From plant compounds to packaging: recent advances in phytochemical added edible films and coatings

1 Introduction

The food supply chain is globally facing an important turning point, which has been influenced not only by the serious issue of ecological damage caused by the constant use of plastic products made from fossil fuels, but also by the extremely high rates of food spoilage before being delivered to consumers. Petroleum-based plastics such as PE, PP, and PET were widely used due to their durability and economic advantages; however, their resistance to degradation leads to a constant buildup, which has led to serious environmental problems. Sustainable food system philosophies, in turn, now require a shift towards edible films and coatings (ECFs), and bioactive film and coating-based substrates based on renewable biological macromolecules, including polysaccharides, proteins, and lipids (Matloob et al., 2023; Xu et al., 2025).

The current research on active packaging focuses on polysaccharides, namely, starch, alginate, and chitosan, capturing roughly two-thirds to four-fifths of contemporary academic focus due to their superior film-forming capacities and cost-effectiveness. Although these biopolymers offer a structural “backbone,” the nature of such biopolymers, including the high hydrophilicity and water vapor permeability of starch or the brittle properties of some proteins, requires sophisticated modification by cross-linking of these biopolymers with green agents such as citric acid, or by the formation of hybrid systems, such as chitosan-gelatin composites (Esfandiari et al., 2025; Siddiqui et al., 2023). The main innovation in modern research in this area is the transition from passive physical barriers to active, intelligent multicomponent systems enabled by the tactical integration of phytochemicals, non-nutritive bioactive substances found in plants. These are dynamic functional agents that are found to be neutralizing reactive oxygen species (ROS) and microbial enzyme systems, thereby stopping the metabolic processes involved in food degradation pathways, with these agents being divided into three primary families: phenolics, flavonoids and terpenoids (Siddiqui et al., 2023; Yang and Ling, 2025).

One critical and new Frontier is the valorization of agri-food residues, which uses agricultural waste to produce high-value functional additives, which would essentially match food packaging with the global circular economy (Kumar N. et al., 2021; Pishyar et al., 2022; Carvalho et al., 2025; Gaspar and Braga, 2023). As an example, a pomegranate peel extract (PPE) that is high in Punica granatum L. punicagalin and punicaellagic acid can offer very strong antifungal properties, whereas carrot juicing waste and onion peels can be used as polymeric bases and bioactive fillers, which can improve tensile strength (TS) and UV-shielding performance (de Almeida Soares and de Aquino Santana, 2023; Pishyar et al., 2022). On the same note, recent advances have shown that avocado by-products, comprising extracts that are rich in hydroxy-octadecadienoic acid and flavonoids, can be successfully upcycled with the use of ethyl cellulose-reinforced paper, where the extracts are impregnated to greatly reduce water permeability and enhance antioxidant properties (Acquavia et al., 2023).

In addition, the phytochemical-loaded systems have enabled the development of smarter packaging that can monitor quality in real time. Researchers have developed colorimetric sensing systems by introducing pH-responsive pigments, e.g., anthocyanins in black wolfberry, plum peels or Clitoria ternatea, to monitor the freshness of highly perishable foods, including milk, shrimp, and poultry (Pastrana et al., 2023; Wang and Liu, 2024). These anthocyanins experience different visual color changes as lactic acid or volatile amines accumulate during the process of spoilage, and this gives consumers a non-invasive signal of the food safety (Pastrana et al., 2023). In addition to sensing, these compounds can also have dual uses, such as shikonin and propolis extract in gelatin/carrageenan films, which can serve as a freshness indicator and a potent UV-blocker that inhibits the oxidation of fats and vitamins by light (Roy and Rhim, 2020c).

Hydrogen bonding and electrostatic interactions between the amino or hydroxyl groups of the biopolymer and the phenolic hydroxyl groups of the plant extracts facilitate integration of these compounds at the molecular level, thereby improving material performance and bioactive retention (de Almeida Soares and de Aquino Santana, 2023; Kumar L. et al., 2021). Another element of structural novelty concerns the development of techniques for the synthesis of materials, moving from lab-scale solvent casting to methods suitable for large-scale industrial manufacture, including hot-melt extrusion (HME), electrospinning, and slot-die casting of matrices.

To address the scientific issues associated with phytochemical instability and volatility, sophisticated techniques have been used, such as microencapsulation in β-cyclodextrin (β-CD) or Nanostructured Lipid Carriers (NLC). This method of encapsulation protects the unstable molecules in the essential oils of ginger, cloves, and cinnamon from thermal degradation during processing, allowing for controlled release (Chen et al., 2026; Jacob et al., 2025). These techniques shield delicate molecules, such as those in ginger, cloves, and cinnamon essential oils, so that they do not break down during the heating process, yet release under control at the food-matrix interface (Chen et al., 2026; Zhang et al., 2023c). Through these strategies, active films and coatings have been developed as the integration of multicomponent steady-state essential oil (EO) composites into typical coating methods has produced >99.9 per cent pathogen inhibition, such as Escherichia coli and Staphylococcus aureus (Chen et al., 2026). Such systems have proved to increase the shelf life of fresh produce by as many as 21 days without loss of nutritional value like strawberries and green chillies (Chen et al., 2026). Finally, the development of these functionalized materials will bring to life the fact that packaging is not a waste product any more, but a crucial and sustainable part of food preservation that complies with the Generally Recognized as Safe (GRAS) regulatory requirements (Matloob et al., 2023).

While several recent publications have compiled the baseline properties of biopolymer carriers, a critical knowledge gap persists regarding the dual-functional behavior of upcycled agri-food residues as both active and intelligent colorimetric modifiers within fully scalable, non-paper matrices. This review fills that gap by providing a comprehensive, state-of-the-art analysis of phytochemical, stabilization via modern nanoencapsulation, hot-melt extrusion and electrospinning. By mapping the mechanical, barrier, and biological structure-property relationships of phytochemical-loaded smart packaging against specific food sector challenges, ranging from lipid oxidation in red meat to moisture migration in multi-component bakery systems, this work serves as a definitive roadmap for harmonising circular economy strategies with rigorous global food safety standards.

2 Preparation of phytochemical-added edible films and coating materials

The design and functionalization of advanced active packaging systems really hinge on that ongoing, kind of systemic synergy between the structural biopolymeric carrier and the immobilised bioactive compounds. This section goes over the core building blocks of modern ECFs, examining the chemical traits of different polysaccharide, protein, and lipid matrices. Also, it covers how these materials are sorted into key plant-derived phytochemical families, then moves into green extraction technologies tuned for better recovery from agricultural by-products, and finally explains the nanoencapsulation protocols you need to maintain molecular stability during industrial processing.

2.1 Edible polymer materials

Sustainable food system philosophies across the world basically call for a shift away from petroleum-based plastics and toward ECFs, like really using the natural biodegradability, lack of toxicity, and broader ecological safety you get with biopolymer materials. These biological macromolecules become the core structural matrix or the real “backbone” thing you need, so phytochemical fillers can be immobilised in a stable way. And depending on molecular weight, monomer profiles, and the chemical behavior under conditions, the film-forming biopolymers tend to fall into three main classes: polysaccharides, proteins, and lipids (Mohamed et al., 2020).

Polysaccharides are among the most widely used macromolecules for ECF production, mostly because they have strong film-forming ability, abundant natural availability, low cost, and relatively well-ordered linear Configurations. Usually, they end up making hydrophilic networks held together by lots of intra- and intermolecular hydrogen bonding, which translates into pretty good barrier performance against gas permeation, especially when the air is dry. For example, starch is built from linear poly- α -(1,4)-D-glucopyranose, often called amylose, and also from a more branched poly- α -(1,4)- and α-(1,6)-D-glucopyranose, aka amylopectin. Even though starch is economically attractive, its glucan chain is packed with hydrophilic hydroxyl groups, so the resulting films tend to suck in moisture easily. Then you get localized swelling and a pretty dramatic drop in mechanical integrity once they are kept at higher ambient humidity (Matloob et al., 2023). So, that is why starch is often mixed with other secondary hydrophobic polymers, or cross-linked with so-called green chemistry agents such as citric acid, to lower water vapour permeability in a more controlled manner (Xue et al., 2025; Zhang et al., 2023a).

In contrast, chitosan is produced by partial alkaline deacetylation of chitin and results in a linear copolymer of β-(1,4)-linked 2-amino-2-deoxy-D-glucopyranose. It’s probably the only cationic polysaccharide found in nature, and so its main edge sits in those protonated amino groups; they basically give the matrix its “built-in” antimicrobial activity (Mohammed et al., 2021). Also, those amino groups become pretty choice reaction sites for electrostatic attraction as well as hydrogen bonding, and in practice, they help create a steady molecular dispersion together with polyphenolic phytochemicals (Kumar L. et al., 2021).

Another polysaccharide that gets used a lot is alginate, which is taken as a polyanionic salt from marine brown algae, and it sits there as a linear block copolymer made from (1,4)-linked β-D-mannuronic acid and α-L-guluronic acid units. When multivalent ions show up, especially divalent calcium (Ca²⁺), the guluronic segments rapidly undergo ionotropic gelation, sort of enclosing the cations to form a very organized, cross-linked coordinate network (Xue et al., 2025). Because of that tight ionic cross-linking, the resulting matrix is unusually compact, and it also supports controlled release kinetics for the encapsulated active compounds while at the same time hindering oxygen passage. Other carbohydrate options like carboxymethyl cellulose (CMC) and pectin, meanwhile, have strong solubility, and they tend to build robust, highly compliant matrices with good structural regularity and baseline physical stability (Xu et al., 2025). Similarly, carrageenan, which is more like a group of sulfated galactans harvested from red seaweeds, can form thermos-reversible helical structures as it cools down, and those helices set up resilient, flexible networks. These networks are usually very compatible both with water-soluble plant extracts and with lipophilic fillers (Roy and Rhim 2020b).

One of the major functional differences between protein and polysaccharide films is that the former offers a range of specific advantages due to their chemical complexity, which is characterized by their amphiphilic character derived from an arrangement of twenty unique amino acids (Matloob et al., 2023). This composition allows them to form multiple types of non-covalent interactions, such as ionic, hydrogen, and hydrophobic bonds, as well as covalent disulfide cross-linking to produce films with higher mechanical strength and improved gas barrier properties in a low relative humidity environment (Matloob et al., 2023). Gelatin, a fibrous protein obtained by partial thermal and chemical hydrolysis of collagen, undergoes a unique transformation from coils to helices at low temperatures, forming a compact triple-helix structure (Rubini et al., 2021). The structure forms very strong protein sheets with limited gas permeability, whereas peptide segments within the molecule create additional binding sites to protect hydrophobic substances, such as curcumin, thereby increasing the antioxidant properties of the films. Unlike gelatin, zein is a prolamine found in corn endosperm, being rich in hydrophobic amino acids, especially leucine, proline, and alanine. Therefore, zein has much better natural water resistance than conventional polysaccharides. Nevertheless, due to strong intermolecular cohesion, this protein produces brittle films that are prone to breaking during production (Matloob et al., 2023). To eliminate such disadvantages, contemporary designs often use hybrid films, in which the use of one compound offsets the drawbacks of another. For example, a chitosan-gelatin composite effectively combines the natural antibacterial activity of chitosan with the high mechanical characteristics of gelatin (Matloob et al., 2023). Likewise, whey protein isolates can form highly transparent film structures by forming intermolecular disulfide bonds after denaturation of the molecules (Akcan et al., 2017), whereas soy protein isolates have great potential for texture formation and stability, providing a large number of binding sites for chemical modification (Wu et al., 2023).

Although polysaccharides and proteins have a robust structure and high stability, their high hydrophilicity makes it impossible to use them for efficient moisture barrier applications. The solution to this technological challenge involves adding hydrophobic lipid compounds to film-forming compositions, which form dense crystalline lipid barriers that prevent the migration of water molecules and reduce the moisture barrier properties of the overall composite packaging material (Jacob et al., 2025). Hydrophobic liquid lipid materials, including plant essential oils (e.g., clove oil, cinnamon oil, and oregano oil) and free fatty acids, serve as a separate type of physical plasticizers in biopolymeric systems. They diffuse into the chain structures of the polymers, increasing the degree of free volume to increase the flexibility of the matrix and adding the necessary antimicrobial and antioxidative properties (Pandey et al., 2024). Being unable to form self-standing films due to poor cohesive properties, lipids nowadays are used as dispersed lipid nanostructured particles in the form of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). When incorporated into continuous phases of polysaccharides and/or proteins, these nanostructure-based lipids create a complex material, where the continuous phase supports mechanical resistance while dispersed lipids form the internal hydrophobic layer blocking moisture penetration (Xue et al., 2025). This feature becomes particularly relevant in the design of functional active packaging films for moisture-sensitive foods, such as fresh produce and dry bakery products (Jacob et al., 2025).

2.2 Overview of phytochemicals

The shift towards active, intelligent packaging approaches depends on the implementation of phytochemicals within edible matrices through strategic means (Yang and Ling, 2025). These are plant secondary metabolites that differ in structure from the polymers and fall into three major chemical classes based on their biosynthetic pathways: phenolics, flavonoids, and terpenoids (Siddiqui et al., 2023). The largest class is phenolics, which have an aromatic system with at least one aromatic ring attached to one or several hydroxyl groups (Vuolo et al., 2019). As a result, the phenolic hydroxyl groups enable them to act as hydrogen donors, reacting with ROS and preventing further lipid oxidation in fatty food products (Siddiqui et al., 2023). Within phenolics, there are two major types: simple phenolic acids and complex polyphenols, the latter including punicalagins and ellagic acid, both derived from pomegranate peels. In this case, the strong electronic distribution among molecules may affect fungal metabolic and membrane functions by interfering with cell wall structures (de Almeida Soares and de Aquino Santana, 2023).

The class of flavonoids includes subclasses of flavonols, flavanols, and anthocyanins, which are characterised by a C₆-C₃-C₆ carbon skeleton consisting of two benzene rings bound by a heterocyclic pyran ring (Yang and Ling, 2025). The high conjugation of double bonds in flavonoid structures, including catechins from grape seeds and quercetin from onion skins, enables them to absorb energy-rich light and act as natural UV radiation screens (Ma and Zhang, 2017). Additionally, some water-soluble flavonoids, specifically anthocyanins, have highly specific and variable molecular structures that depend on the hydronium ion concentration of the medium (Pastrana et al., 2023). In the presence of volatile compounds released by bacteria and/or acids produced during food decay, these anthocyanin molecules change their structure by switching between flavylium cation form and anhydrous base structure, producing drastic changes in color, which may be used as a non-invasive marker of food fresh condition (Pastrana et al., 2023).

Terpenoids are the main constituents of essential oils obtained from plant sources and have structures consisting of five-carbon building blocks (C₅H₈) and are rich in hydrophobic moieties (Liñán-Atero et al., 2024). Lipophilic terpenoids, like eugenol from clove essential oils, cinnamaldehyde from cinnamon essential oil, and carvacrol from oregano oil, have a high affinity for interaction with cell membranes due to hydrophobic properties (Liñán-Atero et al., 2024). This ability enables these terpenoids to penetrate into the bacterial cells like Escherichia coli and Staphylococcus aureus and alter their membrane properties, causing leakage of important components and ATP depletion and blocking enzyme functions, creating antibacterial action zones (Liñán-Atero et al., 2024). At the macro-level, when all three phytochemicals are added to biopolymer systems, they engage in hydrogen and electrostatic interactions with hydroxyl or amino groups of matrices, providing stability and slow release to the active compounds (de Almeida Soares and de Aquino Santana, 2023). As summarized in Table 1, the diversity of phytochemical sources and their specific loadings highlight the tailored approach required for different food applications.

TABLE 1. Various phytochemicals’ bioactivity, loading, and sources used in active edible matrices.

These compounds can also be grouped into three major “families,” based on their chemical structure and chemical behavior, which then offer targeted applications for food preservation. Phenolic fractions represent the most widely distributed secondary metabolites throughout plant ecosystems, possessing one or more aromatic rings with hydroxyl groups, notable for their high free-radical scavenging capacity during DPPH assays often between 50%–95% (Yang and Ling, 2025). Belonging to a major polyphenol subgroup, flavonoids encompass quercetin and anthocyanin structures widely distributed across vegetables, onions, and berries that impart health benefits and visual properties such as color and UV-shielding.

Terpenoids, among those essential oils like clove and cinnamon oils, produce high intensity of their antimicrobial “killing zones” against food-borne pathogens (Liñán-Atero et al., 2024). Clove essential oil (CEO) is derived from Syzygium aromaticum, which, mainly comprised of eugenol (70%-85%), makes it extremely potent; indeed, a single drop of clove oil is said to be 400 times more potent in antioxidant capacity than blueberries. CEO displays wide bactericidal efficacy inhibiting prominent foodborne pathogens, specifically Listeria monocytogenes alongside Escherichia coli, by damaging cell membranes and causing leakage of intracellular contents (Liñán-Atero et al., 2024; Pandey et al., 2024). Sources of these compounds vary from highly pure extracts like curcumin from turmeric (Curcuma longa) to grape seed extract (GSE) obtained from winery by-products. GSE is known to be very rich in proanthocyanidins, which gives it a high DPPH radical scavenging activity and anti-inflammatory properties (Kumar et al., 2025; Ma and Zhang, 2017). Another focus has been to valorize vegetable wastes like carrot peels that are high in concentrations of beta-carotene and phenolic acids, and onion skins that are high in quercetin, a flavonoid with a high thermal stability (Ahmad et al., 2017).

Efficient recovery of these compounds from waste is achieved through specialized extraction methods, from traditional Soxhlet extraction using methanol to “green” alternatives. Ultrasound-assisted extraction (UAE) utilizes the phenomenon of acoustic cavitation to break the plant cell walls, which invokes a localized high pressure and shear stress robust enough to shatter tougher plant tissues and therefore greatly enhance yield while reducing extraction time (Tabaraki and Nateghi, 2011; Mushtaq et al., 2025) Likewise, the utilization of hydrolytic enzymes during enzyme-assisted extraction (EAE) like cellulases and pectinases for selective degradation of polysaccharide-lignin networks of plant cell wall, thereby allowing more facile release of high-purity polyphenols under mild conditions (Xue et al., 2025).

Active packaging presents the challenge of compatibility between phytochemicals and biopolymer matrices; this is particularly difficult when trying to bring hydrophobic essential oils into an aqueous polysaccharide matrix such as starch. The essence of that phase separation is often associated with poor mechanical performance; these obstacles can be approached through nanocapsulation strategies. Nanoencapsulation, such as with nanostructured lipid carriers (NLCs) or nanoemulsions, improves solubility and stability of sensitive bioactives from light and oxygen by as much as 20%-30% in terms of retention in the film (Pandey et al., 2024; Siddiqui et al., 2023; Chen et al., 2020). This ensures that such active properties will be maintained throughout the product’s storage longevity. The commercial passage of this innovation has to ensure the mutual industrial-like production methods from lab-scale solvent casting to industrial-scale extrusion. While it is still mainly solvent casting because of its inherent ease, hot-melt extrusion (HME) is being considered for the industrial scale, catering to large production volumes and continuous processing (Xue et al., 2025).

3 Methods of fabrication of phytochemical-incorporated edible packaging

Both the architectural design and efficacy of edible coatings depend greatly on the selected production procedure used for the creation of the matrix in the packaging stage. As far as sustainability has been widely advocated across the globe as a way to preserve foods, the step-by-step process from the laboratory samples to the large-scale continuous production involves careful assessment of mechanical shear stress and thermal conditions in relation to functional additives. The selection of production procedure works as a decisive factor because it defines molecular dispersion, migration, and distribution of bioactive compounds in the structure of the matrix. Since there are different types of natural bioactive compounds in plants, which are characterized by distinctive chemical properties (i.e., volatilization, heat sensitivity, and pH-dependent dissociation of natural coloring agents), the manufacturing procedure should be selected so that the integrity of structures does not break down prematurely.

3.1 Solvent casting

Solvent casting continues to be the standard technique for laboratory film preparation. The technique usually involves the dissolution of the biopolymer in an aqueous or organic solvent system. Following this, plasticizers, such as glycerol or sorbitol, are added to interrupt the formation of hydrogen bonds between macromolecules. This further increases the total volume of free space within the film structure, resulting in an increased fracture strain value and elastic characteristics of the polymer (Xue et al., 2025). Complete molecular dispersion of the mixture is achieved through heating in the temperature range of 60 °C–90 °C (Xue et al., 2025). This promotes the gelatinization of starch or chain elongation of proteins. Plant extracts with active constituents, like clove oil, grape seed extract, or pomegranate peel extract, are worked into the warm mixture and only then poured into the molds. This part, is sort of crucial for those fleeting volatile substances. Especially, the temperature of the casting liquid needs to be brought down a bit, so there is no flash evaporation of plant volatiles, such as eugenol or cinnamaldehyde (Kong et al., 2022). The prepared solutions are dried at 40 °C for one to 2 days. This procedure facilitates uniform dimensions, solvent removal, and minimizes stress-induced cracks (Xue et al., 2025). Films produced using the described protocol provide satisfactory quality with high transparency and phytochemical extraction efficiency within the range of 80%–90% (Matloob et al., 2023). Nevertheless, a significant limitation related to this approach concerns the necessity to conduct the process in batches, long drying time, and solvent consumption (Matloob et al., 2023).

3.2 Hot-melt extrusion (HME)

To facilitate the transition from laboratory models to industrial manufacturing scale-up, HME offers an environmentally friendly process characterized by high throughput and continuous processing without the need for any solvents, using the melt phase of the biopolymer (Xue et al., 2025). In this case, the natural biopolymer, along with the dried plasticizer agents, is introduced directly to the extruder screw barrel, where a thermoplastic melt is produced through the effect of mechanical and thermal energy of rotating screws on semi-crystalline particles (Xue et al., 2025). While the absence of any solvent-based pollution improves the sustainability of HME processing on an industrial scale, high processing temperatures exceeding 100 °C require a special approach toward protecting the heat sensitive phytochemicals (Xue et al., 2025). For example, vulnerable phytochemicals such as anthocyanin, carotenoid, and polyphenolic compounds would suffer from the destructive impact of the heat during processing, resulting in degradation and even loss of antioxidant activity (Pan et al., 2024).

This problem can be addressed through the use of advanced extrusion designs featuring side feeding of the phytochemical liquids into the cooled down fully melted area of the screw before being injected into the shaping dies (Pan et al., 2024). Furthermore, pre-stabilizing phytochemical agents inside heat stable nanomaterials like solid lipid nanoparticles and nanostructured lipid carriers means they can get protected from shear effects and temperature stress (Xue et al., 2025). Therefore, the biological actions of these phytochemicals that drive antimicrobial along with antioxidant properties end up staying intact (Pan et al., 2024).

3.3 Electrospinning

For cases that require higher bioactive loading and improved structural reinforcement, electrospinning emerges as one of the most efficient techniques available. It entails using a high electric voltage to extrude a biopolymer solution through a nozzling system into ultra-fine fibers with diameters ranging between 50 and 500 nm. The resulting structure features an extremely high surface area to mass ratio, allowing the dense inclusion of bioactive compounds while enclosing them in the secure nanofiber network. Considering the non-thermal nature of electrospinning technique, it provides an ideal means of encapsulation for volatile and heat-sensitive phytochemicals such as essential oils that are usually found in volatile plant extracts (Göksen et al., 2020). In effect, the phytochemicals undergo substantial sub-micronization and get entrapped within the nanofiber cores. Electrospinning is particularly useful in creating active inserts, absorbent pads, or intelligent sensor strips that have a high concentration of volatile antimicrobial compounds in direct contact with foods. For example, adding chitosan nanofibers to vegetable waste results in a tortuous path that restricts the movement of water molecules hence low permeability to water vapor.

3.4 Stabilization and emulsification techniques

For proper distribution and effective prevention of phase separation, the incorporation of phytochemicals needs to be performed by using complex stabilization techniques into the hydrophilic base of polymers. By nature, hydrophobic agents like essential oils and crystalline curcumin can cause difficulties because of their compatibility problem when mixed with aqueous polymeric solutions, leading to phase separation and development of pinholes within the film. In order to eliminate this problem, the bioactive agents are formulated into aqueous emulsion using food-grade emulsifiers such as Tween 80, lecithin, or gum Arabic (Pan et al., 2024). Subsequently, ultrasonic treatment is performed on the solution for 20–30 min. Due to acoustic cavitation caused by ultrasonication treatment, significant shear stress is developed within the mixture leading to reduction in size of the large-sized oil droplets to nano-level size. This leads to prevention of agglomeration of particles and better alignment of molecules of bioactive with those of the polymer matrix. At a molecular level, the interaction between polymer chain and nano-droplets of bioactive occurs effectively via hydrogen bond and electrostatic interactions (de Almeida Soares and de Aquino Santana, 2023). The presence of these agents will not affect the physical properties of the matrix because they will become evenly distributed in it, resulting in high surface-to-volume ratio and improved biological activity against pathogens.

3.5 Others

The technique for applying the active substances themselves determines the consistency of the protective layer covering food matrices, whether whole foods or fresh-cut products. One of the most commonly used post-harvest application techniques is dipping. Here, whole fruits like strawberries or grapes are dipped completely into the liquid formulation consisting of solutions of grape seed extract or olive leaf extract (Díaz-Montes and Castro-Muñoz, 2021). After drying, a thin skin-like film is formed which acts as a locally generated modified atmosphere to reduce transpiration and respiration rates (Díaz-Montes and Castro-Muñoz, 2021). In terms of large-scale manufacturing lines, spray coating methods using atomizer nozzles perform much more efficiently (Pan et al., 2024; Xue et al., 2025). The process allows for quick coating of extensive surface areas within minimal time spans while being fully controllable and minimizing fruit damage (Díaz-Montes and Castro-Muñoz, 2021). Moreover, novel additive manufacturing techniques like 3D printing allow for an even finer layer-by-layer deposition of film-forming solutions into a desired shape (Díaz-Montes and Castro-Muñoz, 2021). Thus, the possibility arises to engineer customized smart patches or absorbent sheets, specifically adjusted to particular respiration rates and geometries (Pan et al., 2024). The evolution of fabrication sciences from simple casting to automated extrusion to nano-engineering as modelled in Table 2 outlines the foresight for the food packaging sector within the global circular economy for the long-term sustenance of food quality.

TABLE 2. Comparative analysis of fabrication methodologies for phytochemical-based active edible packaging.

Figure 1 illustrates the full lifecycle of active packaging development, beginning with the recovery of bioactive compounds from agri-food waste (e.g., carrot peels, winery by-products). It details the stabilization of hydrophobic agents through nanoencapsulation and the molecular integration of phenolics via hydrogen bonding into biopolymer matrices (Starch, Chitosan, Guar Gum). The pathway highlights both laboratory-scale solvent casting and industrially scalable hot-melt extrusion (HME) techniques, leading to high-performance active and intelligent packaging systems with UV-shielding, antimicrobial, and pH-responsive functionalities (Pandey et al., 2024; Siddiqui et al., 2023; Yang and Ling, 2025).

4 Properties of phytochemical-loaded edible films and coating materials

The good physical and functional properties of the edible film, namely, mechanical, barrier, optical, antioxidant and antimicrobial, are key and desirable for the performance in food packaging applications. Phytochemicals are among the most commonly used ingredients to improve the functional properties of films and coatings. Recently, there has been growing interest in various phytochemicals, including those used in edible packaging films and coatings. Many reports have studied various structural and biological performance indices characterising phytochemical-loaded biopolymer sheets and coatings; recent results on this topic are tabulated in Table 3, and some are briefly discussed in this section.

TABLE 3. Phytochemicals added edible active Films and coatings developed for food preservation purposes.

4.1 Mechanical properties

Characterising structural performance is vital for bio-polymeric sheets, as it dictates their durability when subjected to logistical handling or ambient pressures during containment. The mechanical parameters, namely, TS, EB, and YM values refers to the ultimate maximum strength, flexibility, and stiffness exhibited by the matrix. Keawpeng et al. (2022), recently evaluated the performance trends of clove oil on tuning the structural performance of matrices derived from mung bean flour. The TS of the mung bean flour films did not change much, ∼6.6–6.8 MPa, upon being formulated with clove oil. Moreover, the flexibility of the film also remained almost constant, but the YM increased significantly from 208 to 223 MPa. The resulting insights clearly showed that the addition of the essential oils has shown some impact on the mechanical performance of the film. In another work, the addition of GSE in the alginate/carboxymethyl cellulose/starch ternary composite films reduces the mechanical properties of the film slightly as the TS and YM experienced a decline, whereas the EB expanded, a trend potentially stemming from residual plasticising components within the GSE (Ramakrishnan et al., 2023). On the flipside, earlier investigations documented that the incorporation of curcumin into carbohydrate-based matrices (agar, chitosan, and carrageenan) exerted negligible influence on the TS and EB parameters of the sheet (Roy and Rhim, 2020b). The addition of shikonin and propolis, alone and in combination, showed almost no significant change in mechanical strength but a slight improvement in the rigidity and flexibility of the gelatin/carrageenan-based film (Roy and Rhim, 2021). Aparicio-Fernández et al. (2018) studied the effect of Prickly pear peel powder and aqueous solution on the mechanical properties of CMC-based edible packaging film. They reported that the CMC film’s mechanical performance was affected in formulations containing the botanical aqueous extract, while unaltered in the presence of the peel powder.

4.2 Water vapor barrier properties

Moisture permeability indices (WVP) are mainly reliant on sequential Absorption, diffusion and desorption, but the surface hydrophobicity and molecular diffusion also exhibit a key impact on permeability (Roy et al., 2022). The WVP of clove oil added mung bean flour-based films studied by Keawpeng et al. (2022) and they found that water vapor barrier properties of the film pointedly improved (WVP changed from 6.03 × 10^-12 to 5.60 × 10^-12 kg Pa⁻¹ s⁻¹ m⁻¹). The increase in moisture impedance metrics could be due to the improvement of surface hydrophobic traits across the matrix following the inclusion of the essential oils. In contrast the addition of GSE in the ternary biopolymer matrices composed of alginate, carboxymethyl cellulose, and starch composite layers reduces the moisture resistance capabilities of the sheet (3.42–3.86 × g mm⁻² d⁻¹ Pa^{− 1} × 10^–11), which could be attributed to the intensely hydrophilic nature governing the GSE Ramakrishnan et al., 2023). The increase in hydrophilicity of the film was confirmed from the reduction in water contact angle of the film. The addition of curcumin into active polysaccharide-based film showed some improvement in water vapor barrier properties of the film although the changes proved statistically insignificant (Roy and Rhim, 2020b). The reduction in WVP of the film could be associated with the hydrophobic nature of curcumin. On the other side, the mixing of shikonin and propolis alone and in combination only slightly increases the WVP of the gelatin/carrageenan-based film, even though the changes are not very significant (Roy and Rhim, 2021).

4.3 Optical properties

Optical properties mean the color, transparency, and transmittance of the film which have huge impression on the appearance, and acceptance for proper food applications. Furthermore, the UV-light can induce lipid oxidation of food and that can be controlled by adding appropriate ultraviolet-shielding materials (Roy and Rhim, 2021). The presence of GSE in the alginate/carboxymethyl cellulose/starch ternary composite films strongly improved the UV-light barrier properties of the film, which can be applied to protect from UV-light oxidation (Ramakrishnan et al., 2023). Moreover, the film was transparent, and the light transmittance was high,>70%, which could be suitable for transparent food packaging film production. The yellowness of the film was enhanced 30-fold while whiteness was slightly reduced (∼10%), which is presumably due to the yellowish color of GSE. Incorporating curcumin pigments into a hydrophilic carbohydrate film exhibited a strong ultraviolet radiation resistance phenomenon without disturbing the baseline light transmittance parameters of the developed composite matrix (Roy and Rhim, 2020b). The robust UV-light barrier properties of the curcumin integrated layer can be directly attributed to the UV light attenuation and dispersion capabilities of curcumin. The color of all three-films turned golden yellowish from transparent due to the yellowish color of curcumin. Recently, it has been reported that the incorporation of shikonin and propolis showed enhanced resistance against ultraviolet light transmission within the blended protein/polysaccharide film (Roy and Rhim, 2021). While the light transmittance performance of the composite matrix experienced a decline following the introduction of shikonin due to the dark red color of the natural pigment.

4.4 Antioxidant and antimicrobial properties

In active packaging, the addition of antimicrobial and/or antioxidant ingredients improves films’ functional properties and consequently helps expand the life span of food (Ebrahimzadeh et al., 2023; Roy and Rhim, 2020a). The inclusion of bioactive compounds into the film matrix retards the growth of a wide spectrum of bacteria and also restricts the lipid oxidation of fat-rich food products (Bose et al., 2023; Zhang et al., 2023b). Keawpeng et al. (2022) recently investigated the effect of clove oil on improving the antioxidant properties of mung bean flour-based films.

The neat films showed good antioxidant capacity, but it amplified superbly in the presence of the essential oil (∼12% increase in ferric reducing antioxidant activity, ∼15% in ABTS and ∼20% in DPPH antioxidant activity). The sharp rise in the antioxidant activity is owing to the increase in total phenolic (∼30%) and flavonoids (∼15%) content in the film in the presence of the essential oils. The addition of essential oils also significantly reduced the total viable growth count of food borne pathogen (S. aureus and C. jejuni). Interestingly, the reduction is higher in the case of C. jejuni (∼4 log CFU/mL) with respect to the S. aureus (∼1.5 log CFU/mL), which indicates the higher antimicrobial potential for Gram-negative bacteria, and the reason is most presumably due to the variation in cell wall structure. Thus, the highly antioxidative and somewhat antimicrobial edible film could be useful for active food packaging applications. Zam (2019) evaluated the antioxidant activity of olive leaf extract-loaded chitosan and alginate coating used to enhance the shelf-life of sweet cherries. The increase in antioxidant activity was reported in the presence of the plant extract, and that in turn helps in retarding the ripening of the cherry, which also reflects on the significant retention of phenolic compounds and phytochemicals in the fruits compared to the uncoated counterpart.

Parallel studies demonstrated that introducing grape seed extract (GSE) incorporation imparted strong antimicrobial activity. Ternary blended matrices (Ramakrishnan et al., 2023). The GSE addition into the film matrix increased the DPPH and ABTS radical scavenging activity up to 30% and 70%, respectively. GSE is known for its strong antioxidant and antimicrobial activity (Sochorova et al., 2020). The antioxidant activity was higher in aqueous solution (ABTS) than in alcoholic (DPPH) counterpart, and that is owing to the solubility of the film and higher release of bioactive compound to impart antioxidant action (Anyiam et al., 2024). The inclusion of GSE also improved the antibacterial activity of the film, and the activity was superior in S. aureus than in Escherichia coli. It is already well known that the potent germicidal effectiveness exhibited by GSE towards Gram-positive bacterial strains, with the main compound responsible for this action is naringenin (Roy et al., 2023). The highly antioxidant and antimicrobial film-forming solution was used as a coating material for green chilli, and the results showed that the coating extends shelf life by about 3 weeks. The result was further confirmed from weight loss, texture and color change data of coated and uncoated green chilli.

Roy and Rhim (2020b) studied the antioxidant activity of the curcumin incorporated into various polysaccharide (agar, carrageenan and chitosan) based films. It has been reported that blending of curcumin imparts a potent free-radical scavenging capacity, which is indicated via DPPH (∼50%) and ABTS (∼95%) radical scavenging assay. Curcumin is a well-known antioxidant material, but the addition of 1 wt% of curcumin showed different antioxidant behaviour based on the polymer type, peaking within carrageenan structures and decreasing through agar and chitosan networks. The antioxidant action of bioactive components is reliant on many factors, and one of the key ones is release from the film matrix. The release of curcumin from the film totally complemented the antioxidant activity results. Even though curcumin is known for its antimicrobial action, the authors reported very little or no activity against E. coli and L. monocytogenes, which could be due to the lower amount of curcumin in the film. In another work, it has been reported that the incorporation of aloe vera extract in edible film significantly improved antioxidant activity and antimicrobial performance of the film (Mahajan et al., 2021). The film showed strong antimicrobial activity towards E. coli and distinct radical scavenging efficiency during both DPPH and ABTS evaluations. When frozen kulfi is packed with the edible functional film, it enhances the storage stability by reducing the oxidation and total microbial count compared to the unpacked counterparts.

In another study, a whey protein-based edible functional film was prepared by adding phytochemicals derived from bay leaf and sage plant extracts (Akcan et al., 2017). The antioxidant activity of the film showed superb improvement in the presence of the phytochemicals, which is due to the phenolic compounds. The strong antioxidant film was used for cooked meatball storage, and the results showed that the lipid oxidation was lowered and the shelf-life was extended, which was verified from the oxidative stability, sensory properties and consumer acceptability. Göksen et al. (2020) documented that incorporating phytochemicals from volatile plant oils (1,8-cineole) in the zein-nanofiber-based film prepared using the electrospinning method improved the antimicrobial performance profoundly. The antibacterial activity was observed against food-borne pathogens L. monocytogenes and S. aureus, and the film was used to preserve cheese. The application of films demonstrated a significant improvement in the shelf life of cheese slices by reducing the growth of Listeria, Staphylococcus and mesophilic bacterial growth. In another work, Aparicio-Fernández et al. (2018) investigated the antioxidant capacity of Prickly pear peel powder and aqueous extracts in a CMC-derived functional containment film. Elevated antioxidant activity and reducing power trends in the matrix were meaningfully enhanced in the presence of both peel powder and extract, which is anticipated to be due to the presence of various bioactive phenolic components, such as beta betacyanins and betaxanthins (Aparicio-Fernández et al., 2018).

Figure 2 details how the integration of phytochemicals (Essential Oils, Plant Extracts, and Natural Pigments) influences the biopolymer matrix response. It quantifies physical property shifts, such as increases in Young’s Modulus (YM) and reductions in Water Vapour Permeability (WVP). These modulations directly translate into advanced biological efficacies, including radical scavenging and microbial inhibition, ultimately enhancing food shelf life and enabling real-time freshness monitoring through intelligent sensing.

5 Food packaging applications

The successful implementation of phytochemical-loaded edible packaging depends on two main factors, which are the material’s physical design and its ability to release bioactive substances. Table 4 shows that active systems enable controlled delivery of phenolic compounds, terpenoid substances, and organic acids, which occurs at the food-packaging boundary. The phytochemicals function as scavengers for reactive oxygen species (ROS) while they also work to block microbial enzyme systems, which helps them to stop the metabolic and oxidative processes that cause food spoilage.

TABLE 4. Food applications and preservative mechanisms of phytochemical-loaded ECFs.

5.1 Fresh produce preservation

The post-harvest shelf life of fresh produce is primarily limited by ongoing cellular respiration, ethylene-driven maturation cascades, and moisture depletion through transpiration. To control these post-harvest degradation pathways, active biopolymeric frameworks are designed to establish a highly customized internal modified atmosphere around whole or fresh-cut commodities (Anyiam et al., 2024; Yousuf et al., 2021). Ramakrishnan et al. (2023) demonstrated that ternary active packaging systems formulated by blending sodium alginate, carboxymethyl cellulose (CMC), and starch can be successfully functionalized using grape seed extract (GSE) as a bioactive filler.

The addition of GSE altered the matrix hydrophilicity, consistently altering the water contact angle and improving the dispersion of polyphenolic compounds across the biopolymer arrangement. This supported the shelf-life extension of stored green chillies for up to 3 weeks. This coloration functioned as a natural UV filter due to aromatic polyphenols, protecting vitamins and pigments from photodegradation—particularly relevant for green chillies. Murgia et al. (2024) demonstrated that GSE can be successfully applied to protect highly perishable edible mushroom crops (Pleurotus eryngii) from bacterial yellowing and subsequent crop decay. This specific bacteriosis, primarily driven by Pseudomonas fluorescens and Pseudomonas aeruginosa, manifests as small yellow or light brown spots on the cap accompanied by water-rich coalescing areas on the stem that rapidly lead to total rot and severe financial losses. When a non-synthetic GSE solution containing natural citrus flavonoids like naringin and naringenin is atomized on the growth substrate surface at a target concentration of 52,000 μ g / mL across a 20-day cycle spanning pre- and post-sprouting phases, it completely blocks bacterial infection. Treated mushrooms show a 0% bacterises rate while fully maintaining standard commercial parameters in appearance, size, and color. The powerful bactericidal efficiency of GSE relies heavily on non-flavonoid phenolic fractions rather than naringin alone, which operates synergistically to compromise cell survival (Oz and Kafkas, 2017; Han et al., 2021).

Pomegranate peel extract (PPE) has emerged as one of the most potent phytochemical agents for fresh produce preservation, primarily due to its exceptionally high concentration of punicalagins and ellagic acid—hydrolysable tannins that demonstrate potent antifungal and antioxidant activity. Vicente Bertolo et al. (2025) demonstrated that a chitosan/gelatin matrix functionalized with PPE, applied via a simple dipping technique, improved the physicochemical, microbiological, and sensory quality of stored strawberries while significantly delaying fungal contamination by 6–8 days. The coating formed a coherent thin film on the fruit surface that acted simultaneously as a physical barrier against moisture loss and gas exchange, thereby slowing cellular respiration and delaying post-harvest senescence.

The strawberries treated with PPE-functionalized coatings exhibited only 11% weight loss over 12 days of refrigerated storage, compared to substantially higher losses in uncoated controls, while retaining significantly higher ascorbic acid content and overall consumer acceptability. The antifungal mechanism of PPE operates through the disruption of fungal cell membrane integrity by punicalagin-derived phenolics, which chelate metal ions essential for enzymatic function and intercalate into the phospholipid bilayer of pathogenic fungi such as Botrytis cinerea and Penicillium expansum (de Almeida Soares and de Aquino Santana, 2023). At the molecular level, the ellagitannin fraction of PPE also acts as a strong competitive inhibitor of polygalacturonase, the key cell wall-degrading enzyme responsible for tissue softening during over-ripening, thus contributing to superior firmness retention in coated fruit (de Almeida Soares and de Aquino Santana, 2023). This multi-target inhibitory activity, combined with the valorization potential of pomegranate rind as an agri-food processing by-product, makes PPE a highly attractive functional additive for active produce packaging.

Curcumin, the principal polyphenolic curcuminoid extracted from the rhizome of Curcuma longa, represents another versatile phytochemical with multifunctional activity in fresh produce coatings (Roy and Rhim, 2020b). In practical applications, curcumin has been incorporated into biopolymeric matrices to coat climacteric fruits such as mango and tomato, where it effectively retards respiration-driven senescence and suppresses growth of common fungal pathogens, including Aspergillus niger and Colletotrichum gloeosporioides. Karnwal et al. (2025) demonstrated that a 1.5% chitosan coating enriched with turmeric extract significantly reduced weight loss and maintained tissue firmness in mango during storage, with the curcuminoid fraction providing UV-shielding functionality that protected photosensitive pigments like beta-carotene and chlorophyll from light-induced degradation. The UV-blocking mechanism of curcumin arises from its strong chromophore at 420–430 nm, which absorbs the energy-rich wavelengths responsible for initiating oxidative degradation of surface pigments and vitamins.

Furthermore, a light-responsive thermally controlled curcumin-releasing packaging film based on chitosan and copper-modified cellulose (CS/CMC) was developed by Luo et al. (2025), and oranges treated with this system exhibited a longer shelf life and reduced nutrient loss compared to conventional polyethylene packaging, confirming that controlled photodynamic release of curcumin generates in situ antimicrobial activity at the food surface without compromising eating quality. The major technical challenge associated with curcumin in aqueous biopolymer systems is its inherent hydrophobicity, which causes aggregation and phase separation; this is effectively resolved through nanoencapsulation within β-cyclodextrin or zein-based nanoparticles, which improve its aqueous dispersibility and increase bioactive retention in the film matrix by up to 30% (Roy and Rhim, 2020b).

Oregano essential oil (OEO), whose principal bioactive constituent is the phenolic monoterpenoid carvacrol (present at 60%–74%), represents one of the most potent terpenoid-class phytochemicals for active produce coatings and vapor-phase applications. The amphiphilic structure of carvacrol, bearing both a phenolic hydroxyl group and a hydrophobic isopropyl moiety, allows it to partition efficiently into the lipid bilayers of microbial cell membranes, disrupting membrane fluidity, dissipating the proton-motive force, and causing leakage of intracellular ATP, which establishes broad-spectrum germicidal activity against both Gram-positive and Gram-negative spoilage organisms (Matloob et al., 2023). Pirozzi et al. (2020) developed alginate-based edible coatings incorporating OEO nanoemulsions and applied them to tomatoes stored at ambient temperature (20 °C) for 14 days. The OEO nanoemulsion-functionalized coating successfully reduced total microbial load, yeast, and mold counts throughout storage, significantly outperforming plain alginate coatings and demonstrating that nanoemulsification is essential for achieving uniform dispersion of the hydrophobic essential oil within an aqueous polysaccharide matrix.

5.2 Meat and poultry preservation

The primary method to preserve meat involves preventing oxidation processes which damage lipids and proteins and lead to rancidity and off-odors and unappealing browning. The research conducted by Antonino et al. (2024) demonstrated that red meat films which contained botanical additives derived from sage, rosemary, or green tea significantly advanced contemporary meat preservation frameworks. These plant fractions concentrate active components like carnosic acid along with epigallocatechin gallate (EGCG) which function as antioxidants that terminate oxidation chain reactions by donating hydrogen atoms to lipid radicals. Active films maintain TBARS levels in beef patties below the sensory threshold of 0.5 mg MDA/kg for 14 days when stored in refrigeration. The films need mechanical integrity to endure proper vacuum packaging and package handling procedures. Keawpeng et al. (2022) revealed that mixing clove oil with mung bean flour films resulted in a packaging with high antimicrobial potential which achieved a 4-log reduction in C. jejuni presence on meat surfaces. Akcan et al. (2017) found that whey protein coatings which contained Laurus nobilis L. and Salvia officinalis succeeded in reducing thiobarbituric acid (TBA) levels in cooked meatballs. The coatings created by Moghadas et al. (2024) and Díaz-Montes and Castro-Muñoz (2021) showed that when they used camellia oil or plant antimicrobials to load carrageenan and alginate coatings, they effectively reduced total aerobic plate counts by 3-log. The coatings stop “drip loss” which allows the meat to maintain its inner moisture content during cooking, thus improving its final taste quality.

Poultry meat serves as a common transmission route for pathogens which include both Salmonella and Listeria monocytogenes. Moghadas et al. (2024) described research which showed that chicken fillets received a coating treatment using konjac glucomannan or carrageenan emulsions that were infused with camellia oil. The application resulted in a 3-log decrease in total aerobic plate count values. The phytochemicals present in camellia oil disrupt microbial enzyme systems which block the pH increase that occurs when bacteria start to break down proteins. Chen et al. (2023) used plum peel anthocyanins with alginate/gelatin films to create “intelligent” preservation systems that protected food through better preservation methods. The films functioned as two separate systems which delivered an outstanding water vapor barrier to maintain chicken breast moisture while serving as a pH-based colorimetric system to conduct fresh food assessments during their entire duration.

Phytochemical substances which are added to films directly affect their capacity to control water vapor movement through them. Chen et al. (2023) and Keawpeng et al. (2022) discovered that clove oil essential oil enhanced WVP through its water-repellent properties whereas certain extracts produced higher permeability when they contained extreme water-attracting characteristics. The proper moisture balance in poultry operations is essential because excessive moisture loss results in “drip loss” which depletes product weight as it creates an environment that promotes bacterial growth. The researchers developed a moisture-sealing “skin-tight” coating through optimal phytochemical loading which maintained moisture protection while delivering antimicrobial substances to disinfect all surfaces.

5.3 Seafood preservation

The quick spoilage of seafood occurs because it contains neutral pH and high moisture content along with autolytic enzymes. The research conducted by investigators like Díaz-Montes and Castro-Muñoz (2021) alongside Wu coworkers (2023a) demonstrated that sodium alginate and chitosan coatings which contained plant-derived antioxidants effectively delayed the accumulation of total volatile basic nitrogen (TVB-N) within marine matrices. This generic chemical marker indicates the breakdown pathways of flesh proteins which produces volatile nitrogenous bases that create the typical “fishy” smell. Han et al. (2023) created smart carrageenan-derived matrices that combined curcumin inside a complex of zein and EGCG. The films showed better thermal stability and ultraviolet light protection because they served a vital function in preventing fish lipids from photo-oxidation during retail display. The aesthetic issue of “melanosis” which causes black spot formation constitutes the main problem during shrimp preservation. Santos et al. (2022) showed that anthocyanin-enriched films functioned as a gas-sensing system for shrimp while the films enriched with grape seed or green tea extracts worked as effective inhibitors of PPO. The coatings maintain the pink color of shrimp for an extended period of 3–5 days compared to uncoated shrimp samples. Moghadas et al. (2024) noted that linseed oil integrated into chitosan films creates an outstanding moisture barrier which protects against freezer burn and dehydration, which particularly benefits frozen fish fillets.

5.4 Dairy preservation

The dairy field adopts active coatings as protection against both surface mold growth and oxidation damage. Mahajan et al. (2021) studied the use of Aloe vera films with fig powder enhancement to create packaging materials for kulfi which is an authentic frozen dessert. The film’s antimicrobial and antioxidant performance improved significantly because of the phytochemicals in fig powder which resulted in total microbial counts and lipid oxidation that decreased more than what unpacked controls showed. Göksen et al. (2020) used electro-spun zein nanofiber films which contained 1,8-cineole essential oil to create a preservation method for cheese slices. The active film successfully stopped any spoilage of Listeria monocytogenes and Staphylococcus aureus through its effective action during the entire period of frozen storage. Liquid dairy products make smart packaging systems their main innovation of today’s era. Santos et al. (2022) and Zheng et al. (2022) investigated the potential of anthocyanins from Clitoria ternatea and black wolfberry to function as pH-based indicators. The phytochemicals when used with alginate or chitin-whisker matrices become useful for tracking milk freshness through real-time monitoring. The anthocyanins undergo a distinct color change when lactic acid builds up in the milk spoilage process which serves as a visual sign for consumers to observe. Roy and Rhim (2020c) demonstrated that shikonin and propolis extract work effectively in gelatin/carrageenan films to assess milk freshness while providing a dark red pigment that functions as a powerful UV light blocker, preventing oxidation of milk fats and vitamins.

5.5 Bakery product preservation

The bakery sector benefits from phytochemical-enriched edible films because these films solve three main problems comprising texture staling via amylose retrogradation, localized moisture migration across distinct product components, and fungal spoilage triggered by strains like Aspergillus niger or Rhizopus stolonifer. Bakery products differ from fruits or meats because their porous and hygroscopic nature requires the film’s barrier properties to protect their texture. Mariño-Cortegoso et al. (2025) found that active films function as “clean-label” substitutes for chemical preservatives such as calcium propionate which modern consumers now prefer to avoid. The implementation of volatile phytochemicals stands out as one of the most effective methods.

The studies of Mariño-Cortegoso et al. (2025) and Wu et al. (2023) showed that essential oil-loaded films which contain volatile plant fractions like clove, cinnamon, or oregano extracts generate active gaseous envelopes that diffuse into the surrounding packaging atmosphere. This gas-phase suppression mechanism is highly suited for highly porous matrices (Shu et al., 2025) like pre-sliced loaves because its active agents can enter through the irregular crumb surface. According to experimental results, films containing 1%–2% clove oil extend white bread’s mould-free shelf life by 5–7 days when stored in high-humidity environments. The essential oils disrupt fungal cell walls, which leads to the prevention of spores from germinating, thus halting the spoilage process. Products will experience moisture migration, which begins when the high-water-activity filling transfers moisture to the low-water-activity crust, resulting in an exterior that becomes soggy and an interior that remains dry.

The research of Wu et al. (2023) demonstrated that protein-based coatings, utilising whey or soy protein and hydrophobic phytochemicals such as nutmeg oil or sunflower oil, provide an exceptional moisture barrier. The coatings act as an internal “hydrophobic shield” that safeguards the pastry’s “crunch” texture while preserving the filling’s juiciness. Bakery products use optical properties to achieve their preservation goals. Mariño-Cortegoso et al. (2025) proposed that edible coatings serve as delivery systems for heat-sensitive phytochemicals, which include certain polyphenols and vitamins, to the bread surface after baking is complete. The packaging serves as a functional component of food, preserving it while boosting its nutritional content. Figure 3 demonstrates the specific preservative mechanisms of phytochemical-loaded films or coatings across major food types. It highlights critical biological effects, including ROS scavenging, microbial enzyme inhibition, and control of modified atmosphere. Quantifiable outcomes are summarised, such as TBARS maintenance in red meat, TVB-N delay in fish, and vapour-phase mould inhibition in bakery products.

6 Conclusion and future perspectives

The progress in phytochemical-enriched edible films and coatings represents an innovative approach in the development of sustainable packaging and the global food supply chain. By leveraging the inherent bioactivity of plant extracts, researchers have developed materials that effectively mitigate the primary spoilage factors: microbial growth and oxidation. The valorization of agri-food waste—converting residues like pomegranate peels and carrot waste into active fillers—not only supports the circular economy but also provides a cost-effective route for high-value packaging. Commercial scale-up, however, requires overcoming technical challenges in scaling hot-melt extrusion and electrospinning while preserving the bioactivity of thermally sensitive botanical modifiers. The phytochemical-infused edible packaging is beneficial for enhancing fresh or processed food shelf life and enabling real-time freshness monitoring of food through intelligent sensing.

Upcoming investigations must focus on advanced stabilization techniques, including nanoencapsulation within nanostructured lipid carriers, to protect active compounds during high-heat processing. Additionally, engineering multifunctional intelligent systems integrating bioactive layers with electronic components like RFID tags marks an essential evolution in data-driven quality assessment. Market adoption ultimately requires adherence to global regulatory standards ensuring all components achieve Generally Recognized as Safe (GRAS) status. Continued synergy among material researchers, engineers, and microbiologists is required to harmonize such innovations with market trends prioritizing green, ‘clean-label’ commodities that maintain global food safety standards.

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Footnotes

Edited by: Mehran Moradi, Urmia University, Iran

Reviewed by: Slim Smaoui, Centre of Biotechnology of Sfax, Tunisia

Khashayar Sarabandi, Research Institute of Food Science and Technology (RIFST), Iran