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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Étude de l'évolution du ''smart packaging'' alimentaire et analyse des marchés des pays industrialisés : actualité et tendances / Smart packaging market evolution in the industrialized countries : today's and future trends

Monborren-Benabdillah, Linda 04 May 2015 (has links)
D’un simple outil de protection des aliments et de transport des objets, l’emballage est devenu une science qui évolue sans répit. Depuis peu, l’emballage franchit une nouvelle étape, d’un outil de vente, il devient un acteur qui prolonge la durée de conservation des aliments et les préserve, ainsi qu'un langage censé parler au producteur, au distributeur et même au consommateur. En contradiction avec la plupart des législations qui définissaient l’emballage comme inerte, les nouveaux emballages sont des éléments actifs ou intelligents. Cependant, ce qu’en Europe et aux Etats-Unis on considère être de nouvelles technologies d’emballage, existe au Japon depuis plusieurs décennies déjà. Tout l’enjeu est donc de comprendre pourquoi et comment, sur un marché mondialisé où la course vers l’innovation et les nouvelles technologies est permanente, le Smart Packaging arrive en Europe avec quarante ans de retard. Cette étude a pour objectif de donner un aperçu sur les technologies, les applications existantes et les enjeux du Smart Packaging, ainsi que sur les perspectives des innovations. Il est par ailleurs essentiel d'analyser la pérennité et la viabilité des nouvelles technologies de l’emballage dans le secteur agroalimentaire des pays industrialisés, en apportant un éclairage sur l’actualité du marché ainsi que sur sa dynamique et sur les tendances majeures de son évolution à court et à long termes. Le projet a de même pour but de développer les stratégies de marketing, d’export et de gestion des risques à appliquer à un marché international, et de définir les cadres réglementaires des principaux pays industrialisés et les risques pour l’environnement et le consommateur. / Packaging used to be a very common, unnoticed, everyday life object for food protection and transportation. It is now a whole scientific subject that evolves on a daily basis. Recently packaging has crossed a new threshold: it is no more a simple marketing tool. Today packaging acts as a food protector that prolongs the shelf life and provides information to manufacturers, distributors, and even consumers. In complete contradiction with all the legislation that defined it as an inert object, new packaging technologies are active and intelligent devices. However, what is called in Europe and the United States a new technology, has been marketed in Japan for decades. The challenge is to understand how and why Smart Packaging was so late to enter Europe and the US at a time when globalization in trade and communication are stronger than ever, and the race for innovation and new technologies is permanent. The main objective of this report is to give insights into today’s market stakes, its opportunities, major trends and short and long term evolution, as well as its growth potential and the major factors that influence it on one hand. On the other hand it provides analysis for the future and the viability of the new technologies in food and drink sectors on developed countries markets. To achieve these purposes, it is essential to give an overview of the existing technologies and applications and explain the stakes of using Smart Packaging, as well as innovation perspectives. Moreover, this projects highlights how the companies meet the challenge of developing marketing, exportation and risk strategies on a global market, whithin the boundaries of the regulatory frameworks and risks for the environment and the consumer.
42

Funkcionalni materijali na bazi elektrospinovanih nanovlakana / Functional materials based on electrospun nanofibers

Miletić Aleksandra 01 November 2019 (has links)
<p>Funkcionalni materijali na osnovu elektrospinovanih nanovlakana nalaze sve veću primenu u raznim oblastima industrije: biomedicina, farmacija, senzori, filrtacija, ambalaža itd. Elektrospining tehnika je jedna od metoda za dobijanje materijala na osnovu nanovlakana iz polimernih rastvora kori&scaron;ćenjem visokog napona. Kori&scaron;ćenje elekrospining tehnike ima brojne prednosti u odnosu na konvencionalne tehnike, pre svega zbog lakoće inkorporacije aktivne komponente u polimernu matricu, a i specifične morfologije i 3D strukture, jer usled nanometarskih dimenzija, vlakna imaju veliki odnos specifične povr&scaron;ine i zapremine i poroznosti, samim tim veliku kontaktnu povr&scaron;inu sa supstratima, reaktivnim agensima i mikroorganizmima. Zbog proizvodnje materijala na nanonivou, aktivna komponenta se fino dispergije u polimernoj matrici i time se obezbeđuje bolja aktivnost ovih materijala. Za razliku od konvencionalnih filmova, funkcionalni materijali na osnovu elektrospinovanih nanovlakana su aktivni po celoj zapremini. Cilj ove doktorske disertacije bio je optimizicija procesnih parametara elektrospininga i validacija aktivnosti funkcionalnih materijala za različite primene, &scaron;to je postignuto pravilnim odabirom materijala i aktivnih komponenti, optimizacijom sastava materijala, karakterizacijom materijala adekvatnim metodama i validacijom aktivnosti materijala. Razvijeni su materijali za primenu u oblasti kozmetike, ambalaže, filtracije, senzora, stomatologije i provodnih materijala, čija je aktivnost verifikovana u laboratorijskim uslovima (TRL 4).</p> / <p>Functional materials based on electrospun nanofibers are increasingly used in various fields of industry: biomedicine, pharmacy, sensors, filtration, packaging, etc. Electrospining technique is one of the methods for obtaining nanofibers from polymer solutions using high voltage. The use of electrospinning technique has many advantages over conventional techniques, primarily because of the ease of incorporation of the active component into the polymer matrix, as well as the specific morphology and 3D structure, because due to the nanometer dimensions, the fibers have a large ratio of specific surface area to volume and porosity, and thus a high contact surface with substrates, reactive agents, and microorganisms. Due to the production of materials at the nanoscale, the active component is finely dispersed within the polymer matrix, thereby ensuring better activity of these materials. Unlike conventional films, functional materials based on electrospinned nanofibers are active throughout the volume. The aim of this PhD thesis was to optimize the electrospining process parameters and validate the activity of functional materials for various applications, which was achieved by proper selection of materials and active components, optimization of material composition, characterization of materials by appropriate methods and validation of material activity. Materials have been developed for use in the fields of cosmetics, packaging, filtration, sensors, dentistry and conductive materials, the activity of which has been verified under laboratory conditions (TRL 4).</p>
43

DESIGNING STARCH-CONTAINING, ANTIMICROBIAL, PLASTIC FILMS FOR BIODEGRADABLE FOOD PACKAGING / ANTIMICROBIAL, BIODEGRADABLE, STARCH-CONTAINING PACKAGING

Doratt Mendoza, Juan January 2023 (has links)
This thesis has an approved one-year embargo applied to it. Please, refer to the corresponding forms, and please, so not publish immediately until the embargo has been sorted out. The thesis contains two unpublish papers and patents pending. Thank you! / Conventional single-use plastic packaging has contributed significantly to the health and well-being of our society but also negatively impacted our environment due to its persistence after use. Since recycling is not a complete solution, rapidly biodegradable materials like thermoplastic starch (TPS) blends offer a more sustainable alternative. Additionally, to stave off the premature breakdown of starch-containing materials as well as extend the shelf life of enclosed foods, microbial control strategies need to be developed. To overcome the inherent brittleness of TPS, this work explores the potential of xylitol and erythritol as melt plasticizers for waxy corn starch (̴100% amylose). Characterizations revealed that both xylitol and erythritol can gelatinize and plasticize starch under 25% wt. Particularly, xylitol demonstrated superior plasticizing and compatibilizing effects, leading to a ductile TPS packaging film with uncharacteristically high elongation at break (EB, 422% ± 48%). The ductile TPS was blended with up to 70% Ecovio bioplastic without requiring compatibilizers and retaining much of its EB value (298 ± 24%). Using xylitol as a melt plasticizer also enhanced the mechanical and hydrophobic qualities of the TPS/Ecovio film as well as its oxygen permeability and puncture extension. Furthermore, polymerized curcumin copolymer (PCEG) was investigated as a grafted coating onto the developed TPS/Ecovio® blend. The antimicrobial activity of PCEG and PCEG coating film was evaluated against foodborne bacteria. The polymerized curcumin by itself demonstrated antimicrobial activity against the gram-negative bacteria Escherichia coli BL21 and Pseudomonas aeruginosa PA01, as well as the gram-positive bacterium Staphylococcus aureus. Additionally, the PCEG-coated films showed surface inhibition of Glutamicibacter soli (IAI-3), a gram-positive bacterium making polymerized curcumin copolymer coatings a suitable approach to add antimicrobial features in thermoplastic starch composites for biodegradable food packaging. / Thesis / Master of Applied Science (MASc) / Canada's Zero Plastics initiative represents a commitment to the environment while upholding the advancements in food safety and public health that come with single-use food packaging. Achieving this balance demands the creation of novel materials. These materials should mimic the qualities of synthetic polymers but have the added ability to decompose naturally in the environment upon reaching the end of their utility. A significant challenge in this effort is preventing the premature degradation of starch-containing packaging materials. Moreover, extending the shelf life of the food they enclose is equally crucial. To solve this paradox, the development of microbial control strategies becomes imperative. This study highlights the antimicrobial potential of a polymerized curcumin copolymer (PCEG) as a coating on a blend of thermoplastic starch (TPS)/xylitol/Ecovio®, creating an innovative packaging film. The curcumin copolymer coating exhibited antimicrobial properties, suggesting its potential use in thermoplastic starch composites for biodegradable food packaging.
44

Storage Stability of an Antioxidant Active Packaging Coated with Citrus Extract Following a Plasma Jet Pretreatment

Contini, C., Katsikogianni, Maria G., O'Neill, F.T., O'Sullivan, M., Boland, F., Dowling, D.P., Monahan, F.J. 05 October 2013 (has links)
Yes / Antioxidant active packaging was prepared by coating a citrus extract on the surface of polyethylene terephthalate (PET) trays which had been either treated with an atmospheric pressure plasma jet or left untreated. The surface characteristics of the packaging were examined, as were its stability and antioxidant efficacy following storage for up to 24 weeks under the following three storage conditions: room temperature, 0 % relative humidity (RH) or 50 °C. Plasma pretreatment increased coating density, thickness and roughness, and oxygenated functional groups at the polymer surface, whereas water contact angle decreased. Trays stored at room temperature did not lose their antioxidant efficacy over 24 weeks and plasma pretreatment enhanced the efficacy from week 8 onwards. Gravimetric analysis of the coating revealed a loss of antioxidant compounds only after 16 weeks. Trays stored at 0 % RH lost coating from week 1 onwards, with lower loss in plasma pretreated trays, while loss of coating was highest at 50 °C, with lower loss in plasma pretreated trays only after 24 weeks. Overall, the surface characteristics of the antioxidant active packaging were modified by plasma pretreatment of the PET surface, with some improvement in antioxidant efficacy, and the efficacy of the packaging in delaying oxidative deterioration in cooked meats was retained during storage at ambient temperature.
45

Синтеза, карактеризација, оптимизација својстава и примена јестивог, активног амбалажног материјала на бази скроба / Sinteza, karakterizacija, optimizacija svojstava i primena jestivog, aktivnog ambalažnog materijala na bazi skroba / Synthesis, characterization, optimization of properties and application of edible active packaging material based on starch

Šuput Danijela 10 February 2016 (has links)
<p>Предмет докторске дисертације је развој јестивих, биоразградивих, активних филмова на бази скроба са додатком есенцијалних уља зачинског биља и њихова примена за паковање одабраног прехрамбеног производа. Глобални допринос овог рада иде у прилог развоју области биоразградивих, јестивих, активних амбалажних материјала.<br />Основно истраживање се базира на испитивању могућности добијања скробних филмова влажним поступком (&quot;casting&quot; метода), модификацији врста и количина додатих компонената које улазе у састав филмогене смеше и карактеризацији добијених филмова ради побољшања особина формираног филма. Својства значајна за примену добијених материјала су физичко-хемијске особине (садржај влаге, способност бубрења), механичке особине (дебљина, затезна јачина и издужење при кидању), баријерне особине (пропустљивост водене паре), структурне (АТР-ФТИР спектрометрија и дифракција X зрака), термалне, оптичке и биолошке особине (антимикробна и антиоксидативна активност).<br />Обзиром на велики број параметара који утичу на формирање филма, као и на особине формираних филмова, испитано је међусобно деловање више фактора на могућност продукције и особине добијеног филма. Избор и оптимизација процесних параметара и моделовање продукције филмова изведено је имплементирањем компјутерске и аналитичке методологије.<br />На основу приказаних резултата, може се закључити да је синтетисан активан јестиви скробни филм оптимизованих физичко-хемијских, механичких, баријерних, термалних и биолошких карактеристика. Синтетисаном скробном филму смањена је способност бубрења, унапредјене су механичке особине (вредности затезних јачина опадају, уз истовремено повећање вредности издужења при кидању). Значајан је утицај додатка есенцијалних уља на вредности пропустљивости водене паре, а њиховим додатком постигнута је и<br />изражена биолошка активност.<br />На основу детаљне карактеризације, одабрани су филмови оптимизованих својстава за примену у заштити осмотски дехидрираног свињског меса током периода складиштења. Осмотски дехидрирано месо је упаковано у комерцијалан високо-баријеран амбалажни материјал у атмосферским условима и у условима модификоване атмосфере, док је други део узорака претходно заштићен скробним премазом са оптимизованим особинама, а затим упакован на исти начин. Утицај оптимизоване скробне превлаке на осмотски дехидрирано месо испитан је праћењем промена параметара квалитета током<br />складиштења.<br />Резултати су показали да јестиви, активни скробни премаз значајно доприноси стабилности упакованог осмотски дехидрираног меса и то у погледу оксидације липида, микробиолошке стабилности и позитивног утицаја на сензорне карактеристике осмотски дехидрираног меса током периода складиштења.</p> / <p>Predmet doktorske disertacije je razvoj jestivih, biorazgradivih, aktivnih filmova na bazi skroba sa dodatkom esencijalnih ulja začinskog bilja i njihova primena za pakovanje odabranog prehrambenog proizvoda. Globalni doprinos ovog rada ide u prilog razvoju oblasti biorazgradivih, jestivih, aktivnih ambalažnih materijala.<br />Osnovno istraživanje se bazira na ispitivanju mogućnosti dobijanja skrobnih filmova vlažnim postupkom (&quot;casting&quot; metoda), modifikaciji vrsta i količina dodatih komponenata koje ulaze u sastav filmogene smeše i karakterizaciji dobijenih filmova radi poboljšanja osobina formiranog filma. Svojstva značajna za primenu dobijenih materijala su fizičko-hemijske osobine (sadržaj vlage, sposobnost bubrenja), mehaničke osobine (debljina, zatezna jačina i izduženje pri kidanju), barijerne osobine (propustljivost vodene pare), strukturne (ATR-FTIR spektrometrija i difrakcija X zraka), termalne, optičke i biološke osobine (antimikrobna i antioksidativna aktivnost).<br />Obzirom na veliki broj parametara koji utiču na formiranje filma, kao i na osobine formiranih filmova, ispitano je međusobno delovanje više faktora na mogućnost produkcije i osobine dobijenog filma. Izbor i optimizacija procesnih parametara i modelovanje produkcije filmova izvedeno je implementiranjem kompjuterske i analitičke metodologije.<br />Na osnovu prikazanih rezultata, može se zaključiti da je sintetisan aktivan jestivi skrobni film optimizovanih fizičko-hemijskih, mehaničkih, barijernih, termalnih i bioloških karakteristika. Sintetisanom skrobnom filmu smanjena je sposobnost bubrenja, unapredjene su mehaničke osobine (vrednosti zateznih jačina opadaju, uz istovremeno povećanje vrednosti izduženja pri kidanju). Značajan je uticaj dodatka esencijalnih ulja na vrednosti propustljivosti vodene pare, a njihovim dodatkom postignuta je i<br />izražena biološka aktivnost.<br />Na osnovu detaljne karakterizacije, odabrani su filmovi optimizovanih svojstava za primenu u zaštiti osmotski dehidriranog svinjskog mesa tokom perioda skladištenja. Osmotski dehidrirano meso je upakovano u komercijalan visoko-barijeran ambalažni materijal u atmosferskim uslovima i u uslovima modifikovane atmosfere, dok je drugi deo uzoraka prethodno zaštićen skrobnim premazom sa optimizovanim osobinama, a zatim upakovan na isti način. Uticaj optimizovane skrobne prevlake na osmotski dehidrirano meso ispitan je praćenjem promena parametara kvaliteta tokom<br />skladištenja.<br />Rezultati su pokazali da jestivi, aktivni skrobni premaz značajno doprinosi stabilnosti upakovanog osmotski dehidriranog mesa i to u pogledu oksidacije lipida, mikrobiološke stabilnosti i pozitivnog uticaja na senzorne karakteristike osmotski dehidriranog mesa tokom perioda skladištenja.</p> / <p>The subject of the doctoral thesis is the development of<br />edible biodegradable active films based on starch with<br />the addition of herbal essential oils and their<br />application in packaging of selected food products.<br />Basic research is examination of the possibility of<br />obtaining starch films by wet method (&quot;casting&quot;<br />method), modification of the types and amounts of<br />added components that constitute the film forming<br />mixture and characterization of films in order to<br />improve the characteristics. Characteristics important<br />for the implementation of the obtained materials<br />include the physico-chemical properties (moisture<br />content, solubility), mechanical properties (thickness,<br />tensile strength and elongation at break), barrier<br />properties (water vapor permeability), structural (ATRFTIR<br />spectroscopy and X ray diffraction), thermal,<br />optical and biological properties (antimicrobial and<br />antioxidant activity).<br />Considering the large number of parameters that affect<br />the film formation, as well as the properties of the<br />films, interactions of multiple factors on the possibility<br />of production and properties of the produced film were<br />examined. Selection and optimization of process<br />parameters and modeling of film production were<br />performed by implementing computer and analytical<br />methodology.<br />Based on these results, it can be concluded that it were<br />synthesized active edible starch films with optimized<br />physico-chemical, mechanical, barrier, thermal and<br />biological characteristics. Synthesized starch film had<br />reduced solubility, improved mechanical properties (tensile strength values declined, while elongation at</p><p>break increased). There is a significant influence of the<br />addition of essential oils on the water vapor<br />permeability value with expressed biological activity.<br />The global contribution of this investigation favors the<br />development of the biodegradable edible active<br />packaging materials scientific field.<br />Based on the detailed characterization, film with<br />optimized characteristics was selected for protection of<br />osmotically dehydrated pork during storage.<br />Osmotically dehydrated meat is wrapped in commercial<br />high-barrier packaging material in atmospheric<br />conditions and in conditions of modified atmosphere,<br />while the second part of the sample is packaged in the<br />same way, but previously protected with optimized<br />starch edible coating. Influence of optimized starch<br />coating on the osmotic dehydrated meat was examined<br />by monitoring the quality change during storage in<br />order to preserve the quality and shelf life of packed<br />meat.<br />The results showed that an edible starch based active<br />coating contributes significantly to the stability of the<br />packaged osmotically dehydrated meat during the<br />storage period in terms of lipid oxidation,<br />microbiological stability and positive influence on the<br />sensory characteristics of the osmotically dehydrated<br />meat during the storage period.</p>
46

Óleo essencial de pimenta rosa (Schinus terebinthifolius RADDI): atividade antimicrobiana e aplicação como componente ativo em filme para bioconservação de alimentos / Essential oil of pink pepper (Schinus terebinthifolius RADDI): antimicrobial activity and application as active component in film for food bioconservation

Dannenberg, Guilherme da Silva 30 May 2017 (has links)
Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-07-07T15:23:04Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) TESE - Dannenberg 2017.pdf: 1125673 bytes, checksum: 659297f040c56e3fca1291a9ee608e18 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-07-17T19:55:10Z (GMT) No. of bitstreams: 2 TESE - Dannenberg 2017.pdf: 1125673 bytes, checksum: 659297f040c56e3fca1291a9ee608e18 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-17T19:55:10Z (GMT). No. of bitstreams: 2 TESE - Dannenberg 2017.pdf: 1125673 bytes, checksum: 659297f040c56e3fca1291a9ee608e18 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-05-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A utilização de conservantes naturais bem como de embalagens ativas vêm ganhando espaço na indústria de alimentos. Neste trabalho, objetivou-se avaliar as características antimicrobianas do óleo essencial de pimenta rosa (OEPR) e, utilizá- lo como componente ativo na elaboração de filmes para aplicação no desenvolvimento de embalagens bioconservantes para alimentos. Através da análise cromatográfica (CG/MS), detectou-se 18 compostos, 4 monoterpenos e 14 sesquiterpenos, dos quais β-mirceno (41%), β-cuvebeno (12%) e Limoneno (9%) foram os majoritários. Na atividade antimicrobiana do OEPR em ágar e caldo, verificou-se ação contra cinco bactérias patogênicas. A CIM (Concentração Inibitória Mínima) para S. aureus e L. monocytogenes foi de 0,68 e 1,36 mg/mL, respectivamente e a CBM (Concentração Bactericida Mínima) foi de 2,72 mg/mL, para ambas. Em micro-atmosfera a redução foi de 100% no desenvolvimento de S. aureus e L. monocytogenes e, 16 e 15% para E. coli e S. Typhimurium. O tempo de contato necessário para a CBM agir sobre bactérias Gram positivas foi inferior ao período de 12 h, e bactérias Gram negativas não foram inibidas. Além disso, foram verificadas alterações na permeabilidade e integridade da membrana citoplasmática de todas as bactérias avaliadas, indicando que o dano no envoltório celular é um dos seus mecanismos de ação. O OEPR foi aplicado como componente ativo em filmes de acetato de celulose, avaliados in vitro (ágar, caldo e micro-atmosfera) e in situ (queijo mozarela fatiado) contra bactérias patogênicas. Foi verificado que concentrações de 2, 4 e 6% de OEPR na matriz polimérica, conferiu atividade em todos os meios avaliados contra L. monocytogenes e S. aureus. Escherichia coli foi sensível em meio liquido e em micro-atmosfera, enquanto S. Typhimurium não demonstrou sensibilidade aos filmes antibacterianos. A inibição in situ, demonstrou que a afinidade entre as moléculas apolares do OEPR e os componentes lipídicos do queijo permite a migração do OE do interior do polímero para a superfície facilitando sua dispersão no alimento, indicando favorável sua aplicação como embalagem ativa. / The use of natural preservatives as well as active packaging has sparked interest in the food industry. The objective of this work was to evaluate the antimicrobial characteristics of the essential oil of pink pepper (PPEO) and to use it as an active component in the elaboration of films for application in the development of bioconservant packaging for food. Through the chromatographic analysis (GC/MS) 18 compounds, 4 monoterpenes and 14 sesquiterpenes were detected, of which β- myrcene (41%), β-cuvebene (12%) and Limonene (9%) were the majority. In the antimicrobial activity of PPEO in agar and broth, action was observed against five pathogenic bacteria. The MIC for S. aureus and L. monocytogenes was 0.68 and 1.36 mg/mL, and the MBC was 2.72 mg/mL for both. In micro-atmosphere the reduction was 100% in the development of S. aureus and L. monocytogenes, and 16 and 15% for E. coli and S. Typhimurium. The contact time required for MBC to act on Gram positive bacteria was lower than the 12 h period, and Gram negative bacteria were not inhibited. In addition, changes in the permeability and integrity of the cytoplasmic membrane of all evaluated bacteria were observed, indicating that damage in the cellular envelope is one of its mechanisms of action. PPEO was applied as an active component in cellulose acetate films evaluated in vitro (agar, broth and micro-atmosphere) and in situ (sliced mozzarella cheese) against pathogenic bacteria. It was found that concentrations of 2, 4 and 6% PPEO in the polymer matrix conferred activity on all média evaluated against L. monocytogenes and S. aureus. Escherichia coli was sensitive in liquid medium and in microatmosphere, while S. Typhimurium showed no sensitivity to antibacterial films. In situ inhibition has demonstrated that the affinity between the OEPR apolar molecules and the lipid components of the cheese allows migration of the OE from the interior of the polymer to the surface and facilitates its dispersion in the food, indicating its favorable application as an active packaging. Keywords: Essential oil; Antibacterial activity;
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Caracteriza??o das propriedades funcionais de filmes ativos antimicrobianos aditivados com ?leos essenciais e plastificante / Characterization of the functional properties of antimicrobial active films additivated with essential oils and plasticizer

Gon?alves, Sheyla Moreira 23 February 2016 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-13T12:25:00Z No. of bitstreams: 1 2016 - Sheyla Moreira Gon?alves.pdf: 3716146 bytes, checksum: eaee6e62414cd3d497528f597f1abab5 (MD5) / Made available in DSpace on 2016-10-13T12:25:00Z (GMT). No. of bitstreams: 1 2016 - Sheyla Moreira Gon?alves.pdf: 3716146 bytes, checksum: eaee6e62414cd3d497528f597f1abab5 (MD5) Previous issue date: 2016-02-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The use of active packaging incorporated with natural antimicrobials as essential oils (EOs) for food preservation is a modern concept for the food industry. The objective of this study was to characterize cellulose acetate film (CA) incorporated with EOs and their combinations and/or added plasticizer, evaluating the influence of additives on the behavior of these materials. It is characterized as the thickness of the films, visual aspect, chemical structure, surface, mechanical strength, water vapor rate of transmission (WVRT) and antimicrobial activity. Through technique "casting" were obtained films incorporated with 50% (w/v) of EOs oregano or cinnamon or sweet fennel or combinations thereof and/or glycerol (5, 10, 20 and 30% (w/v)). Having as controls only films containing 50% (w/v) glycerol, and CA pure film, a total 41 treatments. The incorporation of EOs did not change the thickness and transparency of the films, but it reduced the WVRT. The color parameters L *, a* and b* were affected by the incorporation with EOs and/or glycerol the films exhibited clear with different colors compared with the AC pure film. Incorporating the most EOs cause increased tensile strength (TS) of the modulus of elasticity (ME) and reduced elongation at break (EB), except for the film with fennel EO (FEO) who presented plasticizer power differing from the other for all the evaluated mechanical parameters. The drilling force (DF) has increased to most films EOs incorporated with the exception of the film incorporated with the three EOs. The scanning electron microscopy (SEM) images revealed that most of the EOs and their combinations did not cause changes in the surface and cross-sectional area of the films, except the film with FEO. In the spectra of infrared spectroscopy with Fourier transform (FTIR), it observed that the interactions between the polymer matrix and most EOs were similar except for the film with FEO. As for the antibacterial efficiency in vitro, only the film incorporated with FEO showed no efficacy against Staphylococcus aureus (Gram +) and Escherichia coli (Gram +). It was observed that glycerol causes increased thickness and WVRT the AC films, however, the active films with EOs does not modify the parameter to most treatments. Transparency was not affected for most films. The addition of glycerol for most films incorporated with EOs caused reduction of TS, the ME and increased EB and DF. From the SEM pictures it can be observed that the glycerol promoted the emergence of porous structures, networked or compact, depending on the EO concentration and glycerol. The FTIR spectral showed that glycerol has different interactions, depending on the embedded EOs. The antibacterial efficiency of films with EO oregano or cinnamon or oregano more cinnamon has been improved with the presence of glycerol, while the others were not affected. In the face of changes in functional properties observed, it appears that with the additivation materials it is necessary to characterize them to define their applicability / O emprego de embalagens ativas incorporadas com antimicrobianos naturais, como os ?leos essenciais (OEs) para conserva??o de alimentos, representa um conceito moderno para a ind?stria aliment?cia. Objetivou-se neste trabalho caracterizar filmes de acetato de celulose (AC) incorporados com OEs e suas combina??es e/ou adi??o de plastificante, avaliando as influ?ncias da aditiva??o no comportamento f?sico e mec?nico destes materiais. Caracterizou-se os filmes quanto ? espessura, aspectos visuais, estrutura qu?mica, superf?cie, resist?ncia mec?nica, taxa de transmiss?o ao vapor de ?gua (TTVA) e atividade antimicrobiana. Atrav?s da t?cnica ?casting? foram obtidos filmes incorporados com 50% (p/v) de OEs de or?gano, canela, funcho doce ou suas combina??es e/ou glicerol (5, 10, 20 e 30% (p/v)). Tendo como controles filmes contendo somente 50% (p/v) de glicerol, e filme de AC puro, totalizando 41 tratamentos. A incorpora??o de OEs n?o modificou a espessura e transpar?ncia dos filmes, por?m causou redu??o da TTVA. Os par?metros de cor L*, a* e b* foram afetados pela incorpora??o de OEs e/ou glicerol tendo os filmes apresentado-se claros com diferentes cores em compara??o com o filme de AC puro. A incorpora??o da maioria dos OEs causou aumento da resist?ncia ? tra??o (RT), do m?dulo de elasticidade (ME) e redu??o do alongamento na ruptura (AR), com exce??o para o filme com OE de funcho (OEF) que apresentou poder plastificante diferindo dos demais para todos os par?metros mec?nicos avaliados. A for?a de perfura??o (FP) aumentou para a maioria dos filmes incorporados com OEs, a exce??o do filme incorporado com os tr?s OEs. As imagens de microscopia eletr?nica de varredura (MEV) revelaram que a maioria dos OEs e suas combina??es n?o causaram mudan?as na superf?cie e regi?o transversal dos filmes, a exce??o do filme com OEF. Nos espectros da espectroscopia no infravermelho com transformada de Fourier (FTIR), notou-se que as intera??es entre a matriz polim?rica e a maioria dos OEs foram semelhantes, com exce??o para o filme com OEF. Quanto ? efici?ncia antibacteriana in vitro, somente o filme incorporado com OEF n?o apresentou efetividade contra Staphylococcus aureus (Gram +) e Escherichia coli (Gram -). Foi observado que o glicerol causou aumento da espessura e TTVA nos filmes de AC, por?m, nos filmes ativos com OEs n?o modificou o par?metro para maioria dos tratamentos. A transpar?ncia n?o foi afetada para a maioria dos filmes. A adi??o de glicerol para a maioria dos filmes incorporados com OEs causou redu??o da RT, do ME e aumento do AR e FP. Pelas imagens do MEV observa-se que o glicerol promoveu o surgimento de estruturas porosas, em rede ou compactas, dependendo do OE e concentra??o de glicerol. Os espectros da FTIR demonstraram que o glicerol apresentou diferentes intera??es, dependendo do OE incorporado. A efici?ncia antibacteriana dos filmes com OE de or?gano ou canela ou or?gano mais canela foi melhorada com a presen?a de glicerol, enquanto os demais n?o sofreram influ?ncia. Diante das varia??es nas propriedades funcionais observadas, verifica-se que com a aditiva??o dos materiais ? necess?rio caracteriza??o para definir sua aplicabilidade
48

Uticaj ambalaže i savremenih uslova pakovanja na održivost tradicionalnih pekarskih proizvoda / Impact of Packaging Material and Contemporary Packaging Conditions on Traditional Bakery Products sustainability

Psodorov Dragan 07 November 2019 (has links)
<p>Predmet doktorske disertacije obuhvata izbor ambalažnog materijala i uslova pakovanja, pakovanje tradicionalnog pekarskog proizvoda pite sa sirom, kao i očuvanje proizvoda tokom skladi&scaron;tenja.<br />Polupečene pite sa sirom su proizvedene i pakovane u petoslojne i sedmoslojne polimerne kese, pri atmosferskim i u uslovima modifikovane atmosfere pakovanja, sa dodatkom i bez dodatka sakupljača kiseonika. Nakon pakovanja, pite su skladi&scaron;tene i ispitivane po sledećoj dinamici: 0, 2, 4, 8, 12 i 16 nedelja skladi&scaron;tenja. Izvr&scaron;ena su ispitivanja ambalažnih materijala i ambalaže, kao i upakovanog proizvoda. Tokom ispitivanja ambalažnih materijala i ambalaže određivana su: fizičko-hemijska i strukturna svojstva ambalažnih materijala, barijerna svojstva ambalaže, koncentracija gasova u ambalaži i kvalitet formiranih varova. Ispitivanja upakovanog proizvoda su se odnosila na: fizičko-hemijska svojstva pite sa sirom, senzorska svojstva pite sa sirom i mikrobiolo&scaron;ka ispitivanja pite sa sirom.<br />Primenjeni ambalažni materijali su pokazali odgovarajuća fizičko, mehanička i strukturna svojstva. Takođe, oba ambalažna materijala pokazuju dobre barijerne karakteristike na ispitivane gasove. Izračunavanjem ukupne zapremine kiseonika koja može biti propu&scaron;tena kroz ambalažu tokom skladi&scaron;tenja je utvrđeno da je upotreba sakupljača kiseonika od 100 ml dovoljna da omogući skladi&scaron;tenje pite sa sirom, pakovane u obe vrste ambalaže, u vremenskom periodu od 122 dana (16 nedelja), bez promene koncentracije kiseonika veće od 1%. Analizom koncentracije gasova u ambalaži je utvrđeno da su najmanje oscilacije merenih gasova tokom skladi&scaron;tenja pokazali uzorci pakovani u petoslojne, kao i sedmoslojne kese, u atmosferi vazduha sa dodatkom sakupljača kiseonika. Fizičko-hemijska svojstva (kiselinski stepen, peroksidni broj, sadržaj vlage, aw vrednost) uzoraka pita sa sirom su se menjala tokom skladi&scaron;tenja, zavisno od vrste ambalaže i uslova pakovanja. Period skladi&scaron;tenja utiče na senzorski kvalitet proizvedenih pita sa sirom. Nakon 16 nedelja skladi&scaron;tenja pita sa sirom upakovanih usa sirom kese od petoslojnog i sedmoslojnog ambalažnog materijala, u atmosferskim uslovima, sa dodatkom sakupljača kiseonika, ne dolazi do promena ukupnog broja kvasaca i plesni.<br />Na osnovu ciljeva doktorske disertacije, izvr&scaron;enih ispitivanja i postignutih rezultata, može se zaklučiti da su predloženi ambalažni materijali, kao i uslovi pakovanja doprineli produženju održivosti tradicionalnog pekarskog proizvoda - pite sa sirom.<br />Primenom barijernih ambalažnih materijala, kombinovanjem atmosferskih uslova pakovanja i sakupljača kiseonika, moguće je skladi&scaron;titi pite sa sirom u dužem periodu.</p> / <p>The subject of doctoral thesis includes the selection of packaging material and packaging conditions, packaging of traditional bakery product phyllo dough pastry with cheese, as well as the preservation of the product during the storage period. Partially baked phyllo dough pastry with cheese have been produced and packed into five and seventh layer polymeric bags, by using atmospheric and modified atmospheric packaging conditions, with and without the addition of the oxygen scavengers. After the packaging, phyllo dough pastries have been stored, and the dynamics of researches has been referred to: 0, 2, 4, 8, 12 and 16 week of storing.<br />Researches of packaging material and the product of packaging have been conducted. Examination of packaging material includes: physicochemical and structural properties, barrier properties, concentration of gases inside the packaging and the quality of welds. Examination of the product of packaging includes: physicochemical properties, sensorial properties and microbiological properties of the phyllo dough with cheese.<br />Applied packaging materials have shown an adequate physical, mechanical and structural performances. Furthermore, both packaging materials have shown good barrier characteristics against examined gases. By the calculation of total oxygen volume, which might penetrate throughout packaging materials during storing period, it can be concluded that the application of 100 ml oxygen scavenger is sufficient to provide the storing of phyllo dough pastry, packed in both packaging materials, during a period of 122 days (16 weeks) without oxygen concentration changes higher than 1%. The analysis of gas concentration in packaging has shown that the smallest oscillations of gas concentration during the storage have been determined inside the packaging of five and seven layer packaging material, in air conditions by using oxygen scavengers.<br />Physicochemical performances (acid number, peroxide value, moisture content and aw value) of the samples vary depending on the packaging material and the packaging conditions, during the storage period. The storage period affects the sensorial quality of phyllo dough pastries. After sixteen weeks of storage, phyllo dough pastry with cheese, packed into five and seven layer packaging material, in air atmosphere, with the addition of oxygen scavenger, did not show the increase of the total number of yeasts and molds.<br />Based on the goals, conducted research and results obtained, it might be concluded that suggested packaging materials, as well as the packaging conditions contribute to the additional sustainability of traditional bakery product - phyllo dough pastry with cheese. By the application of barrier packaging material, and combining the atmosphere packaging conditions and the oxygen scavenger it is possible to store phyllo dough pastry for a longer period.</p>
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Mathematical modelling of active packaging systems for horticultural products : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Packaging Technology at Massey University, New Zealand

Utto, Weerawate January 2008 (has links)
Active packaging systems can offer significant advantages in preventing quality loss in horticultural products through control of microbial and/or physiological activity. By delivering and sustaining volatile active agents at effective levels in a package atmosphere, significant shelf life extension can thus be achieved. Design of these systems is complicated by the number of possible package, product, active agent and carrier combinations that can be employed and the significant interactions that may occur between these components. Mathematical modelling can be used to simplify system design and reduce the number of experimental trials required to achieve optimal active packaging systems. In this study a generalised modelling methodology was developed and validated to facilitate the design of active controlled volatile release packaging systems for horticultural products. The modelling methodology was developed using an example system which comprised tomatoes packed under a modified atmosphere (MA; 5 % (v/v) CO2 and 10 % (v/v) O2) in a LDPE bag with a polymer film sealed sachet containing silica gel pre-saturated with the antifungal agent hexanal. Experimental trials showed that for this system a target sustained hexanal concentration of 40-70 ppm was required. This was shown to be (i) the minimum inhibitory concentration (MIC) for controlling Botrytis cinerea growing on tomatoes stored at 20°C and ~99%RH, (ii) to have only a relatively minor influence on the postharvest quality of tomatoes under these active MA conditions, and (iii) to promote only a small apparent uptake of hexanal from the atmosphere by the tomatoes. The effective hexanal permeabilities of Tyvek , LDPE and OPP sachet films were characterised using the isostatic method and shown to exhibit a dependence on both temperature (10 and 20°C) and concentration (over a range of 0.01-0.22 mol m[superscript -3). Average permeabilities decreased in the order of Tyvek > LDPE > OPP, respectively, at all temperatures at comparable hexanal partial pressures. Hexanal sorption isotherms for silica gel at both 10 and 20ºC were determined using the gravimetric method and were reasonably well described by the Langmuir equation. The equilibrium amount adsorbed was significantly reduced at the higher temperature but the pre-adsorption of water vapour on hexanal uptake on silica gel showed no uniform trend on the sorption characteristics suggesting that multicomponent sorption is complex. A generalised modelling methodology was developed through conceptualising key mass transfer processes involved in these active MA packaging systems. Quantitative methods for deciding the relative importance of each process were established together with guidelines for when simplifying assumptions could be made. This information was formalised into a decision tree to allow appropriate assumptions to be made in model formulation without unacceptable loss of model accuracy. Methods to develop generalised equations from these assumptions to describe changes in the sachet, package headspace and outer bag film with respect to an active agent and MA gases were then identified. The mathematical modelling methodology was applied to the example hexanal release active MAP tomato packaging system. For these systems there was a high initial peak in package headspace concentration during the first 24 h which declined to a quasi steadystate concentration over a period of days. The quasi steady-state headspace concentrations were generally in the MIC range and were well predicted by the model. Interactions between water vapour and silica gel may have been responsible for the relatively higher hexanal concentration at the onset of release from the Tyvek sachet (a highly porous material). However the influence of water vapour (>95% RH in the MA bag containing tomatoes) during the quasi steady-state period appeared to be insignificant for all sachet films. The model was successfully applied to a range of packaging configurations and storage temperatures. A lack of fit was evident between model predictions and experimental trials during the initial (unsteady-state) stages of the release pattern for both headspace vapour concentrations and adsorbed mass on the silica gel. These differences were attributed to (i) model input uncertainties, chiefly with regard to the estimated coefficients of both the Langmuir isotherm equation and film permeability, and (ii) overestimated effective permeability values predicted by extrapolation of the concentration dependence of film permeability beyond the conditions for which the permeability was measured. These results suggest improved models for the effective permeabilities of the films, quantified under a range of vapour concentrations and concentration gradients, are required for better describing fluxes across the sachet film. Despite these limitations, the model did describe the general release pattern. The model was then used to pose a range of ‘what-if’ scenarios investigating the release patterns predicted for different active packaging designs. This analysis gave useful insights into how sorption isotherm shape and package/sachet design parameters can be manipulated to achieve different volatile release platforms. The work clearly demonstrated the importance of accurate data for permeability of volatile compounds through polymer films and for sorption of the active agent on the carrier phase. More work on characterising these systems is recommended to further improve modelbased design methods for active MAP systems. Overall the generalised methodology developed can be confidently adopted for constructing a mathematical model that provides sufficient accuracy and simplicity to be implemented for designing active packaging systems for horticultural and food products.
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Kinetic modeling of oxygen absorption by unsaturated esters and linseed oil to be used as oxygen scavengers / Modélisation cinétique des principes actifs à base de lipides non-saturés pour l'emballage actif

Garcia, Angela 15 January 2016 (has links)
Les capteurs d’oxygène sont le plus grand apport dans la technologie des emballages actifs parce qu’ils permettent de retarder la dégradation oxydante des aliments et ainsi éviter la perte de saveurs et le développement microbien au sein des aliments. Bien que le développement des emballages actes existe depuis les années 70 dans des pays producteur agricole, la recherche sur ces emballages reste encore embryonnaire, en particulier sur les critères techniques portant sur l’absorption d’oxygène de films. Cette thèse constitue une contribution sur l’étude des cinétiques d’absorption d’oxygène de l’huile de lin comme capteur d’oxygène. L’oxydation de l’huile et d’esters insaturés (composé modèle de l’huile) est suivie sous différentes conditions d’exposition (températures comprises entre 40-110°C et pressions partielles d’oxygène entre 0 et 1 bar). Expérimentalement, on propose de caractériser l’absorption d’oxygène liée à l’oxydation de l’huile par thermogravimétrie (ATG), suivi de concentration d’oxygène et titrage de peroxide. Un modèle cinétique basé des schémas classiques avec décomposition des hydroperoxydes, est proposé pour simuler l’oxydation de l’huile de lin et des esters insaturés modèles. Ce modèle est ensuite extrapolé à des films de différentes épaisseurs de polypropylène (PP) contenant 1% d’huile de lin en considérant que cette dernière est bien dispersé dans la matrice PP et que la diffusion d’oxygène est pilotée par la matrice PP. / Oxygen scavengers (OS) are one of the most important technology of active packaging, because prevents oxidative degradation related with off-flavours, off-odours and microbial growth in food. Although active packaging has been proposed since 1970s, in developing countries with a large agricultural base, active packaging still remains unexplored both in terms of application and research, there is a lack of technical criteria on O2 scavenging films, labels, sheets, and trays. This PhD thesis is a contribution in the study of linseed oil as active ingredient for OS providing a kinetic characterization of its thermo-oxidation between 40°C and 110°C in atmospheres with different oxygen concentration. In the experimental approach, innovative application of TGA was proposed to study oxygen uptake capacity complemented by headspace and peroxide value measurements. The kinetic model, derived from a classic mechanistic scheme where initiation of thermo-oxidation results from decomposition of hydroperoxides, was capable to simulated linseed oil oxidation, and also oxygen absorptions of polypropylene films, of different thickness, containing 1% of linseed oil, with hypotheses of well dispersion of linseed oil in PP matrix, and oxygen diffusion governed by the PP matrix.

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