Active antioxidant packaging films: Development and effect on lipid stability of brined sardines

Exploring the Therapeutic Potential of Terpenoids for Depression and Anxiety

This review focus on the terpenoids as potential therapeutic agents for depression and anxiety disorders, which naturally found in a variety of plants and exhibit a wide range of biological activities. Among the terpenoids discussed in this review are α-pinene, β-caryophyllene, α-phellandrene, limonene, β-linalool, 1, 8-cineole, β-pinene, caryophyllene oxide, p-cymene, and eugenol. All of these compounds have been studied extensively regarding their pharmacological properties, such as neuroprotective effect, anti-inflammation, antibacterial, regulation of neurotransmitters and antioxidant effect. Preclinical evidence are reviewed to highlight their diverse mechanisms of action and therapeutic potential to support antidepressant and anxiolytic properties. Additionally, challenges and future directions are also discussed to emphasize therapeutic utility of terpenoids for mental health disorders. Overall, this review provides a promising role of terpenoids as novel therapeutic agents for depression and anxiety, with potential implications for the development of more effective and well-tolerated treatments in the field of psychopharmacology.

Red dragon fruit-soy protein isolate biofilm: UV-blocking, antioxidant & improved mechanical properties for sustainable food packaging

In this study, an active biofilm was developed by incorporating red dragon fruit peel (RDF) extract into soy protein isolate (SPI) film matrix for sustainable food packaging. The addition of betalain-rich-RDF extract (1-7 wt%) significantly improved UV-blocking and antioxidant properties of the film compared to the control film. As wt% of RDF-extract increased, water vapor permeability, water solubility, and elongation at break decreased by 1.06 × 10-10 g m m-2 s-1 Pa-1, 34.25%, and 133.25%, respectively. On the other hand, Tensile strength increased significantly (P < 0.05) by 78.76%. FTIR results confirmed the intermolecular interaction between RDF extract and SPI through hydrogen bonding, while XRD result showed a decrease in the crystallinity degree of the film with RDF extract addition. However, no significant change in the TGA curve between extract-incorporated SPI films was observed. SEM analysis revealed that SPI B and SPI D films had a more compact and denser structure than the control film, while AFM analysis showed an increase in Ra and Rq values representing higher surface roughness of SPI D film. SPI D film also significantly (P < 0.05) decreased the weight loss and increased total soluble solids of freshly cut apples over 7-day storage period.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05940-2.

Seaweed-based biopolymers for food packaging: A sustainable approach for a cleaner tomorrow

With the increasing environmental and health consequences of uncontrolled plastic use, the scientific community is progressively gravitating toward biodegradable and ecofriendly packaging alternatives. Seaweed polysaccharides have attracted attention recently because of their biodegradability, nontoxicity, antioxidant properties, and superior film-forming ability. However, it has some limitations for packaging applications, such as low tensile strength, water solubility, and only modest antimicrobial properties. The incorporation of biopolymers, nanoparticles, or organic active ingredients enhances these characteristics. This review encapsulates the contemporary research landscape pivoting around the role of seaweed polysaccharides in the development of bioplastics, active packaging solutions, edible films, and protective coatings. A meticulous collation of existing literature dissects the myriad food application avenues for these marine biopolymers, emphasizing their multifaceted physical, mechanical, thermal, and functional attributes, including antimicrobial and antioxidant. A key facet of this review spotlights environmental ramifications by focusing on their biodegradability, reinforcing their potential as a beacon of sustainable innovation. This article delves into the prevalent challenges that stymie large-scale adoption and commercialization of seaweed-centric packaging, offering a comprehensive perspective on this burgeoning domain.

Comparison of Polylactide-Based Active Films Containing Berberine and Quercetin as Systems for Maintaining the Quality and Safety of Blueberries

Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative analysis of the effect of individual flavonoids on the antioxidative properties of tested films and blueberry storage was carried out. The influence of active compounds on the water vapor permeability, as well as UV protection, of the obtained materials was investigated. Also, the specific migration of individual flavonoids from obtained materials to food simulants in the form of acetic acid and ethyl alcohol was determined. The crucial point of this study is the storage of blueberries. The obtained results indicate that the selection of packaging, containing individual active compounds, depends on the purpose and requirements that the packaging must meet for particular types of food.

Synthesis and Assessment of Novel Sustainable Antioxidants with Different Polymer Systems

Antioxidants are essential to the polymer industry. The addition of antioxidants delays oxidation and material degradation during their processing and usage. Sustainable phenolic acids such as 4-hydroxybenzoic acid or 3,4-dihydroxybenzoic acid were selected. They were chemically modified by esterification to obtain various durable molecules, which were tested and then compared to resveratrol, a biobased antioxidant, and Irganox 1076, a well-known and very efficient fossil-based antioxidant. Different sensitive matrices were used, such as a thermoplastic polyolefin (a blend of PP and PE) and a purposely synthesized thermoplastic polyurethane. Several formulations were then produced, with the different antioxidants in varying amounts. The potential of these different systems was analyzed using various techniques and processes. In addition to antioxidant efficiency, other parameters were also evaluated, such as the evolution of the sample color. Finally, an accelerated aging protocol was set up to evaluate variations in polymer properties and estimate the evolution of the potential of different antioxidants tested over time and with aging. In conclusion, these environmentally friendly antioxidants make it possible to obtain high-performance materials with an efficiency comparable to that of the conventional ones, with variations according to the type of matrix considered.

Different crosslinking as a strategy to improve films produced from external mesocarp of pequi (Caryocar brasiliense)

The pequi (Caryocar brasiliense) external mesocarp is rich in phenolic compounds and pectin and demonstrates the potential to produce active and biodegradable films. Thus, the present study aimed to produce films with pequi mesocarp as a polymer matrix and evaluate the influence of crosslinking agents (calcium chloride and citric acid) on the film's properties. The films obtained from pequi mesocarp (MF), showed in general, complete biodegradation in 33 days, good antioxidant capacity, and inhibition against S. aureus (24.7 mm) and E. coli (23.0 mm). The crosslinking agents reduced solubility by up to 35% and increased the elongation of the films by up to 3.5-fold. Calcium chloride promoted a higher reduction in solubility, and both agents increase the antioxidant and antimicrobial activities, compared to MF. Citric acid proved to be the best agent to modify the properties of pequi mesocarp films. In addition to the crosslinking action, it presented plasticizing effect.

Matcha-silver nanoparticles reduce gamma radiation-induced oxidative and inflammatory responses by activating SIRT1 and NLRP-3 signaling pathways in the Wistar rat spleen

The biogenic synthesis of nanoparticles has drawn significant attention. The spleen is the largest lymphatic organ that is adversely impacted during irradiation. The current study was designated to evaluate the possible anti-inflammatory effect of matcha-silver nanoparticles (M-AgNPs) to reduce inflammation associated with γ-radiation induced-oxidative stress and inflammation in rats' spleen. Silver nanoparticles (AgNPs) were synthesized by biogenic synthesis using a green sonochemical method from matcha (M) green tea. The obtained M-AgNPs were extensively characterized by dynamic light scattering, transmission electron microscopy, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. Using zetasizer analysis, the surface charge, particle size, and radical scavenging DPPH assay of M-AgNPs were also examined. Biocompatibility and cytotoxicity were analyzed by MTT assay, and the IC50 was calculated. Four groups of 24 Wistar rats each had an equal number of animals. The next step involved measuring the levels of oxidative stress markers in the rat splenic tissue. Additionally, the amounts of inflammatory protein expression were evaluated using the ELISA analysis. The results indicated the formation of spherical nanoparticles of pure Ag° coated with matcha polyphenols at the nanoscale, as well as uniform monodisperse particles suited for cellular absorption. Results revealed that M-AgNPs improved all biochemical parameters. Furthermore, M-AgNPs relieve inflammation by reducing the expression of NOD-like receptor family pyrin domain-containing 3 (NLRP3), interleukin-1β (IL-1β), and enhancing the levels of ileSnt information regulator 1 (SIRT1). Histopathological examinations demonstrated the ability of M-AgNPs to overcome the damage consequent to irradiation and recover the spleen's cellular structure. These results confirmed that matcha is a potential biomaterial for synthesizing AgNPs, which can be exploited for their anti-inflammatory activity.

Effect of lipid oxidation on quality attributes and control technologies in dried aquatic animal products: a critical review

Aquatic animals are viewed as a good source of healthy lipids. Although drying is an effective method for the preservation of aquatic animal products (AAPs), the whole process is accompanied by lipid oxidation. This article reviews the main mechanism of lipid oxidation in the drying process. It also summarizes the effects of lipid oxidation on the quality of dried aquatic animal products (DAAPs), including nutrients, color, flavor, and hazard components, especially for those harmful aldehydes and heterocyclic amines. In addition, it concluded that moderate lipid oxidation contributes to improving the quality of products. Still, excessive lipid oxidation produces hazardous substances and induces health risks. Hence, to obtain high-quality DAAPs, some effective control technologies to promote/prevent lipid oxidation are introduced and deeply discussed, including salting, high-pressure processing, irradiation, non-thermal plasma technology, defatting treatments, antioxidants, and edible coating. A systematic review of the effect of lipid oxidation on quality attributes and control technologies in DAAPs is presented, and some perspectives are made for future research.

Effect of ferulic acid derivative concentration on the release kinetics, antioxidant capacity, and thermal behaviour of different polymeric films

Ferulic acid displays poor thermal resistance during extrusion and compression moulding, slow 2,2-diphenyl-1-picrylhydrazyl (DPPH) reaction kinetics, and undetected release from polylactide (PLA) and polyhydroxyalkanoates (PHA)-based films into polar media. Thus, in this study, a ferulic acid derivative Bis-O-dihydroferuloyl-1,4-butanediol (BDF) was used as an active additive (up to 40 w%) in PLA, poly(3-hydroxybutyrate) (PHB), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrices to produce blends by extrusion. These blends were then used to prepare films by solvent casting. The BDF displayed good stability with 86-93% retention. The release kinetics in Food Simulant A revealed higher BDF release amounts (1.16-3.2%) for PHA-based films as compared to PLA. The BDF displayed faster DPPH reaction kinetics as compared to ferulic acid. The PHA-based films containing BDF displayed > 80% of DPPH inhibition. The growth of crystals inside polymer matrix had a nucleation effect which reduced the glass transition temperature of the films.

Emulsion-Based Coatings for Preservation of Meat and Related Products

One of the biggest challenges faced by the meat industry is maintaining the freshness of meat while extending its shelf life. Advanced packaging systems and food preservation techniques are highly beneficial in this regard. However, the energy crisis and environmental pollution demand an economically feasible and environmentally sustainable preservation method. Emulsion coatings (ECs) are highly trending in the food packaging industry. Efficiently developed coatings can preserve food, increase nutritional composition, and control antioxidants' release simultaneously. However, their construction has many challenges, especially for meat. Therefore, the following review focuses on the essential aspects of developing ECs for meat. The study begins by classifying emulsions based on composition and particle size, followed by a discussion on the physical properties, such as ingredient separation, rheology, and thermal characteristics. Furthermore, it discusses the lipid and protein oxidation and antimicrobial characteristics of ECs, which are necessary for other aspects to be relevant. Lastly, the review presents the limitations of the literature while discussing the future trends. ECs fabricated with antimicrobial/antioxidant properties present promising results in increasing the shelf life of meat while preserving its sensory aspects. In general, ECs are highly sustainable and effective packaging systems for meat industries.

What is the role of active packaging in the future of food sustainability? A systematic review

Nowadays, the strong increase in products consumption, the purchase of products on online platforms as well as the requirements for greater safety and food protection are a concern for food and packaging industries. Active packaging brings huge advances in the extension of product shelf-life and food degradation and losses reduction. This systematic work aims to collect and evaluate all existing strategies and technologies of active packaging that can be applied in food products, with a global view of new possibilities for food preservation. Oxygen scavengers, carbon dioxide emitters/absorbers, ethylene scavengers, antimicrobial and antioxidant active packaging, and other active systems and technologies are summarized including the products commercially available and the respective mechanisms of action. © 2022 Society of Chemical Industry.

Pilot-Scale Processing and Functional Properties of Antifungal EVOH-Based Films Containing Methyl Anthranilate Intended for Food Packaging Applications

Antimicrobial packaging has emerged as an efficient technology to improve the stability of food products. In this study, new formulations based on ethylene vinyl alcohol (EVOH) copolymer were developed by incorporating the volatile methyl anthranilate (MA) at different concentrations as antifungal compound to obtain active films for food packaging. To this end, a twin-screw extruder with a specifically designed screw configuration was employed to produce films at pilot scale. The quantification analyses of MA in the films showed a high retention capacity. Then, the morphological, optical, thermal, mechanical and water vapour barrier performance, as well as the antifungal activity in vitro of the active films, were evaluated. The presence of MA did not affect the transparency or the thermal stability of EVOH-based films, but decreased the glass transition temperature of the copolymer, indicating a plasticizing effect, which was confirmed by an increase in the elongation at break values of the films. Because of the additive-induced plasticization over EVOH, the water vapour permeability slightly increased at 33% and 75% relative humidity values. Finally, the evaluation of the antifungal activity in vitro of the active films containing methyl anthranilate showed a great effectiveness against P. expansum and B. cinerea, demonstrating the potential applicability of the developed films for active food packaging.

Facile fabrication of green synthesized silver-decorated magnetic particles for coating of bioactive packaging

To avoid bacterial and viral infections on food products, the use of antibacterial and antiviral packaging offers great benefit to the food industry. In this study, the coating of paper packaging with silver-decorated magnetic particles (Ag@Fe₃O₄) was developed. The Ag@Fe₃O₄ was prepared by a facile and environmentally friendly method using extracted spent coffee grounds (ex-SCG). The effects of Ag@Fe₃O₄ content on properties of coated paper were investigated. The overall properties of coated paper improved when the Ag@Fe₃O₄ content increased up to 0.15%w/v. An increase in tensile strength of 154.01% and a decrease in water vapor permeability of 48.50% were found in coated paper with 0.15%w/v Ag@Fe₃O₄. Furthermore, the coated paper also exhibited the synergistic effect on antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The release of metal ions in food simulants and kinetic release parameters were also studied. The release of silver ions and ferrous ions in food simulants met the requirement of overall migration limit of the European Standard. The paper coated with 0.15%w/v Ag@Fe₃O₄ had better capabilities to maintain quality and extend shelf-life of tomatoes. The obtained Ag@Fe₃O₄ coated paper is promising for bioactive food packaging to retain food freshness.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10570-022-04636-0.

A Comprehensive Review of the Development of Carbohydrate Macromolecules and Copper Oxide Nanocomposite Films in Food Nanopackaging

Background. Food nanopackaging helps maintain food quality against physical, chemical, and storage instability factors. Copper oxide nanoparticles (CuONPs) can improve biopolymers' mechanical features and barrier properties. This will lead to antimicrobial and antioxidant activities in food packaging to extend the shelf life. Scope and Approach. Edible coatings based on carbohydrate biopolymers have improved the quality of packaging. Several studies have addressed the role of carbohydrate biopolymers and incorporated nanoparticles to enhance food packets' quality as active nanopackaging. Combined with nanoparticles, these biopolymers create film coatings with an excellent barrier property against transmissions of gases such as O2 and CO2. Key Findings and Conclusions. This review describes the CuO-biopolymer composites, including chitosan, agar, cellulose, carboxymethylcellulose, cellulose nanowhiskers, carrageenan, alginate, starch, and polylactic acid, as food packaging films. Here, we reviewed different fabrication techniques of CuO biocomposites and the impact of CuONPs on the physical, mechanical, barrier, thermal stability, antioxidant, and antimicrobial properties of carbohydrate-based films.

Gelatine/PVA copolymer film incorporated with quercetin as a prototype to active antioxidant packaging

Films that incorporate antioxidant agents are widely used and improve the stability of food products that are prone to oxidation. This work evaluated the potential antioxidant activity of PVA/gelatine films incorporated with quercetin. The films were prepared by the casting method and characterised by TG-DSC, FTIR spectroscopy, SEM, optical microscopy and swelling index. Antioxidant properties were evaluated with DPPH, ABTS and FRAP assays. According to the thermal characterisation results, the film was stable up to 68 °C and entirely degraded at 632 °C. The FTIR spectroscopic analysis indicated that there was a physical interaction between the quercetin and the polymeric film, and microscopy indicated a homogeneous and uniform film. The film showed DPPH (315.4 ± 8.2) and ABTS radical potential activity (199.4 ± 9.7), as well as potential iron reduction activity-FRAP (740.6 ± 8.9) mainly when analysed in ethanol: water (95:5 v/v) system, all results expressed as milligram of Trolox per gram of film. Hence, PVA/gelatine films incorporated with quercetin have properties that allow a potential application in active packaging systems to delay oxidative processes in food.

Terpenoids and Polyphenols as Natural Antioxidant Agents in Food Preservation

Synthetic antioxidant food additives, such as BHA, BHT and TBHQ, are going through a difficult time, since these products generate a negative perception in consumers. This has generated an increased pressure on food manufacturers to search for safer natural alternatives like phytochemicals (such as polyphenols, including flavonoids, and essential oils rich in terpenoids, including carotenoids). These plant bioactive compounds have antioxidant activities widely proven in in vitro tests and in diverse food matrices (meat, fish, oil and vegetables). As tons of food are wasted every year due to aesthetic reasons (lipid oxidation) and premature damage caused by inappropriate packaging, there is an urgent need for natural antioxidants capable of replacing the synthetic ones to meet consumer demands. This review summarizes industrially interesting antioxidant bioactivities associated with terpenoids and polyphenols with respect to the prevention of lipid oxidation in high fat containing foods, such as meat (rich in saturated fat), fish (rich in polyunsaturated fat), oil and vegetable products, while avoiding the generation of rancid flavors and negative visual deterioration (such as color changes due to oxidized lipids). Terpenoids (like monoterpenes and carotenoids) and polyphenols (like quercetin and other flavonoids) are important phytochemicals with a broad range of antioxidant effects. These phytochemicals are widely distributed in fruits and vegetables, including agricultural waste, and are remarkably useful in food preservation, as they show bioactivity as plant antioxidants, able to scavenge reactive oxygen and nitrogen species, such as superoxide, hydroxyl or peroxyl radicals in meat and other products, contributing to the prevention of lipid oxidation processes in food matrices.

Valorization of Bio-Residues from the Processing of Main Portuguese Fruit Crops: From Discarded Waste to Health Promoting Compounds

Food processing generates a large amount of bio-residues, which have become the focus of different studies aimed at valorizing this low-cost source of bioactive compounds. High fruit consumption is associated with beneficial health effects and, therefore, bio-waste and its constituents arouse therapeutic interest. The present work focuses on the main Portuguese fruit crops and revises (i) the chemical constituents of apple, orange, and pear pomace as potential sources of functional/bioactive compounds; (ii) the bioactive evidence and potential therapeutic use of bio-waste generated in the processing of the main Portuguese fruit crops; and (iii) potential applications in the food, nutraceutical, pharmaceutical, and cosmetics industries. The current evidence of the effect of these bio-residues as antioxidant, anti-inflammatory, and antimicrobial agents is also summarized. Conclusions of the revised data are that these bio-wastes hold great potential to be employed in specific nutritional and pharmaceutical applications.

Recent Developments in Seafood Packaging Technologies

Seafood products are highly perishable, owing to their high water activity, close to neutral pH, and high content of unsaturated lipids and non-protein nitrogenous compounds. Thus, such products require immediate processing and/or packaging to retain their safety and quality. At the same time, consumers prefer fresh, minimally processed seafood products that maintain their initial quality properties. The present article aims to review the literature over the past decade on: (i) innovative, individual packaging technologies applied to extend the shelf life of fish and fishery products, (ii) the most common combinations of the above technologies applied as multiple hurdles to maximize the shelf life of seafood products, and (iii) the respective food packaging legislation. Packaging technologies covered include: Modified atmosphere packaging; vacuum packaging; vacuum skin packaging; active food packaging, including oxygen scavengers; carbon dioxide emitters; moisture regulators; antioxidant and antimicrobial packaging; intelligent packaging, including freshness indicators; time–temperature indicators and leakage indicators; retort pouch processing and edible films; coatings/biodegradable packaging, used individually or in combination for maximum preservation potential.

Designing Biodegradable and Active Multilayer System by Assembling an Electrospun Polycaprolactone Mat Containing Quercetin and Nanocellulose between Polylactic Acid Films

The design of multilayer systems is an innovative strategy to improve physical properties of biodegradable polymers and introduce functionality to the materials through the incorporation of an active compound into some of these layers. In this work, a trilayer film based on a sandwich of electrospun polycaprolactone (PCL) fibers (PCLé) containing quercetin (Q) and cellulose nanocrystals (CNC) between extruded polylactic acid (PLA) films was designed with the purpose of improving thermal and barrier properties and affording antioxidant activity to packaged foods. PCLé was successfully electrospun onto 70 µm-thick extruded PLA film followed by the assembling of a third 25 µm-thick commercial PLA film through hot pressing. Optical, morphological, thermal, and barrier properties were evaluated in order to study the effect of PCL layer and the addition of Q and CNC. Bilayer systems obtained after the electrospinning process of PCL onto PLA film were also evaluated. The release of quercetin from bi- and trilayer films to food simulants was also analyzed. Results evidenced that thermal treatment during thermo-compression melted PCL polymer and resulted in trilayer systems with barrier properties similar to single PLA film. Quercetin release from bi- and trilayer films followed a similar profile, but achieved highest value through the addition of CNC.

The application of polyphenols in food preservation

Polyphenols are a kind of complex secondary metabolites in nature, widely exist in the flowers, bark, roots, stems, leaves, and fruits of plants. Numerous studies have shown that plant-derived polyphenols have a variety of bioactivities due to their unique chemical structure, such as antioxidant, antimicrobial, and prevention of chronic diseases, cardiovascular disease, cancer, osteoporosis, and neurodegeneration. With the gradual rise of natural product development, plant polyphenols have gradually become one of the research hotspots in the field of food science due to their wide distribution in the plants, and the diversity of physiological functions. Owing to the extraordinary antioxidant and antibacterial activity of polyphenols, plant-derived polyphenols offer an alternative to chemical additives used in the food industry, such as oil, seafood, meat, beverages, and food package materials. Based on this, this chapter provides an overview of the potential antioxidant and antibacterial mechanisms of plant polyphenols and their application in food preservation, it would be providing a reference for the future development of polyphenols in the food industry.

Designing active mats based on cellulose acetate/polycaprolactone core/shell structures with different release kinetics

Core/shell electrospun mats based on cellulose acetate (CA) and polycaprolactone (PCL) were developed as novel active materials for releasing quercetin (Quer) and curcumin (Cur). The effect of polymeric uniaxial and coaxial electrospun systems and the chemical structures of Quer and Cur on the structural, thermal, and mass transfer properties of the developed mats were investigated. Release modelling indicated that the diffusion of the active agents from the uniaxial PCL fibers was highly dependent on the type of food simulant. Higher diffusion coefficients were obtained for both active agents in acid food simulant due to the higher swelling of the electrospun mats. In addition, CA/PCL coaxial structures slowed down the diffusion of both active agents into both food simulants. CA increased the retention of the active compounds in the polymer structure, resulting in partition coefficients values higher than the values obtained for uniaxial active PCL mats.

Migration and Degradation in Composting Environment of Active Polylactic Acid Bilayer Nanocomposites Films: Combined Role of Umbelliferone, Lignin and Cellulose Nanostructures

This study was dedicated to the functional characterization of innovative poly(lactic acid) (PLA)-based bilayer films containing lignocellulosic nanostructures (cellulose nanocrystals (CNCs) or lignin nanoparticles (LNPs)) and umbelliferone (UMB) as active ingredients (AIs), prepared to be used as active food packaging. Materials proved to have active properties associated with the antioxidant action of UMB and LNPs, as the combination of both ingredients in the bilayer formulations produced a positive synergic effect inducing the highest antioxidant capacity. The results of overall migration for the PLA bilayer systems combining CNCs or LNPs and UMB revealed that none of these samples exceeded the overall migration limit required by the current normative for food packaging materials in both non-polar and polar simulants. Finally, all the hydrophobic monolayer and bilayer films were completely disintegrated in composting conditions in less than 18 days of incubation, providing a good insight on the potential use of these materials for application as active and compostable food packaging.

Melt-Processed Bioactive EVOH Films Incorporated with Ferulic Acid

In this work, antimicrobial and antioxidant films based on ethylene vinyl alcohol (EVOH) copolymer containing low amounts of ferulic acid (FA) were successfully developed by melt extrusion. Optically transparent films were obtained, and the presence of FA provided some UV blocking effect. The characterization of the thermal and barrier properties of the developed films showed that the addition of FA improved the thermal stability, decreased the glass transition temperature (Tg) and increased the water vapor and oxygen transmission rates when ferulic acid was loaded above 0.5 wt.%, associated with its plasticizing effect. Mechanical characterization confirmed the plasticizing effect by an increase in the elongation at break values while no significant differences were observed in Young's modulus and tensile strength. Significant antioxidant activity of all active films exposed to two food simulants, 10% ethanol and 95% ethanol, was also confirmed using the 2,2-diphenyl-1-pricylhydrazyl (DPPH) free radical scavenging method, indicating that FA conserved its well-known antioxidant properties after melt-processing. Finally, EVOH-FA samples presented antibacterial activity in vitro against Escherichia coli and Staphylococcus aureus, thus showing the potential of ferulic acid as bioactive compound to be used in extrusion processing for active packaging applications.

On the Use of Phenolic Compounds Present in Citrus Fruits and Grapes as Natural Antioxidants for Thermo-Compressed Bio-Based High-Density Polyethylene Films

This study originally explores the use of naringin (NAR), gallic acid (GA), caffeic acid (CA), and quercetin (QUER) as natural antioxidants for bio-based high-density polyethylene (bio-HDPE). These phenolic compounds are present in various citrus fruits and grapes and can remain in their leaves, peels, pulp, and seeds as by-products or wastes after juice processing. Each natural additive was first melt-mixed at 0.8 parts per hundred resin (phr) of bio-HDPE by extrusion and the resultant pellets were shaped into films by thermo-compression. Although all the phenolic compounds colored the bio-HDPE films, their contact transparency was still preserved. The chemical analyses confirmed the successful inclusion of the phenolic compounds in bio-HDPE, though their interaction with the green polyolefin matrix was low. The mechanical performance of the bio-HDPE films was nearly unaffected by the natural compounds, presenting in all cases a ductile behavior. Interestingly, the phenolic compounds successfully increased the thermo-oxidative stability of bio-HDPE, yielding GA and QUER the highest performance. In particular, using these phenolic compounds, the onset oxidation temperature (OOT) value was improved by 43 and 41.5 °C, respectively. Similarly, the oxidation induction time (OIT) value, determined in isothermal conditions at 210 °C, increased from 4.5 min to approximately 109 and 138 min. Furthermore, the onset degradation temperature in air of bio-HDPE, measured for the 5% of mass loss (T_5%), was improved by up to 21 °C after the addition of NAR. Moreover, the GA- and CA-containing bio-HDPE films showed a high antioxidant activity in alcoholic solution due to their favored release capacity, which opens up novel opportunities in active food packaging. The improved antioxidant performance of these phenolic compounds was ascribed to the multiple presence of hydroxyl groups and aromatic heterocyclic rings that provide these molecules with the features to permit the delocalization and the scavenging of free radicals. Therefore, the here-tested phenolic compounds, in particular QUER, can represent a sustainable and cost-effective alternative of synthetic antioxidants in polymer and biopolymer formulations, for which safety and environmental issues have been raised over time.

Antioxidant Packaging Films Based on Ethylene Vinyl Alcohol Copolymer (EVOH) and Caffeic Acid

The main objective of this research activity was to design and realize active films with tunable food functional properties. In detail, caffeic acid (CA), a polyphenol with high antioxidant effect, was used as active ingredient in poly (vinyl alcohol-co-ethylene) (EVOH) films at 5 wt.% and 15 wt.% and successfully realized by means of the solvent casting process. Optical, morphological, thermal and mechanical studies were considered to define the effect of the presence of the CA component on the structural properties of the matrix. In addition, moisture content and antioxidant activity were evaluated, to have clear information on the CA effect in terms of functional characteristics of realized food packaging systems. Results from tensile tests showed increased values for strength and deformation at break in EVOH_CA based films. Results from colorimetric and transparency analysis underlined that the presence of caffeic acid in EVOH copolymer induces some alterations, whereas the addition of the active ingredient determined a positive radical scavenging activity of the formulations, confirming the possibility of practically using these polymeric systems in the food packaging sector.

Effect of the application of an edible film with turmeric (Curcuma longa L.) on the oxidative stability of meat

The aim of this study was to develop an edible alginate-based film produced with turmeric (EFT), as an active compound, and evaluate its antioxidant capacity for application in fresh pork loin, beef loin, and chicken breast. The EFT was characterized by barrier parameters, color, and mechanical, structural, and antioxidant properties. Meat samples with and without EFT were stored at 4°C and analyzed at 2-day intervals. The meat samples with EFT showed significant differences (p < .05) in color (CIE L*a*b*) and exhibited lower TBARS values compared with those without EFT. The addition of turmeric in the film, besides affecting its physicochemical and structural properties, contributed an important antioxidant effect for the meat.

Novel Antioxidant Packaging Films Based on Poly(ε-Caprolactone) and Almond Skin Extract: Development and Effect on the Oxidative Stability of Fried Almonds

Antioxidant films based on poly(ε-caprolactone) (PCL) containing almond skin extract (ASE) were developed for food packaging applications. The effect of ASE incorporation on the morphological, structural, colour, mechanical, thermal, barrier and antioxidant properties of the prepared films were evaluated. The structural, tensile and thermal properties of the films were not altered due to ASE addition. Although no significant differences were observed for the oxygen permeability of samples, some increase in water absorption and water vapour permeability was observed for active films due to the hydrophilic character of ASE phenolic compounds, suggesting the suitability of this novel packaging for fatty foods conservation. ASE conferred antioxidant properties to PCL films as determined by the DPPH radical scavenging activity. The efficiency of the developed films was evaluated by the real packaging application of fried almonds at different ASE contents (0, 3, 6 wt.%) up to 56 days at 40 °C. The evolution of peroxide and p-anisidine values, hexanal content, fatty acid profile and characteristic spectroscopy bands showed that active films improved fried almonds stability. The results suggested the potential of PCL/ASE films as sustainable and antioxidant food packaging systems to offer protection against lipid oxidation in foods.

On the Use of Gallic Acid as a Potential Natural Antioxidant and Ultraviolet Light Stabilizer in Cast-Extruded Bio-Based High-Density Polyethylene Films

This study originally explores the use of gallic acid (GA) as a natural additive in bio-based high-density polyethylene (bio-HDPE) formulations. Thus, bio-HDPE was first melt-compounded with two different loadings of GA, namely 0.3 and 0.8 parts per hundred resin (phr) of biopolymer, by twin-screw extrusion and thereafter shaped into films using a cast-roll machine. The resultant bio-HDPE films containing GA were characterized in terms of their mechanical, morphological, and thermal performance as well as ultraviolet (UV) light stability to evaluate their potential application in food packaging. The incorporation of 0.3 and 0.8 phr of GA reduced the mechanical ductility and crystallinity of bio-HDPE, but it positively contributed to delaying the onset oxidation temperature (OOT) by 36.5 °C and nearly 44 °C, respectively. Moreover, the oxidation induction time (OIT) of bio-HDPE, measured at 210 °C, was delayed for up to approximately 56 and 240 min, respectively. Furthermore, the UV light stability of the bio-HDPE films was remarkably improved, remaining stable for an exposure time of 10 h even at the lowest GA content. The addition of the natural antioxidant slightly induced a yellow color in the bio-HDPE films and it also reduced their transparency, although a high contact transparency level was maintained. This property can be desirable in some packaging materials for light protection, especially UV radiation, which causes lipid oxidation in food products. Therefore, GA can successfully improve the thermal resistance and UV light stability of green polyolefins and will potentially promote the use of natural additives for sustainable food packaging applications.

The Contribution of a Whey Protein Film Incorporated with Green Tea Extract to Minimize the Lipid Oxidation of Salmon (Salmo salar L.)

Active packaging is becoming progressively more significant as a response to the dynamic changes in current consumer demand and market tendencies. Active packaging is projected to interact directly with the packaged food or with the headspace within the package with the aim of maintaining or extending product quality and shelf-life. Aiming for sustainability, the potential application as biodegradable films of whey protein concentrate (WPC) was evaluated. Aromatic plant's extracts present high antioxidant properties, representing an alternative for synthetic food additives. The main objective of this study was to verify the effectiveness of an edible WPC film incorporated with a plant-based extract on retarding the lipid oxidation of fresh salmon. Green tea extract (GTE) was chosen to be incorporated into the active film. Fresh salmon was packaged with the control film (WPC) and with active film (WPC-GTE). The oxidation level of non-packaged samples and packaged samples were tested for different storage times. Four methods were applied to evaluate lipid oxidation state of fresh salmon: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay, and monitoring of hexanal. The results obtained in this study indicate that the whey protein active film was successfully produced, and it was effective in delaying lipid oxidation of fresh salmon samples until the 14th day of storage.

Active Role of ZnO Nanorods in Thermomechanical and Barrier Performance of Poly(vinyl alcohol-co-ethylene) Formulations for Flexible Packaging

Poly(vinyl alcohol-co-ethylene) (EVOH) films containing zinc oxide nanorods (ZnO Nrods) at 0.1, 0.5, and 1 wt%, were realized by solvent casting. The effect of ZnO Nrods content on morphological, thermal, optical, mechanical, and oxygen permeability properties were analyzed. In addition, moisture content and accelerated-aging test studies were performed, with the intention to determine the influence of zinc oxide nanofillers on the functional characteristics of realized packaging systems. Tensile properties showed increased values for strength and deformation-at-break in EVOH-based formulations reinforced with 0.1 and 0.5 wt% of zinc oxide nanorods. Results from the colorimetric and transparency investigations underlined that the presence of ZnO Nrods in EVOH copolymer did not induce evident alterations. In addition, after the accelerated-aging test, the colorimetric test confirmed the possibility for these materials to be used in the packaging sector. This behavior was induced by the presence of zinc oxide nanofillers that act as a UV block that made them useful as an efficient absorber of UV radiation.