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This study combines the use of corn starch and Tetradesmus obliquus microalgae for the production of antioxidant starch films as flexible packaging material. Starch was plasticized with glycerol and blended with 1 w% polyallylamine chosen as an agent to modify the film physical properties. The addition of polyallylamine improved film water stability and water vapor transmission rate as well as mechanical stiffness and tenacity. The dried Tetradesmus obliquus microalgae, which showed an EC50 value of 2.8 mg/mg DPPH (2.2-Diphenyl-1-picrylhydrazyl radical), was then used as antioxidant filler. The addition of microalgae provided the films with good antioxidant activity, which increased with microalgae content increasing. To our knowledge, this is the first study reporting the development of sustainable bioactive packaging films composed of almost 100% starch, and follows the European union’s goals on plastics strategy concerning the promotion of bio-based, compostable plastics and the setting up of approaches to prevent food waste with a simple plastic packaging.

Razvoj aktivnega pakiranja je posledica potreb sodobnega časa. Koncept aktivne embalaže vključuje interakcijo le-te z živilom preko aktivne spojine v ali na površini embalaže za izboljšanje obstojnosti in kakovosti živila. Cilj dela je bil izboljšati funkcionalnost inertne polipropilenske folije z dvoslojnimi premazi, s prvim slojem na osnovi primarnega ali kvartarnega hitozana in drugim slojem na osnovi naravnih izvlečkov, bodisi rjave alge (Padina pavonica), iglic brina ali listov robide. Pripravili smo folije z različnimi kombinacijami premazov za pridobitev podatkov o vplivu posameznih nanosov ter njihovem učinku pri dvoslojni aplikaciji. Vezavo premazov na folije smo potrdili s tehtanjem folij in z XPS analizo. Določili smo fizikalno-kemijske lastnosti folij, ki so pomembne z vidika pakiranja živil (omočljivost, prepustnost kisika), ter testirali antioksidativni potencial in protimikrobno aktivnost proti S. aureus in E. coli. Prisotnost hitozana ter izvlečkov listov robide in iglic brina je izboljšala antioksidativni potencial folij, medtem ko so veliko slabši antioksidativni potencial izkazale folije s slojem izvlečka alge. Kvartarni hitozan in izvlečka listov robide in iglic brina so izkazali odlično protimikrobno delovanje proti bakteriji S. aureus, proti bakteriji E. coli pa le folija s samostojnim slojem kvartarnega hitozana. Prisotnost tako hitozana kot izvlečkov je pomembna, saj v dvosloju vpelje dobre bioaktivne lastnosti, ključne za koncept aktivne embalaže, prav tako izboljša omočljivost folije oz. zmanjša stični, kot tudi prepustnost kisika, kar je pomembno z vidika funkcionalnosti živilske embalaže. The development of active packaging is a result of the needs of modern times. The concept of active packaging involves its interaction with food through an active compound in or on the surface of the packaging material to improve the shelf-life and quality of food. The goal was to improve the functionality of an inert polypropylene (PP) film with two-layer coatings, with the first layer based on primary or quaternary chitosan and the second layer based on natural extracts, either brown algae (Padina pavonica), juniper needles or blackberry leaves. We prepared films with different combinations of coatings to obtain data on the impact of individual coatings and their effect in a two-layer application. We confirmed the presence of coatings on the films by weighing and by an XPS analysis. We determined the physico-chemical properties of foils, important for food packaging (wettability, oxygen permeability), and tested the antioxidant potential and antimicrobial activity against S. aureus and E. coli. Chitosan and the blackberry leaves and juniper needles extracts improved the antioxidant potential of films, while foils with a layer of algae extract showed a much lower antioxidant potential. Quaternary chitosan and extracts proved excellent antimicrobial activity against S. aureus. Only films with an individual layer of quaternary chitosan proved good antimicrobial activity against E. coli. The presence of both chitosan and extracts is important, as it not only introduces good bioactive properties into the bilayer and is key for the concept of active packaging, but it also improves wettability, i.e. reduces the contact angle, as also oxygen permeability, which are important for the functionality of food packaging.

Date palm pits are highly available and inexpensive palm date by-products, representing a valuable source of natural antioxidants, particularly phenolic compounds. Date palm pit extract (DPPE) was prepared from these waste products and characterized for its phenolic content and in vitro antioxidant activity. Profiling DPPE by liquid chromatography coupled with mass spectrometry (LC/MS) showed the presence of dimers and trimers of (epi)catechin as the main constituents. Alginate-based films with four increasing concentrations of DPPE (10%, 20%, 30%, and 40% w/w) were prepared by the casting method. DPPE incorporation reduced solubility values of alginate films by 37%–64% and their surface wettability by 72%–111%. The incorporation of 10% DPPE improved water vapor barrier properties and increased tensile strength (TS) and elongation at break (%E) of alginate films by more than 23%, 50%, and 45%, respectively. The film containing 40% DPPE showed the lowest loss of phenolic content (32%), DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (38%), and ferric reducing antioxidant power (FRAP) (30%) after storage for 3 months.

Made available in DSpace on 2022-04-28T19:52:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-05-31 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The development of bio-based food packaging with antioxidant properties is an important research topic and has gained prominence these days. In this study, bioactive films were developed based gelatin-corn starch (GCS) incorporated with corn stigma extract (CSE) at different concentrations (15% and 25%; w/v). In preliminary tests, the extract maintained cell viability above 90% indicating that it is safe for application as an active ingredient. Insertion of the extract did not influence the thickness of the films but caused a slight change in optical properties. Scanning electron microscopy (SEM) analysis revealed interactions between the extract's bioactive compounds with gelatin and corn starch compounds, which may have improved the mechanical properties (elongation at break, Young's modulus). The addition of 25% corn stigma extract increased the contact angle, giving the film a hydrophobic character. Furthermore, at this concentration, a 15% reduction in water vapor permeability was observed. The elaborated films showed complete biodegradability before the tenth day of the study. It can be inferred that the films with corn stigma extract have good antioxidant properties, indicating that they can be used as an ingredient for food packaging. Department of Food Science and Technology Universidade Federal de Santa Maria (UFSM), RS Hybrid Composites and Nanocomposites Group Department of Physics and Chemistry Universidade Estadual Paulista (UNESP), SP Department of Industrial Pharmacy Health Sciences Center Universidade Federal de Santa Maria (UFSM), RS Hybrid Composites and Nanocomposites Group Department of Physics and Chemistry Universidade Estadual Paulista (UNESP), SP FAPESP: 2013/07296-2 CEPID FAPESP: 2019/06170-1 CNPq: 312530/2018-8 CAPES: Code 001

Active food packaging represents an innovative way to conceive food packages. The innovation lies in using natural-based and biodegradable materials to produce a system intended to interact with the food product to preserve its quality and shelf-life. Compared to traditional plastics, active packaging is designed and regulated to release substances in a controlled manner, mainly antimicrobial and antioxidant compounds. Conventional technologies are not suitable for treating these natural substances; therefore, the research for innovative and green techniques represents a challenge in this field. The aim of this work is to compare two different polymeric structures: nanofibrous films obtained by electrospinning and continuous films obtained by solvent casting, to identify the best solution and process conditions for subjecting the samples to the supercritical fluids impregnation process (SFI). The supports optimized were functionalized by impregnating alpha-tocopherol using the SFI process. In particular, the different morphologies of the samples both before and after the supercritical impregnation process were initially studied, identifying the limits and possible solutions to obtain an optimization of the constructs to be impregnated with this innovative green technology in the packaging field.

Eco-friendly and antioxidant bioactive films based on polylactic acid (PLA), loaded with cellulose nanocrystals (CNC) and green tea extract (GTE) were prepared by direct melt processing. GTE was chemically characterized by using high performance liquid chromatography (HPLC), coupled with tandem mass spectrometry. The antioxidant, physical, thermal, mechanical and microstructural properties of the produced films were investigated. The efficiency of the active films on retarding the lipid oxidation of the salami, was evaluated by the thiobarbituric acid reactive substances (TBARS) and p-anisidine value. Experimental results highlight that the PLA/ 2%CNC/1%GTE nanocomposite film (film containing 2 wt% of CNC and 1 wt% of GTE) shows the highest reduction in terms of oxygen transmission ratio and water vapor permeability (60 % and 33 % respectively) and the optimal macroscopic mechanical behavior. However, it shows a slight antioxidant activity only at short storage time, namely 7 and 15 days. Overall, PLA/2CNC nanocomposite film exhibits the best compromise in terms of improvement of material properties and of effectiveness in retarding lipid oxidation at short and long storage time, mainly related to its enhanced barrier properties. Highlights: PLA/CNC and PLA/CNC/GTE films prepared by direct melt processing; PLA/2%CNC/1%GTE nanocomposite film, showed good dispersion level of CNC and GTE; PLA/2%CNC/1%GTE nanocomposite film presents an efficient barrier effect; PLA/2%CNC/1%GTE nanocomposite film presents a good macroscopic mechanical behavior; The active films effectiveness on retarding lipid oxidation was evaluated in a model food. Dr. M.F. Vaz acknowledges FCT, through IDMEC, under LAETA, project UIDB/50022/2020. The work was supported by UIDB/00211/2020 with funding from FCT/MCTES through national funds. The authors thank Mrs A. Aldi and M.R. Marcedula for the technical support in the permeability and thermal characterization. L. Barbosa-Pereira is grateful to the Spanish Ministry of Science, Innovation and Universities for her “Juan de la Cierva—Incorporacion´ ” Grant (Agreement No. IJCI2017-31665). info:eu-repo/semantics/publishedVersion

New antioxidant films based on ethylene vinyl alcohol (EVOH) copolymer containing betalain-rich red beet were successfully manufactured and characterized to develop bioactive packaging for food products. Two types of red beet (powder and extract) at different proportions (0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 % (w/w)) were incorporated into EVOH films, with attention focused on the optical, chemical, thermal, structural, and mechanical and antioxidant properties. The incorporation of any red beet type into EVOH resulted in purple-colored and semi-crystalline thin films, without modifying their thermal stability and mechanical properties. The addition of the beet extract led to a film with higher color intensity, antioxidant activity and lower water loss rate, whereas the addition of powdered beet resulted in an improved UV barrier compared to the extract. The results showed that new antioxidant food packaging films based on EVOH could be realized by utilizing beetroot extract or powder obtained from natural resources.

In this study, clove essential oil (CL) or eugenol (EU) containing cellulose acetate (CA) or acrylic component/hydrophobically modified starch (AC/S) coatings on corona treated oriented polypropylene film (OPP) were designed and investigated for their possible applications as antioxidant packaging materials for fresh meat. The antioxidant properties of the coatings were investigated by Vapour Phase-DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The CA coatings containing CL or EU showed 43–92% and 43–94% inhibition against DPPH free radicals through the vapour phase, respectively, whereas AC/S/CL and AC/S/EU coatings resulted in DPPH inhibition of 21–65% and 25–84%, respectively. AC/S/EU and CA/EU coatings on OPP containing from 0.32 ± 0.03 to 6.40 ± 0.14 g/m2 of EU were used to prepare packaging for fresh beef (Longissimus thoracis). After 14 days, the lipid oxidation in beef steaks kept in control and antioxidant packages was 3.33 and 1.00–1.22 mg of malondialdehyde per kilogram of meat, respectively. Moreover, red colour of beef in antioxidant packages was retained.

[EN] Polymer films with antioxidant and antimicrobial properties were manufactured for the active packaging of food products. Green tea extract (GTE) and oregano essential oil (OEO) were incorporated in an ethylene-vinyl alcohol copolymer (EVOH). Release studies of the main active components of the films into three food simulants, 3% acetic acid, 10% ethanol and 50% ethanol, were conducted at 4 degrees C and 23 degrees C. The total antioxidant activity at equilibrium was measured in the food simulants and the antimicrobial capacity of the films was tested in vitro against Listeria monocytogenes, Escherichia coli and Penicillium expansum. The results suggest that the release kinetics depend on the affinity between the active agents and the food simulants. In general, the fastest diffusion was obtained when films were exposed to 50% ethanol and that effect was concurrent with greater antioxidant efficiencies. The films also showed microbial growth inhibition in liquid media and in vapour phases, demonstrating that the developed films show strong potential for development as active food packaging films. (C) 2014 Elsevier Ltd. All rights reserved., The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, Projects AGL2012-39920-C03-01, and fellowship funding for V.M.-G. We gratefully acknowledge Mr Joseph Pelle of Victoria University, Melbourne, Australia for technical support with the GC and HPLC experiments.

In this study, cellulose acetate (CA) films with different morphological features were prepared in order to control the release rates of low molecular weight natural antioxidants, L-ascorbic acid and L-tyrosine. Increasing CA content in the casting solution decreased the average pore size and porosity of the films, thus, reduced the diffusion rates of both antioxidants through the films. Although both antioxidants have similar molecular weights, L-tyrosine released into water much more slowly than L-ascorbic acid. The highest antioxidant activity in release test solutions was observed with highly porous L-tyrosine containing films. However, when the porosity of the films reduced, the antioxidant activity of L-ascorbic acid released into solution was found to be higher due to trapping of significant amount of L-tyrosine in dense films. The use of different antioxidants caused different changes in morphological and mechanical properties of the CA films. Varying the structural features of the films with the preparation conditions or using different surfaces of the films allowed the controlled release of each antioxidant. © 2009 Elsevier Ltd. All rights reserved.