Preparation, characterization and anti-aflatoxigenic activity of chitosan packaging films incorporated with turmeric essential oil

Synthesis, Characterization, and Antifungal Activity of Benzimidazole-Grafted Chitosan against Aspergillus flavus

Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H and 13C NMR). Then, the efficiency of BAC against A. flavus ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of A. flavus. Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.

A novel biopolymeric composite edible film based on sunnhemp protein isolate and potato starch incorporated with clove oil: Fabrication, characterization, and amino acid composition

Composite edible films were developed by casting method using sunnhemp protein isolate (SHPI) and potato starch (PS) at various proportions (100:0, 90:10, 80:20; 70:30, 60:40, and 50:50) containing glycerol as a plasticizer and clove oil. All the edible films were evaluated for thickness, moisture content, solubility, swelling ratio, water activity. Further characterization of edible films was done on the basis of mechanical, optical, thermal and structural attributes along with morphology. Among all the films, composite film containing 50 % SHPI, 50 % PS and 1 % clove oil were having better characteristics. The solubility and WVP decreased, while the tensile strength and elongation at break of composite film increased with the inclusion of potato starch and clove oil. Intermolecular interactions in the composite film matrix were confirmed by FTIR and XRD analysis. SEM images confirmed the structural compactness and integrity of all the developed films. The amino acid composition of edible films indicated presence of most of the essential amino acids. The present finding of this research work shows that the utilization of sunnhemp protein in the development of biocomposite edible films represents an alternative opportunity of sustainable edible food packaging.

Persimmon preservation using edible coating of chitosan enriched with ginger oil and visualization of internal structure changes using X-ray computed tomography

The incorporation of ginger oil (GO) influenced the physical, optical, and structural properties of the chitosan (CH) film including the decreases of moisture content (60.15 %), water solubility (35.37 %) and water vapor permeability (WVP) (32.79 %) and the increases of tensile strength (TS) (125 %), elongation at break (EAB) (2.74 %) and opacity (131.08 %). Antifungal capacity of the CH film was enhanced when GO was added to the film. The CH + GO film showed a less homogeneous surface that the presence of the oil droplets on the film surface. Moreover, the CH and CH + GO coatings reduced weight loss of persimmon by 14.87 %, and 21.13 %, respectively, compared to the control. Moisture content loss of the coated CH- and the coated CH + GO- persimmons was decreased by 1.94 % and 4.92 %, respectively, compared to that of the control persimmon. Furthermore, the CH and CH + GO coatings decreased in color changes, respiration rate, ethylene production, changes in pH and TSS, and remained firmness of persimmon during storage at 25 °C. In addition, X-ray CT images can be used to monitor internal changes and observe the tissue breakdown during storage period. The ΔGS value can be used as a predictor of persimmon internal qualities. Thus, the CH film containing GO can be applied as an active packaging material.

Inclusion complex of turmeric essential oil with hydroxypropyl-β-cyclodextrin: Preparation, characterization and release kinetics

The application of turmeric essential oil (TEO), a natural effective antibacterial agent, in food preservation is limited due to high volatility and low stability. This study aimed to improve its stability and release behavior by synthesizing TEO/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex (IC) in a saturated aqueous solution. An orthogonal experimental design was used to determine the optimal process conditions (HP-β-CD to TEO, g/mL), 16:1; stirring speed, 850 r/min; encapsulation time, 2 h), achieving a comprehensive score value of 85.62% for TEO/HP-β-CD-IC. Through comprehensive characterization, the results showed that TEO was completely embedded in HP-β-CD with increased stability. Free TEO exhibited a weight loss of 67.64% between 30 and 300 °C, while TEO/HP-β-CD-IC had a mass loss of only 9.33%. HP-β-CD and TEO/HP-β-CD-IC showed positive ZP values that were 124.76 mV and 132.16 mV, respectively. The release behavior and release kinetics of TEO/HP-β-CD-ICs were also studied, and the results showed that TEO/HP-β-CD-IC release rate increased under higher temperature and relative humidity-consistent with Fick's diffusion.

Recent advances in delivering free or nanoencapsulated Curcuma by-products as antimicrobial food additives

Food commodities are often contaminated by microbial pathogens in transit or during storage. Hence, mitigation of these pathogens is necessary to ensure the safety of food commodities. Globally, researchers used botanicals as natural additives to preserve food commodities from bio-deterioration, and advances were made to meet users' acceptance in this domain, as synthetic preservatives are associated with harmful effects to both consumers and environments. Over the last century, the genus Curcuma has been used in traditional medicine, and its crude and nanoencapsulated essential oils (EOs) and curcuminoids were used to combat harmful pathogens that deteriorate stored foods. Today, more research is needed for solving the problem of pathogen resistance in food commodities and to meet consumer demands. Therefore, Curcuma-based botanicals may provide a source of natural preservatives for food commodities that satisfy the needs both of the food industry and the consumers. Hence, this article discusses the antimicrobial and antioxidant properties of EOs and curcuminoids derived from the genus Curcuma. Further, the action modes of Curcuma-based botanicals are explained, and the latest advances in nanoencapsulation of these compounds in food systems are discussed alongside knowledge gaps and safety assessment where the focus of future research should be placed.

The Extraction and Impact of Essential Oils on Bioactive Films and Food Preservation, with Emphasis on Antioxidant and Antibacterial Activities-A Review

Essential oils, consisting of volatile compounds, are derived from various plant parts and possess antibacterial and antioxidant properties. Certain essential oils are utilized for medicinal purposes and can serve as natural preservatives in food products, replacing synthetic ones. This review describes how essential oils can promote the performance of bioactive films and preserve food through their antioxidant and antibacterial properties. Further, this article emphasizes the antibacterial efficacy of essential oil composite films for food preservation and analyzes their manufacturing processes. These films could be an attractive delivery strategy for improving phenolic stability in foods and the shelf-life of consumable food items. Moreover, this article presents an overview of current knowledge of the extraction of essential oils, their effects on bioactive films and food preservation, as well as the benefits and drawbacks of using them to preserve food products.

Natural food preservation with ginger essential oil: Biological properties and delivery systems

Recently, the increasing demand from consumers for preservative-free or naturally preserved foods has forced the food industry to turn to natural herbal and plant-derived preservatives rather than synthetic preservatives to produce safe foods. Essential oils derived from ginger (Zingiber officinale Roscoe) are widely known for their putative health-promoting bioactivities, and this paper covers their extraction methods, chemical composition, and antibacterial and antioxidant activities. Especially, the paper reviews their potential applications in food preservation, including nanoemulsions, emulsions, solid particle encapsulation, and biodegradable food packaging films/coatings. The conclusion drawn is that ginger essential oil can be used not only for direct food preservation but also encapsulated using various delivery forms such as nanoemulsions, Pickering emulsions, and solid particle encapsulation to improve its release control ability. The film of encapsulated ginger essential oil has been proven to be superior to traditional methods in preserving foods such as bread, meat, fish, and fruit.

Antifungal effects of selected menthol and eugenol in vapors on green coffee beans during long-term storage

Nowadays, coffee (Coffea Arabica L.) is among the most significant agricultural products of the world and drinking coffee has become one of the most popular habits in the world. The main contamination of stored coffee beans is related with the mycotoxin produced by the toxigenic fungi belonging the genus Aspergillus. Fungal infection followed by mycotoxin biosynthesis in coffee results in notable financial losses. subsequent mycotoxin biosynthesis in coffee leads to major economic losses. Complications ranging from mild to severe can be caused by the mycotoxins produced by this genus. The aim of this investigation was to determine the effect of menthol and eugenol on Aspergillus parasiticus (CBS 100926^T) growth, spore germination, and their potential use as green coffee beans preservative during long-term storage (12 months). The minimum inhibitory concentrations (MICs) values of the menthol and eugenol were recorded to completely inhibit the growth of A. parasiticus in 400 μg/ml and 300 μg/ml, respectively. Both reduced spore germination by 9.33% and 5.66% at 300 μg/ml and 200 μg/ml, respectively. They showed efficacy in fumigated green coffee beans sample during the storage for up to 12 months providing an increase in the protection level of 62.5% for menthol and 73.21% for eugenol against the A. parasiticus contamination. This suggests that menthol and eugenol could be used as good alternatives for decreasing the deteriorations due to the fungal infections in green coffee beans during long-term storage.

Improvement of Chitosan Films Properties by Blending with Cellulose, Honey and Curcumin

Chitosan is a natural biopolymer that can be used in biomedical applications, tissue engineering, and wound dressing because of its biodegradability, biocompatibility, and antibacterial activity. The blending of chitosan films with natural biomaterials such as cellulose, honey, and curcumin was studied at different concentrations in order to improve their physical properties. Fourier transform infrared (FTIR) spectroscopy, mechanical tensile properties, X-ray diffraction (XRD), antibacterial effects, and scanning electron microscopy (SEM) were studied for all blended films. The XRD, FTIR, and mechanical results showed that films blended with curcumin were more rigid and compatible and had higher antibacterial effects than other blended films. In addition, XRD and SEM showed that blending chitosan films with curcumin decreases the crystallinity of the chitosan matrix compared to cellulose and honey blending films due to increased intermolecular hydrogen bonding, which reduces the close packing of the CS matrix.

Nanoencapsulation of garlic essential oil using chitosan nanopolymer and its antifungal and anti-aflatoxin B1 efficacy in vitro and in situ

The present study investigated the comparative efficacy of garlic essential oil (GEO) and its nanoencapsulated within chitosan nanomatrix (GEO-CSNPs) as a novel preservative for the protection of stored food commodities from fungal infestations, aflatoxin B1 (AFB1) contamination and lipid peroxidation against a toxigenic strain of Aspergillus flavus. GC-MS examination of GEO showed the presence of allyl methyl tri-sulfide (23.10 %) and diallyl sulfide (19.47 %) as the major components. GEO-CSNPs were characterized through TEM micrograph, DLS, XRD, and FTIR instrumentation. During the in-vitro investigation, GEO-CSNPs at 1.0 μL/mL dose completely inhibited the growth of A. flavus while preventing the synthesis of AFB₁ at 0.75 μL/mL compared to the pure GEO. The biochemical analysis reveals that A. flavus exposed to GEO-CSNPs significantly changed its ergosterol level, ions leakage, mitochondrial membrane potential (MMP), and antioxidant system. Additionally, GEO-CSNPs exhibited enhanced antioxidant activity against DPPH compared with GEO. Likewise, during in-situ experiments on A. hypogea GEO-CSNPs MIC and 2 MIC concentration prohibited fungal development, AFB₁ synthesis, and lipid peroxidation or inflicting any negative impacts on germinating seeds. Overall, investigations concluded that GEO-CSNPs could be used as a novel preservative agent to improve the shelf life of stored food commodities.

Ar-turmerone suppresses Aspergillus flavus growth and aflatoxin accumulation: Finding a new antifungal agent based on stored maize

Aspergillus flavus (A. flavus) is a common saprophytic pathogenic fungus that produces toxic and carcinogenic aflatoxins prone to contaminate food. Here, we optimized the synthesis method of Ar-turmerone, the main active ingredient in turmeric essential oil, improved its yield and reduced the operation requirements. Moreover, 50.0 μg/mL Ar-turmerone 100.0 % inhibited the colonies growth, spore germination, mycelium biomass and aflatoxin accumulation in 7 days. 2,018 differentially expressed genes (DEGs) such as catA, ppoC, erg7, erg6 and aflO related to the A. flavus growth and aflatoxin product were significantly downregulated including 45 DEGs were 100.0 % suppressed. Besides, Ar-turmerone greatly reduced A. flavus in maize, the optimal storage conditions for maize to avoid A. flavus contamination were determined as 0.940 aw, 400.0 μg/mL Ar-turmerone, and 16.0 °C. Satisfactory odor, luster, taste, and mildew in maize observed after three weeks of storage under the optimal conditions. Thus, Ar-turmerone can be used as a potential food antifungal agent against A. flavus growth and aflatoxin accumulation during food storage.

Antifungal Activity of Menthol, Eugenol and Their Combination against Aspergillus ochraceus and Aspergillus niger In Vitro and in Stored Cereals

Aspergillus ochraceus and Aspergillus niger are spoilage and mycotoxin-producing fungi that can contaminate agricultural commodities and derived products. In the present study, menthol, eugenol, and their combination (mix 1:1) were tested to determine their contact and fumigation toxicity against the two fungi. Menthol, eugenol, and their mixture significantly reduced mycelial growth and spore germination at concentrations from 300 to 600 µg/mL, and the inhibitory effects showed clear dose dependence. The minimum inhibitory concentration (MIC) values against A. ochraceus were 500 µg/mL (menthol), 400 µg/mL (eugenol), and 300 µg/mL (mix 1:1), while the MIC values for A. niger were 500 µg/mL (menthol), 600 µg/mL (eugenol), and 400 µg/mL (mix 1:1). Additionally, the analyzed compounds exhibited more than 50% protection against A. ochraceus and A. niger by fumigation of stored cereal grains (maize, barley, and rice) in sealed containers. The binary mixture of menthol and eugenol showed synergistic effects against both fungi in both in vitro direct contact and stored grain fumigation trials. The results of the present study provide a scientific basis for the application of a combination of natural antifungals in food preservation.

Synthesis, characterization, and assessment of chitosan-nanomatrix enriched with antifungal formulation against biodeterioration of active ingredients of selected herbal raw materials

Aflatoxin B₁ (AFB₁), a potent natural group 1 carcinogen produced by Aspergillus flavus is considered an unavoidable toxic contaminant of herbal raw materials, which often deteriorates their active ingredients making them less effective and hazardous during their formulation in herbal drugs. The present investigation reports the antifungal (0.5 μl/ml) and AFB₁ inhibitory (0.4 μl/ml) effects of the developed formulation CIM based on a mixture of essential oils (Carum carvi, and Illicium verum), and methyl anthranilate using mathematical modeling. The insight into the mechanism of action has also been explored using biochemical, molecular docking, and RT-PCR. Further, the nanoencapsulation of CIM (Ne-CIM) was prepared using a green facile synthesis of chitosan-based nanomatrix and characterized by Dynamic light scattering (DLS), Fourier transform-infrared, (FTIR), and X-ray diffraction analysis (XRD). The in-situ results showed that at MIC doses Ne-CIM effectively controls the A. flavus (81.25-89.57 %), AFB₁ contamination (100 %), and protects the active ingredients deterioration of Piper nigrum, P. longum, Andrographis paniculata, Silybum marianum, and Withania somnifera caused by toxigenic species of A. flavus without affecting their sensory properties. Hence, Ne-CIM could be used as a green chemical agent to protect the biodeterioration of active ingredients of herbal raw materials caused by toxigenic species of A. flavus.

Preparation of robust, water-resistant, antibacterial, and antioxidant chitosan-based films by incorporation of cinnamaldehyde-tannin acid-zinc acetate nanoparticles

Chitosan (CS) films have poor mechanical property, low water-resistance and limited antimicrobial activity, which hinder their application in food preservation industry. Cinnamaldehyde-tannic acid-zinc acetate nanoparticles (CTZA NPs) assembled from edible medicinal plant extracts were successfully incorporated into CS films to solve these issues. The tensile strength and water contact angle of the composite films increased about 5.25-fold and 17.55°. The addition of CTZA NPs reduced the water sensitivity of CS films, which could undergo appreciable stretching in water without breaking. Furthermore, CTZA NPs significantly enhanced the UV adsorption, antibacterial, and antioxidant properties of the films, while reduced their water vapor permeability. Moreover, it was possible to print inks onto the films because the presence of the hydrophobic CTZA NPs facilitated the deposition of carbon powder onto their surfaces. The films with great antibacterial and antioxidant activities can be applied for food packaging application.

Preparation of Vanillin-Taurine Antioxidant Compound, Characterization, and Evaluation for Improving the Post-Harvest Quality of Litchi

Litchi’s post-harvest pericarp browning is one of the main constraints that drastically affect its visual attributes and market potential. Therefore, the vanillin-taurine Schiff base (VTSB) compound prepared from natural compounds of vanillin and taurine exhibited higher DPPH-radical-scavenging invitro antioxidant activity than vanillin. VTSB first-time report to mitigate the postharvest browning of litchi fruit. In this study, litchi fruits were dipped in 0.3 mM (based on pre-experiment) VTSB solution and stored at 25 ± 1 °C for six days to examine their effects on browning and postharvest quality. Fruit treated with VTSB had lower levels of browning degree (BD), browning index (BI), weight loss, soluble quinone (SQ), relative electrolyte leakage (REL), and malondialdehyde (MDA) than control fruit. Additionally, total anthocyanins and phenolic concentrations, Total soluble solids (TSS), and 2,2-diphenyl-1-picrylhydrazyl-free radical scavenging activity (DPPH-RSA) were preserved higher in VTSB-treated litchi fruit. The levels of Ascorbate peroxidase (APX), Superoxide dismutase (SOD), and Catalase (CAT) were higher in treated fruit, whereas polyphenol oxidase (PPO) and Peroxidase (POD) were decreased during the postharvest period. This study suggested that VTSB would be very useful for different post-harvest problems in the fruit and vegetable industry.

Active packaging of corn starch with pectin extract and essential oil of Turmeric Longa Linn: Preparation, characterization and application in sliced bread

The use of active packaging to reduce food waste has been a very effective alternative. An eminent concern is the use of plastic materials of petroleum origin and toxic additives in the processing of these packages. Thus, the focus on the use of biodegradable and natural raw materials that minimize waste generation and promote greater consumer safety has been preferable. The objective of the research was to investigate the effects of turmeric essential oil (TEO) on corn starch and pectin extract films manufactured by solution casting method. The antioxidant and antimicrobial potential of the oil was confirmed by the tests: antimicrobial diffusion disk, determination of the content of phenolic compounds and antioxidant activity by the DPPH and FRAP method. The chromatographic analysis confirmed the presence of active chemical constituents such as Turmerone, Ar-Turmerone and β-Turmerone. The results showed that the oil promoted a change in the color of the films, increased mechanical strength and reduced flexibility, keeping transparency, solubility, WVP and thermal stability unchanged. In the direct application test of the film as packaging for sliced bread, no visible contamination was detected during the nine weeks of analysis. Therefore, the active film with 3 % TEO was shown to be a viable solution for manufacturing biodegradable and safe active films that can be applied as food packaging.

Physicochemical and Antimicrobial Characterization of Chitosan and Native Glutinous Rice Starch-Based Composite Edible Films: Influence of Different Essential Oils Incorporation

Biopolymer-based edible packaging is an effective way of preserving food while protecting the environment. This study developed an edible composite film using chitosan and native glutinous rice starch (NGRS) and incorporated essential oils (EOs) such as garlic, galangal, turmeric, and kaffir lime at fixed concentrations (0.312 mg/mL) to test its physicochemical and antimicrobial properties. The EO-added films were found to significantly improve the overall color characteristics (lightness, redness, and yellowness) as compared to the control film. The control films had higher opacity, while the EO-added films had slightly reduced levels of opacity and produced clearer films. The tensile strength and elongation at break values of the films varied among the samples. The control samples had the highest tensile strength, followed by the turmeric EO-added samples. However, the highest elongation at break value was found in the galangal and garlic EO-added films. The Young's modulus results showed that garlic EO and kaffir lime EO had the lowest stiffness values. The total moisture content and water vapor permeability were very low in the garlic EO-added films. Despite the differences in EOs, the Fourier-transform infrared spectroscopy (FTIR) patterns of the tested films were similar among each other. Microstructural observation of the surface and cross-section of the tested edible film exhibited smooth and fissureless patterns, especially in the EO-added films, particularly in the galangal and kaffir lime EO-added films. The antimicrobial activity of the EO-added films was highly efficient against various gram-positive and gram-negative pathogens. Among the EO-added films, the garlic and galangal EO-added films exhibited superior inhibitory activity against Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Pseudomonas fluorescence, and turmeric and kaffir lime EO-added films showed potential antimicrobial activity against Lactobacillus plantarum and L. monocytogenes. Overall, this study concludes that the addition of EOs significantly improved the physicochemical and antimicrobial properties of the CH-NGRS-based edible films, making them highly suitable for food applications.

Therapeutic potential of Curcuma oil and its terpenoids in gynecological cancers

BACKGROUND

Gynecological cancers encompass all uncontrolled and aberrant cell growth in the female reproductive system, therapeutic interventions are constantly evolving, but there is still a high death rate, significant side effects and medication resistance, making the task of treatment challenging and complex. The essential oil extracted from the rhizome of Curcuma longa is a promising natural drug, which has excellent biological activity on cancer cells and is to be developed as a new type of anti-gynecological tumor therapeutic agent.

PURPOSE

To systematically summarize the available evidence for the efficacy of Curcuma oil and its terpenoids (β-elemene, curcumol, furanodiene, and germacrone) in gynecological cancers, primarily malignancies of the reproductive system, involving ovarian, cervical, and endometrial cancers, explain the underlying mechanisms of preventing and treating gynecological cancers, and assess the shortcomings of existing work.

RESULTS

Through several signaling channels, Curcuma oil and its terpenoids can not only stop the growth of ovarian cancer, cervical cancer, and endometrial cancer cells, limit the formation of tumors, but also raise the effectiveness of chemotherapy drugs and improve the quality of life for patients.

CONCLUSION

It provides a preclinical basis for the efficacy of Curcuma oil as a broad-spectrum anti-tumor agent for the prevention and treatment of gynecological cancers. Even so, further efforts are still needed to improve the bioavailability of Curcuma oil and upgrade related experiments.

Gelatin and Chitosan as Meat By-Products and Their Recent Applications

Meat by-products such as bones, skin, horns, hooves, feet, skull, etc., are produced from slaughtered mammals. Innovative solutions are very important to achieving sustainability and obtaining the added value of meat by-products with the least impact on the environment. Gelatin, which is obtained from products high in collagen, such as dried skin and bones, is used in food processing, and pharmaceuticals. Chitosan is derived from chitin and is well recognized as an edible polymer. It is a natural product that is non-toxic and environmentally friendly. Recently, chitosan has attracted researchers' interests due to its biological activities, including antimicrobial, antitumor, and antioxidant properties. In this review, article, we highlighted the recent available information on the application of gelatin and chitosan as antioxidants, antimicrobials, food edible coating, enzyme immobilization, biologically active compound encapsulation, water treatment, and cancer diagnosis.

Preparation and characterization of chitosan/whey isolate protein active film containing TiO2 and white pepper essential oil

Active packaging films are designed to improve quality and extend the food shelf life by incorporating functional active ingredients into biopolymer films. This study developed a bioactive film based on chitosan (CS) and whey isolated protein (WPI) incorporated with 0.01 wt% TiO2 and 0.1 wt% white pepper essential oil (WPEO). The physicochemical properties of the prepared film were also evaluated comprehensively. The results showed that water solubility and water vapor permeability of the film incorporated with TiO2 and WPEO were 25.09% and 0.0933 g mm m–2 h–1 KPa–1, respectively, which were significantly higher than those of other films (P < 0.05). In addition, the UV barrier properties of films incorporating TiO2 and WPEO have improved. The films were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The FTIR results showed interactions between TiO2 and WPEO with CS/WPI compound, and the SEM results indicated a good incorporation of TiO2 into the composite films. The antioxidative and antibacterial properties of films were significantly enhanced by incorporating WPEO. According to results, the developed biocomposite film can be considered as a packaging material.

Synthesis of Fully Deacetylated Quaternized Chitosan with Enhanced Antimicrobial Activity and Low Cytotoxicity

Fully deacetylated quaternary chitosan (DQCTS) was prepared by replacing the carboxyl group of chitosan with a quaternary ammonium salt. The DQCTS was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and nuclear magnetic resonance (NMR). The antimicrobial activity of DQCTS was evaluated using the minimum inhibitory concentrations (MIC) methods and time-kill assay. DQCTS exhibited strong antibacterial and antifungal activity against Staphylococcus aureus, Escherichia coli O157: H7, Candida albicans, and Aspergillus flavus. Especially, the antifungal activity against C. albicans of DQCTS was greatly improved at 15.6 µg/mL of MIC and 31.3 µg/mL of minimum fungicidal concentration (MFC). Expression levels of virulence genes of microorganisms were also significantly decreased by DQCTS treatment, and the risk of virulence of microorganisms might be decreased. The result of the cytotoxic effect of DQCTS on human skin cells (HaCaT cells) indicated that the cytotoxicity of DQCTS on HaCaT cells was nearly non-toxic at 50 μg/mL. The DQCTS, with strong antimicrobial and low toxicity, has a high potential for use in functional food packaging and biomedical applications.

Antibacterial, Antifungal and Antiviral Polymeric Food Packaging in Post-COVID-19 Era

Consumers are now more concerned about food safety and hygiene following the COVID-19 pandemic. Antimicrobial packaging has attracted increased interest by reducing contamination of food surfaces to deliver quality and safe food while maintaining shelf life. Active packaging materials to reduce contamination or inhibit viral activity in packaged foods and on packaging surfaces are mostly prepared using solvent casting, but very few materials demonstrate antiviral activity on foods of animal origin, which are important in the human diet. Incorporation of silver nanoparticles, essential oils and natural plant extracts as antimicrobial agents in/on polymeric matrices provides improved antifungal, antibacterial and antiviral properties. This paper reviews recent developments in antifungal, antibacterial and antiviral packaging incorporating natural or synthetic compounds using preparation methods including extrusion, solvent casting and surface modification treatment for surface coating and their applications in several foods (i.e., bakery products, fruits and vegetables, meat and meat products, fish and seafood and milk and dairy foods). Findings showed that antimicrobial material as films, coated films, coating and pouches exhibited efficient antimicrobial activity in vitro but lower activity in real food systems. Antimicrobial activity depends on (i) polar or non-polar food components, (ii) interactions between antimicrobial compounds and the polymer materials and (iii) interactions between environmental conditions and active films (i.e., relative humidity, oxygen and water vapor permeability and temperature) that impact the migration or diffusion of active compounds in foods. Knowledge gained from the plethora of existing studies on antimicrobial polymers can be effectively utilized to develop multifunctional antimicrobial materials that can protect food products and packaging surfaces from SARS-CoV-2 contamination.

Development of sodium alginate-based antioxidant and antibacterial bioactive films added with IRMOF-3/Carvacrol

The purpose of this study was to compare the effects of different concentrations of the amine-functionalized isoreticular metal-organic framework-3 loaded with carvacrol (IRMOF-3/CA) on the properties of sodium alginate (SA) composite films, thus determining the optimal addition amount and further preparing bioactive packaging film with antibacterial and antioxidant activities. The morphology, structure, physical properties, antioxidant and antibacterial activities of the films were characterized and analyzed. The results showed that the thermal stability and light barrier property of the films were improved by the addition of IRMOF-3/CA. When the additional concentration was 0.4 wt%, the tensile, water vapor barrier and hydrophobic properties of the films were increased by 30.13%, 9.06% and 46.43% respectively compared with those of pure SA film. Moreover, the film added with IRMOF-3/CA had sustained antioxidant and antibacterial activities, and had an apparent fresh-keeping effect on pork, suggesting its application potential in food packaging.

Essential Oil-Based Nanoparticles as Antimicrobial Agents in the Food Industry

The use of essential oils (EO) loaded with nanoparticles is the most promising alternative to increase food quality and safety. Interesting works describe the antimicrobial properties of EO for pathogen control in natural and processed foods for human health and animal production, also contributing to sustainability. Their association with different nanosystems allows novel developments in the micronutrition, health promotion, and pathogen control fields, preventing the aggravation of bacterial microevolution and combating antibiotic resistance. Benefits to the environment are also provided, as they are biodegradable and biocompatible. However, such compounds have some physicochemical properties that prevent commercial use. This review focuses on recent developments in antimicrobial EO-based nanoparticles and their application in different food matrices.

Application of innovative packaging technologies to manage fungi and mycotoxin contamination in agricultural products: Current status, challenges, and perspectives

The consumer demand for safe, "healthy," and premium foods, preferably with an extended shelf-life; demand for easy packaging; and choice for more sustainable food packaging have contributed to the development of novel packaging technologies. The application of adequate packaging materials has recently become a major post-harvest challenge concerning the control of fungi and mycotoxin. This review will describe the current antifungal packaging technology involved to prevent the contamination of fungi and mycotoxin, along with the characteristics and mechanism of action in food products. Antifungal packaging has incredible potential in the food packaging sector. The most suitable approach for the safe storage of agricultural produce for farmers is the hermetic packaging technology, which maintains quality while providing a good barrier against fungi and mycotoxin. Furthermore, active antifungal packaging is a viable method for incorporating antifungal agents against pathogenic fungi. Essential oils and organic acid have received more scientific attention due to their increased efficacy against mold growth. Polypeptides, chitosan, and natamycin incorporated in active packaging significantly reduced fungi. Even though nanotechnological advancements in antifungal packaging are promising, safety and regulation issues remain significant concerns.

Facile fabrication of sandwich-like anthocyanin/chitosan/lemongrass essential oil films via 3D printing for intelligent evaluation of pork freshness

In this study, chitosan (CH), mulberry anthocyanin (MA), and lemongrass essential oils (LEO) were used as an interlayer using a 3D printer. Further, cassava starch (CS) was used as a protective layer to form indicator films. The indicator films containing LEO showed significant antioxidant and antibacterial properties, and the release rate of LEO increased with a rise in pH. When chilled pork spoiled, the color of the indicator films changed from red to gray-blue, and the RGB values could be automatically analyzed by a smartphone application to determine pork freshness. These films hold implications as easy-to-use indicators of meat freshness, with great potential for monitoring food spoilage, as part of an intelligent packaging system.

Chitosan-based nanoencapsulation of Toddalia asiatica (L.) Lam. essential oil to enhance antifungal and aflatoxin B1 inhibitory activities for safe storage of maize

The present study reports the enhanced antifungal, aflatoxin B₁ (AFB₁) inhibitory activities and mode of action of chitosan-based nanoencapsulated Toddalia asiatica essential oil (neTAEO). Twenty-seven different chemical components were recognized from T. asiatica essential oil (TAEO) using gas chromatography-mass spectrometry (GC-MS). The caryophyllene oxide (CO) (25.4%), and 1,3-hexadiene, 3-ethyl-2,5-dimethyl- (HED) (24.08%) were documented as significant compounds. The Z-average particles diameter (Z-APD) of the neTAEO ranged between 18.41 and 131.8 nm. The neTAEO showed enhanced and most promising antifungal and AFB₁ inhibitory activity than TAEO. In viable maize model assay, neTAEO effectively preserved the maize from fungal invade and AFB₁ biosynthesis. The neTAEO significantly disturbs membrane integrities of Aspergillus flavus by inhibiting ergosterol biosynthesis followed by the extreme release of ions (Mg²⁺ and K⁺) and UV-absorbing (260 and 280 nm) cellular constituents. The in-silico molecular docking showed that the major active components of TAEO viz., CO and HED were active against AFB₁ synthesizing leading genes Ver-1 and Omt-A with docking scores ranging from -4.8 to -7.7. The obtained results confirm that neTAEO showed promising antifungal and AFB₁ inhibitory activities; hence, it could be used as an alternative green strategy to protect food grains from fungal invade and AFB₁ production during storage.

Fabrication of chitosan-based food packaging film impregnated with turmeric essential oil (TEO)-loaded magnetic-silica nanocomposites for surimi preservation

Successful modification of chitosan (CS) film using magnetic-silica nanocomposite to encapsulate turmeric essential oil (TEO) obtained by super critical CO2 extraction for enhanced preservation of surimi was performed. TEO exhibited antioxidant and antibacterial activities against Bacillus cereus. The core magnetic nanoparticles (MNPs) were capped with porous silica (Si) to form core-shell nanocomposites, into which TEO was loaded with 75.24% encapsulation efficiency. The fabricated nanocomposite was characterized, blended with CS to cast a bionanocomposite active film and characterized for efficient impregnation of bionanocomposite. The physical and mechanical properties of film were significantly improved after adding MNPs/Si/TEO nanocomposite. Uncontrolled release of TEO from CS film resulted in bacterial growth after 6 days of storage whereas bionanocomposites exhibited a sustained release of TEO that controlled the microbial load from 4.0 log CFU/g to 2.78 log CFU/g over 14 days. The overall study demonstrated that the CS/MNPs/Si/TEO bionanocomposite film was efficient as a packaging material for prolonged shelf-life of surimi.

Chitosan-based antioxidant films incorporated with root extract of Aralia continentalis Kitagawa for active food packaging applications

Aralia continentalis Kitagawa and ginseng are both perennial herbs of Araliaceae. The study aimed to investigate the composite packaging films with better fresh-keeping ability. The different mass concentrations of Aralia continentalis Kitagawa root extract (ARE) 0.05%, 0.10%, and 0.15% (v/w) were compounded with chitosan (CH) to make composite packaging films. Food-based composite film, its thickness, density, water contact angle (WCA), oxygen barrier properties (OP), solubility, swelling, transparency, water vapor permeability (WVP), and other physical properties, as well as tensile strength (TS), elongation at break (EAB), Young’s modulus (YM), and the mechanical properties were measured, and the oxidation resistance, thermal properties, and biodegradability were also evaluated, and the structure was analyzed by infrared spectroscopy. The results showed that when the ARE content in the film was increased from 0.05 to 0.15 mg·mL−1, high antioxidant capacity of the CH/ARE film was exhibited (the DPPH and ABTS+ free radical scavenging rate was increased), and the thickness, density, swelling degree, solubility, TS, EAB, and YM of the CH/ARE composite film increased, while WCA, OP, WVP, transparency, and biodegradability were slightly reduced. We had noticed that with the increase in the ARE content, the surface microstructure in CH/ARE film changed significantly, indicating the good compatibility between CH and ARE. In summary, as a natural active substance, ARE can be combined with CH to form films, and the packaging film made can effectively improve the performance of the composite film.

Preparation and Characterization of Bioactive Chitosan Film Loaded with Cashew (Anacardium occidentale) Leaf Extract

Chitosan is a biopolymer known for its rapid biodegradability and film-forming properties. This research aimed to synthesize and characterize chitosan films loaded with cashew leaf extract (CLE) obtained from immature and mature cashew leaves via aqueous and 70% ethanolic extraction methods. Freeze-dried CLE samples were dissolved in 50% dimethyl sulfoxide for in vitro analysis and chitosan film preparation. The total phenolic content of mature cashew leaves extracted in ethanol (MECLE) showed higher free radicle scavenging activity by a 2,2-diphenyl-1-picrylhydrazyl assay than the other extracts (p < 0.05). MECLE displayed a lower minimal inhibitory concentration, minimum fungal concentration, and higher zone of inhibition against Aspergillus niger compared to the other treatments (p < 0.05). Film-forming solutions were prepared using 2% chitosan, 2% chitosan with 5% mature cashew leaves extracted in deionized water (MACLE) (w/v), and 2% chitosan with 5% MECLE (w/v), respectively, to cast films. Of these, 2% chitosan (CH) with 5% MECLE (CH-MECLE-5) displayed the highest thickness and water vapor transmission rate, water vapor permeability, and oxygen transmission rate when compared to other film samples (p < 0.05). The CH-MECLE-5 film showed the highest inhibition zone of A. niger compared to the control and treated films (p < 0.05). The lightness (L*) of the CH-MECLE-5 film decreased with increment in b* values, which represented the yellow color of the film. In addition, two-photon microscopy revealed a uniform distribution via the auto-fluorescent 3D structure of MECLE in the CH-MECLE-5 film. Therefore, chitosan combined with 5% MECLE may be a potential bioactive and eco-friendly packaging film.

Screening of Bacillus velezensis E2 and the Inhibitory Effect of Its Antifungal Substances on Aspergillus flavus

Aspergilus flavus is the main pathogenic fungus that causes food mold. Effective control of A. flavus contamination is essential to ensure food safety. The lipopeptides (LPs) produced by Bacillus strains have been shown to have an obvious antifungal effect on molds. In this study, an antagonist strain of Bacillus velezensis with obvious antifungal activity against A. flavus was isolated from the surface of healthy rice. Using HPLC-MS analysis, the main components of LPs produced by strain E2 were identified as fengycin and iturins. Further investigations showed that LPs could inhibit the spore germination, and even cause abnormal expansion of hyphae and cell rupture. Transcriptomic analyses showed that some genes, involved in ribosome biogenesis in eukaryotes (NOG1, KRE33) and aflatoxin biosynthesis (aflK, aflR, veA, omtA) pathways in A. flavus were significantly down-regulated by LPs. In conclusion, this study provides novel insights into the cellular and molecular antifungal mechanisms of LPs against grain A. flavus contamination.

Effect of cellulose nanocrystal-stabilized cinnamon essential oil Pickering emulsions on structure and properties of chitosan composite films

The low water-resistance and limited antibacterial activity of chitosan (CS) film hinder its practical applications in food preservation field. To solve these issues, we have facilely and effectively fabricated cinnamon essential oil (CEO)-loaded composite films via incorporating cellulose nanocrystal (CNC)-stabilized CEO Pickering emulsions into CS-based film-forming matrix. Research results show the well distribution of emulsion droplets in film matrix. The insertion of CEO emulsions can improve film water-resistance and antibacterial activity, but reduces its mechanical strength. Concretely, the water contact angle and inhibition zone of composite films can increase by about 12.3° and 2 times compared with CS control film. Compared with tween-80, CNCs can increase film tensile strength by about 3.52 MPa and observably offset the decline of film mechanical property by CEO. Moreover, the film prepared with 3 w/v% CNC stabilized 30 v/v% CEO Pickering emulsion not only enhances pork preservation, but also maintain its structural stability. The fabricated antimicrobial films have considerable potential for packaging application.

Polysaccharide-Based Active Coatings Incorporated with Bioactive Compounds for Reducing Postharvest Losses of Fresh Fruits

This review reports recently published research related to the application of polysaccharide-based biodegradable and edible coatings (BECs) fortified with bioactive compounds obtained from plant essential oils (EOs) and phenolic compounds of plant extracts. Combinations of polysaccharides such as starches, pectin, alginate, cellulose derivatives, and chitosan with active compounds obtained from clove, lemon, cinnamon, lavender, oregano, and peppermint have been documented as potential candidates for biologically active coating materials for retardation of quality changes in fresh fruits. Additionally, polysaccharide-based active coatings supplemented with plant extracts such as cashew leaves, pomegranate peel, red roselle, apple fiber, and green tea extracts rich in phenolic compounds and their derivatives have been reported to be excellent substituents to replace chemically formulated wax coatings. Moreover, EOs and plant polyphenolics including alcohols, aldehydes, ketones phenols, organic acids, terpenes, and esters contain hydroxyl functional groups that contribute bioactivity to BECs against oxidation and reduction of microbial load in fresh fruits. Therefore, BECs enriched with active compounds from EOs and plant extracts minimize physiological and microbial deterioration by reducing moisture loss, softening of flesh, ripening, and decay caused by pathogenic bacterial strains, mold, or yeast rots, respectively. As a result, shelf life of fresh fruits can be extended by employing active polysaccharide coatings supplemented with EOs and plant extracts prior to postharvest storage.

Spatial variation of volatile organic compounds and antioxidant activity of turmeric (Curcuma longa L.) essential oils harvested from four provinces of China

The objective of this study was to investigate the spatial variation of volatile organic compounds and antioxidant activity of turmeric essential oils (TEOs) harvested from four provinces of China. The major chemical components of these TEOs were analyzed using headspace solid-phase micro-extraction gas chromatography-mass spectrometry. More than forty volatile organic compounds in TEOs were identified, which accounted for 82.09–93.64% of the oil components. The relative abundances of the main volatile organic compounds in TEOs at the genus level were visualized by a heat map. The antioxidant activity of the TEOs of five different origins was characterized by the DPPH free radical scavenging activity, in which the antioxidant activity of the TEOs from Guangxi was superior to those of other sources. Furthermore, the IC₅₀ values of the antioxidants TEOs collected from Guangxi, Sichuan, Yunnan, Changting, and Liancheng were 33.30, 42.5, 35.22, 63.27, and 39.96 mg/mL, respectively, which indicated the excellent free radical scavenging activity of those TEOs. Therefore, the TEOs might be considered as a natural antioxidant with potential applications in food and pharmaceutical industries.

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Turmeric essential oils stemmed from four provinces of China were investigated.

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Multivariate analysis of volatile organic compounds in TEOs was performed.

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The major components of volatile organic compounds exhibited a spatial variation.

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Antioxidant activity of turmeric essential oils demonstrated a spatial variation.

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TEOs of Guangxi had a superior antioxidant activity to those of other origins.

Active PLA Packaging Films: Effect of Processing and the Addition of Natural Antimicrobials and Antioxidants on Physical Properties, Release Kinetics, and Compostability

The performance characteristics of polylactic acid (PLA) as an active food packaging film can be highly influenced by the incorporation of active agents (AAs) into PLA, and the type of processing technique. In this review, the effect of processing techniques and the addition of natural AAs on the properties related to PLA performance as a packaging material are summarized and described through a systematic analysis, giving new insights about the relation between processing techniques, types of AA, physical–mechanical properties, barriers, optical properties, compostability, controlled release, and functionalities in order to contribute to the progress made in designing antioxidant and antimicrobial PLA packaging films. The addition of AAs into PLA films affected their optical properties and influenced polymer chain reordering, modifying their thermal properties, functionality, and compostability in terms of the chemical nature of AAs. The mechanical and barrier performance of PLA was affected by the AA’s dispersion degree and crystallinity changes resulting from specific processing techniques. In addition, hydrophobicity and AA concentration also modified the barrier properties of PLA. The release kinetics of AAs from PLA were tuned, modifying diffusion coefficient of the AAs in terms of the different physical properties of the films that resulted from specific processing techniques. Several developments based on the incorporation of antimicrobial and antioxidant substances into PLA have displayed outstanding activities for food protection against microbial growth and oxidation.

Emerging chitosan-essential oil films and coatings for food preservation - A review of advances and applications

With the rising demand for fresh and ready-to-eat foods, antimicrobial packaging has been developed to control or prevent microbial growth as well as maintain food quality and safety. Chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus, chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. This review summarized the effect of essential oils on modifying the physicochemical characteristics of chitosan-based films. Notably, the antimicrobial efficacy of the developed composite films or coatings was highlighted. The advances in the preparation methods and application of chitosan films were also discussed. Broadly, this review will promote the potential applications of chitosan-essential oils composite films or coatings in antimicrobial packaging for food preservation.

Biodegradable carboxymethyl cellulose-polyvinyl alcohol composite incorporated with Glycyrrhiza Glabra L. essential oil: Physicochemical and antibacterial features

Glycyrrhiza glabra L. root essential oil (GGEO) has well-known antimicrobial and therapeutic features. In this study, a new antimicrobial carboxymethyl cellulose-polyvinyl alcohol (CMC-PVA) binary film was developed using GGEO as an active compound. The effects of various concentrations of GGEO (0.25%, 0.50%, and 0.75%) were scrutinized on the physicochemical and antibacterial properties of composites. It was discovered that GGEO significantly reduced the composite ultimate tensile strength from 17.01 to 3.86 MPa. Further, by increasing the concentration of GGEO to 0.75%, the water vapor permeability and moisture content increased to 13.61 × 10-9 g/m s-1 Pa-1 and 41.06%, respectively. The results indicated that the active films possessed good inhibitory effects against the gram-positive bacteria (L. monocytogenes and Staphylococcus aureus) and were less powerful against gram-negative bacteria (Escherichia coli and S. typhimurium). Finally, the results highlighted that GGEO can act as an excellent antimicrobial agent in combination with CMC-PVA composite.

Application and safety evaluation of an anti-aflatoxigenic chitosan pouch containing turmeric essential oil in the storage of traditional Chinese health food

Aflatoxin contamination is one of the most important factors jeopardizing the quality of traditional Chinese health food (TCHF) during storage. Based on our previous work, we investigated the stability of chitosan (CH) films containing turmeric essential oil (TEO) and employed CH-TEO films as inner pouches, then stored them with inoculated Coix seed, nutmeg, and Ziziphi Spinosae Semen (ZSS). We found that the stability of CH-TEO was most affected by high temperature, and these pouches dramatically decreased aflatoxin accumulation and maintained levels of marker components of each TCHF. We found that glycerol tristearat in Coix seed and jujuboside A and spinosin in ZSS were negatively correlated with aflatoxin accumulation. After three months of storage with a CH-TEO pouch, we found little change in marker components contents, but observed that Coix seed had the relative lower sensory characteristics score. In addition, acute and 90-day subchronic toxicity test in Coix seed stored with the largest amount of TEO showed no significant signs of toxicity or treatment-related changes in animals. The present study is the first report on the study of a green, efficient, and low toxicity solution for aflatoxic contamination in TCHF, and provides strong support for its future use.