Processing and characterization of chitosan films with incorporation of ethanolic extract from “pequi” peels

Characterization and application of Cinnamaldehyde-loaded zein nanoparticles in a polyvinyl alcohol/chitosan film for silver pomfret (Pampus argenteus) packaging

This study aims to prepare and characterize cinnamaldehyde-loaded zein/sodium alginate nanoparticles (ZCNPs) and incorporate them into polyvinyl alcohol/chitosan (PVA/CS) bioactive films (PSCN) to investigate their compatibility, physicochemical properties, and their application as a preservation material for pomfret fish. The results indicate that the anionic sodium alginate coating improved the particle size, zeta potential, and PDI of zein nanoparticles. The ZCNPs were uniformly dispersed within the films, enhancing the mechanical properties and water vapor barrier performance. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses confirmed the amorphous structure of the films and the formation of hydrogen bonds. In the PVA/CS film, with the increase of ZCNPs, the thermal decomposition temperature of the film increased from 298 °C to 308 °C, while the film thickness and water contact angle were not significantly affected, remaining around 0.31 cm and 23°, respectively. Additionally, after the incorporation of ZCNPs, the DPPH radical scavenging rate of the film increased from 14.58 % to 95.38 %, significantly delaying the quality deterioration of pomfret during storage.

Preparation and characterization of chitosan/dialdehyde carboxymethyl cellulose composite film loaded with cinnamaldehyde@zein nanoparticles for active food packaging

In this study, zein-loaded cinnamaldehyde (Cin@ZN) nanoparticles were incorporated into Chitosan (CS)/dialdehyde carboxymethyl cellulose (DCMC) matrix to fabricate the active food packaging materials possessing outstanding antioxidant and antibacterial properties. The research investigated how varying levels of Cin@ZN nanoparticles affected the morphology, microstructure, physicochemical properties of CS/DCMC composite films. The inclusion of Cin@ZN could significantly improve the mechanical strength, reduce the water vapor and oxygen permeability of CS/DCMC composite films and endow films with UV-light blocking properties. It's worth noting that the antibacterial and antioxidant capacities of CS/DCMC films had an astonishing enhancement with Cin@ZN blending, in which ABTS scavenging ratio of the composite films (100 mg) with different Cin@ZN contents reached >90 %. Furthermore, CS/DCMC/Cin@ZN 35 % composite film has the ability to efficiently protect strawberries from microbial damage and decelerate the spoilage rate of strawberries under ambient condition. Consequently, the CS/DCMC/Cin@ZN composite film can be applied as packaging material to extend the lifespan of fruits.

Synthesis, Characterization, and Antimicrobial and Nematicidal Activities of Chitosan-Based Silver-Doped Titanium Dioxide

Chitosan (Cs)-based silver-doped titanium dioxide (Cs-AgTiO₂) films were synthesized intending their end-use application in food packaging. AgTiO₂ NPs were successfully prepared by using electrochemical synthesis. Cs-AgTiO₂ films were synthesized by using the solution casting technique. Various advanced instrumental techniques such as scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of Cs-AgTiO₂ films. Intending their food packaging applications, samples were further investigated to obtain varied biological results including antibacterial (Escherichia coli), antifungal (Candida albicans), and nematicidal activities. Ampicillin (E. coli) and fluconazole (C. albicans) were used as models. FT-IR and XRD confirm the structural modification of Cs. IR peak shifting was observed, which confirmed that AgTiO₂ interacted with chitosan via amide I and amide II groups. This confirmed the stability of the filler in the polymer matrix. SEM also confirmed the successful incorporation of AgTiO₂ NPs. Cs-AgTiO₂ (3%) shows excellent antibacterial (16.51 ± 2.10 μg/mL) and antifungal (15.67 ± 2.14 μg/mL) activities. Nematicidal assays were also done, and Caenorhabditis elegans (C. elegans) was used as a model organism. Cs-AgTiO₂ NPs (3%) exhibited excellent nematicidal potential (64.20 ± 1.23 μg/mL), which could make these films a suitable novel material to control nematode spread in food.

Conjugation of Ctx(Ile21)-Ha Antimicrobial Peptides to Chitosan Ultrathin Films by N-Acetylcysteine Improves Peptide Physicochemical Properties and Enhances Biological Activity

The importance of obtaining new compounds with improved antimicrobial activity is a current trend and challenge. Some polymers such as chitosan have shown promising bactericidal properties when they are structurally modified, which is due to the binding versatility provided by their free amines. Likewise, antimicrobial peptides (AMPs) have received attention in recent years because of their bactericidal activity that is similar to or even better than that of conventional drugs, and they exhibit a low induction rate of antimicrobial resistance. Herein, the modified AMP Ctx(Ile²¹)-Ha-Ahx-Cys was conjugated to chitosan using N-acetylcysteine as an intermediate by the carbodiimide method. Films were prepared using protonated chitosan in 1% acetic acid and Ctx(Ile²¹)-Ha-Ahx-Cys AMP dissolved in N-acetylcysteine-chitosan; 1.6 mmol of ethylcarbodiimide hydrochloride, 1.2 mmol of N-hydroxysulfosucchimide, and 0.1 mol L ^-1of N-morpholino)ethanesulfonic acid buffer at pH 6.5 by continuous stirring at 100 × g for 10 min at 37 °C. Physicochemical properties were evaluated by Fourier-transform infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis, and X-ray diffraction to determine the mechanical properties, solubility, morphology, and thickness. Furthermore, the antimicrobial activities of chitosan-based conjugated films were evaluated againstStaphylococcus aureus,Pseudomonas aeruginosa,SalmonellaTyphimurium, andEscherichia coli. The results showed that the conjugation of a potent AMP could further increase its antibacterial activity and maintain its stable physicochemical properties. Therefore, the developed peptide-chitosan conjugate could be applied as an additive in surgical procedures to prevent and combat bacterial infection.

Antibacterial, Antioxidation, UV-Blocking, and Biodegradable Soy Protein Isolate Food Packaging Film with Mangosteen Peel Extract and ZnO Nanoparticles

The objective of this study was to prepare a functional biodegradable soy protein isolate (SPI) food packaging film by introducing a natural antimicrobial agent, mangosteen peel extract (MPE, 10 wt% based on SPI), and different concentrations of functional modifiers, ZnO NPs, into the natural polymer SPI by solution casting method. The physical, antioxidant, antibacterial properties and chemical structures were also investigated. The composite film with 5% ZnO NPs had the maximum tensile strength of 8.84 MPa and the lowest water vapor transmission rate of 9.23 g mm/m² h Pa. The composite film also exhibited excellent UV-blocking, antioxidant, and antibacterial properties against Escherichia coli and Staphylococcus aureus. The TGA results showed that the introduction of MPE and ZnO NPs improved the thermal stability of SPI films. The microstructure of the films was analyzed by SEM to determine the smooth surface of the composite films. ATR-FTIR and XPS analyses demonstrated the strong hydrogen bonding of SPI, MPE, and ZnO NPs in the films. The presence of ZnO NPs in the composite films was also proved by EDX and XRD. These results suggest that SPI/MPE/ZnO composite film is promising for food-active packaging to extend the shelf life of food products.

Preparation and characterization of Zein-sulfated Cardamine hupingshanensis polysaccharide composite films

Cardamine hupingshanensis polysaccharide (CHP) was modified by the sulfur trioxide-pyridine method to obtain the sulfated C. hupingshanensis polysaccharide (SCHP) with a substitution degree of 0.72. The spectral results revealed that the sulfate group was successfully introduced to CHP. In the in vitro antioxidant assay, SCHP showed the highest scavenging rate of hydroxyl radicals, ABTS, and DPPH. Different concentrations of SCHP were chosen to form a compound with Zein to prepare novel bioactive films successfully. The functional and characterization studies of the films were also conducted. The scavenging ability of the films for hydroxyl radicals, ABTS, and DPPH was improved by adding different concentrations of SCHP. Although the films showed a decrease in transparency with the addition of 4 mg/ml SCHP, there was an improvement in tensile strength compared to films without the addition of SCHP. These findings indicate that Zein-SCHP films can be used as a functional food packaging material with antioxidant properties.

Preparation and characterizations of antibacterial–antioxidant film from soy protein isolate incorporated with mangosteen peel extract

The mangosteen peel extract (MPE) was used to obtain soy protein isolate (SPI) films. The results show that MPE exhibited a high content of total phenolics and antioxidant activity. Moreover, the MPE can enhance the antibacterial–antioxidant properties, UV-visible light barrier properties, and water-resistant properties of the SPI films. The presence of MPE resulted in an increase in water vapor permeability and hydrophobicity. The extract addition also reduced the film’s crystallinity along with a decrease in the mechanical property and lowering of the maximum degradation temperature. Attenuated total reflectance Fourier transform infrared spectroscopy revealed that the polyphenols in MPE could interact with SPI through hydrogen bonds and hydrophobic interactions, and the addition of MPE changed the secondary structure of SPI with a decrease in β-sheets and an increase in β-turns and random coils. Scanning electron microscopy showed that all the films exhibited smooth and homogenous morphology on the surface and on some layers through cross-sectional images. Our results suggested that the MPE would be a promising ingredient to make SPI films used as an active packaging material.

Polysaccharide based films and coatings for food packaging: Effect of added polyphenols

There has been keen interest in developing biodegradable food packaging materials using polysaccharides. Plant polyphenols are natural antioxidants with many health effects. Different types of plant extracts rich in polyphenols have been formulated into polysaccharide based films and coatings for food packaging. The packaging increases the shelf life of food products by decreasing the quality loss due to oxidation and microbiological growth. The release of polyphenols from the films is modulated. Polysaccharide films incorporated with certain types of polyphenols can be used to indicate the freshness of animal based products. To formulate films with desirable mechanical and barrier properties, addition levels and types of plant extracts, plasticisers and composite polysaccharide materials used should be optimized. The potential of polysaccharide based films with added polyphenols to stop the SARS-CoV-2 transmission through food supply chain is discussed. Polysaccharide based films fortified with polyphenol extracts are multifunctional with potential for active and intelligent packaging.

Equilibrium, kinetics and thermodynamics of lead (II) adsorption in bioadsorvent composed by Caryocar coriaceum Wittm barks

The improper disposal of waste containing toxic metals promotes serious environmental problems. Biosorption stands out as a powerful technique in removing toxic metals from aqueous solutions, making it an efficient and low-cost technique, since it makes use of abundant materials and of natural origins. This work aimed to study the application of the bark of Caryocar coriaceum Wittm, as a possible bioabsorbent for the removal of Lead (II) present in aqueous solutions, for this, residues of this material were collected in a public market, where they were washed and dried, then crushed, sieved (32mesh) and washed again, to then be used in the kinetic, isotherm and thermodynamic tests of lead (II) ions adsorption. After the experiments, it was found that the increase of the temperature disfavored the rate of lead (II) adsorption, ranging from 15.6 to 13.5 mg.L^-1, for temperatures of 5 °C and 35 °C, respectively. The pseudo-second order kinetic model best characterizes the adsorption velocity obtaining a linear regression coefficient of 0.9997, while the pseudo-first order obtained a value of 0.7117. Adsorption occurred by chemisorption, with intra-film diffusion. The isothermal model that best represented the adsorption was Langmuir's (R² 0.99). It was concluded that the bark of Caryocar coriaceum Wittm is a good alternative to be used as a bioabsorbent for solutions containing dissolved lead (II).

Edible and Functionalized Films/Coatings—Performances and Perspectives

In recent years, food packaging has evolved from an inert and polluting waste that remains after using the product toward an active item that can be consumed along with the food it contains. Edible films and coatings represent a healthy alternative to classic food packaging. Therefore, a significant number of studies have focused on the development of biodegradable enveloping materials based on biopolymers. Animal and vegetal proteins, starch, and chitosan from different sources have been used to prepare adequate packaging for perishable food. Moreover, these edible layers have the ability to carry different active substances such as essential oils—plant extracts containing polyphenols—which bring them considerable antioxidant and antimicrobial activity. This review presents the latest updates on the use of edible films/coatings with different compositions with a focus on natural compounds from plants, and it also includes an assessment of their mechanical and physicochemical features. The plant compounds are essential in many cases for considerable improvement of the organoleptic qualities of embedded food, since they protect the food from different aggressive pathogens. Moreover, some of these useful compounds can be extracted from waste such as pomace, peels etc., which contributes to the sustainable development of this industry.

Tripolyphosphate crosslinked Triticum aestivum (wheatgrass) functionalized antimicrobial chitosan: Ameliorating effect on physicochemical, mechanical, invitro cytocompatibility and cell migration properties

Polymeric films for various biomedical applications require to be biocompatible and non- toxic. Chemical route of modifications for functionalization of the films for improved properties lead to undesirable effects for biological applications. Hence a natural way to enhancing their properties is by functionalizing them using plant extracts. This report investigates the synthesis of bioactive phytochemical loaded polymer using Triticum aestivum (wheatgrass) extract incorporated in tripolyphosphate crosslinked chitosan. Physical and mechanical properties of the extract functionalized crosslinked chitosan were analyzed and this showed significant changes in thickness, tensile strength and % elongation of the blend. The extract functionalized chitosan was characterized using Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDAX) confirming the interaction between the functional moieties of the extract and polymer. Antimicrobial analysis showed improved activity against Escherichia coli and Staphylococus aureus and Candida albicans. Presence of the extract in crosslinked chitosan enhanced the cytocompatibility in 3T3 cells carried out by MTT assay and showed improved cell migration properties determined by scratch assay.Communicated by Ramaswamy H. Sarma.

Antioxidant Activities and Total Phenolic Content of Malaysian Herbs as Components of Active Packaging Film in Beef Patties

Active packaging containing natural extracts is a promising innovation to prolong the shelf life of perishable food. The objective of this work was to develop a bioactive edible film from semi-refined carrageenan (SRC) and glycerol (G) as plasticizer incorporated with natural extract. Five Malaysian herbs were evaluated to determine their total phenolic content (TPC) and antioxidant activities. The Persicaria minor (PM) extract demonstrated the highest TPC (1.629 mg GAE/L sample) and radical scavenging activity evaluated by the radicals 2,2’-azinobis [3-ethylbenzothiazoline-6-sulfonic acid] (27.166 mg TE/L sample), 2,2-diphenyl-1-picrylhydrazyl (719.89 mg eq. Trolox/L sample) and α,α′-Azodiisobutyramidine dihydrochloride (5.81 mg TE/L sample). Thus, PM extract was selected for active packaging film at concentrations of 0.4, 1.0 and 2.0% and compared with 0.4% Butylatedhydroxianisole in 2% SRC and 0.9% G film formulation. The meat patties were wrapped in the films and stored under refrigeration (4 ± 2 °C) for 14 days. The film with 2% PM exhibited significantly lower lipid deterioration analysed by the thiobarbituric acid reactive substance assay (p < 0.05) and small changes in % metmyoglobin value which indicated the minimum development of brown colour (p < 0.05). Hence, this film can be used as a packaging material to improve meat quality characteristics.

Preparation of chitosan-sodium alginate films through layer-by-layer assembly and ferulic acid crosslinking: Film properties, characterization, and formation mechanism

Chitosan-alginate films were prepared through layer-by-layer assembly combined with ferulic acid crosslinking. Their mechanical properties, opacity, and hydrophobicity were compared to films prepared by direct mixing, crosslinking alone, and LBL assembly alone. Thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the films and analyze their formation mechanism. The results indicated that the layer-by-layer assembly and ferulic acid crosslinking combination increased the tensile strength and light-blocking ability of the films. In addition, the films had a lower water vapor transmission rate, swelling degree, and water solubility, as well as higher hydrophobicity. Scanning electron microscopy showed a good compatibility between the film components of the film prepared by the combination technique. The structural characterization results revealed some strong interactions among the amino, carboxyl, and hydroxyl groups of the ferulic acid, chitosan, and sodium alginate in the film. The driving force for film formation was the generation of non-covalent bonds among the film components rather than covalent bonds.