Development and Characterization of an Active Chitosan-Based Film Containing Quercetin

Development and evaluation of quercetin enriched bentonite-reinforced starch-gelatin based bioplastic with antimicrobial property

Nowadays novel bio-based materials have been widely employed in food and pharmaceutical industry because of their wide acceptability by the consumers rather than the synthetic materials nevertheless, they possess poor mechanical properties. Reinforcement of biopolymers with intercalation of mineral clays can improve their physicochemical properties; so that such biocomposites possess superior barrier and mechanical properties as well as stability and drug loading efficacy. Thus, this research aimed at formulating quercetin loaded bentonite-reinforced starch-gelatin based novel bioplastic with diverse applicability. The methodology of the study included Box Behnken optimization as well as physical, structural, mechanical and antimicrobial properties evaluation of the proposed reinforced bioplastics. Amount of starch, bentonite and glycerin were the independent variables while the tensile strength, swelling index and elongation percentage were studied as dependent variables. The optimized bioplastic film showed excellent physicochemical and morphological characteristics and also for efficient percentage drug content. The antimicrobial activity showed the highest activity against Escherichia coli followed by Pseudomonas aeruginosa and Staphylococcus aureus. Scanning electron microscopy (SEM) revealed the non-homogenous nature of the film. Generally, the results revealed that quercetin loaded bentonite-reinforced starch-gelatin based could be used as ecological friendly active food packaging as well as pharmaceutical application with significant antimicrobial properties.

The multifaceted role of quercetin derived from its mitochondrial mechanism

Quercetin is a flavonoid with promising therapeutic applications; nonetheless, the phenotype exerted in some diseases is contradictory. For instance, anticancer properties may be explained by a cytotoxic mechanism, whereas antioxidant-related neuroprotection is a pro-survival process. According to the available literature, quercetin exerts a redox interaction with the electron transport chain (ETC) in the mitochondrion, affecting its membrane potential. It also affects ATP generation by oxidative phosphorylation, where ATP deprivation could partly explain its cytotoxic effect. Moreover, quercetin may support the generation of free radicals through redox reactions, causing a prooxidant effect. The nutrimental stress and prooxidant effect induced by quercetin might promote pro-survival properties such as antioxidant processes. Thus, in this review, we discuss the evidence supporting that quercetin redox interaction with the ETC could explain its beneficial and toxic properties.

Chitosan Based Biodegradable Composite for Antibacterial Food Packaging Application

A recent focus on the development of biobased polymer packaging films has come about in response to the environmental hazards caused by petroleum-based, nonbiodegradable packaging materials. Among biopolymers, chitosan is one of the most popular due to its biocompatibility, biodegradability, antibacterial properties, and ease of use. Due to its ability to inhibit gram-negative and gram-positive bacteria, yeast, and foodborne filamentous fungi, chitosan is a suitable biopolymer for developing food packaging. However, more than the chitosan is required for active packaging. In this review, we summarize chitosan composites which show active packaging and improves food storage condition and extends its shelf life. Active compounds such as essential oils and phenolic compounds with chitosan are reviewed. Moreover, composites with polysaccharides and various nanoparticles are also summarized. This review provides valuable information for selecting a composite that enhances shelf life and other functional qualities when embedding chitosan. Furthermore, this report will provide directions for the development of novel biodegradable food packaging materials.

Development and characterization of active packaging films based on chitosan, plasticizer, and quercetin for repassed oil storage

Novel chitosan (Ch) films containing choline chloride and citric acid mixture as plasticizer (deep eutectic solvent, DES) and different amounts of quercetin (QUE) as antioxidant additive were prepared. Physicochemical and mechanical characteristics of the developed Ch/DES/QUE films were studied using FTIR, SEM, and AFM techniques. FTIR spectra revealed the possible interactions between all the components. The surface of the films was dense and rough. The addition of quercetin caused an increase in the tensile strength (TS) and Young's modulus, but significantly decreased the elongation at break. The films containing quercetin showed improved antioxidant activity in relation to Ch/DES film. Finally, the oxidation phenomena of rapeseed oils with and without chitosan films were evaluated as amounts of primary and secondary oxidation products and total oxidation index. The addition of Ch/DES films with quercetin to oil samples successfully retarded secondary lipid oxidation processes and improved its antioxidant activity under the accelerated storage condition.

Development of curcumin incorporated composite films based on chitin and glucan complexes extracted from Agaricus bisporus for active packaging of chicken breast meat

Composite films were prepared by combining different concentrations of curcumin with chitin and glucan complexes (CGCs) extracted from Agaricus bisporus via a solution casting method. The developed curcumin doped CGC (CGC/Cu) films were characterized in terms of surface, optical, structural, barrier, mechanical, antioxidant, and antimicrobial properties. The biodegradability of CGC/Cu films was determined in soil for 14 days. The incorporation of curcumin significantly affected the surface morphology and improved light barrier properties, radical scavenging activity, and total phenolic content of the films. The CGC/Cu films containing different concentrations of curcumin showed antibacterial activity against Escherichia coli, while antibacterial activity against Staphylococcus aureus was not observed with the developed films. Afterward, the microbial properties of the fresh chicken breast were examined during refrigerated storage for 10 days. The shelf-life of chicken samples wrapped in the developed film was extended at least 40 % compared to the control sample. In conclusion, curcumin incorporated CGC based films can serve as a promising biodegradable active packaging material to improve the shelf-life of meat products.

Physicochemical, Mechanical, and Structural Properties of Bio-Active Films Based on Biological-Chemical Chitosan, a Novel Ramon (Brosimum alicastrum) Starch, and Quercetin

The properties of biological-chemical chitosan (BCh) films from marine-industrial waste and a non-conventional Ramon starch (RS) (Brosimum alicastrum) were investigated. Blended films of BCh/RS were prepared to a volume ratio of 4:1 and 1:4, named (BChRS-80+q, biological-chemical chitosan 80% v/v and Ramon starch, BChRS-20+q, biological-chemical chitosan 20% v/v and Ramon starch, both with quercetin), Films from commercial chitosan (CCh) and corn starch (CS), alone or blended (CChCS-80+q, commercial chitosan 80% v/v and corn starch, CChCS-20+q commercial chitosan 20% v/v and corn starch, both with quercetin) were also prepared for comparison purposes. Films were investigated for their physicochemical characteristics such as thickness, moisture, swelling, water-vapor permeability, and water solubility. In addition, their mechanical and structural properties were studied using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Scanning Electron Microscopy (SEM) techniques. Antioxidant activity was evaluated as radical scavenging, and antimicrobial effect was also determined. The BCh and RS films presented similar tensile strength values compared with commercial biopolymers. Only films with chitosan presented antioxidant and antimicrobial activity. The FTIR spectra confirmed the interactions between functional groups of the biopolymers. Although, BChRS-80+q and BChRS-20+q films exhibited poor mechanical performance compared to their commercial counterparts, they showed good thermal stability, and improved antioxidant and antimicrobial activity in the presence of quercetin. BChRS-80+q and BChRS-20+q films have promising applications due to their biological activity and mechanical properties, based on a novel material that has been underutilized (Ramon starch) that does not compete with materials for human feeding and may be used as a coating for food products.

Quercetin-Crosslinked Chitosan Films for Controlled Release of Antimicrobial Drugs

Natural polymer-based films, due to their favorable biological and mechanical properties, have demonstrated great potential as coatings for biomedical applications. Among them, chitosan films have been widely studied both as coating materials and as controlled drug release systems. Crosslinkers are often used to tune chitosan’s crosslinking degree and thus to control the drug release kinetics. For this purpose, quercetin, a plant-derived natural polyphenol, has gained attention as a crosslinker, mainly for its intrinsic anti-inflammatory, antioxidant, and antibacterial features. In this study, chitosan films crosslinked with three different concentrations of quercetin (10, 20, and 30% w/w) have been used as controlled release systems for the delivery of the antibacterial drug trimethoprim (TMP, 10% w/w). Physicochemical and antimicrobial properties were investigated. Surface wettability and composition of the films were assessed by contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR), respectively. The release kinetic of TMP in phosphate-buffered saline (PBS) and 2-(N-morpholino) ethanesulfonic acid (MES) was studied over time. Finally, antibacterial properties were assessed on E. coli and S. aureus through Kirby–Bauer disc diffusion and micro-dilution broth assays. Results show that quercetin, at the tested concentrations, clearly increases the crosslinking degree in a dose-dependent manner, thus influencing the release kinetic of the loaded TMP while maintaining its bactericidal effects. In conclusion, this work demonstrates that quercetin-crosslinked chitosan films represent a promising strategy for the design of antibiotic-releasing coatings for biomedical applications.

Biological modification of pentosans in wheat B starch wastewater and preparation of a composite film

BACKGROUND

Petrochemical resources are becoming increasingly scarce, and petroleum-based plastic materials adversely impact the environment. Thus, replacement of petroleum-based materials with new and effective renewable materials is urgently required.

RESULTS

In this study, a wheat pentosan-degrading bacterium (MXT-1) was isolated from wheat-processing plant wastewater. The MXT-1 strain was identified using molecular biology techniques. The degradation characteristics of the bacteria in wheat pentosan were analyzed. The results show that wheat pentosan was effectively degraded by bacteria. The molecular weight of fermented wheat pentosan decreased from 1730 to 257 kDa. The pentosan before and after the biological modification was mixed with chitosan to prepare a composite film. After fermentation, the water-vapor permeability of the wheat pentosan film decreased from 0.2769 to 0.1286 g mm (m² h KPa)^-1. Results obtained from the Fourier-transformed infrared experiments demonstrate that the wave number of the hydroxyl-stretching vibration peak of the membrane material decreased, and the width of the peak widened. The diffraction peak of the film shifted to the higher 2θ, as seen using X-ray diffraction. The cross-section of the modified composite membrane was observed via scanning electron microscopy, which revealed that the structure was denser; however, no detectable phase separation was observed. These results may indicate improved molecular compatibility between wheat pentosan and chitosan and stronger hydrogen bonding between the molecules. Given the increased number of short-chain wheat pentosan molecules, although the tensile strength of the film decreased, its flexibility increased after fermentation modification.

CONCLUSION

The findings of this study established that the physical properties of polysaccharide films can be improved using strain MXT-1 to ferment and modify wheat pentosan. The compatibility and synergy between pentosan and chitosan molecules was substantially enhanced, and hydrogen bonding was strengthened after biological modification. Therefore, modified pentosan film could be a potential candidate material for edible packaging films.

Natural Biocidal Compounds of Plant Origin as Biodegradable Materials Modifiers

The article presents a literature review of the plant origin natural compounds with biocidal properties. These compounds could be used as modifiers of biodegradable materials. Modification of polymer material is one of the basic steps in its manufacturing process. Biodegradable materials play a key role in the current development of materials engineering. Natural modifiers are non-toxic, environmentally friendly, and renewable. The substances contained in natural modifiers exhibit biocidal properties against bacteria and/or fungi. The article discusses polyphenols, selected phenols, naphthoquinones, triterpenoids, and phytoncides that are natural antibiotics. Due to the increasing demand for biodegradable materials and the protection of the natural environment against the negative effects of toxic substances, it is crucial to replace synthetic modifiers with plant ones. This work mentions industries where materials containing natural modifying additives could find potential applications. Moreover, the probable examples of the final products are presented. Additionally, the article points out the current world's pandemic state and the use of materials with biocidal properties considering the epidemiological conditions.

Effect of ethanol extract of black soybean coat on physicochemical properties and biological activities of chitosan packaging film

Chitosan (CS) with an ethanol extract of black soybean coat (EBSC) was prepared, and its physicochemical properties and antioxidant and antibacterial activities were tested. The results showed that EBSC significantly increased the thickness and UV-Vis light barrier ability of the CS-based films, while the swelling degree, water vapor permeability, and tensile strength decreased. The CS-EBSC films had smooth surfaces, compact cross-sections, and no cracks, and they had higher crystallinity than the CS film. Fourier transform-infrared spectroscopy indicated that there were noncovalent bonds (hydrogen bonds) between EBSC and CS. Furthermore, the CS-EBSC III film presented a stronger ABTS radical scavenging ability (66.58%) and could effectively inhibit Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. The lipid oxidation test proved that CS-EBSC films significantly reduced the peroxide value of lard. The results above indicate that CS-EBSC films could be used as an active packaging material to improve the shelf life of food.

Aging Resistance of Biocomposites Crosslinked with Silica and Quercetin

This research focuses on revealing the double role of quercetin accompanied by silica in epoxidized natural rubber. A crosslinking ability with antioxidative properties exists and reveals the dependence of these functions on quercetin content. Here, the aging resistance of self-healable biocomposites was analyzed. The self-healing properties were presented in our previous work. The stabilizing effect of quercetin applied as a crosslinking agent has been studied in epoxidized natural rubber with a 50 mol% of epoxidation (ENR-50). Some of five -OH moiety groups existing in the quercetin structure are able to react with epoxy rings of ENR-50 and cure this elastomer, whereas other free hydroxyl groups can donate the hydrogen molecule to a radical molecule, stabilizing it. The aging resistance of prepared composites was estimated by mechanical tests conducted before and after different types of aging, as well as by differences in color and surface energy between aged and un-aged samples. Changes within the oxygen function, which occurred as a result of the aging process, were observed using FT-IR absorbance spectroscopy. Furthermore, the impact of quercetin content on composites’ thermal stability was investigated by thermogravimetry (TGA). According to the results, a proper dose of quercetin can act as a crosslinker and antioxidant in ENR-50 at the same time.

Gelatine/PVA copolymer film incorporated with quercetin as a prototype to active antioxidant packaging

Films that incorporate antioxidant agents are widely used and improve the stability of food products that are prone to oxidation. This work evaluated the potential antioxidant activity of PVA/gelatine films incorporated with quercetin. The films were prepared by the casting method and characterised by TG-DSC, FTIR spectroscopy, SEM, optical microscopy and swelling index. Antioxidant properties were evaluated with DPPH, ABTS and FRAP assays. According to the thermal characterisation results, the film was stable up to 68 °C and entirely degraded at 632 °C. The FTIR spectroscopic analysis indicated that there was a physical interaction between the quercetin and the polymeric film, and microscopy indicated a homogeneous and uniform film. The film showed DPPH (315.4 ± 8.2) and ABTS radical potential activity (199.4 ± 9.7), as well as potential iron reduction activity-FRAP (740.6 ± 8.9) mainly when analysed in ethanol: water (95:5 v/v) system, all results expressed as milligram of Trolox per gram of film. Hence, PVA/gelatine films incorporated with quercetin have properties that allow a potential application in active packaging systems to delay oxidative processes in food.

Elaboration and Characterization of Bioactive Films Obtained from the Incorporation of Cashew Nut Shell Liquid into a Matrix of Sodium Alginate

The objective of this work was to obtain and characterize sodium alginate-based biopolymer films with the addition of cashew nut shell liquid (CNSL). The study employed a completely randomized design, including 0%, 0.5%, 1%, and 1.5% inclusion of CNSL. Uniform formation of the films was observed, and the addition of CNSL provided better thermal resistance than did the treatment without inclusion, while the addition of CNSL reduced the homogeneity of the microstructure, especially for the 1.5% inclusion level. The permeability of the film increased as the level of CNSL increased, especially in response to the concentrations of 1% and 1.5%, and no significant difference in permeability was observed between these treatments. The tensile strength decreased proportionally as a function of the addition of CNSL, as its inclusion increased the elasticity and elongation of the films. In addition, the films with CNSL demonstrated strong antioxidant activity and discrete antimicrobial activity, and ecotoxicity analysis showed that the levels of CNSL tested and the films produced were nontoxic. Thus, these films are promising and self-sustainable alternatives for the agrifood industry.

Development and Characterization of Bioactive Poly(butylene-succinate) Films Modified with Quercetin for Food Packaging Applications

The preparation of biodegradable active packaging materials is still a major challenge. Here, we report the fabrication and characterization of poly(butylene succinate)-based (PBS) films enriched with a natural polyphenolic antioxidant—quercetin. The PBS-based films with various quercetin content (0.05; 0.10; 0.25 and 0.50 pph on PBS) were prepared via a solvent casting method. Physical (optical, mechanical, thermal, moisture and water sorption, water vapor and UV–vis barrier) and biofunctional (antioxidant and antibacterial against Escherichia coli and Staphylococcus aureus) film properties were tested. The migration of quercetin into model food liquid systems was determined. As a result of quercetin addition, significant changes in color, opacity and UV-blocking effect were observed. The presence of the active substance did not significantly affect the thermal properties of the PBS matrix. However, the mechanical properties of the films were slightly decreased. The films exhibited excellent free radicals (DPPH, ABTS, O₂⁻) scavenging and some bactericidal activities. PBS-quercetin films with superior functional properties have many possibilities for active food packaging applications.

Antimicrobial, antioxidant and physical properties of chitosan film containing Akebia trifoliata (Thunb.) Koidz. peel extract/montmorillonite and its application

A novel active packaging film was prepared in this study that incorporated Akebia trifoliata (Thunb.) Koidz. peel extracts (APE) and montmorillonite (MMT) into chitosan (CH) films. Compared with the pure CH film, the CH/APE film showed significantly higher tensile strength, elongation at break, UV light resistance, and antibacterial activity; the CH/MMT film displayed significant increases in contact angle, antioxidant activity, oxygen permeability, and thermal stability. SEM and AFM analyses showed that the additions were well-distributed into the CH matrix, but MMT induced a more compact and rougher structure. The CH-based film formula was optimized using the single-factor test and Box-Behnken design and was 0.15% MMT, 0.15% APE, and 1.50% CH. Besides, the optimized coating was applied in the postharvest preservation of A. trifoliata fruits, which yielded a significant effect on the delaying crack and mature of the fruits during 35 days of storage at 5 °C.

Functional polysaccharide-based film prepared from chitosan and β-acids: Structural, physicochemical, and bioactive properties

β-Acids are natural antibacterial and antioxidant ingredients, obtained from supercritical CO₂ hop extract. In this study, β-acids/chitosan complex films were prepared using the casting method. Complex films were characterized using scanning electron microscopy (SEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). Structure analysis revealed that β-acids can be successfully combined with the chitosan matrix. Mechanical tests demonstrated that the tensile strength of the films showed a significant upward trend (1.9 MPa to 9.6 MPa) with increase in β-acids content (0.1%-0.3%). Interestingly, the chitosan-based films showed excellent UV barrier capability below 400 nm. The release of β-acids from the film followed Fickian diffusion (n < 0.45). In addition, the complex films inhibited the growth of five food-borne pathogens (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Salmonella enteritidis and Listeria monocytogenes). This study highlights the promising nature of composite film as a desirable alternative for active packaging.

Development of active packaging films based on chitosan and nano-encapsulated luteolin

Luteolin is a flavone with potent antioxidant and antimicrobial activities. In this study, luteolin was encapsulated in oil-in-water nanoemulsions that were emulsified by glycerol monooleate and Tween 20. Results showed 68 mg luteolin-loaded nanoemulsions had the highest stability (zeta potential of -39.8 mV) and encapsulation efficiency (89.52%). Then, active packaging films were developed by incorporating free or nano-encapsulated luteolin into chitosan-based matrix. The microstructure, physical and functional properties of CS film containing free luteolin (CS-LL) or nano-encapsulated luteolin (CS-LLNEs) were compared. Different from CS film, CS-LL and CS-LLNEs films had compact inner microstructure and strengthened intermolecular interactions. Moreover, CS-LLNEs film was more homogenous and compact than CS-LL film. As a result, CS-LLNEs film presented higher water vapor and oxygen barrier abilities and mechanical properties in comparison with CS-LL film. In addition, CS-LLNEs film showed slower release rate of luteolin in 95% ethanol (fatty food stimulant) as compared with CS-LL film. The controlled release of luteolin from film matrix could guarantee CS-LLNEs film to exert antioxidant activity up to 10 days. Our results suggest CS-LLNEs film can be developed as an emerging active packaging material that has potential applications in food industry.

Properties of novel chitosan incorporated with hexahydro-β-acids edible films and its effect on shelf life of pork

Edible packaging films have been widely studied because of its safety, green, and effective characteristics. In this paper, chitosan (CH) edible films containing hexahydro-β-acids (HBA) were prepared, and its physical and mechanical properties, bioactivity, and their impact on the shelf life of pork were investigated. The infrared spectra indicated that the molecular interaction between CH and HBA was observed. Scanning electron microscopy was used to analyze the surface morphology of the film, and light transmittance analysis displayed that the addition of HBA enhanced the film's UV blocking performance. Compared to the CH film, the tensile strength of CH-HBA film increased to 29.19 ± 0.45 MPa, and the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) reached 1.40 ± 0.01 mg rutin/cm² of the film. The antibacterial activity of the CH-HBA film on Escherichia coli (44825) and Staphylococcus aureus (26001) showed that the CH-HBA film is a feasible antibacterial package. Furthermore, compared to pork packaged in CH and polyethylene films, fresh pork packaged with CH-HBA films displayed prolongation of shelf life due to reduction in microbial proliferation, thiobarbituric values, pH, and total volatile base nitrogen contents during storage at 4 °C for 16 days. The freshness of pork was prolonged by 7-8 days when the dosage of HBA was increased to 0.3% from 0.1% (w/v). These results revealed that the CH-HBA film can effectively extend the shelf life of pork. PRACTICAL APPLICATION: This study effectively prolonged the shelf life of pork. A chitosan-edible film combined with hexahydro-β-acids has a potential application value in replacing traditional packaged fresh meat.

Gallic Acid and Quercetin as Intelligent and Active Ingredients in Poly(vinyl alcohol) Films for Food Packaging

Gallic acid (GA) and quercetin (QC) were used as active ingredients in poly(vinyl alcohol) (PVA) film formulations obtained by solvent casting process. The effect of two different percentages (5 and 10 % wt.) on morphological behavior, thermal stability, optical, mechanical, and release properties of PVA were investigated, while migration with food stimulants and antioxidant properties were tested taking into account the final application as food packaging systems. The results showed how different dispersability in PVA water solutions gave different results in term of deformability (mean value of ε PVA/5GA = 280% and ε PVA/5QC = 255%, with 190% for neat PVA), comparable values for antioxidant activity at the high contents (Radical Scavenging Activity, RSA(%) PVA/10GA = 95 and RSA(%) PVA/10QC = 91) and different coloring attitude of the polymeric films. It was proved that GA, even if it represents the best antioxidant ingredient to be used with PVA and can be easily dispersed in water, it gives more rigid films in comparison to QC, that indeed was more efficient in tuning the deformability of the PVA films, due the presence of sole hydroxyl groups carrying agent. The deviation of the film coloring towards greenish tones for GA films and redness for QC films after 7 and within 21 days in the simulated conditions confirmed the possibility of using easy processable PVA films as active and intelligent films in food packaging.

Biopolymeric Films of Amphiphilic Derivatives of Chitosan: A Physicochemical Characterization and Antifungal Study

The chemical modification of chitosan has been an active subject of research in order to improve the physicochemical and antifungal properties of chitosan-based films. The aim of this study was to evaluate the physiochemical and antifungal properties of films prepared with chitosan and its derivatives containing diethylaminoethyl (DEAE) and dodecyl groups (Dod). Chitosans and selected derivatives were synthesized and characterized, and their films blended with glycerol and sorbitol (5%, 10%, and 20%). They were studied by means of the evaluation of their mechanical, thermal, barrier, and antifungal properties. The collected data showed that molecular weight (Mw), degree of acetylation, and grafting with DEAE and Dod groups greatly affected the mechanical, thickness, color, and barrier properties, all of which could be tailored by the plasticizer percentage. The antifungal study against Aspergillus flavus, Alternaria alternata, Alternaria solani, and Penicillium expansum showed that the films containing DEAE and Dod groups exhibited higher antifungal activity than the non-modified chitosans. The mechanical properties of highly soluble films were improved by the plasticizers at percentages of 5% and 10%, indicating these derivatives as potential candidates for the coating of seeds, nuts and fruits of various crops.

Development and characterization of antioxidant active packaging and intelligent Al3+-sensing films based on carboxymethyl chitosan and quercetin

Different amounts of quercetin were mixed with carboxymethyl chitosan (CMCS) to develop novel antioxidant active packaging and intelligent Al³⁺-sensing films. The physical properties, structure, antioxidant and Al³⁺-sensing abilities of CMCS-quercetin composite films were investigated. Results showed CMCS-quercetin composite films presented a dark yellowish color. When compared with CMCS film, CMCS-quercetin composite films containing 5 and 7.5 wt% of quercetin on CMCS basis exhibited higher thicknesses, opacity and thermal stability; however, presented lower moisture contents, UV-vis light transmittance and elongation at break. Besides, the incorporation of quercetin could not significantly change the water solubility and water vapor barrier property of CMCS film. Morphological observation showed the surface of CMCS-quercetin composite film became coarse when 7.5 wt% of quercetin was incorporated. Infrared spectra and X-ray diffraction patterns of CMCS-quercetin composite films further indicated quercetin was compatible with CMCS. Importantly, CMCS-quercetin composite films could sustainably release antioxidant ability into aqueous and fatty food stimulants. Moreover, CMCS-quercetin composite films were sensitive to Al³⁺. The color and UV-vis absorption patterns of CMCS-quercetin composite films were changed by the addition of Al³⁺. Results suggested that CMCS-quercetin composite films could be used as novel antioxidant and intelligent Al³⁺-sensing materials in food packaging.