Migration study of carvacrol as a natural antioxidant in high-density polyethylene for active packaging

Smart food packaging: Recent advancement and trends

Food packaging plays an important role in protecting the safety and quality of food products and enables communication with consumers. With the improved consumers' awareness of safety and quality of food products, the changes in consumers' lifestyle, and the growing demand for transparency of food products along the supply chain, food packaging technologies have evolved from only providing the four fundamental functions (i.e., protection and preservation, containment, communication and marketing, and convenience) to possessing additional functions including active modification of the inside microenvironment (i.e., active packaging) and monitoring the safety and quality of products in real-time (i.e., intelligent packaging). A variety of active and intelligent packaging systems have been developed to better protect and monitor the quality and safety of food products during the past several decades. Recently, advanced versions of smart packaging technologies, such as smart active packaging and smart intelligent packaging technologies have also been developed to enhance the effectiveness of conventional smart packaging systems. Additionally, smart packaging systems that harvest the advantages of both active packaging and intelligent packaging have also been developed. In this chapter, a brief overview of smart packaging technologies was provided. Specific technologies being covered include conventional smart packaging technologies and advanced smart packaging technologies, such as smart active packaging, smart intelligent packaging and dual-function smart packaging.

Preparation and characterization of chitosan/dialdehyde carboxymethyl cellulose composite film loaded with cinnamaldehyde@zein nanoparticles for active food packaging

In this study, zein-loaded cinnamaldehyde (Cin@ZN) nanoparticles were incorporated into Chitosan (CS)/dialdehyde carboxymethyl cellulose (DCMC) matrix to fabricate the active food packaging materials possessing outstanding antioxidant and antibacterial properties. The research investigated how varying levels of Cin@ZN nanoparticles affected the morphology, microstructure, physicochemical properties of CS/DCMC composite films. The inclusion of Cin@ZN could significantly improve the mechanical strength, reduce the water vapor and oxygen permeability of CS/DCMC composite films and endow films with UV-light blocking properties. It's worth noting that the antibacterial and antioxidant capacities of CS/DCMC films had an astonishing enhancement with Cin@ZN blending, in which ABTS scavenging ratio of the composite films (100 mg) with different Cin@ZN contents reached >90 %. Furthermore, CS/DCMC/Cin@ZN 35 % composite film has the ability to efficiently protect strawberries from microbial damage and decelerate the spoilage rate of strawberries under ambient condition. Consequently, the CS/DCMC/Cin@ZN composite film can be applied as packaging material to extend the lifespan of fruits.

Brazilian native fruit pomace as a source of bioactive compounds on starch-based films: Antimicrobial activities and food simulator release

The bioactive compounds extraction from fruit pomace is an ecological alternative for these abundant and low-added-value by-products. This study aimed to evaluate the antimicrobial potential of pomace extracts from Brazilian native fruits (araçá, uvaia, guabiroba and butiá) and the effect on physicochemical, mechanical properties and the migration of antioxidants and phenolic compounds from starch-based films. The film with butiá extract had the lowest mechanical resistance (1.42 MPa) but the highest elongation (63 %). In comparison, uvaia extract had less impact on film mechanical properties (3.70 MPa and 58 %) compared to the other extracts. The extracts and films showed antimicrobial activity against Listeria monocytogenes, L. inoccua, B. cereus and S. aureu. Approximately 2 cm inhibition halo was noticed for the extracts, while films ranged from 0.33 to 1.46 cm inhibition halo. Films with guabiroba extract had the lowest antimicrobial activity (0.33 to 0.5 cm). The phenolic compounds were released from the film matrix in the first hour at 4 °C with maintenance in the stability. The fatty-food simulator showed a controlled release of antioxidant compounds, which can assist in controlling food oxidation. Brazilian native fruit has shown to be a viable alternative to isolate bioactive compounds and produce film packaging with antimicrobial and antioxidant activities.

Phytochemical Compounds, Acute Toxicity, Anti-Inflammatory and Antioxidant Activities of Thymus leptobotrys Murb Essential Oil

The present study was conducted to evaluate the acute toxicity and anti-inflammatory effect in vivo, as well as the antioxidant activity, of the essential oil of Thymus leptobotrys Murb. The results indicate that the tested essential oil is non-toxic, with an estimated LD50 of 2500 mg kg^-1 of mice body weight. The anti-inflammatory test revealed that, at a dose of 200 mg kg^-1, the essential oil reduced rat paw edemas by 89.59% within 3 h of oral administration, this reduction in edema size was greater than that obtained with indomethacin (75.78%). The antioxidant activity (IC50) of Thymus leptobotrys Murb essential oil was 346.896 µg mL^-1 and 861.136 mg Trolox equivalent/g essential oil in the 2.2-diphenyl1-picryl-hydrazyl radical scavenging capacity (DPPH) and Trolox equivalent antioxidant capacity (TEAC) assays, respectively. The toxicity test reveals an LD₅₀ greater than 2500 mg kg^-1 of body weight of mice which classifies it within category 5 of non-toxic substances that can be administered orally. These results suggest that the essential oil of Thymus leptobotrys Murb is not toxic, and it represents a valuable source of anti-inflammatory and antioxidant metabolites.

Migration study of phenolic endocrine disruptors from pacifiers to saliva simulant by solid phase microextraction with amino-functionalized microporous organic network coated fiber

Parabens, bisphenols, and triclosan are used in many baby products, including pacifiers. However, the migration through oral saliva will result in a potential health risk. The present study proposes a sensitive and simple method for the analysis of these chemicals in saliva simulants by solid phase microextraction (SPME) with amino-functionalized microporous organic network (MON-NH₂) coated fiber. The MON-NH₂ showed an excellent adsorption ability for phenolic compounds. The adsorption isotherm fitted the Langmuir isotherm model and the adsorption kinetics followed the pseudo second-order model. The developed SPME method exhibited wide linear ranges (0.005-500 µg/L), good linearity, low limits of quantitation (0.005 µg/L), great recoveries (87.0-112.5 %), and excellent precision (RSD < 8.3 % for intra-day and RSD < 13.7 % for inter-day). Mathematical models based on Fick's second law were applied to predict migration from pacifiers into saliva simulants and a good fit between theoretical and experimental migration results was found. The daily exposure assessment results indicated that these chemicals in pacifiers do not pose unacceptable health risks to infants. However, exposure risks still should be monitored and appropriate precautions are still needed to protect infants from exposure to these chemicals.

New Antioxidant Active Packaging Films Based on Yeast Cell Wall and Naphtho-γ-Pyrone Extract

The main objective of this work is the development of new active films based on yeast cell wall obtained by high-pressure homogenization (YCW-H) supplemented with naphtho-γ-pyrone (CL-NGP) extract, which is a bioactive compound produced by Aspergillus tubingensis G131 with great antioxidant potential. A complete characterization of the functional properties of the bioactive films, such as their structural, colour, thermal, mechanical, hydration and water vapour transport, was carried out to evaluate the influence of the addition of the antioxidant compounds. Likewise, the antioxidant capacity of the developed materials and the specific migration of NGPs in food simulants were evaluated. The results showed that CL-NGP extract possessed an important antioxidant activity, which was maintained after incorporation in YCW-H films. The addition of 2 and 5% CL-NGPs decreased the hydration of films and consequently improved the water vapour barrier properties. It was observed that CL-NGPs migrate in fatty food simulants and retain their antioxidant capacity in the simulant. The results obtained in this work showed that bioactive films based on yeast cell walls with the addition of CL-NGPs have the potential to be used as packaging material in systems of interest in the food industry.

Application of cellulose plate modified with encapsulated Cinnamomum zelanicum essential oil in active packaging of walnut kernel

In this study, Cinnamomum zelanicum essential oil was encapsulated with β-cyclodextrin and sodium caseinate (EO/BCD/Ca) and nanoemulsion was optained. In order to encapsulation of essential oil, different formulations of nanoemulsions containing essential oil were produced by ultrasound method and the effect of different polymers on the particle size and turbidity of the nanoemulsion was investigated. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) techniques were used to study the structure and morphology of the produced nanoemulsions. Cinnamomum zelanicum essential oil encapsulated with β-cyclodextrin and sodium caseinate was used to modify porous cellulose plates (Cel/EO/BCD/Ca). Cellulose/encapsulated essential oil plates were used to package the walnut kernel to control oxidative changes during storage. The effect of packaging type (under vacuum and ordinal), plate type and storage time on quality control of walnut kernel and oil extracted from walnut kernel was investigated. The results showed that the particle size of essential oil, essential oil/β-cyclodextrin and essential oil/β-cyclodextrin/sodium caseinate were in the range of 84-85, 713-713 and 237-234 (nm), respectively. The encapsulation efficiency of both formulations was above 70%. Zeta potential was negative for essential oil/β-cyclodextrin/sodium caseinate samples and free essential oil samples. The effect of different polymers on the turbidity of emulsions was significant. The results of sensory evaluation of walnut kernel showed that the use of encapsulated essential oil compared to free essential oil caused the protection of color, taste and other quality characteristics during storage. Also, the essential oil encapsulated with β-cyclodextrin/sodium caseinate had a greater effect on quality control of walnut kernel and its oil than the essential oil encapsulated with β-cyclodextrin. Also, the quality characteristics of walnut kernels and walnut kernel oil packed in vacuum conditions were better than walnut kernels and walnut kernel oil packed in non-vacuum conditions during storage.

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high-pressure food processing

The migration study of nano-Ag migration from polylactic acid (PLA) films was studied. Samples treated by high-pressure food processing (0, 100, 200, 300, and 400 MPa pressure) were soaked in acetic acid solution and incubated at 20 °C for 90 days. At the end of storage, nano-Ag particles (AgNPs) migration from the PLA/AgNPs composite film treated under 200 MPa high pressure was the lowest. However, AgNPs migration was accelerated under 400 MPa high pressure. High-pressure processing (200 MPa) could cause denser structure and higher crystallinity degree in films than other treatments. Lower amount of AgNPs induced a decline in the intensity of specific characteristic peaks. The diffraction peak intensity of α-crystal for the film sample treated with 400 MPa was the lowest on day 60. The crystallization index of the PLA matrix changed with different high-pressure processing. The result indicated that appropriate high-pressure food processing could effectively suppress AgNPs migration from PLA-based film while contacting with acidic acid food simulant. PRACTICAL APPLICATION: The release of nanoparticles from food packaging material is a very important matter when the migration is concerned with regulatory and toxicity issues. The study described the migration kinetic of AgNPs from PLA nanocomposite film into acidic food simulant after different high-pressure food processing. The results indicated that the PLA/AgNPs nanocomposite film was safe for acidic food after high-pressure treatment.

Characterisation of Bioactive Ingredients in Extracts of Fresh and Dried Coniferous Trees for the Development of Sustainable Packaging Materials

Background: Coniferous woods (Abies nordmanniana (Stev.) Spach, Abies procera Rehd, Picea abies (L.) H.Karst, and Picea pungens Engelm.) could contain useful secondary metabolites to produce sustainable packaging materials, e.g., by substitution of harmful petrol-based additives in plastic packaging. This study aims to characterise the antioxidant and light-absorbing properties and ingredients of different coniferous wood extracts with regard to different plant fragments and drying conditions. Furthermore, the valorisation of used Christmas trees is evaluated. Methods: Different drying and extraction techniques were applied with the extracts being characterised by determining the total phenolic content (TPC), total antioxidant capacity (TAC), and absorbance in the ultraviolet range (UV). Gas chromatography coupled with mass spectrometry (GC-MS) and an acid–butanol assay (ABA) were used to characterise the extract constituents. Results: All the extracts show a considerably high UV absorbance while interspecies differences did occur. All the fresh and some of the dried biomass extracts reached utilisable TAC and TPC values. A simplified extraction setup for industrial application is evaluated; comparable TAC results could be reached with modifications. Conclusion: Coniferous woods are a promising renewable resource for preparation of sustainable antioxidants and photostabilisers. This particularly applies to Christmas trees used for up to 12 days. After extraction, the biomass can be fully valorised by incorporation in paper packaging.

Biodegradable Poly(ε-Caprolactone) Active Films Loaded with MSU-X Mesoporous Silica for the Release of α-Tocopherol

In this study, new active PCL (poly(ε-caprolactone)) films containing α-tocopherol (TOC) and MSU-X mesoporous silica were prepared by melt blending. The studied additives were directly incorporated into the polymer matrix or by impregnating TOC into MSU-X silica (PCL-IMP). Thermal, optical, oxygen and water barrier properties as well as oxidation onset parameters, were studied. Films containing MSU-X and/or TOC showed a significant increase in oxidative onset temperature (OOT) and oxidative induction time (OIT), improving thermal stability against materials oxidation by the addition of mesoporous silica and TOC into the polymer matrix. In addition, the effect of MSU-X addition on the migration behaviour of α-tocopherol from active films was investigated at 40 °C using 50% (v/v) ethanol as fatty food simulant, showing PCL-IMP films the lower release content and diffusion coefficient (3.5 × 10⁻¹⁵ cm² s⁻¹). Moreover, radical scavenging (DPPH and ABTS) and antibacterial activity against E. coli and S. aureus were favoured by the release of α-tocopherol in the developed films. The obtained results have demonstrated the potential of the new PCL-based active formulations for TOC controlled release in antioxidant and antibacterial food packaging applications.

Perspectives on medicinal properties of natural phenolic monoterpenoids and their hybrids

Carvacrol, thymol and eugenol belong to a class of naturally presenting phenols with a ten-carbon unit, which are present in essential oils of many plants. These versatile molecules are incorporated as useful ingredients in many food products and find applications in agricultural, pharmaceutical, fragrance, cosmetic, flavor and other industries. They are wide ranging of biological and pharmaceutical activities: anti-inflammatory, antimicrobial, analgesic, anticancer and antioxidant. This review summarizes pharmacological and medicinal activities of these phytochemicals and their synthetic hybrids.

On the Use of PLA-PHB Blends for Sustainable Food Packaging Applications

Poly(lactic acid) (PLA) is the most used biopolymer for food packaging applications. Several strategies have been made to improve PLA properties for extending its applications in the packaging field. Melt blending approaches are gaining considerable interest since they are easy, cost-effective and readily available processing technologies at the industrial level. With a similar melting temperature and high crystallinity, poly(hydroxybutyrate) (PHB) represents a good candidate to blend with PLA. The ability of PHB to act as a nucleating agent for PLA improves its mechanical resistance and barrier performance. With the dual objective to improve PLAPHB processing performance and to obtain stretchable materials, plasticizers are frequently added. Current trends to enhance PLA-PHB miscibility are focused on the development of composite and nanocomposites. PLA-PHB blends are also interesting for the controlled release of active compounds in the development of active packaging systems. This review explains the most relevant processing aspects of PLA-PHB based blends such as the influence of polymers molecular weight, the PLA-PHB composition as well as the thermal stability. It also summarizes the recent developments in PLA-PHB formulations with an emphasis on their performance with interest in the sustainable food packaging field. PLA-PHB blends shows highly promising perspectives for the replacement of traditional petrochemical based polymers currently used for food packaging.

Predicting diffusion coefficients of chemicals in and through packaging materials

Most of the physicochemical properties in polymers such as activity and partition coefficients, diffusion coefficients, and their activation with temperature are accessible to direct calculations from first principles. Such predictions are particularly relevant for food packaging as they can be used (1) to demonstrate the compliance or safety of numerous polymer materials and of their constitutive substances (e.g. additives, residues…), when they are used: as containers, coatings, sealants, gaskets, printing inks, etc. (2) or to predict the indirect contamination of food by pollutants (e.g. from recycled polymers, storage ambiance…) (3) or to assess the plasticization of materials in contact by food constituents (e.g. fat matter, aroma…). This review article summarizes the classical and last mechanistic descriptions of diffusion in polymers and discusses the reliability of semi-empirical approaches used for compliance testing both in EU and US. It is concluded that simulation of diffusion in or through polymers is not limited to worst-case assumptions but could also be applied to real cases for risk assessment, designing packaging with low leaching risk or to synthesize plastic additives with low diffusion rates.

Sugar-based poly (anhydride-ester) containing natural antioxidants and antimicrobials: Synthesis and formulation into polymer blends

Thymol, a naturally occurring antioxidant and antimicrobial, is commonly researched for active packaging applications to deter food spoilage and bacterial growth. However, the high temperature necessary for processing often volatilizes the thymol, reducing its utility. To overcome this processing limitation, sugar-based poly(anhydride-esters) comprising thymol and compounds generally regarded as safe (succinic and tartaric acid) were successful prepared via mild solution polymerization methods. In vitro release studies demonstrated a sustained thymol release over 3 weeks at therapeutically relevant concentrations. Furthermore, the released thymol displayed antioxidant and antimicrobial activities as indicated by a 2,2-diphenyl-1-picrylhydrazyl radical scavenging and Kirby–Bauer disk diffusion assays, respectively. High-temperature melt blending with low-density polyethylene revealed that the chemical incorporation of thymol into a polymer backbone overcame volatility issues and maintained relevant bioactivity.

Chitosan films incorporated with nettle (Urtica Dioica L.) extract-loaded nanoliposomes: II. Antioxidant activity and release properties

Chitosan films were loaded with NE nettle (Urtica dioica L.) extract (NE) at concentrations of 0, 0.5, 1 and 1.5%w/w in the free or nanoliposomal form to obtain active and nanoactive films, respectively. The antioxidant potential of the films containing NE-loaded nanoliposomes was decreased in comparison of free NE incorporated films. Diffusion of NE to soybean oil was enough to delay the induction of the oxidation of soybean oil stored for 60 days in contact with chitosan based films. Release studies indicated that the release rate of NE in 95% ethanol simulant significantly decreased by the nanoencapsulation of NE. The diffusion coefficient (D) for chitosan films containing 1.5%w/w of free and encapsulated NE at 25 °C was 18.80 and 3.68 × 10^-7 cm² s^-1, respectively. Moreover, the formation of nanoliposomes diminished the increasing effect of temperature on the release rate as when storage temperature increased from 4 °C to 40 °C.

Enhanced antioxidant activity of polyolefin films integrated with grape tannins

BACKGROUND

A natural antioxidant derived from an agro-waste of the wine industry, grape tannin, was incorporated by melt blending into three different polyolefins (high-density polyethylene, linear low-density polyethylene and polypropylene) to introduce antioxidant functionality.

RESULTS

Significant antioxidant activity was observed at 1% tannin inclusion in all polymer blends. The antioxidant activity was observed to increase steadily with a greater concentration of grape tannins, the highest increases being seen with polypropylene. The mechanical and thermal properties of the polymer films following antioxidant incorporation were minimally altered with up to 3% grape tannins. All of the polyolefin-grape tannin films successfully passed the leachability test following USP661 standard protocol.

CONCLUSION

Superior antioxidant activity was established in polyolefin thin films by utilization of a bulk grape extract obtained from winery waste. Significant increases in antioxidant activity were seen with 1% extract inclusion. This not only demonstrates the potential for food packaging applications of the polyolefin blends, but also valorizes the agro-waste. © 2015 Society of Chemical Industry.

Trends in the use of natural antioxidants in active food packaging: a review

The demand for natural antioxidant active packaging is increasing due to its unquestionable advantages compared with the addition of antioxidants directly to the food. Therefore, the search for antioxidants perceived as natural, namely those that naturally occur in herbs and spices, is a field attracting great interest. In line with this, in the last few years, natural antioxidants such as α-tocopherol, caffeic acid, catechin, quercetin, carvacrol and plant extracts (e.g. rosemary extract) have been incorporated into food packaging. On the other hand, consumers and the food industry are also interested in active biodegradable/compostable packaging and edible films to reduce environmental impact, minimise food loss and minimise contaminants from industrial production and reutilisation by-products. The present review focuses on the natural antioxidants already applied in active food packaging, and it reviews the methods used to determine the oxidation protection effect of antioxidant active films and the methods used to quantify natural antioxidants in food matrices or food simulants. Lastly consumers' demands and industry trends are also addressed.

Controlling lipid oxidation of food by active packaging technologies

Active packaging is an innovative strategy in preventing lipid oxidation. Different active substances with different mechanisms of action have been investigated for imparting antioxidant activity to active packaging systems, including free radical scavengers, metal chelators, ultraviolet (UV) absorbers, oxygen scavengers, and singlet oxygen quenchers. Antioxidant agents have been incorporated into active packaging systems in different forms, mainly including independent sachet packages, adhesive-bonded labels, physical adsorption/coating on packaging material surface, being incorporated into packaging polymer matrix, multilayer films, and covalent immobilization onto the food contact packaging surface. In this paper, we review recent advances in antioxidant active packaging with the highlight of the development and application of non-migratory active packaging systems. The potential use of emerging technologies in antioxidant active packaging is also emphasized. We further describe challenges and opportunities towards the commercial application of such antioxidant active packaging systems, with a focus on maintaining safety, quality and nutrition of packaged foods.

Improving the capacity of polypropylene to be used in antioxidant active films: incorporation of plasticizer and natural antioxidants

Two types of active antioxidant food packages with improved release properties, based on polypropylene (PP) as one of the most common polymers used in food-packaging applications, were developed. Incorporation of catechin and green tea as antioxidant provided PP with 6 times higher stabilization against thermal oxidation. Release of natural antioxidants (catechins, gallic acid, caffeine, and quercetin) into various food simulants from that nonpolar matrix were improved by blending poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPG-PEG-PPG) as plasticizer into the polymer formulation. Increasing release levels between 10- and 40-fold into simulant A and between 6 and 20-fold into simulant D1 resulted from the incorporation of catechin and green tea as antioxidants and PPG-PEG-PPG as plasticizer into the film formulation. The efficiency of the antioxidants in the food simulants after the release process was also corroborated through antioxidant activity tests. Therefore, the developed PPG-PEG-PPG-modified polypropylene resulted in a potential system to be used in active packaging.

Development of new antioxidant active packaging films based on ethylene vinyl alcohol copolymer (EVOH) and green tea extract

Ethylene vinyl alcohol copolymer (EVOH) films containing green tea extract were successfully produced by extrusion. The films were brown and translucent, and the addition of the extract increased the water and oxygen barrier at low relative humidity but increased the water sensitivity, the glass transition temperature, and the crystallinity of the films and improved their thermal resistance. An analysis by HPLC revealed that the antioxidant components of the extract suffered partial degradation during extrusion, reducing the content of catechin gallates and increasing the concentration of free gallic acid. Exposure of the films to various food simulants showed that the liquid simulants increased their capacity to reduce DPPH(•) and ABTS(•+) radicals. The release of green tea extract components into the simulant monitored by HPLC showed that all compounds present in the green tea extract were partially released, although the extent and kinetics of release were dependent on the type of food. In aqueous food simulants, gallic acid was the main antioxidant component released with partition coefficient values ca. 200. In 95% ethanol (fatty food simulant) the K value for gallic acid decreased to 8 and there was a substantial contribution of catechins (K in the 1000 range) to a greatly increased antioxidant efficiency. Kinetically, gallic acid was released more quickly than catechins, owing to its faster diffusivity in the polymer matrix as a consequence of its smaller molecular size, although the most relevant effect is the plasticization of the matrix by alcohol, increasing the diffusion coefficient >10-fold. Therefore, the materials here developed with the combination of antioxidant substances that constitute the green tea extract could be used in the design of antioxidant active packaging for all type of foods, from aqueous to fatty products, the compounds responsible for the protection being those with the higher compatibility with the packaged product.

Improving the antioxidant protection of packaged food by incorporating natural flavonoids into ethylene-vinyl alcohol copolymer (EVOH) films

Ethylene-vinyl alcohol copolymer (EVOH) films containing catechin or quercetin as antioxidant agents were successfully produced by extrusion. The addition of these bioactive compounds did not modify greatly their water and oxygen permeabilities, Tg, or crystallinity but improved their thermal resistance. Exposure of the films to different food simulants showed that both compounds were released, although the extent and kinetics of release were dependent on the type of food. In aqueous and alcoholic food simulants their release was greater in the case of the catechin-containing samples. Exposure of the films to isooctane and ethanol 95% (fatty food simulants) provided controversial results; no release was observed in isooctane, whereas both bioactive compounds were extracted by ethanol due to their high solubility in alcohol and the plasticizing effect of ethanol on the polymer. Packaging applications of these films can improve food stability and provide a method for adding such bioactive compounds.