Preservation of strawberry fruit quality via the use of active packaging with encapsulated thyme essential oil in zein nanofiber film

Chitosan/pullulan edible coatings containing thyme essential oil nanoemulsion: Preparation, characterization and application in strawberry preservation

In order to extend the shelf life of fruits, edible coatings have been widely studied as a potential alternative strategy to traditional preservatives. This study developed a novel chitosan (CH)/pullulan (PUL) composite edible coating incorporated with 2 % thyme essential oil nanoemulsion (TEON) to enhance antifungal and preservative properties, which consisted of five CH/PUL edible coating groups: C100, C100/T, C75/P25/T, C50/P50/T and C25/P75/T. TEON was characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM), revealing an average particle size of 89.56 nm. In vitro antifungal test demonstrated that the CH coating with TEON reduced Botrytis cinerea mycelial area from 14.03 mm2 to 6.35 mm2 compared to C100 coatings, achieving a 54.7 % inhibition rate. The microstructure, mechanical properties, antifungal properties, and the effect of CH/PUL edible coating on the preservation of strawberry were investigated. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed intermolecular interactions between CH and PUL. The addition of PUL increased the water permeability of CH-based films from 0.69 m2‧h‧kpa to 0.13 m2‧h‧kpa and the tensile properties from 45 % to 88 %. Strawberry preservation at 2 °C for 12 days showed C50/P50/T-treated samples had the lowest weight loss, decay incidence, and Botrytis cinerea area, compared with the other treatment groups. In summary, this paper successfully developed CH/PUL edible coating with antifungal and preservation effects, which have potential applications in improving strawberry quality and extending the storage period of strawberries.

Encapsulation of black soldier fly larvae oil in zein ultrafine fibers via electrospinning: Characterization and antioxidant properties

Black soldier fly larvae (BSFL) have several advantages, such as rapid growth and sustainable production. The electrospinning encapsulation shows promise for encapsulating oils, as it does not use high temperatures, preventing degradation. This study analyzed the incorporation of oil (15, 30, and 45 % w/w) from BSFL into fibers by electrospinning using zein (20 and 25 % w/v). The results demonstrated that BSFL has a predominance of lauric acid. The morphology of fibers with 25 % zein showed a ribbon shape, whereas beads were formed in fibers with 20 % zein. The infrared showed bands that indicated successful encapsulation. Thermal properties show an interaction between the oil and zein, which decreases the mass loss of generated fibers. The contact angle showed that the addition of oil influenced the increase in the hydrophobicity of the fibers. Fibers showed high encapsulation efficiency (>91 %), and antioxidants was higher in fibers with 45 % oil.

Research Progress on Cereal Protein-Based Films: A Review

Recently, to address plastic pollution and food safety issues, the development of biodegradable materials has become a research hotspot. Cereal proteins have been widely used in natural biodegradable packaging films due to their excellent hydrophobicity and film-forming ability, including wheat gluten protein, zein, rice protein, and oat protein. Although pure cereal protein-based films have the disadvantages of insufficient stability and lack of functionality, a variety of measures have been taken to enhance the performance of the films to expand the application range of cereal protein-based films. This Review briefly reviews the fabrication process of cereal protein-based films. The interaction of various additives (plasticizers, biopolymers, nanoparticles, bioactive ingredients, and indicators) with cereal proteins is highlighted. Four methods for fabricating cereal protein-based films (casting, extrusion, electrospinning, and 3D printing) are summarized. Additionally, the impact of several novel technologies on the performance improvement of cereal protein-based films, including ultrasonic, cold plasma, and high-pressure treatment, is discussed. Finally, the application scenarios of cereal protein-based films in active and smart food packaging are discussed, and the challenges of stability and safety of these packaging films are pointed out. In conclusion, this Review identifies the development potential of cereal protein-based films in food packaging fields.

Preparation and Efficacy of Microemulsion Carvacrol-Based Fruit and Vegetable Cleaner and Its Application on Cherry Tomatoes

Carvacrol, a natural plant compound with antibacterial, antioxidant, and various biological activities, serves as the basis for developing a micro-emulsion fruit and vegetable cleaner. The study found that carvacrol demonstrated a minimum inhibitory concentration (MIC) ranging between 0.25 and 0.5 mg/mL against four foodborne pathogenic bacteria and three spoilage fungi. The formulated cleaner, containing 67 mg/mL of carvacrol, demonstrated superior characteristics (a particle size of 228 nm, an absolute zeta potential of 21.4 mv, and a stability coefficient of 91.2%). Remarkably, the cleaner remained stable when stored at room temperature for at least 3 months. Its efficacy against pesticides ranged from 76% to 91%. The cleaning effectively inhibited microbial colonies and the decay rate of cherry tomatoes during storage at 4 °C. Furthermore, the cleaning treatment was found to minimize changes in color and hardness. Overall, this study provides evidence that a fruit and vegetable cleaner based on carvacrol enhances the safety of the food industry effectively.

Encapsulation of Thymol in Ethyl Cellulose-Based Microspheres and Evaluation of Its Sustained Release for Food Applications

Food waste is a global concern with enormous economic, environmental and social impacts that has contributed to active packaging evolution. However, incorporating bioactive substances into the packaging can deteriorate its physicochemical and mechanical characteristics. Thus, the objective of this work was to entrap the natural bioactive compound thymol into microparticles and apply them in the form of pads for the controlled release of bioactivity in food packaging material. The physicochemical characteristics and bioactivity of five different ethyl cellulose-based microparticles were evaluated. Increasing the amount of thymol in the formulation led to higher encapsulation efficiency. Encapsulation resulted in a substantial increase of >10-20 °C in the volatilization temperature of thymol, and the release of thymol occurred following a sustained profile, best described by the Higuchi release kinetic model. Increasing the polymer to thymol ratio in the microparticles resulted in higher thermal stability and a more gradual release profile. While all formulations demonstrated considerable inhibition of E. coli growth, the ones with the highest thymol content maintained their antimicrobial activity for at least one month of microparticle storage. Furthermore, the ability of the microparticles in retaining pH and titratable acidity of cherry tomatoes was evaluated, and it was confirmed that these characteristics were maintained during 21 days of storage.

Zein-based nisin-loaded electrospun nanofibers as active packaging mats for control of Listeria monocytogenes on peach

Zein-based nanofibers (NFs) functionalized with nisin (NS), reinforced with montmorillonite nanoclay (nMMT) were fabricated by uniaxial electrospinning (ES) for the first time to preserve yellow peach. Spinnability/viscosity/conductivity optimizations generated porous (95.09%), bead-free, ultrathin (119 nm) NFs of low hydrophobicity (26.05°). Glutaraldehyde (GTA) crosslinking fostered positive outcomes of tensile strength (1.23 MPa), elongation (5.0%), hydrophobicity (99.46°), surface area (201.38 m2.g-1), pore size (2.88 nm), thermal stability (Tmax = 342 °C), antioxidant/cytotoxic activities in optimized NFs that released NS sustainably according to Korsmeyer-Peppas model indicating a Fickian diffusion mechanism with R2 = 0.9587. The novel NFs inhibited growth of Listeria monocytogenes/aerobic mesophilic populations in peach after 4 days of abusive storage, evincing their robustness in food contact applications. Simultaneously, quality parameters (moisture/texture/browning/total soluble solids/pH) and peach physical appearance were maintained for up to 8 days, endorsing the practical value of zein-based NFs as a non-thermal postharvest intervention for prolonging fruits storage life.

Advances in biomaterials based food packaging systems: Current status and the way forward

World hunger is getting worse, while one-third of food produced around the globe is wasted and never consumed. It is vital to reduce food waste to promote the sustainability of food systems, and improved food packaging solutions can augment this effort. The utilization of biomaterials in smart food packaging not only enhances food preservation and safety but also aligns with current demands for eco-friendly technologies to mitigate the impacts of climate change. This review provides a comprehensive overview of the developments in the field of food packaging based on the innovative use of biomaterials. It emphasizes the potential use of biomaterials derived from nature including cellulose, chitosan, keratin, etc. for this purpose. Various smart food packaging technologies such as active and intelligent packaging are discussed in detail including scavenging additives, colour-changing environment indicators, sensors, RFID tags, etc. The article also delves into the utilization of edible films and coatings, nanoparticle fillers and 2D materials in food packaging systems. Furthermore, it outlines the challenges and opportunities in this dynamic domain, emphasizing the ongoing need for research and innovation to shape the future of sustainable and smart food packaging solutions to enhance and monitor the shelf-life of food products.

Improving the oxidative stability of butter oil with nanoencapsulated Ferulago angulata essential oil during accelerated shelf-life storage

This experiment aimed to encapsulate Ferulago angulata essential oil (FEO) into the zein nanofibers through an electrospinning approach and evaluate their application in retarding the lipid oxidation of butter oil during accelerated shelf-life storage. The main constituents of FEO were α-pinene (35.08%), followed by limonene (21.85%) and ɣ-terpinene (8.03%), respectively. Based on the results of scanning electron microscopy, the obtained electrospun nanofibers were cylindrical, uniformly disordered network structures with smooth surfaces and good continuity. The study findings showed that zein + FEO 1% and zein + FEO 1.5% nanofiber mats had better inhibitory effects to improve the oxidative stability of butter oil during accelerated storage for 24 days compared to the samples enriched with butylated hydroxytoluene 100 mg/Kg (P < 0.05). At the end of the study period, the peroxide value, thiobarbituric acid-reactive substances, p-anisidine value, and acid value of treated butter oils with zein + FEO 1% and zein + FEO 1.5% nanofiber mats were in the range of 0.79-1.03 meq oxygen/Kg, 0.35-0.45 MDA/Kg, 1.36-1.66, and 0.53-0.65 mg KOH/g, respectively.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05980-8.

Physical properties of zein-alginate-glycerol edible films and their application in the preservation of chili peppers (Capsicum annuum L.)

Edible films elaborated from macromolecules, like carbohydrates, proteins, and lipids, must protect and maintain the integrity of foods during their handling, storage, and transportation. In this work, the effect of the concentration of zein (1-2% w/v), sodium alginate (1.5-2% w/v), and glycerol (2-4% w/v) on edible films physicochemical properties was evaluated. The Zein-Alginate-Glycerol interaction was evidenced by the FTIR analysis, the high permeability to water vapor and contact angles less than 90° of the polymer matrices formed. The film made with 2% zein, 1.5% sodium alginate and 4% glycerol preserved the quality of the chili pepper during 15 days of storage at 20 °C, the edible films allowed 3 more days of shelf life for weight loss and 10 more days for firmness. Edible films could be used in chili peppers that are destined for industrial processing, and before use, remove the film with a simple wash.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01393-z.

Effects of Litsea cubeba Essential Oil-Chitosan/Corn Starch Composite Films on the Quality and Shelf-Life of Strawberry (Fragaria × ananassa)

In this work, we have developed a composite chitosan film incorporating the Litsea cubeba essential oil (LCEO) and starch with good physical properties, and investigated the effect of coating strawberries with this composite film. The best formula of the LCEO/chitosan/corn starch/glycerol (LCEO/CH/CS/gly) composite films is 0.25% LCEO, 2.75% CH, 0.40% corn starch, and 0.75% glycerol. Coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly films resulted in significantly lower respiration intensity and a slower decay rate, much slower decreases in the firmness, and reductions in the sugar and ascorbic acid content of the fruit during storage (p < 0.05). The coatings also led to a much slower accumulation of malondialdehyde and anthocyanins (p < 0.05). The LCEO/CH/CS/gly film was generally more effective than the CH/CS/gly film; however, the effect was more obvious in the later stages of storage. Thus, coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly film can be a viable method for extending the shelf-life of the fruit.

Electrospun zein nanofibers containing anthocyanins extracted from red cabbage (Brassica oleracea L.)

This study aims to fabricate and characterize the zein nanoribbons loaded with different concentrations (2.5, 3, 3.5, 4, and 4.5°wt%) of the anthocyanins extracted from red cabbage through the electrospinning technique. It was demonstrated that an increase in anthocyanin concentration caused an increase in viscosity and electrical conductivity without any significant change in the surface tension of the electrospinning solution. It was shown by scanning electron microscopy that an increase in anthocyanins concentration reduced the porosity of the bead-free ribbons compared with blank zein. The Fourier transform infrared spectroscopy analysis, X-ray diffraction patterns, and differential scanning calorimetry results reflected the presence of significant molecular interactions between zein and anthocyanins. Zein-anthocyanins showed high encapsulation efficiency of close to 100%. As a result, it can conclude that electrospinning is a promising method to encapsulate functional ingredients like anthocyanins.

Fabrication, performance, and potential environmental impacts of polysaccharide-based food packaging materials incorporated with phytochemicals: A review

Although food packaging preserves food's quality, it unfortunately contributes to global climate change since the considerable carbon emissions associated with its entire life cycle. Polysaccharide-based packaging materials (PPMs) are promising options to preserve foods, potentially helping the food industry reduce its carbon footprint. PPMs incorporated with phytochemicals hold promise to address this critical issue, keep food fresh and prolong the shelf life. However, phytochemicals' health benefits are impacted by their distinct chemical structures thus the phytochemicals-incorporated PPMs generally exhibit differential performances. PPMs must be thoughtfully formulated to possess adequate physicochemical properties to meet commercial standards. Given this, this review first-time provides a comprehensive review of recent advances in the fabrication of phytochemicals incorporated PPMs. The application performances of phytochemicals-incorporated PPMs for preserving foods, as well as the intelligent monitoring of food quality, are thoroughly introduced. The possible associated environmental impacts and scalability challenges for the commercial application of these PPMs are also methodically assessed. This review seeks to provide comprehensive insights into exploring new avenues to achieve a greener and safer food industry via innovative food packaging materials. This is paramount to preserve not only food shelf life but also the environment, facilitating the eco-friendly development of the food industry.

Essential oil encapsulation by electrospinning and electrospraying using food proteins: A review

Proteins are excellent polymeric materials for encapsulating essential oils (EOs) by electrospinning and electrospraying to protect these compounds and form nanomaterials with active properties. Proteins can encapsulate bioactive molecules by several mechanisms, including surface activity, absorption and stabilization mechanisms, amphiphilic nature, film-forming capacity, foaming, emulsification, and gelation, due to interactions among their functional groups. However, proteins have some limitations in encapsulating EOs by the electrohydrodynamic process. Their properties can be improved by using auxiliary polymers, increasing their charges by adding ionic salts or polyelectrolytes, denaturing their structure by heat, and exposure to specific pH conditions and ionic strength. This review addresses the main proteins used in electrospinning/electrospraying techniques, production methods, their interactions with EOs, bioactive properties, and applications in food matrices. Multivariate analysis associated with bibliometrics of metadata extracted from studies in Web of Science using the keywords electrospinning and essential oil (EO) were used as the search strategy.

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.

Electrospun plant protein-based nanofibers loaded with sakacin as a promising bacteriocin source for active packaging against Listeria monocytogenes in quail breast

The main objective of this study was to fabricate nanofibers from zein incorporated with two concentrations of sakacin (9 and 18 AU/mL) with anti-Listeria properties by electrospinning technique. The efficacies of the resulting active nanofibers against L. innocua, in quail breast during 24 days of refrigerated storage (4 ± 1 °C) were evaluated. The minimum inhibitory concentration (MIC) of bacteriocin against L. innocua was approximate 9 AU/mL. Fourier-transform infrared spectra of bacteriocin-loaded nanofibers indicated characteristic peaks of zein and sakacin and that the nanofibers showed an encapsulation efficiency close to 91.5 %. The thermal stability of sakacin increased by electrospinning. Scanning electron microscopy images showed that nanofibers prepared from electrospinning zein/sakacin solutions exhibited smooth and continuous nanofibers with no defects with an average diameter between 236 and 275 nm. The presence of sakacin led to decreased contact angle properties. Nanofibers with 18 AU/mL sakacin exhibited the highest zone of inhibition of 226.14 ± 8.05 mm. The lowest L. innocua (6.1 logs CFU/cm²) growth after 24 days at 4 °C were obtained in quail breast wrapped with zein containing 18 AU/mL sakacin. The results demonstrate an outlook for the potential use of zein nanofibers containing sakacin to reduce L. innocua contamination in ready-to-eat (RTE) products.

Screening of Different Essential Oils Based on Their Physicochemical and Microbiological Properties to Preserve Red Fruits and Improve Their Shelf Life

Strawberries and raspberries are susceptible to physiological and biological damage. Due to the consumer concern about using pesticides to control fruit rot, recent attention has been drawn to essential oils. Microbiological activity evaluations of different concentrations of tested EOs (cinnamon, clove, bergamot, rosemary and lemon; 10% DMSO-PBS solution was used as a diluent) against fruit rot fungal strains and a fruit-born human pathogen (Escherichia coli) indicated that the highest inhibition halos was found for pure cinnamon and clove oils; according to GC-MS analysis, these activities were due to the high level of the bioactive compounds cinnamaldehyde (54.5%) in cinnamon oil and eugenol (83%) in clove oil. Moreover, thermogravimetric evaluation showed they were thermally stable, with temperature peak of 232.0 °C for cinnamon and 200.6/234.9 °C for clove oils. Antibacterial activity evaluations of all tested EOs at concentrations from 5-50% (v/v) revealed a concentration of 10% (v/v) to be the minimum inhibitory concentration and minimum bactericidal concentration. The physicochemical analysis of fruits in an in vivo assay indicated that used filter papers doped with 10% (v/v) of cinnamon oil (stuck into the lids of plastic containers) were able to increase the total polyphenols and antioxidant activity in strawberries after four days, with it being easier to preserve strawberries than raspberries.

The role of essential oils in maintaining the postharvest quality and preservation of peach and other fruits

Fruits are highly susceptible to postharvest losses induced majorly by postharvest diseases. Peach are favored by consumers because of their high nutritional value and delicious taste. However, it was easy to be affected by fungal infection. The current effective method to control postharvest diseases of fruits is to use chemical fungicides, but these chemicals may cause adverse effects on human health and the residual was potentially harmful to nature and the environment. So, it is especially important to develop safe, non-toxic, and highly effective strategies for the preservation of the fruits. Essential oil, as a class of the natural bacterial inhibitor, has been proven to exhibit strong antibacterial activity, low toxicity, environmental friendliness, and induce fruit resistance to microorganism, which could be recognized as one of the alternatives to chemical fungicides. This paper reviews the research progress of essential oils (Eos) in the storage and preservation of fruits, especially the application in peach, as well as the application in active packaging such as edible coatings, microcapsules, and electrospinning loading. Electrospinning can prepare a variety of nanofibers from different viscoelastic polymer solutions, and has broad application prospects. The paper especially summarizes the application of the new Eos technology on peach. The essential oil with thymol, eugenol, and carvacrol as the main components has a better inhibitory effect on the postharvest disease of peaches, and can be further applied. PRACTICAL APPLICATIONS: As an environmentally friendly natural antibacterial agent, essential oil can be used as a substitute for chemical preservatives to keep fruits fresh. This paper summarizes the different preservation methods of essential oils for fruits, and especially summarizes the different preservation methods of essential oils for peaches after harvesting, as well as their inhibitory effects on pathogenic fungi. It could provide ideas for preservation of fruits and vegetables by essential oils.

Antifungal Activities of Essential Oils in Vapor Phase against Botrytis cinerea and Their Potential to Control Postharvest Strawberry Gray Mold

Essential oils (EOs) from aromatic plants seem to have the potential to control several fungal pathogens and food contaminants. Botrytis cinerea is the main strawberry fruit contaminant causing high losses during storage. Here, thirteen EOs applied in the vapor phase were evaluated for their potential to inhibit the growth of three different strains of B. cinerea isolated from strawberry fruits. Eight EOs (lemongrass, litsea, lavender, peppermint, mint, petitgrain, sage, and thyme) were able to completely inhibit the growth of B. cinerea for 7 days when applied at a concentration of 625 μL·L⁻¹. Four EOs with the lowest minimal inhibition concentrations (thyme, peppermint, lemongrass, and litsea) have been tested on strawberry fruits intentionally inoculated by B. cinerea. All four EOs showed high inhibition at a concentration of 250 or 500 μL·L⁻¹, but only peppermint EO was able to completely inhibit B. cinerea lesion development at a concentration of 125 μL·L⁻¹. The sensory evaluation of strawberries treated by EOs at a concentration 125 μL·L⁻¹ resulted in a statistically significant decrease in taste, aftertaste, aroma, and overall quality. Lemongrass and litsea EOs scored better than thyme and peppermint ones, thus forming two viable methods for B. cinerea suppression and the extension of packed strawberries’ shelf life.

New perspectives on electrospun nanofiber applications in smart and active food packaging materials

Packaging plays a critical role in determining the quality, safety, and shelf-life of many food products. There have been several innovations in the development of more effective food packaging materials recently. Polymer nanofibers are finding increasing attention as additives in packaging materials because of their ability to control their pore size, surface energy, barrier properties, antimicrobial activity, and mechanical strength. Electrospinning is a widely used processing method for fabricating nanofibers from food grade polymers. This review describes recent advances in the development of electrospun nanofibers for application in active and smart packaging materials. Moreover, it highlights the impact of these nanofibers on the physicochemical properties of packaging materials, as well as the application of nanofiber-loaded packaging materials to foods, such as dairy, meat, fruit, and vegetable products.

Electrospun Nisin-Loaded Poly(ε-caprolactone)-Based Active Food Packaging

Packaging for fresh fruits and vegetables with additional properties such as inhibition of pathogens grown can reduce food waste. With its biodegradability, poly(ε-caprolactone) (PCL) is a good candidate for packaging material, especially in the form of an electrospun membrane. The preparation of nonwoven fabric of PCL loaded with food additive, antimicrobial nisin makes them an active packaging with antispoilage properties. During the investigation of the nonwoven fabric mats, different concentrations of nisin were obtained from the solution of PCL via the electrospinning technique. The obtained active porous PCL loaded with varying concentrations of nisin inhibited the growth of Staphylococcus aureus and Escherichia coli. Packages made of PCL and PCL/nisin fibrous mats demonstrated a prolongation of the fruits’ freshness, improving their shelf life and, consequently, their safety.

Plant protein-based nanocomposite films: A review on the used nanomaterials, characteristics, and food packaging applications

Consumer demands to utilize environmentally friendly packaging have led researchers to develop packaging materials from naturally derived resources. In recent years, plant protein-based films as a replacement for synthetic plastics have attracted the attention of the global food packaging industry due to their biodegradability and unique properties. Biopolymer-based films need a filler to show improved packaging properties. One of the latest strategies introduced to food packaging technology is the production of nanocomposite films which are multiphase materials containing a filler with at least one dimension less than 100 nm. This review provides the recent findings on plant-based protein films as biodegradable materials that can be combined with nanoparticles that are applicable to food packaging. Moreover, it investigates the characterization of nanocomposite plant-based protein films/edible coatings. It also briefly describes the application of plant-based protein nanocomposite films/coating on fruits/vegetables, meat and seafood products, and some other foods. The results indicate that the functional performance, barrier, mechanical, optical, thermal and antimicrobial properties of plant protein-based materials can be extended by incorporating nanomaterials. Recent reports provide a better understanding of how incorporating nanomaterials into plant protein-based biopolymers leads to an increase in the shelf life of food products during storage time.

Application of Nanotechnology to Improve the Performance of Biodegradable Biopolymer-Based Packaging Materials

There is great interest in developing biodegradable biopolymer-based packaging materials whose functional performance is enhanced by incorporating active compounds into them, such as light blockers, plasticizers, crosslinkers, diffusion blockers, antimicrobials, antioxidants, and sensors. However, many of these compounds are volatile, chemically unstable, water-insoluble, matrix incompatible, or have adverse effects on film properties, which makes them difficult to directly incorporate into the packaging materials. These challenges can often be overcome by encapsulating the active compounds within food-grade nanoparticles, which are then introduced into the packaging materials. The presence of these nanoencapsulated active compounds in biopolymer-based coatings or films can greatly improve their functional performance. For example, anthocyanins can be used as light-blockers to retard oxidation reactions, or they can be used as pH/gas/temperature sensors to produce smart indicators to monitor the freshness of packaged foods. Encapsulated botanical extracts (like essential oils) can be used to increase the shelf life of foods due to their antimicrobial and antioxidant activities. The resistance of packaging materials to external factors can be improved by incorporating plasticizers (glycerol, sorbitol), crosslinkers (glutaraldehyde, tannic acid), and fillers (nanoparticles or nanofibers). Nanoenabled delivery systems can also be designed to control the release of active ingredients (such as antimicrobials or antioxidants) into the packaged food over time, which may extend their efficacy. This article reviews the different kinds of nanocarriers available for loading active compounds into these types of packaging materials and then discusses their impact on the optical, mechanical, thermal, barrier, antioxidant, and antimicrobial properties of the packaging materials. Furthermore, it highlights the different kinds of bioactive compounds that can be incorporated into biopolymer-based packaging.

Application of essential oils in packaging films for the preservation of fruits and vegetables: A review

Fruits and vegetables are highly perishable in nature. Several factors could affect the quality and shelf life of fruits and vegetables. Packaging materials (usually made up of polymers, proteins, lipids, polysaccharides, etc.,) are incorporated with essential oil (EO) which is high in antimicrobial and antioxidant compounds that can enhance the shelf life of fruits and vegetables without affecting their quality. However, the use of EO for postharvest preservation can alter the organoleptic properties of fresh produce. Exploiting synergistic interactions between several EOs, encapsulation of EO, or combining EO with non-thermal techniques such as irradiation, UV-C, cold plasma, ultrasound, etc., may help in preventing the spoilage of food products at lower concentrations without altering their organoleptic properties. This review aims to discuss the overview and current scenario of packaging film with EO for the preservation of fruit and vegetables. We have also discussed the spoilage mechanism of fruits and vegetables, mode of action of EOs, and the effect of EO with packaging film on antimicrobial and sensory properties of fruits and vegetables.

Nanoencapsulation-Based Edible Coating of Essential Oils as a Novel Green Strategy Against Fungal Spoilage, Mycotoxin Contamination, and Quality Deterioration of Stored Fruits: An Overview

Currently, applications of essential oils for protection of postharvest fruits against fungal infestation and mycotoxin contamination are of immense interest and research hot spot in view of their natural origin and possibly being an alternative to hazardous synthetic preservatives. However, the practical applications of essential oils in broad-scale industrial sectors have some limitations due to their volatility, less solubility, hydrophobic nature, and easy oxidation in environmental conditions. Implementation of nanotechnology for efficient incorporation of essential oils into polymeric matrices is an emerging and novel strategy to extend its applicability by controlled release and to overcome its major limitations. Moreover, different nano-engineered structures (nanoemulsion, suspension, colloidal dispersion, and nanoparticles) developed by applying a variety of nanoencapsulation processes improved essential oil efficacy along with targeted delivery, maintaining the characteristics of food ingredients. Nanoemulsion-based edible coating of essential oils in fruits poses an innovative green alternative against fungal infestation and mycotoxin contamination. Encapsulation-based coating of essential oils also improves antifungal, antimycotoxigenic, and antioxidant properties, a prerequisite for long-term enhancement of fruit shelf life. Furthermore, emulsion-based coating of essential oil is also efficient in the protection of physicochemical characteristics, viz., firmness, titrable acidity, pH, weight loss, respiration rate, and total phenolic contents, along with maintenance of organoleptic attributes and nutritional qualities of stored fruits. Based on this scenario, the present article deals with the advancement in nanoencapsulation-based edible coating of essential oil with efficient utilization as a novel safe green preservative and develops a green insight into sustainable protection of fruits against fungal- and mycotoxin-mediated quality deterioration.