In vitro study of bioaccessibility, antioxidant, and α-glucosidase inhibitory effect of pelargonidin-3-O-glucoside after interacting with beta-lactoglobulin and chitosan/pectin

Formulation and characterization of nanocapsules loaded with roselle anthocyanins extract and enhancement of anthocyanins bioaccessibility

Hibiscus sabdariffa L. (roselle) is a medicinal and edible plant which rich in anthocyanins with potent antioxidant properties. To enhance the stability of roselle anthocyanins, they were encapsulated in nanocapsules composed of carboxymethyl chitosan (CMC), chitosan hydrochloride (CHC), and β-lactoglobulin (β-Lg). In vitro simulated digestion assays evaluated the impact of various core-to-wall ratios and β-Lg concentrations on the bioaccessibility of seven anthocyanins. Nanocapsules with a core-to-wall ratio of 1:2 and β-Lg at 10 mg/mL exhibited the highest encapsulation efficiency (EE). Cyanidin-3-glucoside had the highest EE, while cyanidin-3-sambubioside showed the outstanding retention rate. Furthermore, simulated digestion experiments combined with molecular docking revealed that peonidin-3-glucoside and petunidin-3-glucoside likely interact with and bind to the outer β-Lg layer of the nanocapsules, increasing their release during in vitro digestion. This study demonstrates that encapsulating roselle anthocyanins in CMC, CHC, and β-Lg nanocapsules significantly enhances their bioaccessibility.

Basal metabolic rate mediates the causal relationship between gut microbiota and osteoarthritis: a two-step bidirectional Mendelian randomization study

Background

The relationship between gut microbiota and osteoarthritis (OA) occurrence remains unclear. Existing research needs to clearly understand how basal metabolic rate (BMR) regulates this relationship. Therefore, using a two-step bidirectional Mendelian Randomization approach, our study aims to investigate whether BMR levels mediate the causal relationship between gut microbiota and OA.

Methods

In this study, we examined publicly available summary statistics from Genome-Wide Association Studies (GWAS) to determine the correlation between gut microbiota and OA. The analysis included one primary dataset and two secondary datasets. Initially, a two-step, two-sample, and reverse MR analysis was performed to identify the causal relationship between gut microbiota and OA. Subsequently, a two-step MR analysis revealed that the relationship between microbiota and OA is mediated by BMR. Sensitivity analyses confirmed the robustness of the study results.

Results

In our analysis of the primary dataset, we discovered a positive correlation between three taxa and the outcome of OA, and eight taxa exhibited a negative correlation with the OA outcome. Through comparisons with the secondary dataset and multiple testing corrections, we found a negative association between the class Actinobacteria (OR=0.992886277, p-value = 0.003) and the likelihood of OA occurrence. Notably, knee osteoarthritis (KOA) and hip osteoarthritis (HOA) had a strong negative correlation (OR = 0.927237553/0.892581219). Our analysis suggests that BMR significantly mediates the causal pathway from Actinobacteria to OA, with a mediated effect of 2.59%. Additionally, BMR mediates 3.98% of the impact in the path from the order Bifidobacteriales and the family Bifidobacteriaceae to OA. Besides these findings, our reverse analysis did not indicate any significant effect of OA on gut microbiota or BMR.

Conclusion

Our research results indicate that an increase in the abundance of specific gut microbial taxa is associated with a reduced incidence of OA, and BMR levels mediate this causal relationship. Further large-scale randomized controlled trials are necessary to validate the causal impact of gut microbiota on the risk of OA. This study provides new insights into the potential prevention of OA by modulating the gut microbiota.

Synergistic effects of lactobacillus strains and Acetobacter pasteurianus on jujube puree's product functionality and quality

Commercial lactic acid bacteria strains and indigenous Chinese acetic acid bacterium were co-cultivated bi- and tri-culturally in Junzao jujube puree for the first time to investigate their effects on physicochemical properties and quality attributes. Lactic-acetic acid bacteria co-fermentation was performed at 37 °C for 48 h during the anaerobic fermentation phase and at 30 °C for 144 h during aerobic fermentation. FTIR results showed that predominant wave numbers at 1716-1724 cm-1 and 2922-3307 cm-1 exhibited discernible alterations in the lactic-acetic acid co-fermented jujube purees compared to the control sample. Pearson correlation analysis showed that the flavonoid and flavonol contents were responsible for the enhanced 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl scavenging activities of the fermented jujube purees. Consequently, fermented jujube puree from tricultures of Lactobacillus casei, Lactobacillus plantarum, and Acetobacter pasteurianus gave the best results, with the highest phenolics, flavonoid, and flavonol contents and the most improved antioxidative properties and color. Overall, lactic-acetic acid bacteria co-culture holds significant promise in valorizing Junzao jujube purees for functional ingredient development, paving the way for further research into similar interactions with different food matrices or microbial strains.

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.

Effects of Jujube Powder on Growth Performance, Blood Biochemical Indices, and Intestinal Microbiota of Broiler

In total, 576 Cobb broilers were randomized into 6 treatment groups, with 8 replicates in each treatment group and 12 broilers in each replicate. Each treatment group was fed six different experimental diets containing 0%, 2%, 4%, 6%, 8%, and 10% jujube powder. The group receiving 0% jujube powder was considered the blank control group. The experimental period was 42 days and was divided into two periods: starter (0-21 days) and finisher (22-42 days). Compared with the control group, the addition of 8% jujube powder significantly improved the ADG of broilers (p < 0.05), and 8% and 10% jujube powder significantly improved the total tract apparent digestibility of organic matter in broilers (p < 0.05). Adding 10% jujube powder significantly improved the apparent metabolic energy of broilers (p < 0.05). Compared with the control group, 4-10% jujube powder significantly increased IgA, IgG, IgM, and sCD4 levels (p < 0.05) and T-AOC and SOD contents, and it reduced the MDA content in the serum of broilers (p < 0.05). In addition, the relative abundance of Firmicutes, Bacteroidetes, Lactobacillus, and Romboutsia significantly increased in the broiler ileum, whereas that of Proteobacteria and Enterobacter decreased significantly (p < 0.05) when 8% jujube powder was added to the diet. The relative abundance of Proteobacteria, Bacteroides, and Faecalibacterium in the cecum increased significantly (p < 0.05), whereas that of Bacteroidetes decreased significantly (p < 0.05).

Ultrasound-assisted preparation of protein-polyphenol conjugates and their structural and functional characteristics

Herein, ultrasound-assisted conventional covalent binding methods (alkali treatment, free radical mediation, and an enzymatic method) were used to prepare soybean protein isolate (SPI)-(-)-epigallocatechin gallate (EGCG) conjugates to investigate the enhancement effect of the ultrasound synergistic treatment. In addition, the influence of EGCG grafting on the structure and properties of SPI was evaluated via reactive group analysis, spectral analysis, surface hydrophobicity measurements, emulsification property assessment, and α-glucosidase inhibition analysis. The obtained results revealed that the enzymatic method produced the highest polyphenol grafting content among the conventional techniques. Meanwhile, ultrasound treatment increased the amount of grafted polyphenol species during the alkali treatment and free radical mediation procedure, decreased the grafting efficiency in the enzymatic method, and maximized the grafting efficiency during the alkali treatment. In addition, reactive group and spectral analyses demonstrated that EGCG formed C-N and C-S bonds with SPI and decreased the α-helix content in the protein structure, thereby increasing the molecular flexibility of SPI. It also produced hydrogen bonds and hydrophobic interactions, as demonstrated by the results of molecular docking. Furthermore, the EGCG grafting of SPI conducted under the ultrasound-assisted conditions endowed SPI with unique functional characteristics, including good emulsification and antioxidant properties and high α-glucosidase inhibitory activity, while the ultrasound-assisted alkali treatment resulted in the optimal functional properties. The results of this study provide new insights into the effective preparation of SPI-EGCG complexes with multiple functionalities, thereby expanding the scope of high-value SPI utilization.

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.

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.

Synthesis and Characterization of a Novel Resveratrol Xylobioside Obtained Using a Mutagenic Variant of a GH10 Endoxylanase

Resveratrol is a natural polyphenol with antioxidant activity and numerous health benefits. However, in vivo application of this compound is still a challenge due to its poor aqueous solubility and rapid metabolism, which leads to an extremely low bioavailability in the target tissues. In this work, rXynSOS-E236G glycosynthase, designed from a GH10 endoxylanase of the fungus Talaromyces amestolkiae, was used to glycosylate resveratrol by using xylobiosyl-fluoride as a sugar donor. The major product from this reaction was identified by NMR as 3-O-ꞵ-d-xylobiosyl resveratrol, together with other glycosides produced in a lower amount as 4'-O-ꞵ-d-xylobiosyl resveratrol and 3-O-ꞵ-d-xylotetraosyl resveratrol. The application of response surface methodology made it possible to optimize the reaction, producing 35% of 3-O-ꞵ-d-xylobiosyl resveratrol. Since other minor glycosides are obtained in addition to this compound, the transformation of the phenolic substrate amounted to 70%. Xylobiosylation decreased the antioxidant capacity of resveratrol by 2.21-fold, but, in return, produced a staggering 4,866-fold improvement in solubility, facilitating the delivery of large amounts of the molecule and its transit to the colon. A preliminary study has also shown that the colonic microbiota is capable of releasing resveratrol from 3-O-ꞵ-d-xylobiosyl resveratrol. These results support the potential of mutagenic variants of glycosyl hydrolases to synthesize highly soluble resveratrol glycosides, which could, in turn, improve the bioavailability and bioactive properties of this polyphenol.

Onion anthocyanins: Extraction, stability, bioavailability, dietary effect, and health implications

Anthocyanins are high-value compounds, and their use as functional foods and their natural colorant have potential health benefits. Anthocyanins seem to possess antioxidant properties, which help prevent neuronal diseases and thereby exhibit anti-inflammatory, chemotherapeutic, cardioprotective, hepatoprotective, and neuroprotective activities. They also show different therapeutic effects against various chronic diseases. Anthocyanins are present in high concentrations in onion. In recent years, although both conventional and improved methods have been used for extraction of anthocyanins, nowadays, improved methods are of great importance because of their higher yield and stability of anthocyanins. In this review, we compile anthocyanins and their derivatives found in onion and the factors affecting their stability. We also analyze different extraction techniques of anthocyanins. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability and subsequently potentiate its bioavailability or beneficial health effects. We present up-to-date information on bioavailability, dietary effects, and health implications of anthocyanins such as antioxidant, antidiabetic, anticancerous, antiobesity, cardioprotective, and hepatoprotective activities.

Advances in dietary proteins binding with co-existed anthocyanins in foods: Driving forces, structure-affinity relationship, and functional and nutritional properties

Anthocyanins, which are the labile flavonoid pigments widely distributed in many fruits, vegetables, cereal grains, and flowers, are receiving intensive interest for their potential health benefits. Proteins are important food components from abundant sources and present high binding affinity for small dietary compounds, e.g., anthocyanins. Protein-anthocyanin interactions might occur during food processing, ingestion, digestion, and bioutilization, leading to significant changes in the structure and properties of proteins and anthocyanins. Current knowledge of protein-anthocyanin interactions and their contributions to functions and bioactivities of anthocyanin-containing foods were reviewed. Binding characterization of dietary protein-anthocyanins complexes is outlined. Advances in understanding the structure-affinity relationship of dietary protein-anthocyanin interaction are critically discussed. The associated properties of protein-anthocyanin complexes are considered in an evaluation of functional and nutritional values.

Chemical composition, quality attributes and antioxidant activity of stirred-type yogurt enriched with Melastoma dodecandrum Lour fruit powder

Incorporation of Melastoma dodecandrum Lour fruit powder as a promising functional ingredient for stirred-type yogurt (STY) improved physicochemical properties, polyphenol contents, antioxidant activity, microstructure, and texture of STY.

Preparation of blueberry anthocyanin liposomes and changes of vesicle properties, physicochemical properties, in vitro release, and antioxidant activity before and after chitosan modification

The preparation of blueberry anthocyanin liposomes (BAL) was optimized by response surface methodology. Then, chitosan was used to modify BAL and the environmental stability, in vitro release, and antioxidant activity studies of anthocyanin liposome (An-Lip), and chitosan-modified anthocyanin liposome (CS-An-Lip) was studied. The results showed that the particle size, zeta potential, and entrapment efficiency of BAL were 210.7 ± 1.8 nm, - 20.0 ± 1.0 mV, and 82.13%, respectively. After chitosan modification, the encapsulation efficiency and zeta potential of anthocyanin liposomes were improved. The results of environmental stability analysis showed that under certain conditions, the addition of chitosan could stabilize the color characteristics of anthocyanins and the loading amount of anthocyanins (LC%). In vitro release and simulated gastrointestinal digestion experiments showed that the addition of chitosan not only prolonged the sustained-release time of anthocyanins, but also prolonged the residence time of anthocyanins in vivo, giving full play to the drug effect. In addition, the antioxidant activity test results showed that CS-An-Lip increased the antioxidant activity of anthocyanins.

Advances in smart delivery of food bioactive compounds using stimuli-responsive carriers: Responsive mechanism, contemporary challenges, and prospects

Many important food bioactive compounds are plant secondary metabolites that have traditional applications for health promotion and disease prevention. However, the chemical instability and poor bioavailability of these compounds represent major challenges to researchers. In the last decade, therefore, major impetus has been given for the research and development of advanced carrier systems for the delivery of natural bioactive molecules. Among them, stimuli-responsive carriers hold great promise for simultaneously improving stability, bioavailability, and more importantly delivery and on-demand release of intact bioactive phytochemicals to target sites in response to certain stimuli or combination of them (e.g., pH, temperature, oxidant, enzyme, and irradiation) that would eventually enhance therapeutic outcomes and reduce side effects. Hybrid formulations (e.g., inorganic-organic complexes) and multi-stimuli-responsive formulations have demonstrated great potential for future studies. Therefore, this review systematically compiles and assesses the recent advances on the smart delivery of food bioactive compounds, particularly quercetin, curcumin, and resveratrol through stimuli-responsive carriers, and critically reviews their functionality, underlying triggered-release mechanism, and therapeutic potential. Finally, major limitations, contemporary challenges, and possible solutions/future research directions are highlighted. Much more research is needed to optimize the processing parameters of existing formulations and to develop novel ones for lead food bioactive compounds to facilitate their food and nutraceutical applications.

Laccase Catalyzed Oxidative Polymerization of Phloridzin: Polymer Characterization, Antioxidant Capacity and α-Glucosidase Inhibitory Activity

Phloridzin is a naturally occurring dihydrochalcone with various therapeutic properties. However, its low aqueous solubility and poor enzyme inhibitory capacity have limited its application in functional foods and medicines. Inspections of the properties of natural polymeric flavonoids suggest that these limitations could be mitigated by the polymerization of phloridzin, although to date, no relevant studies have been conducted. Here, oxidative polymerization was used to prepare polymeric phloridzin using laccase as the catalyst, and its structure, antioxidant capacity and α-glucosidase inhibitory activity were characterized. The results showed that laccase catalyzed polymerization via oxidative generation of phenolic radicals in the B ring of phloridzin to achieve the polymerization. The 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacity of the polymer (IC50, 0.48 mg/mL) was inferior to that of phloridzin (IC50, 0.20 mg/mL), but the α-glucosidase inhibitory activity of the polymer (IC50, 0.12 mg/mL) was significantly higher than that of phloridzin (IC50, 0.21 mg/mL). These effects could be attributed to the reduction of available phenolic groups and binding of the polymer to the enzyme, respectively.

Potential micro-/nano-encapsulation systems for improving stability and bioavailability of anthocyanins: An updated review

Anthocyanins (ACNs) are notable hydrophilic compounds that belong to the flavonoid family, which are available in plants. They have excellent antioxidants, anti-obesity, anti-diabetic, anti-inflammatory, anticancer activity, and so on. Furthermore, ACNs can be used as a natural dye in the food industry (food colorant). On the other hand, the stability of ACNs can be affected by processing and storage conditions, for example, pH, temperature, light, oxygen, enzymes, and so on. These factors further reduce the bioavailability (BA) and biological efficacy of ACNs, as well as limit ACNs application in both food and pharmaceutics field. The stability and BA of ACNs can be improved via loading them in encapsulation systems including nanoemulsions, liposomes, niosomes, biopolymer-based nanoparticles, nanogel, complex coacervates, and tocosomes. Among all systems, biopolymer-based nanoparticles, nanohydrogels, and complex coacervates are comparatively suitable for improving the stability and BA of ACNs. These three systems have excellent functional properties such as high encapsulation efficiency and well-stable against unfavorable conditions. Furthermore, these carrier systems can be used for coating of other encapsulation systems (such as liposome). Additionally, tocosomes are a new system that can be used for encapsulating ACNs. ACNs-loaded encapsulation systems can improve the stability and BA of ACNs. However, further studies regarding stability, BA, and in vivo work of ACNs-loaded micro/nano-encapsulation systems could shed a light to evaluate the therapeutic efficacy including physicochemical stability, target mechanisms, cellular internalization, and release kinetics.

The interactions between anthocyanin and whey protein: A review

Anthocyanins (ACN) are natural pigments that produce bright red, blue, and purple colors in plants and can be used to color food products. However, ACN sensitivity to different factors limits their applications in the food industry. Whey protein (WP), a functional nutritional additive, has been shown to interact with ACN and improve the color, stability, antioxidant capacity, bioavailability, and other functional properties of the ACN-WP complex. The WP's secondary structure is expected to unfold due to heat treatment, which may increase its binding affinity with ACN. Different ACN structures will also have different binding affinity with WP and their interaction mechanism may also be different. Circular dichroism (CD) spectroscopy and Fourier transform infrared (FTIR) spectroscopy show that the WP secondary structure changes after binding with ACN. Fluorescence spectroscopy shows that the WP maximum fluorescence emission wavelength shifts, and the fluorescence intensity decreases after interaction with ACN. Moreover, thermodynamic analysis suggests that the ACN-WP binding forces are mainly hydrophobic interactions, although there is also evidence of electrostatic interactions and hydrogen bonding between ACN and WP. In this review, we summarize the information available on ACN-WP interactions under different conditions and discuss the impact of different ACN chemical structures and of WP conformation changes on the affinity between ACN and WP. This summary helps improve our understanding of WP protection of ACN against color degradation, thus providing new tools to improve ACN color stability and expanding the applications of ACN and WP in the food and pharmacy industries.

Development and evaluation of a novel nanofibersolosome for enhancing the stability, in vitro bioaccessibility, and colonic delivery of cyanidin-3-O-glucoside

The development of colon-specific carrier systems using polysaccharides for oral delivery of nutraceuticals is of great importance for the treatment and/or prevention of inflammatory bowel diseases. In this study, self-assembly with the assistance of vortexing and pulsed-ultrasonication was employed to develop a Fibersol®-2 (a digestion-resistant polysaccharide) and lipoid S75 based novel nanocarrier (denoted as nanofibersolosome) for the colonic delivery of cyanidin-3-O-glucoside (C3G). A series of nanofibersolosome formulations (CFS-0.5-4, 0.5-4 represent the ratios of Fibersol®-2:lipoid S75) were developed and their performance was compared with Fibersol®-2-free reference lipid formulation (CFS-0). The nanofibersolosomes (<150 nm) were spherical and unilamellar with high negative surface charge (-38 to -51 mV) and good encapsulation efficiency (EE > 90%). They performed much better than CFS-0 in retaining their physical properties during freeze drying, preventing particle aggregation, and retaining C3G during storage (4 and 25 ℃) and thermal treatments (40, 60, and 80 ℃). They also exhibited significantly higher stability during simulated gastrointestinal digestion than CFS-0. These desirable features of the nanofibersolosomes (especially CFS-0.5 and CFS-1) led to the efficient delivery of higher concentrations of C3G to the colon than CFS-0. Moreover, gastrointestinal-digested and colonic-fermented nanofibersolosome samples exhibited significantly higher DPPH radical scavenging activity and stronger promoting effect on short-chain fatty acid generation than CFS-0. These in vitro findings indicate that the novel nanofibersolosome possesses great potential for the colonic delivery of C3G and likely other hydrophilic labile phytochemicals that merits further evaluation in in vivo models.

Inhibition Mechanism of α-Amylase/α-Glucosidase by Silibinin, Its Synergism with Acarbose, and the Effect of Milk Proteins

As a natural flavonolignan, silibinin is reported to possess multiple biological activities, while the inhibitory potential of silibinin on carbohydrate-hydrolyzing enzymes is still unclear. Therefore, in this study, the inhibitory effect and underlying mechanism of silibinin against α-amylase/α-glucosidase were investigated. The results indicated that silibinin showed a strong inhibitory efficiency against α-amylase/α-glucosidase in noncompetitive manners and exhibited synergistic inhibition against α-glucosidase with acarbose. However, interestingly, the inhibitory effect of silibinin was significantly hindered in various milk protein-rich environments, but this phenomenon disappeared after simulated gastrointestinal digestion of milk proteins in vitro. Furthermore, silibinin could combine with the inactive site of α-amylase/α-glucosidase and change the microenvironment and secondary structure of the enzymes, thereby influencing the catalytic efficiency of enzymes. This research suggested that silibinin could be used as a novel carbohydrate-hydrolyzing enzyme inhibitor, and milk beverages rich in silibinin had the potential for further application in antidiabetic dietary or medicine.

Molecular interaction between pectin and catechin/procyanidin in simulative juice model: Insights from spectroscopic, morphology, and antioxidant activity

The interactions between polysaccharides and phenolics in foods affect their physicochemical properties and bioactivity. Pectin and catechin/procyanidin present in plants ubiquitously and attracting more attentions for the potential health benefits. This work investigates the interactions between high methoxyl pectin and catechin/procyanidin in a simulative juice model using multiple microscopic and spectroscopic approaches and their influences on the antioxidant activity of phenolics were evaluated in the Caco-2 cells model. The results showed that pectin with either of phenolic compunds exhibited lower transmittance, zeta potential, viscosity, and larger particle size than it alone. The morphology of pectin complexes with either of phenolics under experimental conditions (pH = 3.5) was observed. The ΔH° (-6.821 kJ mol^-1 ) and ΔS° (6.357×10^-2  kJ mol^-1 ) indicated that pectin interacts with procyanidin via electrostatic interaction, whereas hydrophobic interaction was the dominant drive force between pectin and catechin (ΔH° = 1.422 kJ mol^-1 ; ΔS° = 13.048 × 10^-2  kJ mol^-1 ). The antioxidant activities of catechin/procyanidin decreased while binding with pectin based on indexes of glutathione peroxidase, total superoxide dismutase, total antioxidant capacity, and malondialdehyde. PRACTICAL APPLICATION: The findings of this work indicated that the physicochemical property of pectin and the antioxidant activity of catechin/procyanidin were influenced by the interactions between pectin and catechin/procyanidin in a simulative food system. This study provides insights into the molecular interactions between pectin and phenolics in a simulative food system.

Preparation, characterization and antibacterial mechanism of the chitosan coatings modified by Ag/ZnO microspheres

BACKGROUND

To improve the physicochemical and antibacterial properties of coatings, the chitosan (CS) coatings were respectively prepared by a casting method with zinc oxide (ZnO) and silver (Ag)/ZnO microspheres as modifiers. The chemical structures and micromorphology of ZnO, Ag/ZnO microspheres and CS coatings were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. Furthermore, using the dominant spoilage bacteria of aquatic products, Shewanella putrefaciens and Pseudomonas aeruginosa, as objects, the antibacterial activities and mechanism of the CS coatings were investigated.

RESULTS

The results show that ZnO and Ag/ZnO microspheres are dispersed homogeneously in the CS coatings. After modified by ZnO and Ag/ZnO microspheres, the mechanical properties and antibacterial abilities of the CS coatings are improved, and that of 0.5% Ag/ZnO-CS coating is the optimal. For pure CS coating, the bacterial cell membrane is damaged slightly because of the electrostatic interaction between NH³⁺ of CS and the negative charge on bacterial surface. After treated by ZnO-CS composite coating, the bacterial cell membrane is destroyed badly on account of the earlier-mentioned ion interaction and disturbing the synthesis of high molecular weight total protein.

CONCLUSION

With regard to Ag/ZnO-CS composite coating, the bacterial cell membrane is damaged seriously and cell contents are completely released due to ion interaction, disturbing the synthesis of high molecular weight total protein and low molecular weight membrane protein. Hence, Ag/ZnO-CS composite coatings are antimicrobial materials and food preservative materials with great potential application. © 2020 Society of Chemical Industry.

Brás N, Mateus N, de Freitas V, Fernandes I. Anthocyanins as Antidiabetic Agents-In Vitro and In Silico Approaches of Preventive and Therapeutic Effects

Many efforts have been made in the past two decades into the search for novel natural and less-toxic anti-diabetic agents. Some clinical trials have assigned this ability to anthocyanins, although different factors like the food source, the amount ingested, the matrix effect and the time of consumption (before or after a meal) seem to result in contradictory conclusions. The possible mechanisms involved in these preventive or therapeutic effects will be discussed-giving emphasis to the latest in vitro and in silico approaches. Therapeutic strategies to counteract metabolic alterations related to hyperglycemia and Type 2 Diabetes Mellitus (T2DM) may include: (a) Inhibition of carbohydrate-metabolizing enzymes; (b) reduction of glucose transporters expression or activity; (c) inhibition of glycogenolysis and (d) modulation of gut microbiota by anthocyanin breakdown products. These strategies may be achieved through administration of individual anthocyanins or by functional foods containing complexes of anthocyanin:carbohydrate:protein.

Improving the physicochemical stability and functionality of nanoliposome using green polymer for the delivery of pelargonidin-3-O-glucoside

This study aimed to improve the physicochemical stability of nanoliposome (NL) with enhanced functionality for the delivery of Pelargonidin-3-O-glucoside (P3G) using biopolymers, i.e. chitosan (CH) and pectin (P). In this study, we successfully developed stabilized liposomal carriers, i.e. CH-conjugated NL (CH-NL) and P-conjugated CH-NL (P-CH-NL) using an optimum concentration of CH (0.6 wt%) and P (0.5 wt%). Results revealed that P-CH-NL had better physical stability to salt and pH with maximum P3G retention (>97%) under oxidative, thermal, and UV conditions. Nanoliposomes were more stable under refrigerated-storage and ensured high P3G retention (>96%). In vitro mucoadhesion study revealed that CH-NL had better mucin adsorption efficiency (59.72%) followed by P-CH-NL and NL. Furthermore, CH-NL and P-CH-NL alternatively had better stability to serum than NL. Taken together, the stabilization of nanoliposome using chitosan and pectin can be a promising approach for the delivery of hydrophilic compounds in association with enhanced stability and functionality.

State of the Art of Anthocyanins: Antioxidant Activity, Sources, Bioavailability, and Therapeutic Effect in Human Health

The antioxidant activity of anthocyanins in food is well known. Numerous antioxidant assays have been proposed to measure the capacity of anthocyanins to prevent the oxidation process that naturally occurs. Different solvents, temperatures, and pH levels are applied in each assay, and these factors should be taken into account in order to obtain useful and reproducible results. The concentration and the structure of these compounds are directly related to their antioxidant capacity and their environment. However, the effectiveness of the anthocyanin ingestion against diseases is also influenced by its bioavailability. Novel methodologies that simulate the digestion process have been developed in order to facilitate the current knowledge of anthocyanins bioavailability. Studies highlight the potential synergy effect between parent compounds and their derivatives (metabolites, conjugated products, and microbe-generated metabolites). The aim of this review is to provide an overview of advantages and disadvantages of the most common methods to determine the antioxidant activity of anthocyanins, chemical structure, and concentration of these compounds in different edible fruits, vegetables, and plants; their bioavailability after intake; as well as the main therapeutic effect described in the scientific literature.