Preparation and characterisation of Chlorogenic acid-gelatin: A type of biologically active film for coating preservation

Development of chemiluminescence enzyme immunoassay (CLEIA) for the determination of chlorogenic acid in pharmaceutical products

Chlorogenic acid (CGA) is an important and abundant bioactive compound, exhibiting various pharmacological properties including antifungal, anti-inflammatory, antioxidant, antiviral, neuroprotective and antispasmodic activities. CGA is available in many types of pharmaceutical products in the form of tablets, capsules, and injections derived from plants. The CGA content is typically regarded as an important indicator for the quality control of these pharmaceutical products. Therefore, it is particularly important to develop a reliable and accurate method for the determination of CGA. In this study, CGA was coupled to bovine serum albumin (BSA) and ovalbumin (OVA) using an active ester method to synthesise artificial antigens. A sensitive and specific monoclonal antibody (mAb) against CGA was obtained. To analyse CGA efficiently, an indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) was developed on the basis of the generated mAb. Under optimal conditions, the limit of detection (LOD) and half-maximal inhibitory concentration (IC50) were 1.76 ng mL-1 and 18 ng mL-1, respectively. The linear range was from 2.5-100 ng mL-1, with an R2 value of 0.9963. The recoveries of CGA in spiked pharmaceutical products ranged from 77.2% to 118.3%, with coefficients of variation (CVs) ranging from 1.7% to 11.2%. The samples were validated by high-performance liquid chromatography (HPLC) coupled to a UV detector at 327 nm. The ic-CLEIA results showed a high correlation coefficient of 0.9718 when compared with those obtained by HPLC, demonstrating that the proposed ic-CLEIA would be a credible method for the quantification of CGA in pharmaceutical products.

Long-term antioxidant and ultraviolet light shielding gelatin films for the preservation of leather artifacts

In this study, CA-Gel complexes were prepared by crosslinking gelatin with chlorogenic acid (CA) by EDC/NHS chemistry, and incorporated into gelatin to produce CA-Gel/Gel films for leather artifact preservation. The synthesized CA-Gel complex had a total phenolic content of 139.62 ± 1.8 mg/g. The moisture content of CA-Gel/Gel film is 37.84 % lower than that of Gel film. The addition of CA-Gel complexes enhanced the hydrophobic and antibacterial properties of Gel films. CA-Gel/Gel films showed excellent antioxidant properties, as evidenced by the increase in the DPPH radical scavenging rate from 0 to 98.18 %. Additionally, CA-Gel/Gel films effectively shield UV light, preventing almost the transmission of ultraviolet rays. Notably, CA-Gel/Gel films maintain their antioxidant properties and UV light shielding after one month at ambient temperature. Therefore, their long-term antioxidant and UV light shielding properties were indicated. In addition, the UV light aging tests were carried out on leathers with and without CA-Gel/Gel film coverage. The results showed that CA-Gel/Gel films effectively preserved the original color of leathers, with no changes in their random coil structure before and after UV light irradiation. This work emphasizes the potential use of CA-Gel/Gel films as an innovative protective packaging solution for long-term preservation of leather artifacts.

Investigating the synergistic antibacterial effects of chlorogenic and p-coumaric acids on Shigella dysenteriae

Chlorogenic acid (CGA) is a well-known plant secondary metabolite exhibiting multiple physiological functions. The present study focused on screening for synergistic antibacterial combinations containing CGA. The combination of CGA and p-coumaric acid (pCA) exhibited remarkably enhanced antibacterial activity compared to that when administering the treatment only. Scanning electron microscopy revealed that a low-dose combination treatment could disrupt the Shigella dysenteriae cell membrane. A comprehensive analysis using nucleic acid and protein leakage assay, conductivity measurements, and biofilm formation inhibition experiments revealed that co-treatment increased the cell permeability and inhibited the biofilm formation substantially. Further, the polyacrylamide protein- and agarose gel-electrophoresis indicated that the proteins and DNA genome of Shigella dysenteriae severely degraded. Finally, the synergistic bactericidal effect was established for fresh-cut tomato preservation. This study demonstrates the remarkable potential of strategically selecting antibacterial agents with maximum synergistic effect and minimum dosage exhibiting excellent antibacterial activity in food preservation.

Exploring the potential of chlorogenic acid/chitosan nanoparticle-loaded edible films with photodynamic technology for Mongolian cheese application

This study aimed to evaluate the efficiency of edible films made from chlorogenic acid/chitosan (CGA/CS) nanoparticles combined with photodynamic technology (PDT). Hydroxypropyl starch (HS) and κ-carrageenan (KC) were used as the main ingredients in the preservation of Mongolian cheese under the PDT condition. The mechanical characteristics, water vapor adsorption, solubility, permeability, and release of chlorogenic acid in aqueous media were evaluated. The incorporation of CGA/CS significantly enhanced the tensile strength and barrier characteristics of the edible films. The antimicrobial efficacy of the edible film was assessed over a period of 7 days while the cheese was being stored, followed by PDT application. The use of antimicrobial PDT did not cause lipid oxidation in cheese samples. Additionally, the combination of CGA/CS@HS/KC helped to reduce fat oxidation in Mongolian cheese. Utilizing an edible film in conjunction with PDT presents a viable solution for prolonging the shelf life of Mongolian cheese while maintaining its sensory attributes and nutritional qualities.

Protective effects of chlorogenic acid against cyclophosphamide induced liver injury in mice

We investigated possible protective effects of chlorogenic acid (CGA) against cyclophosphamide (CP) induced hepatic injury in mice. We measured aminotransferase alanine transaminase (ALT) and aspartate transaminase (AST) levels in the serum. We assayed catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in hepatic tissue. We assessed expression of nuclear transcription factor 2 (Nrf2) and Kelch sample related protein-1 (keap1) proteins in hepatic tissues using immunohistochemistry. The relative mRNA expression levels of heme oxygenase-1 (HO-1), NADH quinone oxidoreductase 1 (NQO1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Hematoxylin & eosin staining was used to assess liver histopathology. We found that administration of CGA prior to induction of injury by CP decreased serum ALT, AST and MDA expressions in hepatic tissue, while CAT, SOD, GSH and GSH-Px concentrations were increased. We found that hepatocytes of animals administered CGA gradually returned to normal morphology. CGA increased the protein expression of Nrf2 in murine hepatic tissue. Administration of CGA up-regulated mRNA expression levels of HO-1, NQO1, TNF-α and IL-6 in hepatic tissue. CGA exhibited a marked protective effect on CP induced liver injury in mice.

Biopolymer-polyphenol conjugates: Novel multifunctional materials for active packaging

The development of natural active packaging materials and coatings presents a promising alternative to petroleum-based packaging solutions. These materials are engineered by incorporating functional ingredients with preservative capabilities. Concurrently, research has highlighted the diverse physicochemical, functional, and health-promoting properties of protein-polyphenol, polysaccharide-polyphenol, and protein-polysaccharide-polyphenol conjugates within various food formulations. However, a critical gap exists regarding the exploration of these biopolymers as active packaging materials. In contrast to conventional approaches for developing active packaging materials, this review presents a novel perspective by focusing on biopolymer-polyphenol conjugates. In this work, we delve into the realm of active packaging materials and coatings constructed from these conjugates, highlighting their potential as multifunctional active components in food packaging and preservation. This review comprehensively investigates the physicochemical properties, functionalities, and health-promoting activities associated with biopolymer-polyphenol conjugates. Their emulsification, antioxidant, and antimicrobial activities, coupled with enhancements in mechanical strength and permeability properties, contribute to their multifunctional nature. Furthermore, we explore the potential advantages and limitations of utilizing these conjugates in active packaging applications. Finally, the review concludes by proposing crucial research avenues for further exploration of biopolymer-polyphenol conjugates within the domain of active food packaging.

Polyphenols: Chemistry, bioavailability, bioactivity, nutritional aspects and human health benefits: A review

Polyphenols, including phenolics, alkaloids, and terpenes, are secondary metabolites that are commonly found in fruits, vegetables, and beverages, such as tea, coffee, wine, chocolate, and beer. These compounds have gained considerable attention and market demand because of their potential health benefits. However, their application is limited due to their low absorption rates and reduced tissue distribution efficiency. Engineering polyphenol-protein complexes or conjugates can enhance the antioxidant properties, bioavailability, and stability of polyphenols and improve digestive enzyme hydrolysis, target-specific delivery, and overall biological functions. Complex polyphenols, such as melanin, tannins, and ellagitannins, can promote gut microbiota balance, bolster antioxidant defense, and improve overall human health. Despite these benefits, the safety of polyphenol complexes must be thoroughly evaluated before their use as functional food additives or supplements. This review provides a detailed overview of the types of macromolecular polyphenols, their chemical composition, and their role in food enrichment. The mechanisms by which complex polyphenols act as antioxidative, anti-inflammatory, and anticancer agents have also been discussed.

Rosmarinic acid-grafted gelatin nanogels for efficient diquafosol delivery in dry eye disease therapy

Dry eye disease (DED) is a prevalent ocular disorder characterized by unstable tear film condition with loss of aqueous or mucin, excessive oxidative stress, and inflammation, leading to discomfort and potential damage to the ocular surface. Current DED therapies have shown restricted therapeutic effects such as frequent dosing and temporary relief with potential unwanted side effects, urgently necessitating the development of innovative efficient therapeutic approaches. Herein, we developed rosmarinic acid (RosA) conjugated gelatin nanogels loading diquafosol sodium (DQS), DRGNG, for simultaneous ROS-scavenging and mucin-secreting DED treatment. Mechanically, DRGNG suppressed the ROS production, reduced inflammatory factors, and prompted mucin secretion in vitro and in vivo. The whole transcriptome RNA sequencing in vitro further provided a detailed analysis of the upregulation of anti-oxidant, anti-inflammatory, and mucin-promotion pathways. Therapeutically, both in evaporative DED and aqueous deficient DED models, the dual-functional DRGNG could prolong the retention time at the ocular surface, efficiently suppress the oxidative stress response, reverse ocular surface morphology, and recover tear film homeostasis, thus alleviating the DED when the dosage is halved compared to the commercial Diquas®. Our findings contribute to developing innovative therapies for DED and offer insights into the broader applications of nanogels in ocular drug delivery and oxidative stress-related conditions.

Protein-Chlorogenic Acid Interactions: Mechanisms, Characteristics, and Potential Food Applications

The interactions between proteins and chlorogenic acid (CGA) have gained significant attention in recent years, not only as a promising approach to modify the structural and techno-functional properties of proteins but also to enhance their bioactive potential in food systems. These interactions can be divided into covalent (chemical or irreversible) and non-covalent (physical or reversible) linkages. Mechanistically, CGA forms covalent bonds with nucleophilic amino acid residues of proteins by alkaline, free radical, and enzymatic approaches, leading to changes in protein structure and functionality, such as solubility, emulsification properties, and antioxidant activity. In addition, the protein-CGA complexes can be obtained by hydrogen bonds, hydrophobic and electrostatic interactions, and van der Waals forces, each offering unique advantages and outcomes. This review highlights the mechanism of these interactions and their importance in modifying the structural, functional, nutritional, and physiological attributes of animal- and plant-based proteins. Moreover, the potential applications of these protein-CGA conjugates/complexes are explored in various food systems, such as beverages, films and coatings, emulsion-based delivery systems, and so on. Overall, this literature review provides an in-depth overview of protein-CGA interactions, offering valuable insights for future research to develop novel protein-based food and non-food products with improved nutritional and functional characteristics.

Unleashing the power of chlorogenic acid: exploring its potential in nutrition delivery and the food industry

In the contemporary era, heightened emphasis on health and safety has emerged as a paramount concern among individuals with food. The concepts of "natural" and "green" have progressively asserted dominance in the food consumption market. Consequently, through continuous exploration and development, an escalating array of natural bioactive ingredients is finding application in both nutrition delivery and the broader food industry. Chlorogenic acid (CGA), a polyphenolic compound widely distributed in various plants in nature, has garnered significant attention. Abundant research underscores CGA's robust biological activity, showcasing notable preventive and therapeutic efficacy across diverse diseases. This article commences with a comprehensive overview, summarizing the dietary sources and primary biological activities of CGA. These encompass antioxidant, anti-inflammatory, antibacterial, anti-cancer, and neuroprotective activities. Next, a comprehensive overview of the current research on nutrient delivery systems incorporating CGA is provided. This exploration encompasses nanoparticle, liposome, hydrogel, and emulsion delivery systems. Additionally, the article explores the latest applications of CGA in the food industry. Serving as a cutting-edge theoretical foundation, this paper contributes to the design and development of CGA in the realms of nutrition delivery and the food industry. Finally, the article presents informed speculations and considerations for the future development of CGA.

Design and manufacture of new hybrid hydrogel and superabsorbent polymer for controlled release of fulvic acid based on grafted xanthan gum/gelatin using electron irradiation and its use in fodder corn cultivation

A humic acid-gelatin (HA-Gel) hydrogel, a gallic acid-xanthan gum (GA-XG) hydrogel, a HA-Gel/GA-XG hydrogel, and superabsorbent polymer (SAP) of HA-Gel/GA-XG/polyacrylamide (PAM) hydrogel were synthesized using electron beam irradiation method. The capability of synthesized hydrogels in loading and controlled release of fulvic acid (FA) was studied. The chemical and physical structure of sorbents was confirmed by various analyses. The effect of irradiation dose on mechanical properties, gel percentage, swelling, and absorbency under load (AUL) of the sorbents was investigated. By changing the hydrogel structures into the SAP form, its swelling capacity was increased from 37 to 320 g/g. Both hybrid hydrogel and SAP were reusable for up to 7 cycles. The maximum fertilizer loading capacities for SAP and hybrid hydrogel were 402.1 and, 175.5 mg g-1, respectively. In comparison to hydrogels, the SAP showed a slower FA-release performance. Thus, in soil media, 86 % of FA was released in 15-20 days from the hybrid hydrogel while with the SAP, 81 % of FA was released in 30-35 days. The significant improvement in the growth of fodder corn treated with FA-loaded SAP in the greenhouse media in comparison to the control groups showed the effective performance of the designed SAP, favoring its practical applications.

Influence of myoglobin on the antibacterial activity of carvacrol and the binding mechanism between the two compounds

BACKGROUND

Myoglobin (MB), a pigmentation protein, can adversely affect the antibacterial activity of carvacrol (CAR) and weaken its bacteriostasis effect. This study aimed to clarify the influence of MB on the antibacterial activity of CAR and ascertain the mechanism involved in the observed influence, especially the interaction between the two compounds.

RESULTS

Microbiological analysis indicated that the presence of MB significantly suppressed the antibacterial activity of CAR against Listeria monocytogenes. Ultraviolet-visible spectrometry and fluorescence spectroscopic analysis confirmed the interaction between CAR and MB. The stoichiometric number was determined as ~0.7 via double logarithmic Stern-Volmer equation analysis, while thermodynamic analysis showed that the conjugation of the two compounds occurred as an exothermal reaction (ΔH° = -32.3 ± 11.4 kJ mol-1 and ΔS° = -75 J mol-1  K-1 ). Circular dichroism, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy showed hydrogen bonding in the carvacrol-myoglobin complex (CAR-MB). Molecular docking analysis confirmed that amino acid residues, including GLY80 and HIS82, were most likely to form hydrogen bonds with CAR, while hydrogen bonds represented the main driving force for CAR-MB formation.

CONCLUSION

CAR antibacterial activity was significantly inhibited by the presence of MB in the environment due to the notable reduction in the effective concentration of CAR caused by CAR-MB formation. © 2023 Society of Chemical Industry.

Integrative analysis of potential diagnostic markers and therapeutic targets for glomerulus-associated diabetic nephropathy based on cellular senescence

Introduction

Diabetic nephropathy (DN), distinguished by detrimental changes in the renal glomeruli, is regarded as the leading cause of death from end-stage renal disease among diabetics. Cellular senescence plays a paramount role, profoundly affecting the onset and progression of chronic kidney disease (CKD) and acute kidney injuries. This study was designed to delve deeply into the pathological mechanisms between glomerulus-associated DN and cellular senescence.

Methods

Glomerulus-associated DN datasets and cellular senescence-related genes were acquired from the Gene Expression Omnibus (GEO) and CellAge database respectively. By integrating bioinformatics and machine learning methodologies including the LASSO regression analysis and Random Forest, we screened out four signature genes. The receiver operating characteristic (ROC) curve was performed to evaluate the diagnostic performance of the selected genes. Rigorous experimental validations were subsequently conducted in the mouse model to corroborate the identification of three signature genes, namely LOX, FOXD1 and GJA1. Molecular docking with chlorogenic acids (CGA) was further established not only to validate LOX, FOXD1 and GJA1 as diagnostic markers but also reveal their potential therapeutic effects.

Results and discussion

In conclusion, our findings pinpointed three diagnostic markers of glomerulus-associated DN on the basis of cellular senescence. These markers could not only predict an increased risk of DN progression but also present promising therapeutic targets, potentially ushering in innovative treatments for DN in the elderly population.

Revolutionizing single-use food packaging: a comprehensive review of heat-sealable, water-soluble, and edible pouches, sachets, bags, or packets

Edible food packaging has emerged as a critical focal point in the discourse on sustainability, prompting the development of innovative solutions, notably in the realm of edible pouches. Often denoted as sachets, bags, or packets, these distinct designs have garnered attention owing to their water-soluble and heat-sealable attributes, tailored explicitly for single-use applications encompassing oils, instant or dry foods, and analogous products. While extant literature extensively addresses diverse facets of edible films, this review addresses a conspicuous void by presenting a consolidated and specialized overview dedicated to the intricate domain of edible pouches. Through a meticulous synthesis of current research, we aim to illuminate the trajectory of advancements made thus far, delving into critical aspects, including materials, production techniques, functional attributes, consumer perceptions, and regulatory considerations. By furnishing a comprehensive perspective on the potential, challenges, and opportunities inherent in edible pouches, our overarching aim is to stimulate collaborative endeavors in research, innovation, and exploration. In doing so, we aspire to catalyze the broader adoption of sustainable packaging solutions tailored to the exigencies of single-use applications.

Waste to Wealth Approach: Improved Antimicrobial Properties in Bioactive Hydrogels through Humic Substance-Gelatin Chemical Conjugation

Exploring opportunities for biowaste valorization, herein, humic substances (HS) were combined with gelatin, a hydrophilic biocompatible and bioavailable polymer, to obtain 3D hydrogels. Hybrid gels (Gel HS) were prepared at different HS contents, exploiting physical or chemical cross-linking, through 1-ethyl-(3-3-dimethylaminopropyl)carbodiimide (EDC) chemistry, between HS and gelatin. Physicochemical features were assessed through rheological measurements, X-ray diffraction, attenuated total reflectance (ATR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM). ATR and NMR spectroscopies suggested the formation of an amide bond between HS and Gel via EDC chemistry. In addition, antioxidant and antimicrobial features toward both Gram(-) and Gram(+) strains were evaluated. HS confers great antioxidant and widespread antibiotic performance to the whole gel. Furthermore, the chemical cross-linking affects the viscoelastic behavior, crystalline structures, water uptake, and functional performance and produces a marked improvement of biocide action.

An all-cellulose sponge with a nanofiller-assisted hierarchical cellular structure for fruit maintaining freshness

Cellulose sponges with compressibility and resilience are an ideal packaging material for fruits with fragile skin. Here, a soft and elastic all-cellulose sponge (CS) with a hierarchical cellular structure was fabricated, where the long molecular chain cellulose constructed major pores, the cellulose at nanoscale acted as an elastic nanofiller to fill the gaps of long molecular chain cellulose fibers and constructed minor pores. With these two kinds of pores, this structure can absorb strain hierarchically. The sponge can protect fruits from mechanical damage when dropped or repeated vibration. Furthermore, the CS modified with chlorogenic acid (C-CGAS) had excellent antibacterial and antifungal abilities. Therefore, C-CGAS could extend the storage time of strawberries to 18 days without any microbial invasion, which is the longest storage time reported thus far. This study provides a new idea for the preparation of polymer sponges and a new design for the development of antimicrobial packaging materials.

Phenolic-protein interactions: insight from in-silico analyses – a review

Phenolic compounds are ubiquitous plant secondary metabolites that possess various biological activities and are known to interact with proteins, altering their structure and properties. Therefore, interactions between these compounds and proteins has gained increasing attention due to their potential benefits to human health and for exploitation by the food industry. Phenolic compounds and proteins can form complexes via covalent linkages and/or non-covalent interactions through hydrophobic, electrostatic, van der Waals forces and hydrogen bonding. This review describes possible mechanisms of phenol-protein complex formation, their physiological action and activities that are important in the food industry, and possible outcomes in the terms of molecular docking and simulation analysis. The conformational changes of the protein upon binding with polyphenols can lead to the folding or unfolding of the protein molecules, forming insoluble or soluble complexes. The concentration of polyphenols, their molecular weight and structure, ions/cofactors and conditions of the system determine the precipitation or solubilization of the complex, affecting their nutritional and functional properties as well as their bioactivities. In this regard, molecular docking and simulation studies of phenolic-protein interactions allows comprehensive virtual screening of competitive/non-competitive and site-specific/non-specific conjugation of phenolics with different protein targets and facilitates understanding the observed effects. The docking analysis of flavonoids with enzymes and milk proteins has indicated their potential application in producing nutraceuticals and functional foods. Thus, combining molecular docking and simulation studies with experimental techniques is vital for better understanding the reactions that take place during digestion to engineer and manufacture novel food ingredients with desirable pharmacological properties and as potential food additives.

Graphical Abstract

Simultaneously enhanced stability and biological activities of chlorogenic acid by covalent grafting with soluble oat β-glucan

Chlorogenic acid (CA) has a wide range of biological activities but the chemical structure is extremely unstable. In this study, CA was grafted onto a soluble oat β-glucan (OβGH) to improve the stability. Although the crystallinity and thermal stability of CA-OβGH conjugates reduced, the storage stability of CA significantly improved. The DPPH and ABTS scavenging ability of CA-OβGH IV (graft ratio 285.3 mg CA/g) were higher than 90 %, which is closed to activities of equivalent concentration of Vc (93.42 %) and CA (90.81 %). The antibacterial abilities of CA-OβGH conjugates are improved compared to the equivalent content of CA and potassium sorbate. Particularly, the inhibition rate of CA-OβGH for gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) are significantly higher than that of gram-negative bacteria (Escherichia coli). The results demonstrated that covalent grafted CA with soluble polysaccharide is an effective strategy to enhance its stability and biological activities.

Influence of Gelatin-Chitosan-Glycerol Edible Coating Incorporated with Chlorogenic Acid, Gallic Acid, and Resveratrol on the Preservation of Fresh Beef

Chlorogenic acid (CA), gallic acid (GA), and resveratrol (RES) were added to a gelatin (GEL)-chitosan (CHI)-glycerol (GLY) edible coating, and their effects on the coating of fresh beef preservation were investigated. The results revealed that CA had the most significant improvement effect on fresh beef preservation. The combination of GEL-CHI-GLY-CA preserved the color of the beef better and delayed the increase of the total volatile base nitrogen, even though its total phenolic content decreased at a faster rate during beef preservation. GA also improved the preservation effect as on the 12th day of storage, the beef samples treated with GEL-CHI-GLY-GA had the lowest thiobarbituric acid reactive substances (0.76 mg Malondialdehyde (MDA)/kg) and total viable count (6.0 log cfu/g). On the whole, though RES showed an improvement on beef preservation, the improvement was not as good as the other two polyphenols. After 12 days of storage, the beef samples treated with GEL-CHI-GLY-RES had a higher pH value (6.25) than the other two polyphenol treatmed groups. Overall, the three polyphenol-added combinations increased the shelf life of beef by approximately 3-6 days compared to the control group (treated GEL-CHI-GLY with distilled water).

Current Research on the Extraction, Functional Properties, Interaction with Polyphenols, and Application Evaluation in Delivery Systems of Aquatic-Based Proteins

Globally, aquatic processing industries pay great attention to the production of aquatic proteins for the fulfillment of the nutritive requirements of human beings. Aquatic protein can replace terrestrial animal protein due to its high protein content, complete amino acids, unique flavor, high quality and nutritional value, and requirements of religious preferences. Due to the superior functional properties, an aquatic protein based delivery system has been proposed as a novel candidate for improving the absorption and bioavailability of bioactive substances, which might have potential applications in the food industry. This review outlines the extraction techniques for and functional properties of aquatic proteins, summarizes the potential modification technologies for interaction with polyphenols, and focuses on the application of aquatic-derived protein in delivery systems as well as their interaction with the gastrointestinal tract (GIT). The extraction techniques for aquatic proteins include water, salt, alkali/acid, enzyme, organic solvent, and ultrasound-assisted extraction. The quality and functionality of the aquatic proteins could be improved after modification with polyphenols via covalent or noncovalent interactions. Furthermore, some aquatic protein based delivery systems, such as emulsions, gels, films, and microcapsules, have been reported to enhance the absorption and bioavailability of bioactive substances by in vitro GIT, cell, and in vivo animal models. By promoting comprehensive understanding, this review is expected to provide a real-time reference for developing functional foods and potential food delivery systems based on aquatic-derived proteins.

Chemistry of Protein-Phenolic Interactions Toward the Microbiota and Microbial Infections

Along with health concerns, interest in plants as food and bioactive phytochemical sources has been increased in the last few decades. Phytochemicals as secondary plant metabolites have been the subject of many studies in different fields. Breakthrough for research interest on this topic is re-juvenilized with rising relevance in this global pandemics' era. The recent COVID-19 pandemic attracted the attention of people to viral infections and molecular mechanisms behind these infections. Thus, the core of the present review is the interaction of plant phytochemicals with proteins as these interactions can affect the functions of co-existing proteins, especially focusing on microbial proteins. To the best of our knowledge, there is no work covering the protein-phenolic interactions based on their effects on microbiota and microbial infections. The present review collects and defines the recent data, representing the interactions of phenolic compounds -primarily flavonoids and phenolic acids- with various proteins and explores how these molecular-level interactions account for the human health directly and/or indirectly, such as increased antioxidant properties and antimicrobial capabilities. Furthermore, it provides an insight about the further biological activities of interacted protein-phenolic structure from an antiviral activity perspective. The research on the protein-phenolic interaction mechanisms is of great value for guiding how to take advantage of synergistic effects of proteins and polyphenolics for future medical and nutritive approaches and related technologies.

Polycaprolactone/polyvinyl pyrrolidone nanofibers developed by solution blow spinning for encapsulation of chlorogenic acid

Study on the application of nanofibers in food active packaging has been a research hotspot in recent years. In this work, the solution blow spinning (SBS) was applied to rapidly fabricate the polycaprolactone (PCL), polyvinyl pyrrolidone (PVP), and PCL/PVP nanofibrous films to encapsulate chlorogenic acid (CGA). All the films showed uniform and smooth nanofibers, and the FTIR and XRD proved the success of mixed spinning of PCL and PVP. With the increase of PVP content, the thermal stability of the PCL/PVP nanofibrous films improved. The PCL/PVP (4:1) film possessed better mechanical properties than PCL and PVP films because of the stronger fiber-fiber interactions. The addition of PCL endowed the hydrophobic surfaces to the PCL/PVP films, and the PCL/PVP films had better water vapor barrier ability. The PCL/PVP (4:1) film exhibited the best long-term continuous release of CGA during 72 h. The PVP nanofibrous film exhibited no inhibition against S. aureus and E. coli due to the low encapsulation efficiency, but the PCL and PCL/PVP films exhibited good antimicrobial activity. The above results suggested that the nanofibrous films developed by SBS possessed the promising prospects in food packaging.

Application of Gelatin in Food Packaging: A Review

Owing to the increasing environmental concerns and requirements for high-quality foods, edible films and coatings (based on proteins, polysaccharides, natural phenolic active substances, etc.) are being developed as effective alternatives to traditional plastic packaging. Gelatin is extracted from collagen. It is an ideal material for food packaging due to its versatile advantages such as low price, polymerization, biodegradability, good antibacterial and antioxidant properties, etc. However, gelatin film exists poor waterproof and mechanical properties, which limit its developments and applications in food packaging. Previous studies show that pure gelatin can be modified by adding active ingredients and incorporating them with bio-polymers to improve its mechanical properties, aiming to achieve the desirable effect of preservation. This review mainly shows the preparation and molding ways of gelatin-based edible films and the applications of gelatin modified with other biopolymers. Furthermore, this review provides the latest advances in gelatin-based biodegradable packaging and food applications that exhibit outstanding advantages in food preservation.

The combination of ultrasound and chlorogenic acid to inactivate Staphylococcus aureus under planktonic, biofilm, and food systems

This study aimed to investigate the mechanism of different treatments, namely, ultrasound (US), chlorogenic acid (CA), and ultrasound combined with chlorogenic acid (US plus CA) on the inactivation of Staphylococcus aureus planktonic and biofilm cells. Results showed that the combined treatment of US and CA exhibited remarkable synergistic antibacterial and antibiofilm effects. Scanning electron microscopy images indicated that the combined treatment of US and CA caused the most serious damage to the cell morphology. Confocal laser scanning microscopy images revealed that the combined treatment led to sharp increase and severe damage to the permeability of the cell membrane, causing the release of ATP and nucleic acids and decreasing the exopolysaccharide contents in S. aureus biofilm. Finally, the combined treatment of US plus 1% CA for 60 min inactivated S. aureus cells by 1.13 lg CFU/g on mutton. Thus, the combined treatment of US and CA had synergistic effect against S. aureus under planktonic, biofilm, and food systems.

Interactions between Phenolic Acids, Proteins, and Carbohydrates-Influence on Dough and Bread Properties

The understanding of interactions between proteins, carbohydrates, and phenolic compounds is becoming increasingly important in food science, as these interactions might significantly affect the functionality of foods. So far, research has focused predominantly on protein-phenolic or carbohydrate-phenolic interactions, separately, but these components might also form other combinations. In plant-based foods, all three components are highly abundant; phenolic acids are the most important phenolic compound subclass. However, their interactions and influences are not yet fully understood. Especially in cereal products, such as bread, being a nutritional basic in human nutrition, interactions of the mentioned compounds are possible and their characterization seems to be a worthwhile target, as the functionality of each of the components might be affected. This review presents the basics of such interactions, with special emphasis on ferulic acid, as the most abundant phenolic acid in nature, and tries to illustrate the possibility of ternary interactions with regard to dough and bread properties. One of the phenomena assigned to such interactions is so-called dry-baking, which is very often observed in rye bread.

Evaluation of some in vitro bioactivities of sunflower phenolic compounds

Phenolic compounds in crude extracts were obtained from defatted sunflower seed flour using sodium bisulfite and ethanol solutions as extracting agents. The antioxidant, antimicrobial, anti-proliferative, and DNA protective activities of the phenolic compounds in crude extract were analyzed. The phenolic compound contents were determined as chlorogenic acid (CGA) equivalent, presenting 11.57 and 15.44 g CGA eq/100g regarding the sodium bisulfite extract and ethanolic extract, respectively. The ORAC, DPPH, and ABTS methods were used to evaluate antioxidant activity. Both extracts presented antioxidant properties, considering that the ethanolic extract demonstrated higher values (EC₅₀ 0.36 g extract/g DPPH•). The antimicrobial action was analyzed as to the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of 4 kinds of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis). The ethanolic extract was effective against all of these microorganisms, out of which E. coli was the most sensitive, with a MIC of 11.6 mg CGA/mL. The ethanolic extract presented DNA protective activity without cytotoxic activity concerning in vitro anti-proliferative assay. These findings can be considered as initial evidence of the potential use of phenolic compounds obtained from sunflower seed flour as natural additives in the food industry.

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Sunflower flour processing provides a phenolic extract as a byproduct.

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Sunflower phenolic extract exhibited antioxidant and antibacterial activity.

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Ethanolic sunflower phenolic extract exhibited DNA protection.

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Phenolic compounds extracts from sunflower has a potential as a food additive.

Protein-polyphenol conjugates: Preparation, functional properties, bioactivities and applications in foods and nutraceuticals

Protein is a crucial nutritional ingredient in the daily human diet. Polyphenols (PPNs) are the abundant phytochemicals in plants, which are associated with health promotion as well as affect functionality in food systems. Both ingredients possess different types of functionalities (crosslinking, gelling, emulsifying, film-forming, etc.) and bioactivities (antioxidant, antimicrobial, anti-inflammatory, etc.). In the past decade, various methods have been implemented to enhance the functionalities and bioactivities of foods. Conjugation or grafting methods has been introduced widely. Conjugations of PPNs with proteins through various methods have been performed for the synthesis of the protein-polyphenol conjugate. Those potential grafting methods are alkaline associated, free-radical mediated, enzyme catalyzed, and chemical coupling methods. Several factors such as reaction conditions, type of proteins, and PPNs also influenced the conjugation efficiency. Various technologies, e.g., mass spectroscopy, fluorescence spectroscopy, UV spectroscopy, Fourier transform infrared spectroscopy, circular dichroism, and sodium dodecyl sulfate polyacrylamide gel electrophoresis have been used to elucidate conjugation and structural alternation of proteins and some properties of resulting conjugates. The prepared protein-PPN conjugates have been documented to enhance the bioactivities and functional properties of an initial protein. Moreover, conjugates have been employed in emulsions or as nanoparticles for nutraceutical delivery. Edible-films for food packaging and hydrogels for controlled drug release have been developed using protein-PPN conjugates. This chapter focuses on the methodologies and characteristics of protein-PPN conjugates and their applications in various food systems and nutraceutical field.

Hydroxycinnamic Acids and Derivatives Formulations for Skin Damages and Disorders: A Review

Alterations of skin homeostasis are widely diffused in our everyday life both due to accidental injuries, such as wounds and burns, and physiological conditions, such as late-stage diabetes, dermatitis, or psoriasis. These events are locally characterized by an intense inflammatory response, a high generation of harmful free radicals, or an impairment in the immune response regulation, which can profoundly change the skin tissue' repair process, vulnerability, and functionality. Moreover, diabetes diffusion, antibiotic resistance, and abuse of aggressive soaps and disinfectants following the COVID-19 emergency could be causes for the future spreading of skin disorders. In the last years, hydroxycinnamic acids and derivatives have been investigated and applied in several research fields for their anti-oxidant, anti-inflammatory, and anti-bacterial activities. First, in this study, we give an overview of these natural molecules' current source and applications. Afterwards, we review their potential role as valid alternatives to the current therapies, supporting the management and rebalancing of skin disorders and diseases at different levels. Also, we will introduce the recent advances in the design of biomaterials loaded with these phenolic compounds, specifically suitable for skin disorders treatments. Lastly, we will suggest future perspectives for introducing hydroxycinnamic acids and derivatives in treating skin disorders.

Cyan-emitting silicon quantum dots as a fluorescent probe directly used for highly sensitive and selective detection of chlorogenic acid

As an important bioactive component in plants, chlorogenic acid (CGA) has been widely studied for its potential role in human health. In this work, cyan fluorescent silicon quantum dots were successfully synthesized via a simple one-pot method for the rapid detection of CGA. The optimal excitation and emission wavelength of the obtained SiQDs was 350 nm and 470 nm, respectively. When the CGA was added, the maximum emission intensity of the SiQDs can be effectively quenched due to dynamic and static mixed quenching mechanisms. More significantly, there was a remarkable linear correlation between fluorescence quenching efficiency and a broad concentration of CGA solution range from 10 to 150 μmol/L with a limit of detection (LOD) of 0.43 μmol/L. Furthermore, the proposed SiQDs were successfully applied to analyze CGA in coffee beans and instant coffee after simple pretreatment with satisfactory results. Based on these, a high sensitivity and excellent selectivity fluorescent probe detection system was constructed, and it provides a valuable platform for the detection of CGA and has broad application prospects in the biological and pharmaceutical analysis field.

Toxicity assessment of saline extract and lectin-rich fraction from Microgramma vacciniifolia rhizome

Microgramma vacciniifolia is broadly used in folk medicine but safety information is unavailable. Therefore, we evaluated the toxicity of a saline extract and a lectin-rich fraction of M. vacciniifolia rhizome. The extract showed hemolytic activity on mice erythrocytes at 1000 μg/mL, whereas the fraction promoted hemolysis (8.57-26.15%) at all tested concentrations (10-1000 μg/mL). Acute toxicity test in mice indicated an LD₅₀ of >5000 mg/kg. Hematological alterations and increased serum alkaline phosphatase level were observed in the treated animals. Transaminases and urea levels increased in the groups treated with the extract or fraction at 5000 mg/kg. Leukocyte infiltration was observed in the liver of extract-treated animals and in the liver and lungs of mice treated with the fraction. The kidneys of animals treated with the fraction at 5000 mg/kg presented hydropic degeneration. The extract and fraction did not induce oxidative stress in the liver and did not show genotoxicity, as examined by micronucleus and comet assays. In conclusion, the preparations were not lethal to mice but caused some signs of toxicity, mainly the fraction. The results indicated the need to evaluate the toxicity of M. vacciniifolia rhizome in other models and in chronic assays.

Doxycycline drug delivery using hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide synthesized by electron beam irradiation

Two hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide were synthesized using electron beam irradiation. The synthesized hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and mechanical properties studies. The hydrogels were loaded with doxycycline by swelling and its release was investigated in various media. The effect of the dose of electron beam irradiation and PAAm amount on the properties of hydrogels including swelling, drug loading, drug release, mechanical properties, and gel content were studied. The release of doxycycline form hydrogels in different media obeyed the mechanism of non-Fickian diffusion and best fitted to the Higuchi model and Korsmeyer-Peppas. In-vitro doxycycline release consideration indicated that the drug's release from composite hydrogel occurs with higher amounts than the other one. The cytotoxic study confirmed the non-toxicity of the prepared hydrogels dressing. Moreover, the growth inhibition of permissive bacteria against Staphylococcus aureus and Escherichia coli were observed for doxycycline-loaded hydrogels. So, the synthesized hydrogels are appropriate for practical application as a new antibacterial wound dressing.

Synthesis of silver nanoparticles using oxidized amylose and combination with curcumin for enhanced antibacterial activity

Many kinds of multi-drug-resistant microorganisms have appeared. Moreover, monotherapy is increasingly no longer adequate for many complicated bacterial infections. Therefore, development of efficient combination antibacterial agent is becoming crucial. Herein, we present a hybrid antibacterial agent with enhanced antibacterial activity and high aqueous dissolubility based on silver nanoparticles and curcumin. The silver nanoparticles were firstly synthesized using oxidized amylose as an environmentally friendly reducing agent and stabilizer. Then, curcumin was added into the above mixture to get the hybrid antibacterial agent. The hybrid antibacterial agent presented high dissolubility in aqueous solution and enhanced antibacterial activity. In addition, the hybrid antibacterial agent presented good antioxidant activity and cell compatibility. Overall, the developed hybrid antibacterial agent has a potential to combat multiple bacteria-induced infections of wound surfaces.

Recent advances in phenolic-protein conjugates: synthesis, characterization, biological activities and potential applications

Proteins and phenolic compounds are two types of food ingredients with distinct functionalities. In the past decade, many attempts have been made to conjugate phenolic compounds with proteins through covalent linkages. Four types of conjugation reactions including alkaline, free radical mediated grafting, enzyme catalyzed grafting and chemical coupling methods are frequently used to synthesize phenolic-protein conjugates. The synthesized phenolic-protein conjugates can be well characterized by several different instrumental methods, such as UV spectroscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy, circular dichroism, mass spectroscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis and differential scanning calorimetry. Importantly, phenolic-protein conjugates exhibit improved biological properties (e.g. antioxidant, anticancer and antimicrobial activities) as compared with native proteins. Moreover, the applications of native proteins can be greatly widened by conjugation with phenolic compounds. Phenolic-protein conjugates have been developed as antioxidant emulsions for nutraceutical delivery, edible films for food packaging, stabilizers for metal nanoparticles, and hydrogels and nanoparticles for controlled drug release. In this review, recent advances in the synthesis, characterization, biological properties and potential applications of phenolic-protein conjugates were summarized.

Strengthened and Thermally Resistant Poly(lactic acid)-Based Composite Nanofibers Prepared via Easy Stereocomplexation with Antibacterial Effects

Strengthened poly(lactic acid) (PLA)-based materials with improved mechanical performance and improved thermal resistance, notably, are prepared by introducing stereocomplex crystallite (SC), an ideal filler, into the materials. Owing to the intermolecular hydrogen bond among the stereoisomer chains, the melting point of the special crystallite is up to 200 °C, which is 50 °C higher than the isostatic crystallite. The modulus of the PLA-based materials can be enhanced to several 100 MPa because of the integrated polymer chain arrangement. In this study, we electrospun hybrid nanofibers consisted of PLA stereoisomers and induced the stereocomplex crystallization under a mild condition (65 °C for 1 h). The mild warming is favorable for the protection of chlorogenic acid (CA) that was selected as the antibacterial agent. Both of Gram-positive and Gram-negative bacteria were efficiently cleared away using the warmed nanofibers that released CA rapidly within just a few hours. Used as filters, the SC electrospinning membrane also presented a potent filtering effect, leaving no bacteria retained in the filtrates. Attributing to SC, the PLA-based nanofibers showed extremely increased melting temperature over 200 °C and improved Young's modulus up to 270.0 MPa. The durable nanofibers prepared in present study are meaningful for enlarging the application of PLA-based materials, for example, as filters, masks, and packages.

Physical properties and antioxidant activity of gelatin-sodium alginate edible films with tea polyphenols

Active edible films were prepared by incorporating tea polyphenols (TP) into gelatin and sodium alginate. The effects of 0.4%-2.0% TP (w/w, TP/gelatin) on physical, antioxidant, and morphological properties of gelatin-sodium alginate films were evaluated. Tensile strength (Ts), contact angle (CA), and cross-linking degree showed an enhanced trend as TP concentration in the film increased, whereas elongation at break (EAB) and water vapor permeability (WVP) possessed a decline trend. The light transmittance of the film was decreased by the incorporation of TP. Antioxidant capacity was improved by increasing TP content in the films. For DPPH and ABTS radical, the films with 2.0% TP possessed the highest values of 90.62 ± 2.48% and 53.36 ± 1.06 Trolox (mg Trolox equivalent/g film), respectively. Fourier transform infrared spectroscopy analyses (FTIR) indicated the interactions existed between gelatin‑sodium alginate and TP. Smooth and continuous surface and dense internal structure of the films with TP were observed by scanning electron microscopy (SEM). Thus, incorporating TP into gelatin and sodium alginate film solution was an effective method in order to improve physical properties and antioxidant activity of the films. Gelatin-sodium alginate films with TP could be used as an edible film for food packaging applications.

Novel aldose reductase inhibitory and antioxidant chlorogenic acid derivatives obtained by heat treatment of chlorogenic acid and amino acids

A heating model system (HMS) of chlorogenic acid (CGA) and 20 amino acids was produced by heating at 120 °C for 4 h and evaluated for in vitro antioxidant and aldose reductase (AR). The CGA-glutamic acid (GT) HMS showed high in vitro antiradical activity indicated by ABTS⁺ (82.37%) and DPPH radical scavenging (83.21%) as well as AR (83.21%) inhibition. The structure of the new compound was established by NMR spectroscopy, as methyl-3-(((E)-3-(3,4-dihydroxyphenyl)acryloyl)oxy)-4,5-dihydroxycyclohexanecarboxylate (1) and 4-O-caffeoylquinic acid (2) from the CGA-GT HMS. The IC₅₀ values of compound 1 for ABTS⁺, DPPH and AR were 8.21, 56.97 and 3.68 μM, respectively. These activities were similar to or higher than those of known positive controls (5.49, 63.58 and 13.60 μM). We suggest that heat treatment generates novel CGA-GT HMS with increased antioxidant and AR inhibitory effects and contributes to the development of novel functional materials from CGA food products.