Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure

Color protection, aroma enhancement and sensory improvement of red wines: Comparison of pre-fermentation additions of cyclodextrins and polysaccharides

The effect of pre-fermentation single additions of four cyclodextrins (CDs) as stabilizing factors on the color, aroma, and sensory characteristics of red wines was systematically investigated for the first time and compared with control and single polysaccharide treatments. The results showed that α-cyclodextrin (α-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) increased red-green color channel (a⁎) by 41.85 % and 28.84 %, respectively, compared to the control group, exhibiting a stronger copigmentation effect than the three polysaccharides. Mantel test and heatmap analyses revealed that α-CD enhanced color stability by promoting copigmentation between phenolics and monomeric anthocyanins, whereas HP-β-CD enhanced color through direct copigmentation with anthocyanins. Furthermore, volatile compound content and principal component analysis demonstrated that α-CD and HP-β-CD effectively protected esters and selectively protected alcohols, compared to the control and polysaccharide treatments. Sensory evaluation confirmed that HP-β-CD and α-CD improved the sensory profile by enhancing color appeal, rich floral and fruity aromas, and harmonious taste.

Molecular interactions and binding mechanisms of the homogalacturonan and rhamnogalacturonan-I fractions of pectin and different anthocyanins

This study investigated the interactions between different structural regional fractions of pectin, specifically homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) fractions, and three anthocyanin monomers: cyanidin-3-O-glucoside (C3G), peonidin-3-O-glucoside (P3G), and pelargonidin-3-O-malonylglucoside (P3M). The binding ratios, physicochemical and structural characteristics of these pectin-anthocyanin complexes, and their binding mechanisms were analyzed. The HG fraction exhibited the highest binding ratio with C3G. Zeta potential and particle size analyses indicated that the HG fraction had a significantly higher negative charge compared to RG-І at pH 3.7, and the complexes exhibited an increase in particle size relative to the individual pectin fractions. Furthermore, data from 1H NMR and isothermal titration calorimetry (ITC) confirmed that hydrogen bonding, electrostatic interactions, and hydrophobic interactions primarily facilitated the binding interactions. In the binding interactions involving HG/RG-І and C3G/P3G, the Δδmax, binding constant, and Gibbs free energy (ΔG) of the HG fraction were greater than those of the RG-І fraction, while C3G exhibited stronger binding characteristics than P3G. However, the RG-І fraction demonstrated stronger binding to P3M than to HG. The interactions between pectin and anthocyanins are highly dependent on the structural characteristics of both components. These results offer further insights into the interactions between pectin fractions and anthocyanins at the molecular level.

Composition and distribution of phenolic compounds of optimized bilberry microcapsules using wood hemicelluloses as protecting materials

Bilberry anthocyanins, known for their antioxidant and functional properties, are highly sensitive to processing conditions, which limits their applications in the food and nutraceutical industries. In this study, we systematically optimized the encapsulation efficiency (EE) of spray-dried bilberry anthocyanins using wood-derived hemicelluloses-galactoglucomannans (GGM) and glucuronoxylans (GX)-as protective materials. We evaluated the effects of spray-drying parameters, including inlet/outlet air temperatures and hemicellulose concentrations, to understand their impact on anthocyanin retention. The results showed that increasing the inlet temperature (140-170 °C) improved EE by approximately 20 %, with GGM achieving a higher EE (86 %) compared to GX (81 %) under optimal conditions. Chromatographic analysis confirmed a 100 % recovery of individual anthocyanins, while confocal laser scanning microscopy demonstrated their homogeneous distribution within the microcapsules, ensuring product quality. Additionally, the microcapsules exhibited a spherical morphology with minimal surface anthocyanin distribution, enhancing their stability against environmental stressors. Raman spectroscopy provided further evidence of anthocyanin-hemicellulose interactions, assumingly non-covalent binding mechanisms such as hydrogen bonding and hydrophobic interactions. These findings advance knowledge on process optimization for anthocyanin microencapsulation using hemicelluloses as protective materials and highlight advanced characterization techniques for food microcapsules.

Role of Phytonutrients in the Prevention and Treatment of Chronic Diseases: A Concrete Review

Delving into the intricate role of phytonutrients is paramount to effectively preventing and treating chronic diseases. Phytonutrients are "plant-based nutrients" that positively affect human health. Phytonutrients perform primary therapeutic functions in the management and treatment of various diseases. It is reported that different types of pathogenesis occur due to the excessive production of oxidants (reactive nitrogen species and reactive oxygen species). The literature shows that a higher intake of fruits, vegetables, and other plant-based food is inversely related to treating different chronic diseases. Due to many phytonutrients (antioxidants) in fruits, vegetables, and other medicinal plants, they are considered major therapeutic agents for various diseases. The main purpose of this review is to summarize the major phytonutrients involved in preventing and treating diseases. Fourteen major phytonutrients are discussed in this review, such as polyphenols, anthocyanin, resveratrol, phytosterol (stigmasterol), flavonoids, isoflavonoids, limonoids, terpenoids, carotenoids, lycopene, quercetin, phytoestrogens, glucosinolates, and probiotics, which are well-known for their beneficial effects on the human body and treatment of different pathological conditions. It is concluded that phytonutrients play a major role in the prevention and treatment of diabetes mellitus, obesity, hypertension, cardiovascular disorders, other types of cancers, neurological disorders, age-related diseases, and inflammatory disorders and are also involved in various biological activities.

Enhancing stability and physiological activity of Aronia melanocarpa L. anthocyanin by polysaccharides

BACKGROUND

The existence of multiple phenolic hydroxyl groups in anthocyanins makes their structure unstable and leads to the degradation of anthocyanins. At present, there are few studies on the stability and physiological activity of Aronia melanocarpa L. anthocyanins by different polysaccharides. The present study investigated the effects of carboxymethyl cellulose (CMC), pectin and xanthan gum (XG) on the stability and biological activities of A. melanocarpa L. anthocyanins.

RESULTS

The anthocyanins of A. melanocarpa L. (AAM) were successfully extracted from A. melanocarpa L. with an extraction rate of 3.07 mg g-1 by single factor and response surface experiments. The results of scanning electron microscopy and a multispectral technique showed that AAM-polysaccharides complex was combined by hydrogen bond, cation-π interaction and electrostatic interaction. The AAM-polysaccharides complex improved the retention rate of anthocyanins after treatment with light, heating, oxidant reducing agent, metal ions and preservatives compared to the results for AAM alone. Determination of DPPH· scavenging capacity, ABTS+ scavenging capacity and total reducing capacity indicated that the presence of polysaccharide could improve the antioxidant activity of AAM in vitro. The three polysaccharides combined with AAM showed higher binding ability to taurocholate and glycocholate compared to the AAM group, with the AAM-XG binding rate being the highest at 27.61% and 20.61%, respectively. The tyrosinase inhibition rate significantly increased with the incorporation of XG, reaching 72.22%.

CONCLUSION

The stability and physiological activity of AAM were improved after the addition of CMC, pectin and XG in the simulated system, and the presence of XG showed greater advantages. The present study strongly suggests that anthocyanins driven by polysaccharides have a positive effect on the stability and physiological activity of anthocyanins and may also provide a research basis for the development of processing technology for anthocyanins in food. © 2024 Society of Chemical Industry.

Enzymatic treatment shapes in vitro digestion pattern of phenolic compounds in mulberry juice

The health benefits of mulberry fruit are closely associated with its phenolic compounds. However, the effects of enzymatic treatments on the digestion patterns of these compounds in mulberry juice remain largely unknown. This study investigated the impact of pectinase (PE), pectin lyase (PL), and cellulase (CE) on the release of phenolic compounds in whole mulberry juice. The digestion patterns were further evaluated using an in vitro simulated digestion model. The results revealed that PE significantly increased chlorogenic acid content by 77.8 %, PL enhanced cyanidin-3-O-glucoside by 20.5 %, and CE boosted quercetin by 44.5 %. Following in vitro digestion, the phenolic compound levels decreased differently depending on the treatment, while cyanidin-3-O-rutinoside content increased across all groups. In conclusion, the selected enzymes effectively promoted the release of phenolic compounds in mulberry juice. However, during gastrointestinal digestion, the degradation of phenolic compounds surpassed their enhanced release, with effects varying based on the compound's structure.

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.

Microfluidic paper-based analytical device for measurement of pH using as sensor red cabbage anthocyanins and gum arabic

The objective of this study was to develop and validate a novel microfluidic paper-based analytical device (μPADpH) for determining the pH levels in foods. Anthocyanins from red cabbage aqueous extract (RCAE) were used as its analytical sensor. Whatman No. 1 filter paper was the most suitable for the device due to its porosity and fiber organization, which allows for maximum color intensity and minimal color heterogeneity of the RCAE in the detection zone of the μPADpH. To ensure the color stability of the RCAE for commercial use of the μPADpH, gum arabic was added. The geometric design of the μPADpH, including the channel length and separation zone diameter, was systematically optimized using colored food. The validation showed that the μPADpH did not differ from the pH meter when analyzing natural foods. However, certain additives in processed foods were found to increase the pH values.

Potential interventions and interactions of bioactive polyphenols and functional polysaccharides to alleviate inflammatory bowel disease - A review

Inflammatory bowel disease is a multifaceted condition that is influenced by nutritional, microbial, environmental, genetic, psychological, and immunological factors. Polyphenols and polysaccharides have gained recognition for their therapeutic potential. This review emphasizes the biological effects of polyphenols and polysaccharides, and explores their antioxidant, anti-inflammatory, and microbiome-modulating properties in the management of inflammatory bowel disease (IBD). However, polyphenols encounter challenges, such as low stability and low bioavailability in the colon during IBD treatment. Hence, polysaccharide-based encapsulation is a promising solution to achieve targeted delivery, improved bioavailability, reduced toxicity, and enhanced stability. This review also discusses the significance of covalent and non-covalent interactions, and simple and complex encapsulation between polyphenols and polysaccharides. The administration of these compounds in appropriate quantities has proven beneficial in preventing the development of Crohn's disease and ulcerative colitis, ultimately leading to the management of IBD. The use of polyphenols and polysaccharides has been found to reduce histological scores and colon injury associated with IBD, increase the abundance of beneficial microbes, inhibit the development of colitis-associated cancer, promote the production of microbial end-products, such as short-chain fatty acids (SCFAs), and improve anti-inflammatory properties. Despite the combined effects of polyphenols and polysaccharides observed in both in vitro and in vivo studies, further human clinical trials are needed to comprehend their effectiveness on inflammatory bowel disease.

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.

Antioxidant Activity and Structural Characterization of Anthocyanin-Polysaccharide Complexes from Aronia melanocarpa

Anthocyanins and polysaccharides are among the primary components of numerous foodstuffs, and their interaction exerts a considerable influence on the texture and nutritional value of foods. In order to improve the antioxidant properties and stability of anthocyanins as well as their bioavailability, in this study, anthocyanin-polysaccharide complexes with varying compounding ratios (1:0.5, 1:1.0, 1:1.5, 1:2.0, 1:2.5, 1:3.0) were prepared from Aronia melanocarpa anthocyanins and polysaccharides derived from the fruit pomace of Aronia melanocarpa. These compounds were characterized, and their antioxidant capacity was determined. The findings demonstrated that the antioxidant activity of anthocyanins was markedly enhanced through the process of compounding with polysaccharides. The most efficacious antioxidant effect was determined by measuring the IC50 of the antioxidant activity of mixtures at different anthocyanin/polysaccharide complexing ratios. The results of ultraviolet-visible spectroscopy, infrared spectroscopy, and scanning electron microscopy revealed the features of the anthocyanin-polysaccharide complexes with ratios of 1:0.5, 1:1.0, 1:1.5, and 1:2.5. The anthocyanins and polysaccharides were observed to enhance the intensity of ultraviolet absorption with respect to that of the individual molecules, and it was noted that they were able to bond to each other through hydrogen bonding. Additionally, the morphology of the compositions differed from that of the individual components. This provides a theoretical foundation for the structural design of anthocyanin-polysaccharide-containing foods and the development and utilization of novel food ingredients.

The composition and structure of plant fibers affect their fining performance in wines

In recent years, the wine industry has shifted towards plant-based fining agents for food safety reasons and consumer preferences. This study analysed the interaction of five plant fibers with red wine phenolic compounds to determinate their performance as fining agents. Chemical composition, polysaccharide profile, and physical properties were examined. Pea, cellulose, and Sauvignon Blanc pomace fibers effectively reduced tannin content while minimally affecting the concentration of anthocyanins, flavonols and wine color. Contrary to previous beliefs, the presence of pectins in fibers didn't play a crucial role in phenolic compound interaction since cellulose-rich fibers with low pectin concentration also bound tannins effectively, especially those with small particle size and high contact surface. Pea fiber, rich in cellulose and pectins, showed remarkable tannin retention while minimally affecting wine color. This research highlights the potential of plant fibers as effective fining agents in wine production and how their composition affects their performance.

New Insights into pH-dependent Complex Formation between Lignosulfonates and Anthocyanins: Impact on Color and Oxidative Stability

Anthocyanins have limited application as natural colorants and antioxidants due to their color loss and instability under certain conditions. This research explores the formation of a complex between lignosulfonates (LS) and cyanidin-3-O-glucoside (C3G) using a multitechnique approach as well as the effect on C3G's red color, oxidative stability, and antioxidant activity in acidic mediums. All data revealed pH-dependent LS-C3G interactions. The thermodynamic parameters showed weak noncovalent interactions, mainly electrostatic interactions, hydrogen bonds, and hydrophobic effect, with a higher association constant determined at pH 3. Fourier-transform infrared spectroscopy and Zeta-potential experiments further corroborate evidence of these LS-C3G interactions. Fluorescence quenching and lifetime experiments revealed static and dynamic quenching at pH 1 and 3, respectively. UV-visible spectroscopy demonstrated a bathochromic shift upon complex formation and a hyperchromic effect at pH 3 and 4, as a consequence of the improved red color of C3G. Electrochemical results suggested that at pH 3 the LS enhances C3G stability by protecting its oxidizable moieties over time, as well as improving the antioxidant activity of the anthocyanin in the complex.

Effects of acetylated polysaccharide on the prebiotic properties of grape seed proanthocyanidins - Based on in vitro fermentation with Artemisia sphaerocephala Krasch glucomannan

This study evaluated the impact of Artemisia sphaerocephala Krasch glucomannan with different degrees of acetyl group substitution (DS) on the prebiotic properties of grape seed proanthocyanidins (GSP). UV spectra, CIELab, and dynamic light scattering analyses indicated DS-influenced variable interactions between GSP and glucomannan. In vitro fermentation demonstrated that glucomannan enhanced the solubility of some phenolic compounds, and decreased the pH value of fermentation liquids. The production of acetate acid and total short chain fatty acids in the GSP fermentation liquid increased with the degree of DS of glucomannan. Notably, acetylated glucomannan exerted dramatic effects on GSP-induced gut microbiota modulation. The relative abundances of Bacteroides ovatus and Bacteroides decreased as DS increased. Meanwhile, Bacteroides acidifaciens and Akkermansia muciniphila have a positive correlation, even though the GSP-promoted enrichment of A. muciniphila was inhibited by the added glucomannan. Moreover, glucomannan enhanced the metabolism of nucleotides, secondary bile acid, and glycan inhibited by GSP. These findings suggest that acetylated glucomannan affect the prebiotic properties of GSP with its DS serving as a key factor.

Plant-derived polyphenolic compounds: nanodelivery through polysaccharide-based systems to improve the biological properties

Plant-derived polyphenols are naturally occurring compounds widely distributed in plants. They have received greater attention in the food and pharmaceutical industries due to their potential health benefits, reducing the risk of some chronic diseases due to their antioxidant, anti-inflammatory, anticancer, cardioprotective, and neuro-action properties. Polyphenolic compounds orally administered can be used as adjuvants in several treatments but with restricted uses due to chemical instability. The review discusses the different structural compositions of polyphenols and their influence on chemical stability. Despite the potential and wide applications, there is a need to improve the delivery of polyphenolics to target the human intestine without massive chemical modifications. Oral administration of polyphenols is unfeasible due to instability, low bioaccessibility, and limited bioavailability. Nano-delivery systems based on polysaccharides (starch, pectin, chitosan, and cellulose) have been identified as a viable option for oral ingestion, potentiate biological effects, and direct-controlled delivery in specific tissues. The time and dose can be individualized for specific diseases, such as intestinal cancer. This review will address the mechanisms by which polysaccharides-based nanostructured systems can protect against degradation and enhance intestinal permeation, oral bioavailability, and the potential application of polysaccharides as nanocarriers for the controlled and targeted delivery of polyphenolic compounds.

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.

Intermolecular interactions between malvidin-3-O-glucoside and caffeic acid: Structural and thermodynamic characterization and its effect on real wine color quality

The copigmentation effect between malvidin-3-O-glucoside and caffeic acid was comprehensive inquiry on the model wine solution, theoretical simulation and real wine. Thermodynamic parameters were determined by UV/Visible spectroscopy and Isothermal titration calorimetry (ITC). Theoretical data were obtained employing a dispersion-corrected density functional approach. The effects in real wines were investigated by adding the caffeic acid during different fermentation periods. Results shown that the copigmentation reaction between caffeic acid and malvidin-3-O-glucoside is a spontaneous exothermic reaction driven by hydrogen bonding and dispersions forces. Computations show that the polyhydroxyl sugar moiety and phenolic hydroxyl groups are the key active sites. The addition of caffeic acid in post-alcohol fermentation samples evidences an improving color characteristics in the wine.

Formation of chlorophyll-anionic polysaccharide complex coacervates to improve chlorophyll color stability: Thermodynamic and kinetic stability studies

Chlorophyll (Chl) is the predominant pigment in green plants that can act as a food color and possesses various functional activities. However, its instability and rapid degradation on heating compromise the sensory qualities of its products. This study aimed to enhance the heat resistance of Chl by forming complex coacervates with two negatively charged polysaccharides, sodium alginate (SA) and K-carrageenan (KC). Dynamic light scattering and scanning electron microscopy analyses confirmed the formation of coacervates between Chl and the polysaccharides, whereas Fourier-transform infrared spectroscopy revealed that hydrogen bonding and electrostatic attraction were the primary forces behind complex formation. Electron spin resonance and thermodynamic studies further revealed that these complexes bolstered the thermal stability of Chl, with a maximum improvement of 70.38 % in t1/2 and a reduction of 50.72 % in the degradation rate constant. In addition, the antioxidant capacity of Chl was enhanced up to 35 %. Therefore, this study offers a novel approach to Chl preservation and suggests a viable alternative to artificial pigments in food products.

Plant-Based Meat Analogues: Exploring Proteins, Fibers and Polyphenolic Compounds as Functional Ingredients for Future Food Solutions

As the lack of resources required to meet the demands of a growing population is increasingly evident, plant-based diets can be seen as part of the solution, also addressing ethical, environmental, and health concerns. The rise of vegetarian and vegan food regimes is a powerful catalyzer of a transition from animal-based diets to plant-based diets, which foments the need for innovation within the food industry. Vegetables and fruits are a rich source of protein, and bioactive compounds such as dietary fibres and polyphenols and can be used as technological ingredients (e.g., thickening agents, emulsifiers, or colouring agents), while providing health benefits. This review provides insight on the potential of plant-based ingredients as a source of alternative proteins, dietary fibres and antioxidant compounds, and their use for the development of food- and alternative plant-based products. The application of these ingredients on meat analogues and their impact on health, the environment and consumers' acceptance are discussed. Given the current knowledge on meat analogue production, factors like cost, production and texturization techniques, upscaling conditions, sensory attributes and nutritional safety are factors that require further development to fully achieve the full potential of plant-based meat analogues.

Stabilization effect and interaction mechanism of mannoprotein on anthocyanins in mulberry juice

This study aimed to investigate the problem of color instability in mulberry juice, examine the effect of mannoprotein (MP) dosage on improving the stability of anthocyanins in mulberry juice, and explore the molecular binding mechanism between them. As the mass ratio of anthocyanins to MP of 1.07 × 10-3: 1-1.65 × 10-3: 1, the retention rates of anthocyanins in mulberry juice and simulated system were significantly improved in the photostability experiment, with the highest increase of 128.89 % and 24.11 %, respectively. In the thermal stability experiment, it increased by 7.96 % and 18.49 %, respectively. The synergistic effect of combining MP with anthocyanins has been demonstrated to greatly enhance their antioxidant capacity, as measured by ABTS, FRAP, and potassium ferricyanide reduction method. Furthermore, MP stabilized more anthocyanins to reach the intestine in simulated in vitro digestion. MP and cyanidin-3-glucoside (C3G) interacted with each other through hydrogen bonding and hydrophobic interactions. Specific amino acid residues involved of MP in binding process were identified as threonine (THR), isoleucine (ILE) and arginine (ARG). The identification of the effective mass concentration ratio range and binding sites of MP and anthocyanins provided valuable insights for the application of MP in mulberry juice.

Pectin forms polymeric pigments by complexing anthocyanins during red winemaking and ageing

The long-term stability of red wine color depends on the formation of polymeric pigments from anthocyanins. Although there is still a lot of uncertainty about the specific structure of this diverse group of pigments, there is consensus that they are reaction products of anthocyanins and other polyphenols. Interactions between anthocyanins and pectic polysaccharides have been suggested to stabilize anthocyanins. This study explores the impact of such interactions by adding pectin during red winemaking. The results demonstrate that these interactions induce the formation of additional polymeric pigments which enhance the pigment stability during fermentation and aging. While initial pigment formation is higher in wines with added pectin, a notable proportion of the complexes degrades in the later stages of fermentation. Presumably, tannins form insoluble complexes with pectin, reducing tannin concentration by more than 300 mg/L. Anthocyanin concentrations decrease by over 400 mg/L, and polymeric pigments double. Anthocyanins that form polymeric pigments with pectic polysaccharides expand the range of pigments in red wines with possible consequences for the sensory properties of the wine. These findings highlight the complex interactions between pectin, anthocyanins, and tannins, and their influence on pigment formation and wine composition during fermentation and aging.

Unveiling the impact of high-pressure processing on anthocyanin-protein/polysaccharide interactions: A comprehensive review

Anthocyanins, natural plant pigments responsible for the vibrant hues in fruits, vegetables, and flowers, boast antioxidant properties with potential human health benefits. However, their susceptibility to degradation under conditions such as heat, light, and pH fluctuations necessitates strategies to safeguard their stability. Recent investigations have focused on exploring the interactions between anthocyanins and biomacromolecules, specifically proteins and polysaccharides, with the aim of enhancing their resilience. Notably, proteins like soy protein isolate and whey protein, alongside polysaccharides such as pectin, starch, and chitosan, have exhibited promising affinities with anthocyanins, thereby enhancing their stability and functional attributes. High-pressure processing (HPP), emerging as a non-thermal technology, has garnered attention for its potential to modulate these interactions. The application of high pressure can impact the structural features and stability of anthocyanin-protein/polysaccharide complexes, thereby altering their functionalities. However, caution must be exercised, as excessively high pressures may yield adverse effects. Consequently, while HPP holds promise in upholding anthocyanin stability, further exploration is warranted to elucidate its efficacy across diverse anthocyanin variants, macromolecular partners, pressure regimes, and their effects within real food matrices.

The effects of inulin on solubilizing and improving anti-obesity activity of high polymerization persimmon tannin

High polymerization persimmon tannin has been reported to have lipid-lowering effects. Unfortunately, the poor solubility restricts its application. This research aimed to investigate the effect and mechanism of inulin on solubilizing of persimmon tannin. Furthermore, we examined whether the addition of inulin would affect the attenuated obesity effect of persimmon tannin. Transmission electron microscope (TEM), Isothermal titration calorimetry (ITC) and Fourier transform infrared spectroscopy (FT-IR) results demonstrated that inulin formed a gel-like network structure, which enabled the encapsulation of persimmon tannin through hydrophobic and hydrogen bond interactions, thereby inhibiting the self-aggregation of persimmon tannin. The turbidity of the persimmon tannin solution decreased by 56.2 %, while the polyphenol content in the supernatant increased by 60.0 %. Furthermore, biochemical analysis and 16s rRNA gene sequencing technology demonstrated that persimmon tannin had a significant anti-obesity effect and improved intestinal health in HFD-fed mice. Moreover, inulin was found to have a positive effect on enhancing the health benefits of persimmon tannin, including improving hepatic steatosis and gut microbiota dysbiosis. it enhanced the abundance of beneficial core microbes while decreasing the abundance of harmful bacteria. Our findings expand the applications of persimmon tannin in the food and medical sectors.

Partitioning and in vitro bioaccessibility of apple polyphenols during mechanical and physiological extraction: A hierarchical clustering analysis with LC-ESI-QTOF-MS/MS

Polyphenol partitioning during mechanical (cold-pressing) and physiological (digestion) extraction at the individual polyphenol and subclass level was investigated. UHPLC-ESI-QTOF-MS/MS analysis yielded a comprehensive identification of 45 polyphenols whose semi-quantification revealed a hierarchical clustering strongly determined by polyphenol structure and their location within the apple tissue. For instance, pomace retained most flavonols and flavanols (degree of polymerization DP 5-7), which were highly hydrophobic, hydroxylated, or large (>434 Da), and more abundant in peel. In vitro digestion UHPLC-ESI-QTOF-MS/MS analysis of whole apple (and its corresponding matrix-free extract) clustered polyphenols into five main groups according to their interaction with plant cell walls (PCWs) during each digestion phase. This grouping was not reproduced in pomace, which exhibited a greater matrix effect than whole apple during oral and gastric digestion. Nevertheless, the interaction between most polyphenol groups, including dihydrochalcones, flavanols (DP 1-4) and hydroxycinnamic acid derivatives, and pomace PCWs was lost during intestinal digestion.

Influence of Grape Flesh on the Retention and Composition of Polyphenols from Skins and Seeds

This study examined the impact of grape flesh polysaccharide, protein, and amino acid contents on polyphenol retention from skins and seeds in Pinot noir (Vitis vinifera) and cold-hardy interspecific cultivars Marquette and Frontenac (Vitis spp.). After isolating grape tissues (skin, seed, and flesh), they were soaked either individually or combined with other tissues in a wine-like solution for up to 7 days. Findings revealed that flesh significantly reduces the concentration of condensed tannin, and mono- and diglucoside forms of anthocyanins in the supernatants, due to its rich content in polysaccharides and proteins. Frontenac skin and flesh tissues were the main sources of soluble proteins, amino acids, and soluble polysaccharides. Surprisingly, Marquette exhibited a higher retention of skin tannin than Pinot noir, likely due to its smaller tannin molecular mass, and a potential competitive effect with anthocyanins for the binding sites of flesh.

Effect of ultrasonic modification on the binding ability of pectin to anthocyanin

BACKGROUND

Pectin was considered as a potential candidate to improve the thermal stability of anthocyanins, and the binding ability of pectin to anthocyanins was influenced by its structure. In this study, sunflower pectins, modified by ultrasound (40 kHz) for different periods of time, were prepared and used to bind with anthocyanins, extracted from purple sweet potato.

RESULTS

Characterization and thermal stability of pectin-anthocyanin complexes were investigated. The ultrasonic modification of pectin resulted in many changes in pectin chemical structure, including degradation of neutral sugar side chains, breakage of methoxyl groups, and increased molecular flexibility. Extension of ultrasonic modification time led to greater changes in pectin chemical structure. Analysis of the binding ability, as determined by Fourier transform infrared spectroscopy and molecular dynamics simulations, revealed that the interaction between pectin and anthocyanins was driven by hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Pectins with different ultrasonic modification times bound with anthocyanins to different extents, mainly resulting from an increase in the number of hydrogen bonds. According to high-performance liquid chromatographic analysis, during heating at 90 °C the stronger the binding ability of pectin and anthocyanin complex, the better was its thermal stability.

CONCLUSION

Ultrasonic modification of pectin could effectively enhance its binding ability to anthocyanin. © 2023 Society of Chemical Industry.

Study on the Digestive Behavior of Chlorogenic Acid in Biomimetic Dietary Fiber and the Antioxidative Synergistic Effect of Polysaccharides and Chlorogenic Acid

Chlorogenic acid (CA) is often combined with dietary fiber polysaccharides in plant foods, which may affect its digestive behavior and antioxidant activity. This study constructed a biomimetic dietary fiber (BDF) model by combining bacterial cellulose (BC) and pectin with CA and investigated the digestive behavior of CA in BDF. Additionally, the study examined the interaction and synergistic effects of polysaccharides and CA against oxidation. Results showed that BDF and natural dietary fiber had similar microstructures, group properties, and crystallization properties, and polysaccharides in BDF were bound to CA. After simulated gastrointestinal digestion, 41.03% of the CA existed in a conjugated form, and it was possibly influenced by the interaction between polysaccharides and CA. And the release of CA during simulated digestion potentially involved four mechanisms, including the disintegration of polysaccharide-CA complex, the dissolution of pectin, escape from BC-pectin (BCP) network structure, and diffusion release. And polysaccharides and CA may be combined through noncovalent interactions such as hydrogen bonding, van der Waals force, or electrostatic interaction force. Meanwhile, polysaccharides-CA combination had a synergistic antioxidant effect by the results of free-radical scavenging experiments, it was probably related to the interaction between polysaccharides and CA. The completion of this work has a positive significance for the development of dietary intervention strategies for oxidative damage.

Pectin conformation influences the bioaccessibility of cherry laurel polyphenols and gut microbiota distribution following in vitro gastrointestinal digestion and fermentation

Interactions between dietary fiber and phenolic compounds in foods can influence their gastrointestinal fate. This study aimed to examine the effect of four types of pectin on the polyphenols of cherry laurel puree and human gut microbiota during a simulated in vitro gastrointestinal digestion and large intestine fermentation. Results revealed that the combined addition of different pectins and pectinase to cherry laurel puree significantly affected the content and bioaccessibility of phenolics. The addition of pectins and pectinase distinctively impacted the phenolic subclasses in both raw and post-digested/fermented cherry laurel puree, suggesting differential interactions due to structural features. Both pectins and pectinase modulated the composition of fecal microbiota after in vitro fermentation, increasing bacterial diversity following pectinase treatment. The combined addition of pectins followed by pectinase had differential impacts on polyphenol bioaccessibility and gut microbiome diversity, hence having a potential outcome in terms of human health.

Effects of sunflower pectin on thermal stability of purple sweet potato anthocyanins at different pH

The present study aimed to examine the impact of sunflower pectin (SFP) on the thermal stability and antioxidant activity of purple sweet potato anthocyanins (PSPA) at varying pH levels. It was observed that the pH value significantly influenced the ability of pectin to protect anthocyanins from thermal degradation, which was found to be associated with the rate of binding between PSPA and SFP. The binding rate of PSPA-SFP was observed to be highest at pH 4.0, primarily due to the influence of electrostatic interaction and hydrogen bonding. Monoacylated anthocyanins exhibited a binding rate approximately 2-4 % higher than that of diacylated anthocyanins. The PSPA-SFP demonstrated its highest thermal stability at pH 4.0, with a corresponding half-life of 14.80 h at 100 °C. Molecular dynamics simulations indicated that pectin had a greater affinity for the flavylium cation and hemiketal form of anthocyanins. The antioxidant activity of anthocyanins in PSPA and PSPA-SFP increased with increasing pH, suggesting that anthocyanins at high pH had higher antioxidant activity than anthocyanins at low pH.

Research progress in extraction, purification, structure of fruit and vegetable polysaccharides and their interaction with anthocyanins/starch

Fruits and vegetables contain polysaccharides, polyphenols, antioxidant enzymes, and various vitamins, etc. Fruits and vegetables polysaccharides (FVPs), as an important functional factor in health food, have various biological activities such as lowering blood sugar, blood lipids, blood pressure, inhibiting tumors, and delaying aging, etc. In addition, FVPs exhibit good physicochemical properties including low toxicity, biodegradability, biocompatibility. Increasing research has confirmed that FVPs could enhance the stability and biological activities of anthocyanins, affecting their bioavailability to improve food quality. Simultaneously, the addition of FVPs in natural starch suspension could improve the physicochemical properties of natural starch such as viscosity, gelling property, water binding capacity, and lotion stability. Hence, FVPs are widely used in the modification of natural anthocyanins/starch. A systematic review of the latest research progress and future development prospects of FVPs is very necessary to better understand them. This paper systematically reviews the latest progress in the extraction, purification, structure, and analysis techniques of FVPs. Moreover, the review also introduces the potential mechanisms, evaluation methods, and applications of the interaction between polysaccharides and anthocyanins/starch. The findings can provide important references for the further in-depth development and utilization of FVPs.

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Why is it important to understand the nature and chemistry of tannins to exploit their potential as nutraceuticals?

Tannins comprise a large group of polyphenols that can differ widely in chemical composition and molecular weight. The use of tannins dates back to antiquity, but it is only in recent years that their potential use as nutraceuticals associated with the human diet is beginning to be exploited. Although the biological effects of these phytocomplexes have been studied for many years, there are still several open questions regarding their chemistry and biotransformation. The vastness of the molecules that make up the class of tannins has made their characterisation, as well as their nomenclature and classification, a daunting task. This review has been written with the aim of bringing order to the chemistry of tannins by including aspects that are sometimes still overlooked or should be updated with new research in order to understand the potential of these phytocomplexes as active ingredients or technological components for nutraceutical products. Future trends in tannin research should address many questions that are still open, such as determining the exact biosynthetic pathways of all classes of tannins, the actual biological effects determined by the interaction of tannins with other molecules, their metabolization, and the best extraction methods, but with a view to market requirements.

Soluble polysaccharides decrease inhibitory activity of banana condensed tannins against porcine pancreatic lipase

The inhibition of soluble polysaccharides (SPs) (arabic gum, dextran and pectin from citrus) on the binding between banana condensed tannins (BCTs) and pancreatic lipase (PL) was studied from variant aspects. Molecular docking simulations predicted that BCTs strongly bound SPs and PL through non-covalent interactions. The experimental results showed that SPs reduced the inhibition of BCTs on PL, and the IC₅₀ value increased. However, the addition of SPs did not change the inhibitory type of BCTs on PL, which all were non-competitive inhibition. BCTs quenched PL fluorescence through static quenching mechanism and changed the secondary structure of PL. The addition of SPs alleviated the trending. The effect of SPs on the binding of BCTs-PL was mainly due to the strong non-covalent interaction between SPs and BCTs. This study emphasized that attention should be paid to the counteracting effects of polysaccharides and polyphenols in dietary intake to maximize their respective roles.

Stabilization of anthocyanins by simultaneous encapsulation-copigmentation via protein-polysaccharide polyelectrolyte complexes

This study prepared a series of polyelectrolyte complexes (PECs) composed of heated whey protein isolate (HWPI) and different polysaccharides for simultaneous encapsulation and copigmentation of anthocyanins (ATC) and their ultimate stabilization. Four polysaccharides including chondroitin sulfate, dextran sulfate, gum arabic, and pectin were chosen due to their abilities to simultaneously complex with HWPI and copigment ATC. At pH 4.0, these PECs were formed with an average particle size of 120-360 nm, the ATC encapsulation efficiency of 62-80%, and the production yield of 47-68%, depending on the type of polysaccharides. The PECs effectively inhibited the degradation of ATC during storage and when exposed to neutral pH, ascorbic acid, and heat. Pectin had the best protection, followed by gum arabic, chondroitin sulfate, and dextran sulfate. The stabilizing effects were associated with the hydrogen bonding, hydrophobic and electrostatic interactions between HWPI and polysaccharides, conferring dense internal network and hydrophobic microenvironment in the complexes.

Interaction of starch and non-starch polysaccharides in raw potato flour and their effects on thickening stability

The present study sought to explore the potential of raw potato flour prepared from two common potato varieties (Atlantic and Favorita) as a thickener and the underlying mechanisms of its thickening stability based on the chemical component content, chemical group, starch, pectin, cell wall integrity, and the cell wall strength of raw potato flour. The raw potato flour prepared from Favorita potato (FRPF) showed great potential as a thickener with a valley viscosity/peak viscosity of 97.24 %. Additionally, the viscosity of FRPF after heat treatment, acid treatment and shear treatment was maintained at 70.73 %, 65.99 % and 78.89 % of the original viscosity, respectively, which is better than that of ARPF (44.98 %, 47.03 % and 61.57 %, respectively). The results also revealed that high pectin content, cell wall integrity and strength contributed significantly to the thickening stability of potato meal, which was achieved by limiting the swelling and disintegration of starch. Finally, the correctness of the principle was verified using the raw potato flour prepared from four types of potatoes (Heijingang, Innovator, Qingshu No. 9, and Guinongshu No. 1). Overall, the development of thickener from raw potato flour has broadened the variety of clean label additives in the food industry.

Intermolecular binding of blueberry anthocyanins with water-soluble polysaccharides: Enhancing their thermostability and antioxidant abilities

This study investigated the protective effect of β-glucan (BG), konjac glucomannan (KGM) and xanthan gum (XG) on thermo-stability and antioxidant capacities of blueberry anthocyanins (ACN) and their interaction mechanisms. Twenty-six glycosylated and acylated ACN were identified, and malvidin-3-O-galactose was predominant (36.78 %) in ACN extracts. Three polysaccharides retained colour and stability and antioxidant capabilities of ACN under thermal-treatments (XG > KGM > BG). Rheological properties (shear stress, apparent viscosity) of three polysaccharides were enhanced in presence of ACN. UV-visible spectra, SEM and DLS results indicated that co-aggregation between ACN and specific zones of these polysaccharides was formed. TGA and DSC studies confirmed that introductionof three polysaccharides, especially XG could improve thermostability of ACN. FTIR, and molecular dynamics simulations revealed that thermo-stabilization of polysaccharides-ACN conjugates might be attributedto their intermolecular interactions mainly via hydrogen bindings. The protection by water-soluble polysaccharides foresees novel anthocyanins in food products with increased heat-resistant stability.

Valorization of polyphenolic compounds from food industry by-products for application in polysaccharide-based nanoparticles

In the last decades, evidence has indicated the beneficial properties of dietary polyphenols. In vitro and in vivo studies support that the regular intake of these compounds may be a strategy to reduce the risks of some chronic non-communicable diseases. Despite their beneficial properties, they are poorly bioavailable compounds. Thus, the main objective of this review is to explore how nanotechnology improves human health while reducing environmental impacts with the sustainable use of vegetable residues, from extraction to the development of functional foods and supplements. This extensive literature review discusses different studies based on the application of nanotechnology to stabilize polyphenolic compounds and maintain their physical-chemical stability. Food industries commonly generate a significant amount of solid waste. Exploring the bioactive compounds of solid waste has been considered a sustainable strategy in line with emerging global sustainability needs. Nanotechnology can be an efficient tool to overcome the challenge of molecular instability, especially using polysaccharides such as pectin as assembling material. Complex polysaccharides are biomaterials that can be extracted from citrus and apple peels (from the juice industries) and constitute promising wall material stabilizing chemically sensitive compounds. Pectin is an excellent biomaterial to form nanostructures, as it has low toxicity, is biocompatible, and is resistant to human enzymes. The potential extraction of polyphenols and polysaccharides from residues and their inclusion in food supplements may be a possible application to reduce environmental impacts and constitutes an approach for effectively including bioactive compounds in the human diet. Extracting polyphenolics from industrial waste and using nanotechnology may be feasible to add value to food by-products, reduce impacts on nature and preserve the properties of these compounds.

Enhanced TSG stability through co-assembly with C3G: the mechanism behind processing Polygonum multiflorum Thunb with black beans via supramolecular analysis

Elucidating the underlying mechanism of the processing of Chinese herbal medicine (CHM) is crucial and also challenging for the modernization of Traditional Chinese Medicine (TCM). Herein, inspired by the traditional method for processing the Chinese herb Polygonum multiflorum (PM) Thunb with excipient black beans, the representative herbal components trans-2,3,5,4'-tetrahydroxystilbene 2-O-β-D-glucopyranoside (TSG) and cyanidin-3-O-β-glucoside (C3G) from each herbal medicine were selected to investigate the processing mechanism at the supramolecular level. The co-assemblies of TSG/C3G were found to be formed, and their structure was characterized by electronic microscopy and a small angle X-ray scattering (SAXS) technique. In addition, the supramolecular interactions between TSG and C3G were fully probed with UV-Vis, fluorescence, XRD, and NMR spectroscopy. Molecular dynamics were further performed to simulate the assembly processes of TSG and C3G. Notably, the formation of TSG/C3G co-assemblies was found to significantly enhance the stability of TSG against light, Fe3+, and simulated intestinal fluids. The co-assembly of TSG and C3G that leads to supramolecular aggregates discovered here may imply the underlying mechanism of processing PM with black beans. Our results may also suggest that a new effective form of TCM is supramolecular aggregates rather than each component.

Toward gentle chokeberry juice production by ultrasound-assisted enzymatic maceration

Sustainable processes accompanied by high extraction yields and minimized amounts of by-products are a major goal of current fruit juice production. Controlled degradation of cell wall polysaccharides, in particular pectin, may contribute to reduced emergence of side streams. Possible strategies for the optimization are the selection of enzyme preparations based on comprehensive studies of their activities, the adjustment of maceration temperature toward more gentle conditions, and the application of alternative technologies such as ultrasound (US) during maceration. The present study provides insights into the effects of ultrasound-assisted enzymatic maceration (UAEM) on pectin degradation, total anthocyanin content, thermal and storage stability, and juice yield during chokeberry juice production on pilot-plant scale. The two enzyme preparations applied predominantly possessed polygalacturonase or pectin lyase activity. Cell wall polysaccharide degradation was improved by US and resulted in a 3% increase in juice yield by UAEM using an enzyme preparation that shows mostly polygalacturonase activity. Thermostability of anthocyanins was improved in juices produced using pectin lyase and applying US and matched the stability of anthocyanins in juices produced using polygalacturonase. Storage stability of anthocyanins was improved in juice produced using polygalacturonase during UAEM. UAEM also resulted in lower yields of pomace making the production more resource-efficient. Overall, the use of polygalacturonase has promising potential to advance conventional chokeberry juice production by applying US at gentle conditions.

Physicochemical Properties, Antioxidant Capacity, and Bioavailability of Laurus nobilis L. Leaf Polyphenolic Extracts Microencapsulated by Spray Drying

Laurel (Laurus nobilis L.) leaves are a rich source of polyphenols with the potential for use in functional foods, where the main obstacle is their low stability and bioavailability, which can be improved by spray drying (SD). This research examined the influence of SD parameters, including inlet temperature (120, 150, and 180 °C), carrier type (β-cyclodextrin (β-CD); β-CD + maltodextrin (MD) 50:50; β-CD + gum arabic (GA) 50:50), and sample:carrier ratio (1:1, 1:2 and 1:3) on the physicochemical properties, encapsulation efficiency, polyphenolic profile, antioxidant capacity and bioaccessibility of laurel leaf polyphenols. The highest encapsulation efficiency was achieved at a sample:carrier ratio 1:2 and the temperature of 180 °C by using either of the applied carriers. However, the application of β-CD + MD 50:50 ensured optimal solubility (55.10%), hygroscopicity (15.32%), and antioxidant capacity (ORAC 157.92 μmol Trolox equivalents per g of powder), while optimal moisture content (3.22%) was determined only by temperature, demanding conditions above 150 °C. A total of 29 polyphenols (dominantly flavonols) were identified in the obtained powders. SD encapsulation increased the bioaccessibility of laurel flavonols in comparison to the non-encapsulated extract by ~50% in the gastric and ~10% in the intestinal phase, especially for those powders produced with carrier mixtures.

Exploring the influence of S. cerevisiae mannoproteins on wine astringency and color: Impact of their polysaccharide part

The impact of the polysaccharide moiety of mannoproteins (MPs) on the color and astringency of red wines was studied respectively through spectrophotometry and their impact on tannin interactions with BSA. To this end, MPs with conserved native structures from four different Saccharomyces cerevisiae strains were used: a Wild-Type strain (BY4742, WT) taken as reference, mutants ΔMnn4 (with no mannosyl-phosphorylation) and ΔMnn2 (linear N-glycosylation backbone), and a commercial enological strain. MPs affected tannin-BSA interactions by delaying aggregation kinetics. To achieve it, a well-balanced density/compactness of the polysaccharide moiety of MPs was a key factor. MP-WT and MP-Mnn2 acted as weak copigments and induced a slight increase in the absorbance of Malvidin-3-O-Glucoside. The same MPs also promoted a synergistic effect during the copigmentation of Quercetin-3-O-Glucoside with Malvidin-3-O-Glucoside. The intensity of these hyperchromic effects was related to the accessibility of anthocyanins to negatively charged mannosyl-phosphate groups within the polysaccharide moiety.

Focus on the relationships between the cell wall composition in the extraction of anthocyanins and tannins from grape berries

Concentrations of anthocyanins and tannins after extraction from berries in wines and from skin macerations in model solutions have been studied for two grape varieties, two maturation levels and two vintages berries. Characterization of the cell wall polysaccharides has also been performed, the classical method based on the analysis of the neutral sugars after depolymerization being completed by a comprehensive microarray polymer profiling (CoMPP). Extraction was lower in model solutions than in wines, with the same ranking: non acylated anthocyanins> tannins > p-coumaroylated anthocyanins. The polysaccharidic composition suggested a role of homogalacturonans, rhamnogalacturonans and extensins in the extraction process. A global explanation of the interactions between anthocyanins, tannins and polysaccharides is proposed.

Extraction of polyphenols associated with pectin from olive waste (alperujo) with choline chloride

The main by-product from olive oil extraction (alperujo) was extracted with hot water, citric acid, natural deep eutectic solvent (choline chloride: citric acid), and only choline chloride. The purified extracts were composed of macromolecular complexes constituting polyphenols associated with pectin. The extracts were structurally characterized by FT-IR and solid-NMR spectroscopy and an in vitro test revealed distinct antioxidant and antiproliferative activity, depending on the extracting agents. The choline chloride-extracted complex contained the highest amount of polyphenols among the examined agents, which exhibited a strong antioxidant activity and significant antiproliferative capacity. However, the complex extracted by hot water showed the highest antiproliferative capacity in vitro against the colon carcinoma Caco-2 cell line. In this finding, choline chloride could be used as a novel, green and promising alternative to the conventional extracting agent for the production of complexes that combine the antioxidant activity of phenolic compounds and the physiological effects of pectic polysaccharides.

Anthocyanins: Modified New Technologies and Challenges

Anthocyanins are bioactive compounds belonging to the flavonoid class which are commonly applied in foods due to their attractive color and health-promoting benefits. However, the instability of anthocyanins leads to their easy degradation, reduction in bioactivity, and color fading in food processing, which limits their application and causes economic losses. Therefore, the objective of this review is to provide a systematic evaluation of the published research on modified methods of anthocyanin use. Modification technology of anthocyanins mainly includes chemical modification (chemical acylation, enzymatic acylation, and formation of pyran anthocyanidin), co-pigmentation, and physical modification (microencapsulation and preparation of pickering emulsion). Modification technology of anthocyanins can not only increase bioavailability and stability of anthocyanin but also can improve effects of anthocyanin on disease prevention and treatment. We also propose potential challenges and perspectives for diversification of anthocyanin-rich products for food application. Overall, integrated strategies are warranted for improving anthocyanin stabilization and promoting their further application in the food industry, medicine, and other fields.

Pectin-based nanoencapsulation strategy to improve the bioavailability of bioactive compounds

Pectin is one of the polysaccharides to be used as a coating nanomaterial. The characteristics of pectin are suitable to form nanostructures for protection, increased absorption, and bioavailability of different active compounds. This review aims to point out the structural features of pectins and their use as nanocarriers. It also indicates the principal methodologies for the elaboration and application of foods. The research carried out shows that pectin is easily extracted from natural sources, biodegradable, biocompatible, and non-toxic. The mechanical resistance and stability in different pH ranges and the action of digestive enzymes allow the nanostructures to pass intact through the gastrointestinal system and be effectively absorbed. Pectin can bind to macromolecules, especially proteins, to form stable nanostructures, which can be formed by different methods; polyelectrolyte complexes are the most frequent ones. The pectin-derived nanoparticles could be added to foods and dietary supplements, demonstrating a promising nanocarrier with a broad technological application.

Protein-binding approaches for improving bioaccessibility and bioavailability of anthocyanins

Color is an important characteristic of food. Over the last 15 years, more attention has been paid to natural colorants because of the rising demand for clean-label food products. Anthocyanins, which are a group of phytochemicals responsible for the purple, blue or red hues of many plants, offer a market advantage. In addition, anthocyanin-rich foods are associated with protection against cardiovascular disease, thrombosis, diabetes, cancer, microbial-based disorders, neurological disorders, and vision ailments. However, the real health value of anthocyanins, whether as a natural colorant or a functional ingredient, is dependent on the ultimate bioaccessibility and bioavailability in the human body. Many animal and human clinical studies revealed that, after intake of anthocyanin-rich foods or anthocyanin extracts, only trace amounts (< 1% of ingested content) of anthocyanins or their predicted metabolites were detected in plasma after a standard blood draw, which was indicative of low bioavailability of anthocyanins. Protein binding to anthocyanins is a strategy that has recently been reported to enhance the ultimate bioactivity, bioaccessibility, and bioavailability of anthocyanins as compared to anthocyanins delivered without a protein carrier. Therefore, in this review, we address anthocyanin properties in food processing and digestion, anthocyanin-protein complexes used in food matrices, and changes in the bioaccessibility and bioavailability of anthocyanins when bound into anthocyanin-protein complexes in foods. Finally, we summarize the challenges and prospects of this delivery system for anthocyanin pigments.

Grape-derived pectic polysaccharides alter the tannin and pigment composition of Cabernet Sauvignon red wines

Tannins, anthocyanins, and polymeric pigments are essential phenolic constituents of red wine because they provide color, color stability, and mouthfeel properties like astringency. The behavior of these compounds is significantly affected by pectic polysaccharides, whereby the extent of their influence on red wine quality depends on their structural features and their interactions with the polyphenols. In the present study, the composition of the pectic polysaccharides of commercially available Cabernet Sauvignon wines and their impact on anthocyanin, tannin, and polymeric pigment analyses was characterized. This was accomplished by preparation of polysaccharide deprived wines and comparison of the polyphenolic composition of both, the wines and their corresponding polysaccharide-free counterparts. The results show that the cell wall fragments enhance the spectral absorbance of anthocyanins by facilitating anthocyanin self-association, leading to a co-pigmentation-like effect. Low molecular weight pectins like rhamnogalacturonan II and polygalacturonic acids with a low degree of esterification are assumed to form soluble complexes with anthocyanins and also prevent protein precipitation of tannins, which was reduced by 6-13%. High molecular weight pectins with a high degree of esterification lead to the increased precipitability of pigments and tannins by a factor of 1.3 to 32.4 and 1.1 to 1.9, respectively, seemingly impairing the incorporation of anthocyanins in tannins to form precipitable polymeric pigments that are responsible for the longevity of red wine color. The increased precipitability of the pigments due to the interactions with the polysaccharides may indicate the formation of pigmented yet non-covalent aggregates that show comparable properties to the covalently formed precipitable pigments. The formation of those non-covalent structures may affect red wine color stability and astringency.

Jabuticaba (Plinia sp.) Peel as a Source of Pectin: Characterization and Effect of Different Extraction Methods

The peel of jabuticaba, a small fruit native to Brazil, has been shown to be a potential source of antioxidants and soluble dietary fibers. In this study, flours prepared from these peels were evaluated as a source of pectin. Different extraction methods were employed: ultrasound (US) extraction followed by low temperature heating (40 °C); in a microwave (MW) without (method 1) or with cellulase (method 2) or hemicellulase (method 3); or in a water bath (method 4). Pectin yields ranged from approximately 18% for methods 1 and 4 up to 22% for enzyme-assisted extractions (methods 2 and 3). Methods that did not employ enzymes resulted in low amounts of methoxyl pectins, as opposed to high amounts of methoxyl pectins obtained after enzyme treatment. Cyanidin-3-O-glucoside (C3G) and ellagic acid were the main phenolic compounds found in jabuticaba peel pectins, with higher C3G levels obtained with enzyme-free extraction (methods 1 and 4). All pectins from jabuticaba peel presented a reddish tone, good emulsifying properties and high swelling capacity. The pectin extracted using US+MW+cellulase (method 2) presented better emulsifying performance (higher values of emulsifying activity and emulsion stability), more effective than commercially available citrus pectin.

Improved Stability of Blue Colour of Anthocyanins from Lycium ruthenicum Murr. Based on Copigmentation

Natural blue food colourant is rare. The aim of this work was to screen compounds from the common copigments that could improve the blue tones of anthocyanins (ACNs) and to investigate the effect of different copigments on the colour stability of anthocyanins in neutral species. International Commission on Illumination (CIE) colour space, UV, IR, NMR, atomic force microscopy (AFM) and computational chemistry methods were utilised to evaluate ACNs from Lycium ruthenicum Murr. (LR), which is complexed with food additives and biological agents. The results indicate that Pro-Xylane (PX), Ectoin (ECT) and dipotassium glycyrrhizinate (DG) enhance the blue colour of the ACNs. ACNs-PX presents a colour close to Oxford Blue and has a surface height of 2.13 ± 0.14 nm and slightly improved stability. The half-life of ACNs-DG is improved 24.5-fold and had the highest complexation energy (-50.63/49.15) kcal/mol, indicating hydrogen bonds and π-π stacking forces enhance stability. These findings offer a new perspective for anthocyanin utilisation as a blue colourant and contribute to the large-scale application of LR.