Chitosan-Based Edible Coatings Containing Essential Oils to Preserve the Shelf Life and Postharvest Quality Parameters of Organic Strawberries and Apples during Cold Storage

Efficient production, computational screening, molecular docking, quantum chemical calculations, and application of novel antioxidant peptides from Tartary buckwheat in composite preservation films

Tartary buckwheat is a protein-rich pseudocereal. This research developed an efficient method for extracting antioxidant peptides from buckwheat. Alkaline hydrolysis of buckwheat albumin protein produced antioxidant peptides with higher extraction efficiency and antioxidant activity (p < 0.05). LC-MS/MS analysis identified 1284 novel antioxidant peptide sequences. Computational screening identified 16 peptides with high abundance and superior antioxidant capacity. Molecular docking and quantum chemical calculations determined WPWR, FLQL, and HGLFSPF as the peptides with the highest bioactivity. Among these, WPWR demonstrated excellent in vitro antioxidant activity and was successfully applied in peptide-polysaccharide composite preservation films, effectively extending the shelf life of strawberries, highlighting the potential of Tartary buckwheat-derived antioxidant peptides for advanced food preservation technology.

Effect of gelatin and salicylic acid incorporated in chitosan coatings on strawberry preservation

Strawberries are highly prone to rapid post-harvest deterioration due to their high nutritional content and lack of protective peel, demanding the development of alternative preservation methods. This study evaluates chitosan (CH) edible coatings enhanced with gelatin (GE) and salicylic acid (SA) for extending shelf life while maintaining fruit quality. Through atomic force microscopy, it was demonstrated that GE and SA showed increased surface roughness, besides improved the ultraviolet barrier properties and reduced water vapor permeability. Over 14 days of storage (3.0 ± 1.0 °C), all coatings minimized weight loss, firmness reduction, and color changes while delaying total soluble solids and pH increases. The effectiveness of the CH (0.8 %) with GE (0.2 %) and SA (2 mM) coating was mainly determined by the reduction of the development of natural disease development (84.30 ± 3.62 %), whereas the physicochemical properties tend to be similar in the assessed formulations. Principal Component Analysis (PCA) was used to investigate the effects of the treatments on strawberry shelf life and to determine the correlations between the responses studied. Considering the variability of the dimensions of the responses, correlation coefficients were used to form the matrix and extract the eigenvalue. PCA showed that the properties of the strawberries change continuously regardless of the treatments and indicated that four principal components accounted for 82.7 % of data variability. This study demonstrates that coatings, combined with cold storage, offer an effective solution for extending the shelf life of strawberries while preserving their quality throughout storage.

Preparation and Application of Edible Chitosan Coating Incorporating Natamycin

In this paper, edible composite coatings, which used chitosan (CTS) as the matrix material, glycerol as the plasticizer, and natamycin as the antibacterial material, were prepared and composite films were prepared by a casting method. Taking cherry tomatoes as the research models, the optimal preservation effect of the composite coating was achieved using 10 g/L CTS, 2.5 g/L glycerol, and 125 mg/L natamycin under conditions of 25 °C and 50% RH. The thickness, transparency, water vapor transmittance (WVT), tensile strength (TS), and elongation at break (EB) of composite film were measured and the results showed the film prepared using 10 g/L CTS, 2.5 g/L glycerol and 125 mg/L natamycin was the best. The direct application of the optimal coating to cherry tomatoes kept the cherry tomatoes valuable for 20 days. The weight loss rate and hardness loss rate were reduced by 22.13% and 12.55%, respectively. The total soluble solid (TSS) content and vitamin c (Vc) content were increased by 2.54% and 20.35%, respectively. The malondialdehyde (MDA) content and peroxidase (POD) activity were decreased by 19.38% and 28.03%, respectively. Based on the significant preservation effect of the composite coating, it is expected to be widely used in the preservation of fruits and vegetables with skin morphologies similar to cherry tomatoes.

Edible Alginate-Fungal Chitosan Coatings as Carriers for Lacticaseibacillus casei LC03 and Their Impact on Quality Parameters of Strawberries During Cold Storage

This study investigated the efficacy of an innovative edible coating, composed of fungal chitosan and alginate, functionalized with Lacticaseibacillus casei LC03, in both free and microencapsulated forms, to extend the shelf life and enhance the nutritional value of strawberries. L. casei LC03 cells were successfully encapsulated in alginate microparticles (MAL) and further coated with chitosan (MALC), resulting in enhanced protection (cell reduction below 1.4 CFU/mL), viability (8.02 log CFU/mL), and encapsulation efficiencies exceeding 90%. The edible coating with L. casei microencapsulated in alginate and coated with fungal chitosan (CACLM) significantly improved strawberry preservation by maintaining pH (3.16 ± 0.41), titratable acidity (0.94 ± 0.20), moisture (90.74 ± 0.27), and microbial quality, and delayed the decrease in total phenolic compounds (below 40%) during the storage time of strawberries. While coatings with free L. casei (CALF) slightly reduced color parameters (L* value 29.13 ± 2.05), those with chitosan (CACLM) demonstrated lower weight loss (below 6%). Overall, the alginate-chitosan coating, particularly when combined with microencapsulated L. casei, proved effective in maintaining the quality, safety, and nutritional value of strawberries during refrigerated storage, highlighting its potential for developing functional, eco-friendly packaging solutions. This research contributes to the development of sustainable food preservation strategies and functional foods.

Natural biopolymers in edible coatings: Applications in food preservation

Edible coatings are revolutionizing food preservation by offering a sustainable and effective solution to key industry challenges. Made from natural biopolymers such as proteins, polysaccharides, and lipids, these coatings form a thin, edible layer on food surfaces. This barrier reduces moisture loss, protects against oxidative damage, and limits microbial growth, thereby extending shelf life while preserving food quality. Enhanced with natural additives like essential oils and antioxidants, these coatings offer antimicrobial benefits and contribute to health. Applications span from fresh produce, where they control respiration and moisture, to meat, dairy, and bakery products, maintaining sensory and nutritional properties. Innovations in coating technologies-such as composite materials, nano-emulsions, and bio-nanocomposites-are improving their mechanical strength, barrier properties, and compatibility with other preservation methods like modified atmosphere packaging. Although challenges remain in cost, consumer acceptance, and regulation, edible coatings represent a significant stride towards sustainable food systems and reduced dependence on synthetic packaging.

Recent Advances in Cellulose Nanofiber Modification and Characterization and Cellulose Nanofiber-Based Films for Eco-Friendly Active Food Packaging

There is growing interest in the use of bio-based materials as viable alternatives to petrochemical-based packaging. However, the practical application of bio-based films is often hampered by their poor barrier and poor mechanical properties. In this context, cellulose nanofibers (CNFs) have attracted considerable attention owing to their exceptional biodegradability, high aspect ratio, and large surface area. The extraction of CNFs from agricultural waste or non-food biomass represents a sustainable approach that can effectively balance cost and environmental impacts. The functionalization of CNFs improves the economics of raw materials and production processes while expanding their applications. This paper reviews recent advances in cellulose nanofibers, including their sources, surface modification, and characterization techniques. Furthermore, we systematically discuss the interactions of CNFs with different composites in the development of functional food films. Finally, we highlight the application of cellulose nanofiber films in food preservation. Due to their environmentally friendly properties, CNFs are a promising alternative to petroleum-based plastics. The aim of this paper is to present the latest discoveries and advances in CNFs while exploring the future prospects for edible food films, thereby encouraging further research and application of CNFs in the field of active food packaging.

Chitosan-based sustainable packaging and coating technologies for strawberry preservation: A review

Strawberry fruits are popular all over the world due to their rich organoleptic properties and enormous health benefits. However, it is highly susceptible to postharvest spoilage due to various factors, including moisture loss, nutrient oxidation, and microbial spoilage. Recently, various researchers have studied the effect of chitosan-based flexible films and surface coatings on the shelf life of strawberries. Despite various reviews providing general information on the effects of chitosan-based films and coatings on various food products, no review has focused solely on their effects on postharvest preservation and the shelf life of strawberries. The purpose of this review is to summarize the current research on chitosan-based formulations for extending the shelf life of strawberries. Chitosan, a cationic carbohydrate polymer, possesses excellent properties such as film formation, mechanical strength, non-toxicity, biodegradability, edibility, UV-blocking ability, antioxidant activity, and antibacterial functionality, justifying its potential as packaging/coating material for fresh agricultural products, including strawberries. This review covers the various factors responsible for strawberry spoilage and the properties of chitosan that help counteract these factors. Additionally, the advantages of chitosan-based preservation technology compared to existing strawberry preservation methods were explained, efficiency was evaluated, and future research directions were suggested.

Applications of chitosan in the agri-food sector: A review

Chitosan is a natural and renewable polysaccharide that can form biopolymers. It is derived from the deacetylation of chitin mainly from crustaceans' shells, but also from fungi and insects. Thanks to unique characteristics such as antimicrobial effects, antioxidant properties or film forming capacities, it has triggered an important amount of research in the last decade about possible applications in industrial fields. The main application field of chitosan is the food industry where it can be used for preservation purposes and shelf-life improvement for fresh food products such as fruits or meat. For beverages, it is used for clarification and fining as well as elimination of spoilage flora in beverages like fruit juices or wine. And in agriculture, it can be used as a plant protection product through different mechanisms like the elicitation of plant defences. The mechanisms of action of chitosan on microorganisms are multiple and complex but revolve mostly around the disturbance of microorganisms' membranes and cell walls resulting in the leakage of cell material. The use of chitosan is still minor but is promising in finding environmentally friendly alternatives to synthetic chemicals and plastics. Therefore, its characterization is primordial for the future of sustainable production and preservation processes.

Characterization of antifungal properties of avocado leaves and majagua flowers extracts and their potential application to control Alternaria alternata

Plant extracts are used as an alternative to a wide range of foods against different types of fungal pathogens. In the present study, the extracts of avocado leaves (Persea americana) and majagua flowers (Talipariti elatum) were tested according to their antifungal activity against different fungi. The most promising extracts were those of majagua flowers that were applied lyophilized and in aqueous extract, being very effective against Alternaria alternata and reaching a 50 % in vitro reduction. Antifungal properties were also evaluated during infection of apples by A. alternata. A decrease in infection progression was confirmed with up to a 30 % reduction in disease incidence and a 20 % reduction in disease severity. Majagua extracts were also tested combined with edible pectin coatings, greatly increasing their effectiveness up 60 % reduction. Thus, extracts of majagua could provide a feasible alternative to control fungal pathogens during postharvest.

"Review of strategic methods for encapsulating essential oils into chitosan nanosystems and their applications"

Essential oils (EOs) are hydrophobic, concentrated extracts of botanical origin containing diverse bioactive molecules that have been used for their biomedical properties. On the other hand, the volatility, toxicity, and hydrophobicity limited their use in their pure form. Therefore, nano-encapsulation of EOs in a biodegradable polymeric platform showed a solution. Chitosan (CS) is a biodegradable polymer that has been intensively used for EOs encapsulation. Various approaches such as homogenization, probe sonication, electrospinning, and 3D printing have been utilized to integrate EOs in CS polymer. Different CS-based platforms were investigated for EOs encapsulation such as nanoparticles (NPs), nanofibers, films, nanoemulsions, 3D printed composites, and hydrogels. Biological applications of encapsulating EOs in CS include antioxidant, antimicrobial, and anticancer functions. This review explores the principles for nanoencapsulation strategies, and the available technologies are also reviewed, in addition to an in-depth overview of the current research and application of nano-encapsulated EOs.

Recent Highlights in Sustainable Bio-Based Edible Films and Coatings for Fruit and Vegetable Applications

The present review paper focuses on recent developments in edible films and coatings made of base compounds from biological sources, namely plants, animals, algae, and microorganisms. These sources include by-products, residues, and wastes from agro-food industries and sea products that contribute to sustainability concerns. Chitosan, derived from animal biological sources, such as crustacean exoskeletons, has been the most studied base compound over the past three years. Polysaccharides typically constitute no more than 3-5% of the film/coating base solution, with some exceptions, like Arabic gum. Proteins and lipids may be present in higher concentrations, such as zein and beeswax. This review also discusses the enrichment of these bio-based films and coatings with various functional and/or bioactive compounds to confer or enhance their functionalities, such as antimicrobial, antioxidant, and anti-enzymatic properties, as well as physical properties. Whenever possible, a comparative analysis among different formulations was performed. The results of the applications of these edible films and coatings to fruit and vegetable products are also described, including shelf life extension, inhibition of microbial growth, and prevention of oxidation. This review also explores novel types of packaging, such as active and intelligent packaging. The potential health benefits of edible films and coatings, as well as the biodegradability of films, are also discussed. Finally, this review addresses recent innovations in the edible films and coatings industry, including the use of nanotechnologies, aerogels, and probiotics, and provides future perspectives and the challenges that the sector is facing.

Development of Active Antibacterial CEO/CS@PLA Nonwovens and the Application on Food Preservation

The biodegradable activity antibacterial materials have been widely applied on food preservation because they not only protect foods from pathogenic attacks but also relieve environmental pollution. Biodegradable melt-blown nonwovens (MB) have several advantages over the other materials in terms of a simpler and more environmentally friendly fabrication process, higher specific surface area, and lower cost. Herein, polylactic acid (PLA) MB is first modified by polydopamine (PDA) to activate the surface. Then, chitosan (CS) and cinnamon essential oil (CEO) are used to decorate the surface of the modified PLA MB via a simple one-pot method to prepare CEO/CS@PLA MB with different CEO contents. Compared with PLA MB, CEO/CS@PLA MB had a rougher surface and larger average fiber diameter, while the average pore diameter and air permeability reduced. The input of CEO led to a decrease in the tensile strength of CEO/CS@PLA MB and an obvious increase in the elongation at break. The combination of CS and CEO shows excellent synergistic antibacterial effect. The antibacterial efficiencies of CEO/CS@PLA MB against Escherichia coli and Staphylococcus aureus enhance with the increase of the CEO content. When the weight ratio of CS to CEO is 1:2, the antibacterial efficiencies of CEO2/CS@PLA MB against E. coli and S. aureus are 99.98 and 99.99%, respectively. When being applied to the preservation of fresh strawberry, CEO2/CS@PLA MB can effectively inhibit the microbial growth in strawberry and reduce decay, which extends the shelf time of strawberry.

Smart Packaging Based on Polylactic Acid: The Effects of Antibacterial and Antioxidant Agents from Natural Extracts on Physical-Mechanical Properties, Colony Reduction, Perishable Food Shelf Life, and Future Prospective

Changes in consumer lifestyles have raised awareness of a variety of food options and packaging technologies. Active and smart packaging is an innovative technology that serves to enhance the safety and quality of food products like fruit, vegetables, fish, and meat. Smart packaging, as a subset of this technology, entails the integration of additives into packaging materials, thereby facilitating the preservation or extension of product quality and shelf life. This technological approach stimulates a heightened demand for safer food products with a prolonged shelf life. Active packaging predominantly relies on the utilization of natural active substances. Therefore, the combination of active substances has a significant impact on the characteristics of active packaging, particularly on polymeric blends like polylactic acid (PLA) as a matrix. Therefore, this review will summarize how the addition of natural active agents influences the performance of smart packaging through systematic analysis, providing new insights into the types of active agents on physical-mechanical properties, colony reduction, and its application in foods. Through their integration, the market for active and smart packaging systems is expected to have a bright future.

Innovative Integration of Arrayan (Luma apiculata) Extracts in Chitosan Coating for Fresh Strawberry Preservation

Strawberries are a rich source of vitamins and antioxidants, among other nutrients, but they are highly susceptible to mechanical injuries, dehydration, and microbial spoilage, and thus have a limited post-harvest shelf-life. Bioactive edible coatings have been studied to decrease or prevent these damages. In this study, ethanolic extracts of Arrayan (Luma apiculata), a traditional berry from the south of Chile, were used to enrich a chitosan-based edible film and coat fresh strawberries. A long-term storage (10 °C) study was conducted to determine the strawberries' weight loss, microbial stability, fruit firmness impact, and antioxidant activity. Later, a sensory panel was conducted to determine overall consumer acceptance. Our results show that the bioactive coating inhibited the growth of different pathogenic bacteria and spoilage yeast. In the stored strawberries, the weight loss was significantly lower when the bioactive coating was applied, and the samples' firmness did not change significantly over time. Microbial growth in the treated strawberries was also lower than in the control ones. As expected, the antioxidant activity in the coated strawberries was higher because of the Arrayan extract, which has high antioxidant activity. Regarding sensory qualities, the covered strawberries did not show significant differences from the uncoated samples, with an overall acceptance of 7.64 on a 9-point scale. To our knowledge, this is the first time an edible coating enriched with Arrayan extracts has been reported as able to prevent strawberries' decay and spoilage.

Edible Coatings and Future Trends in Active Food Packaging-Fruits' and Traditional Sausages' Shelf Life Increasing

The global food production industry faces environmental concerns exacerbated by substantial food waste. European countries are striving to reduce food waste towards a circular bioeconomy and sustainable development. To address environmental issues and reduce plastic waste, researchers are developing sustainable active packaging systems, including edible packaging made from industry residues. These innovations aim to increase food safety and quality, extend shelf life, and reduce plastic and food waste. Particularly important in the context of the growing demand for fresh and minimally processed fruits, edible coatings have emerged as a potential solution that offers numerous advantages in maintaining fruit quality. In addition to fruit, edible coatings have also been investigated for animal-based foods to meet the demand for high-quality, chemical-free food and extended shelf life. These products globally consumed can be susceptible to the growth of harmful microorganisms and spoilage. One of the main advantages of using edible coatings is their ability to preserve meat quality and freshness by reducing undesirable physicochemical changes, such as color, texture, and moisture loss. Furthermore, edible coatings also contribute to the development of a circular bioeconomy, promoting sustainability in the food industry. This paper reviews the antimicrobial edible coatings investigated in recent years in minimally processed fruits and traditional sausages. It also approaches bionanocomposites as a recently emerged technology with potential application in food quality and safety.

Thymol@Natural Zeolite Nanohybrids for Chitosan/Polyvinyl-Alcohol-Based Hydrogels Applied as Active Pads

Currently, food saving, a circular economy, and zero environmental fingerprints are of major interest. Scientific efforts for enhanced food preservation using "green" methods have been intensified. Even though chemicals could achieve such targets effectively, the global trend against the "greenhouse effect" suggests the use of environmentally friendly biobased materials for this purpose. In this study, the promising biopolymer chitosan is incorporated with the promising biodegradable polymer polyvinyl alcohol to produce an improved biopolymeric matrix. This biodegradable biopolymer was further mixed homogeneously with 15% thymol/nano-zeolite nanohybrid material. The properties of the final developed film were improved compared to the relevant values of chitosan/polyvinyl alcohol film. The mechanical properties were enhanced significantly, i.e., there was a 34% increase in Young's modulus and a 4.5% increase in the ultimate tensile strength, while the antioxidant activity increased by 53.4%. The antibacterial activity increased by 134% for Escherichia coli, 87.5% for Staphylococcus aureus, 32% for Listeria monocytogenes, and 9% for Salmonella enterica. The water vapor diffusion coefficient and the oxygen permeability coefficient decreased to -51% and -74%, respectively, and thus, the water vapor and oxygen barrier increased significantly. The active pads were used in strawberries, and the antimicrobial activity evaluation against the mold of fungi was carried out. The visual evaluation shows that the active pads could extend the shelf life duration of strawberries.

Chitosan-based nanocomposites as coatings and packaging materials for the postharvest improvement of agricultural product: A review

The perishability nature of harvested fruits and vegetables, along with the effect of environmental factors, storage conditions, and transportation, reduce the products' quality and shelf-life. Considerable efforts have been allocated to alternate conventional coatings based on new edible biopolymers for packaging. Chitosan is an attractive alternative to synthetic plastic polymers due to its biodegradability, antimicrobial activity, and film-forming properties. However, its conservative properties can be improved by adding active compounds, limiting microbial agents' growth and biochemical and physical damages, and enhancing the stored products' quality, shelf-life, and consumer acceptability. Most of the research on chitosan-based coatings focuses on antimicrobial or antioxidant properties. Along with the advancement of polymer science and nanotechnology, novel chitosan blends with multiple functionalities are required and should be fabricated using numerous strategies, especially for application during storage. This review discusses recent developments in using chitosan as a matrix to fabricate bioactive edible coatings and their positive impacts on increasing the quality and shelf-life of fruits and vegetables.

Effect of Essential Oils from Lemongrass and Tahiti Lime Residues on the Physicochemical Properties of Chitosan-Based Biodegradable Films

This work aimed to evaluate the impact of adding two essential oils (EO) from lemongrass (LEO) and Tahiti lime (TLEO) on the physical, mechanical, and thermal properties of chitosan-based biodegradable films. Six film formulations were prepared: two controls with chitosan concentrations of 1% and 1.5% v/w, two formulations combining the two chitosan concentrations with 1% LEO v/v, and two formulations combining the two chitosan concentrations with 1% TLEO v/v. The films' morphological, water affinity, barrier, mechanical, and thermal properties were evaluated. The films' surface showed a heterogeneous morphology without cracks, whereas the cross-section showed a porous-like structure. Adding EO to the films promoted a 35-50% decrease in crystallinity, which was associated with an increase in the elasticity (16-35%) and a decrease in the tensile strength (9.3-29.2 MPa) and Young's modulus (190-1555 MPa) on the films. Regarding the optical properties, the opacity of the films with TLEO increased up to 500% and 439% for chitosan concentrations of 1% and 1.5%, respectively. While the increase in opacity for the films prepared with LEO was 357% and 187%, the reduction in crystallinity also reduced the resistance of the films to thermal processes, which could be explained by the reduction in the enthalpy of fusion. The thermal degradation of the films using TLEO was higher than those where LEO was used. These results were indicative of the great potential of using TLEO and LEO in biodegradable films. Likewise, this work showed an alternative for adding value to the cultivation of Tahiti lime due to the use of its residues, which is in accordance with the circular economy model. However, it was necessary to deepen the study and the use of these essential oils in the preparation of biodegradable films.