Active Packaging Applications Research Articles

Development of active films with thymol-based hydrophobic eutectic solvents

Thymol, known for its antimicrobial properties, was combined with acetic acid, betaine, and caprylic acid to form hydrophobic natural eutectic solvents (NAES), whose influence on the properties of bovine gelatin films was investigated. Films showed enhanced mechanical performance and a clear plasticizing effect provided by the natural eutectic solvents. At 300 wt% concentration, tensile strength and elongation at break reached 871 ± 78 kPa and 141 ± 10 % for acetic acid, 391 ± 41 kPa and 159 ± 10 % for betaine, and 1209 ± 52 kPa and 198 ± 15 % for caprylic acid. Water vapor permeability and total soluble matter were reduced, and swelling decreased to ~250 %, ~150 %, and ~ 200 % for films with 300 wt% of acetic acid, betaine, and caprylic acid, respectively. Pure thymol exhibited significant volatility, with 17.10 ± 1.50 % weight loss over one week, while the NADES demonstrated dramatically reduced losses (up to 1.15 ± 0.04 %). The films displayed exceptional antibacterial activity, achieving inhibition diameters of 34 mm against Gram-positive and Gram-negative bacteria, and films with caprylic or acetic NAES achieved undetectable CFU levels for major pathogens on chicken breast. These results highlight the antimicrobial potency and enhanced stability of NAES-based gelatin films for active packaging applications.

Development of carboxymethyl cellulose/starch films enriched with ZnO-NPs and anthocyanins for antimicrobial and pH-indicating food packaging

Active packaging, which can monitor food freshness and extend the shelf life, has gained significant attention in recent years. This study aims to develop a novel carboxymethyl cellulose (CMC)/starch/anthocyanins/ZnO active films with enhanced properties and specific functionalities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that the addition of anthocyanins and nano-ZnO particles (ZnO-NPs) led to heterogeneous microstructures and a slight decrease in the crystallinity. Fourier transform infrared spectroscopy (FTIR) indicated that there were no chemical interactions among film components. Active films containing ZnO-NPs exhibited improved ductility, as well as enhanced light barrier and water resistance properties. Notably, a shift from hydrophilic to hydrophobic behavior of the films was observed with high ZnO-NP content, as evidenced by a significant increase in the water contact angle (from 63.44° to 114.22°). Furthermore, the presence of only 1 % ZnO-NPs resulted in efficient inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth. Moreover, active films containing both anthocyanins and ZnO-NPs were highly sensitive to pH changes in buffer solutions (pH 2–11). Based on the results, a recommended film formulation for future active packaging applications is a 80:20 CMC/starch blend with 3 % ZnO-NPs and 0.1 g anthocyanins.

Review: clay-based ethylene scavengers for sustainable active packaging applications

Review: clay-based ethylene scavengers for sustainable active packaging applications

Xanthan/ carboxymethyl cellulose-based edible coatings enriched with greenly synthesized ZnO-NPs for active packaging applications

The limited use of xanthan (Xa) and carboxymethyl cellulose (CMC) in the food packaging industry is due to their poor barrier and antimicrobial properties. The objective of this work was to enhance the characteristics of the CMC/Xa composite coating by incorporating ZnO nanoparticles (ZnO-NPs) that were prepared through a green method through Coriandrum sativum extract. FTIR and XRD confirmed the successful preparation of the coating and verified the interactions between its components. Compared to the neat CMC/Xa system, systems incorporated with ZnO-NPs exhibited excellent water barrier, mechanical, thermal, and antimicrobial characteristics. The CMC/Xa/ZnO-NP systems effectively prolonged the shelf life of tomatoes for a storage period of 20 days without any significant indications of spoilage or mass loss of the coated tomatoes. The obtained results indicated that the developed coating has the potential to replace traditional plastic packaging and effectively preserve food products.

Fabrication of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/ZnO Nanocomposite Films for Active Packaging Applications: Impact of ZnO Type on Structure-Property Dynamics.

Bio-based and biodegradable polyhydroxyalkanoates (PHAs) have great potential as sustainable packaging materials. The incorporation of zinc oxide nanoparticles (ZnO NPs) could further improve their functional properties by providing enhanced barrier and antimicrobial properties, although current literature lacks details on how the characteristics of ZnO influence the structure-property relationships in PHA/ZnO nanocomposites. Therefore, commercial ZnO NPs with different morphologies (rod-like, spherical) and silane surface modification are incorporated into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) via extrusion and compression molding. All ZnO NPs are homogeneously distributed in the PHBHHx matrix at 1, 3 and 5 wt.%, but finer dispersion is achieved with modified ZnO. No chemical interactions between ZnO and PHBHHx are observed due to a lack of hydroxyl groups on ZnO. The fabricated nanocomposite films retain the flexible properties of PHBHHx with minimal impact of ZnO NPs on crystallization kinetics and the degree of crystallinity (53 to 56%). The opacity gradually increases with ZnO loading, while remaining translucent up to 5 wt.% ZnO and providing an effective UV barrier. Improved oxygen barrier and antibacterial effects against S. aureus are dependent on the intrinsic characteristics of ZnO rather than its morphology. We conclude that PHBHHx retains its favorable processing properties while producing nanocomposite films that are suitable as flexible active packaging materials.

Novel copper-based metal–organic skeleton smart tags that respond to ammonia for real-time visual freshness monitoring of shrimp

In recent years, an amount of attention has been paid to natural pigment-based pH/ammonia-responsive colorimetric smart labels in the field of real-time visual food freshness monitoring. However, the drawbacks of natural pigments, such as complicated extraction processes, poor photostability, and easy inactivation, have severely limited their application in smart packaging. In this research, natural pigments were replaced with copper-based metal–organic frameworks (Cu-MOF) to serve as ammonia-responsive indicators. It attained the benefits of excellent mechanical qualities, high photostability, and greenness. The changes of ΔE values of the smart label composite films of starch/polyvinyl alcohol (PVA)/Cu-MOF were less than 4.8 after being placed in a constant temperature and humidity environment for 40 d, indicating that they have excellent color stability. Within an atmosphere of 0.8 mM ammonia, the composite film can produce a significant color change from teal green to deep blue in 1 min, indicating that the film has ammonia sensitivity. The composite film, in addition, successfully monitored the changes in shrimp freshness at temperatures of 4 °C and 28 °C, effectively prolonging the shelf life of the shrimp. Therefore, starch/ PVA/Cu-MOF composite films have good prospects for smart and active packaging applications.

Preparation of the double cross-linking carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film for food active packaging application

This paper prepared a new kind of carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film with antibacterial properties. Carbon dots and citric acid were used as cross-linking agents, and polyvinyl alcohol and carboxymethyl cellulose were used as matrices respectively. The mechanical properties, UV shielding performance, thermal stability, antioxidant capability, and antibacterial activities of the carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film were researched. The prepared carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film was applied in the strawberry freshness preservation test. And test results indicated that the carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film could prevent rotting and extend the shelf life of strawberries. This carbon dots-polyvinyl alcohol-carboxymethyl cellulose composite film could be applied in the food active packaging field.

Carboxymethyl cellulose/gelatin film incorporated with eggplant peel waste-derived carbon dots for active fruit packaging applications

Carbon dots (CDs) were derived using eggplant peel by a hydrothermal approach and incorporated into the carboxymethyl cellulose (CMC) and gelatin (Gel) blend to develop sustainable and functional packaging films for fruit preservation. The CD was uniformly dispersed within the CMC/Gel blend to form a dense and continuous film and fashioned a strong interaction with the polymer chain, increasing the tensile strength of the film by 5.0–16.0 %. Also, with the impregnation of CDs, the UV-blocking potential of the CMC/Gel film was greatly improved to the extent of blocking 94.3 % of UV-B and 72.5 % of UV-A, while the water vapor permeability slightly decreased (by 2.7–5.4 %), and the water contact angle of the film marginally expand (by 6.2–19.1 %). The CMC/Gel film with 3 wt% of CD added depicted strong antioxidant efficacy of 100 % against ABTS and 59.1 % against DPPH and displayed strong antibacterial action that inhibited the progress of Listeria monocytogenes and Escherichia coli by 99.8 %. In addition, when table grapes were packaged using a CMC/Gel composite film containing CD and stored at 4 °C for 24 days, the fruits packed with the composite film maintained excellent external quality and extended the shelf life.

Polycaprolactone (PCL)-based films integrated with hairy cellulose nanocrystals and silver nanoparticles for active Tilapia packaging applications

The migration of metal ions to the food matrix has been always a challenge in the production of active food packaging films. In this study, it was tried to evaluate the idea of using hairy cellulose nanocrystals (HCNs) in controlling the migration of Silver Nanoparticles (AgNPs) from polycaprolactone (PCL)-based films to the Tilapia fish. HCNs and the final films (integrated with various amounts of HCNs and AgNPs) were evaluated physicochemically and mechanically. Tilapia fish were packed using the films and after specific periods, the fish samples were assessed microbiologically and physiochemically. According to the results, incorporating NPs into PCL films enhanced tensile strength, elasticity, and toughness making the films more resistant to breakage and deformation under stress. The introduction of HCNs reduced the surface roughness level, decreasing AgNPs migration, but also accelerated the degradation rate. Films with [1% AgNPs +2% HCNs] and [1% AgNPs] had the lowest and highest water vapor transmission rate. The use of AgNPs (1%) + HCNs (2%) incorporated into PCL films resulted in a lower pH value, TVB-N, TBARs, and PV. It also decreased microbial activities in samples in comparison to the control. Therefore, the idea of using HCNs along with antibacterial metal-based nanoparticles can control the rate of ion migration.

Development of biocomposite films incorporated with the extract from pitcher associated bacteria for the postharvest protection from fungi.

Pythium aphanidermatum is known to cause diseases likedamping-off, root rot, stem rot and fruit rot in a wide range of plants. Eventhough many chemical methods have been demonstrated to have the potential to manage these diseases, their benefits are being offset equally by the negative side effects. Therefore, the control of Pythium spp. using natural antifungal agents is of immense significance due to its environmental safety. Here, the plant associated microorganisms with antifungal metabolites have significant promises to be explored both as sustainable biocontrol agents and also as active constituents of antifungal materials. Antimicrobial packaging films prepared using such components can have significant applications to meet the requirements to prevent postharvest loss of agricultural produce by inhibiting the fungal growth. Eventhough there are reports on the development of antimicrobial packaging films for such applications, the use of bacterial extracts with antifungal activity for the same is least investigated. Hence, the present study demonstrates the development of biocomposite films prepared using polyvinyl alcohol (PVA) incorporated with the extracts prepared from bacterial isolates (Serratia sp. NhPB1, Kocuria sp. NhPB49, and Pantoea dispersa NhPB54) previously isolated from the pitcher plant. Here, the individual films were prepared by incorporating 1mL of bacterial extract in 40mL of 3% PVA solution and the developed films were then subjected to antifungal activity screening against P. aphanidermatum. The antifungal activity analysis of the films prepared with the incorporation of extracts from Serratia sp. NhPB1, Kocuria sp. NhPB49, and Pantoea dispersa NhPB54 showed remarkable activity against the tested pathogen. The application of biocomposite films on Solanum lycopersicum and Capsicum annuum fruits for its protection from P. aphanidermatum by dip coating method further indicates the promises of developed biocomposite films for active packaging applications.

Fabrication and characterisation of electrospun zein‐based fibres functionalised by caffeic and p‐coumaric acid for potential active packaging applications

SummaryThis study focused on the fabrication of zein‐based coatings functionalised by two phenolic acids, caffeic acid (CA) and p‐coumaric acid (pCA), using electrospinning. The electrospun fibres were fabricated with three different concentrations (5%, 10% and 20% w/w) of CA and pCA individually. The average fibre diameter (AFD) increased due to the addition of phenolic acids. Thermogravimetric analysis (TGA) revealed that degradation temperatures of the zein electrospun fibres were not significantly affected (P > 0.05) after the incorporation of CA and pCA. Meanwhile, interactions between zein and the phenolic acids were indicated by surface characterisation. CA‐loaded zein electrospun fibres exhibited increasing antioxidant activity with increasing CA concentration. Both phenolic acid‐loaded zein electrospun fibres displayed favourable antibacterial activities against S. aureus and E. coli foodborne pathogens. Overall, zein electrospun fibres with 20% w/w CA demonstrated the most desirable properties for potential active food packaging application.

Physico-Chemical Characteristics of pH-Driven Active Film Loading with Curcumin Based on the Egg White Protein and Sodium Alginate Matrices.

The low solubility and stability of fat-soluble curcumin in water limit its application in active packaging. This study explored the use of a pH-driven method to investigate the preparation and enhancement of the performance of films loaded with curcumin in a matrix of sodium alginate (Alg) and egg white protein (EWP). In this study, the EWP, Alg, and curcumin primarily bind through hydrogen bonding, electrostatic interactions, and hydrophobic interactions. Compared to EWP films, the films loaded with curcumin through the pH-driven method exhibited enhanced extensibility and water resistance, with an elongation at break (EB) of 103.56 ± 3.13% and a water vapor permeability (WVP) of 1.67 ± 0.03 × 10-10 g·m/m2·Pa·s. The addition of Alg improved the encapsulation efficiency and thermal stability of curcumin, thereby enhancing the antioxidant activity of the film through the addition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, which resulted in 106.95 ± 2.61 μg TE/g and 144.44 ± 8.89 μg TE/g, respectively. It is noteworthy that the detrimental effect of Alg on the color responsiveness of films containing curcumin has also been observed. This study provides a potential strategy and consideration for the loading of low water-soluble active substances and the preparation of active packaging.

Periodate oxidation of nanofibrillated cellulose films for active packaging applications

An alternative packaging material based on cellulose that possesses excellent barrier properties and is potentially useful for active packaging has been developed. Cellulose nanofibril was efficiently and selectively oxidized with sodium periodate generating reactive aldehyde groups. These groups formed hemiacetal and hemialdal bonds during film formation and, consequently, highly transparent, elastic and strong films were created even under moisture saturation conditions. The periodate oxidation treatment additionally decreased the polarity of the films and considerably enhanced their water barrier properties. Thus, the water contact angle of films treated for 3 and 6 h was 97° and 102°, their water drop test value was higher than in untreated film (viz., 138 and 141 min with 3 and 6 h of treatment) and their water vapour transmission rate was substantially better (3.31 and 0.78 g m−2 day−1 with 3 and 6 h, respectively). The presence of aldehyde groups facilitated immobilization of the enzyme laccase, which efficiently captures oxygen and prevents food decay as a result. Laccase-containing films oxidized 80 % of Methylene Blue colorant and retained their enzymatic activity after storage for 1 month and 12 reuse cycles, opening the door to the possible creation of a reusable packaging to replace the single-use packaging.

Olive stone as a filler for recycled high-density polyethylene: A promising valorization of solid wastes from olive oil industry

The valorization of solid residues generated from olive oil production is a challenging issue for olive oil-producing countries such as Greece, Italy, Spain, etc. Olive stone waste is a type of lignocellulosic biomass with potential use as a natural additive in polymeric composites. In the present study, olive stone waste was compounded with recycled high-density polyethylene (rHDPE) via melt mixing in 5 %, 10 %, and 20 % wt. Additionally, the effect of Joncryl (JC) and polyethylene-grafted maleic anhydride (PE-g-MA) as compatibilizers on the properties of the green composites was also investigated. It is worth mentioning that JC was employed for the first time as a compatibilizer for polyolefin composites with olive stone. The materials underwent structural, thermal, and mechanical characterization using multiple complementary techniques. Scanning electron microscopy showed good dispersion of the filler for all composites, while in the compatibilized samples a markedly better adhesion was observed. Tensile tests revealed an increase in the elastic modulus for the composite with 10 % wt. olive stone. Furthermore, all materials demonstrated a strong antioxidant activity, rendering them interesting for active packaging applications. Overall, the solid residue from olive processing can enhance the properties of rHDPE, paving the way to promote circular economy.

Improving structural and functional properties of starch-catechin-based green nanofiber mats for active food packaging by electrospinning and crosslinking techniques

The hydrophilic and low mechanical properties limited the application of starch-based films. In this work, a hydrophobic starch-based nanofiber mat was first successfully prepared from aqueous solution at room temperature by using electrospinning and glutaraldehyde (GTA) vapor phase crosslinking techniques for active packaging applications. Catechin (CAT) was immobilized in the nanofibers by electrospinning, resulting in higher thermal stability (Tdmax = 315.23 °C), antioxidant (DPPH scavenging activity = 94.31 ± 2.70 %) and antimicrobial (inhibition zone diameter = 15.6 ± 0.3 mm) of the fibers, which further demonstrated hydrogen bonding and electrostatic interaction between CAT and fibers. Nanofibers after GTA vapor phase crosslinking exhibited enhanced hydrophobicity (water contact angle: 15.6 ± 1.5° → 93.5 ± 2.3°) and mechanical properties (tensile strength: 1.82 ± 0.06 MPa → 7.64 ± 0.24 MPa, elastic modulus: 19.35 ± 0.63 MPa → 45.34 ± 0.51 MPa). The results demonstrated that preparation of starch-based electrospun nanofiber mats in aqueous system at room temperature overcame the challenges of organic solvent pollution and thermosensitive material encapsulation, while GTA vapor phase crosslinking technique improved the hydrophobicity and mechanical properties of nanofiber mats, which facilitated the application of starch-based materials in the field of packaging.

Development, characterization and application of colorimetric active packaging based on soy protein isolate, trehalose and Oxalis triangularis extract

Colorimetric active packaging based on soy protein isolate (SPI)/trehalose (TRE) and Oxalis triangularis extract (OTE) was developed for monitoring pork spoilage and preserving Actinidia arguta. The formation of intermolecular hydrogen bonds among TRE, OTE, and the SPI matrix resulted in a more compact film structure and improved mechanical, barrier and water resistance properties. The addition of OTE greatly increased the antibacterial and antioxidant activities of the films. The stability of the films improved due to their dense network structure and good barrier and antioxidant capacity. Among all samples, SPI films containing both TRE and OTE (ST-OTE) exhibited the best barrier and mechanical properties after 45 days of storage and maintained a high level of antioxidant activity after heating and UV irradiation. SPI-OTE and ST-OTE films showed good pH sensitivity and responsiveness and exhibited visible color changes during the monitoring of pork spoilage. Compared to the control group, ST-OTE effectively prolonged the storage period of A. arguta.

CURRENT STRATEGIES FOR THE USE OF ACTIVE PACKAGING IN FOOD PRODUCTS

Food quality and safety is one of the most important aspects of the food industry. One of the key factors to ensure food safety is packaging. Increasing number of food packaging materials is creating a demand for promoting products and brands that are safe for consumption. Food spoilage due to poor quality packaging causes huge loss not only to businesses but also to consumers. Despite the effectiveness of existing practices, retailers still face many challenges, including the materials used and their possible interaction with food. In addition, the transfer of harmful materials from packaging materials to food is still an issue. It is important to use the right material for the right type of product. This review discusses the recent research on the application of active packaging used in various types of food packaging to enhance the safety performance and shelf life of various food products by using antifungal peptides, ethanol and plant extracts. This is in response to consumer demand for preservative-free products as well as more natural, disposable, biodegradable and recyclable food packaging materials.

A comparison of the antioxidant properties of two different Brazilian propolis

Propolis is a resinous substance of complex chemical composition, varied color and consistency, with high antioxidant potential. This study aimed to investigate the content of phenolic, flavonoids, condensed tannins, and antioxidant potential present in two kinds of propolis: green propolis (GP) (Apis mellifera), and Mandaçaia propolis (MP) (Melipona quadrifasciata anthidiodes), through ultrasound-assisted extraction by three different methods. All extraction methods used equal propolis mass/solvent volume ratio. The EA method kept the mixture under stirring solvation (25 °C/48 h), and the mixture was submitted to sonication (1 h). The second EB method was performed by sonication (1 h) before solvation (25 °C/48 h) and again sonication (30 min). The third EC method was sonicated with a cell disruption ultrasonic probe (10 min), followed by stirring solvation (25 °C/1h). Related to the phenolic content and antioxidant activity, the GP extracts obtained for methods EA and EC were similar. In contrast, the EA method was more effective for MP extracts. In addition, the results indicated a diversified phenolic profile for the extracts obtained highlighting: 3,4-dihydroxybenzoic, caffeic, p-coumaric acids, myricetin, kaempferol, and catechin for the GP extracts. In contrast, MP extracts highlighted: ellagic, vanillic, caffeic acids, myricetin, kaempferol, and hesperetin. The EA method is the most cost-effective, especially for Mandaçaia propolis extracts, while the EC method is recommended when time efficiency is a priority. The results obtained will promote advanced studies to evaluate the antioxidant effect of propolis extracts in pharmaceutical and food industries, such as active packaging, capsules, and other possible applications of this important bioactive material.

Low-Density Polyethylene-Based Novel Active Packaging Film for Food Shelf-Life Extension via Thyme-Oil Control Release from SBA-15 Nanocarrier.

The use of natural raw substances for food preservation could provide a great contribution to food waste reduction, circular economy enhancement, and green process application widening. Recent studies indicated that the use of porous materials as adsorbents for natural essential oils provided nanohybrids with excellent antioxidant and antimicrobial properties. Following this trend in this work, a thymol oil (TEO) rich SBA-15 nanohybrid was prepared and characterized physiochemically with various techniques. This TEO@SBA-15 nanohybrid, along with the pure SBA-15, was extruded with low-density polyethylene (LDPE) to develop novel active packaging films. Results indicated that TEO loading was higher than other porous materials reported recently, and the addition of both pure SBA-15 and TEO@SBA-15 to the LDPE increased the water/oxygen barrier. The film with the higher thyme-oil@SBA-15 nanohybrid content exhibited a slower release kinetic. The antioxidant activity of the final films ignited after 48 h, was in the range of 60-70%, and was almost constant for 7 days. Finally, all tests indicated a sufficient improvement by the addition of thyme-oil@SBA-15 nanohybrids in the pure LDPE matrix and the concentration of wt. 10% of such nanocarriers provided the optimum final LDPE/10TEO@SBE-15 active packaging film. This material could be a potential future product for active packaging applications.

Development of antimicrobial starch-based composite films reinforced with soybean expeller for sustainable active packaging applications.

The online version contains supplementary material available at 10.1007/s10068-023-01516-6.