracts have exhibited hepatoprotective, hypolipidemic, antioxidant, anti-inflammatory, and antimicrobial effects. Moreover, a variety of phytochemicals, including terpenoids, sterols, and fatty acids, as well as vitamins and minerals, have been identified in this genus. This study reviewed the ethnobotany, phytochemicals, and biological activities of the plants in the Gundelia genus as functional foods and herbal remedies.

Advancements in Genetic Biomarkers and Exogenous Antioxidant Supplementation for Safeguarding Mammalian Cells against Heat-Induced Oxidative Stress and Apoptosis

Heat stress represents a pervasive global concern with far-reaching implications for the reproductive efficiency of both animal and human populations. An extensive body of published research on heat stress effects utilizes controlled experimental environments to expose cells and tissues to heat stress and its disruptive influence on the physiological aspects of reproductive phenotypic traits, encompassing parameters such as sperm quality, sperm motility, viability, and overall competence. Beyond these immediate effects, heat stress has been linked to embryo losses, compromised oocyte development, and even infertility across diverse species. One of the primary mechanisms underlying these adverse reproductive outcomes is the elevation of reactive oxygen species (ROS) levels precipitating oxidative stress and apoptosis within mammalian reproductive cells. Oxidative stress and apoptosis are recognized as pivotal biological factors through which heat stress exerts its disruptive impact on both male and female reproductive cells. In a concerted effort to mitigate the detrimental consequences of heat stress, supplementation with antioxidants, both in natural and synthetic forms, has been explored as a potential intervention strategy. Furthermore, reproductive cells possess inherent self-protective mechanisms that come into play during episodes of heat stress, aiding in their survival. This comprehensive review delves into the multifaceted effects of heat stress on reproductive phenotypic traits and elucidates the intricate molecular mechanisms underpinning oxidative stress and apoptosis in reproductive cells, which compromise their normal function. Additionally, we provide a succinct overview of potential antioxidant interventions and highlight the genetic biomarkers within reproductive cells that possess self-protective capabilities, collectively offering promising avenues for ameliorating the negative impact of heat stress by restraining apoptosis and oxidative stress.