Abstract The use of natural antimicrobial additives, such as orange essential oil (OO), can be a promising possibility to increase food shelf life with the aid of active packaging. This study aimed to develop an active packaging using orange oil and PBAT - poly (butylene adipate co- terephthalate) to store mozzarella cheese produced by a fine film extruder with 5, 10, and 15% OO (w/w). In the results, D-limonene was oil’s main constituent with antimicrobial activity against E. aerogenes, E. coli, and S. aureus. The addition of the oil did not alter the thermal stability of the film. The water vapor permeability increased with increasing oil concentration. All films presented high strength. However, films with higher OO concentrations favored the degradation process, as observed in the activation energy. The active packaging added with 15% OO (PBAT15) was efficient, reducing microbial growth up to 6 days of storage of mozzarella cheese.

Abstract Biotechnology can be used to convert waste into valuable products. In this context, there is bacterial cellulose (BC), a natural biopolymer that can be transformed into several useful materials, but its production is limited due to the high cost of the culture media used for its industrialization. In this work, BC was produced from the bacteria Komagataeibacter rhaeticus, using coffee grounds, sugarcane molasses and ethanol. The experiments were carried out under static conditions. The products were collected every 48 h, with a total period of 240 h. The maximum BC production (11.08 g.L-1) was obtained in a culture medium supplemented with coffee powder, hydrolyzed cane molasses and the addition of 1% (v/v) ethanol. The results show that the use of different carbon sources of the evaluated by-products are viable alternatives in reducing costs in BC production.

RESUMO As embalagens têm como função básica proteger o alimento e garantir a sua integridade comercial. Podem ser produzidas a partir de materiais biodegradáveis com funcionalidades específicas, tais como ação antimicrobiana e antioxidante. Além disso, pesquisas vêm sendo desenvolvidas de modo a substituir os aditivos sintéticos por outros naturais, como os extratos vegetais, devido aos compostos químicos presentes em suas misturas. O poli(butileno adipato co-tereftalato) - (PBAT) vem sendo extensivamente estudado como uma possível substituição aos polímeros convencionais devido à sua biodegradabilidade. Desse modo, o objetivo desse trabalho foi avaliar as potencialidades dos extratos vegetais de jurema preta (Mimosa tenuiflora) e cajueiro (Anacardium occidentale Linn), a fim de aplicá-los como aditivos em embalagens de PBAT com propriedades ativas antioxidantes e antimicrobianas. Os extratos foram obtidos pela técnica de extração Sohxlet em três diferentes tempos, 4, 6 e 8 horas, cujo melhor rendimento ocorreu nos tempos de 6 horas para jurema preta e 4 horas para cajueiro. No teste de presença de flavonóides o extrato de jurema preta apresentou maior concentração e no teste de fenólicos totais, utilizando o método de Folin-Ciocalteau, o cajueiro obteve maior concentração. Ambos os extratos apresentaram capacidades antioxidantes significativas pelos dois métodos, fosfomolibdênio e DPPH. cajueiro apresentou melhor halo de inibição frente ao Staphylococcus aureus, e, por isso, foi determinada a sua concentração mínima inibitória (CMI), 0,0170 g.mL-1. Esse extrato foi incorporado ao PBAT, para o ensaio de migração no meio etanólico, por meio do qual foi determinado um modelo cinético e foi observado que a taxa de migração, 0,0167 ?g.mL-1.min-1, foi reduzida em cerca de um dia, indicando bom potencial do extrato para esses tipos de embalagem.

ABSTRACT Packaging has the basic function of protecting the food and ensuring its commercial integrity. They can be produced from biodegradable materials with specific functionalities such as antimicrobial and antioxidant action. In addition, research has been carried out to replace synthetic additives with natural additives, such as plant extracts, due to the chemical compounds present in their mixtures. Poly (butylene adipate co-terephthalate) - (PBAT) has been extensively studied as a possible replacement for conventional polymers due to its biodegradability. Thus, the objective of this work was to evaluate the potentialities of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale Linn) plant extracts in order to apply them as additives in PBAT packages with antioxidant and antimicrobial active properties. The extracts were obtained by the Sohxlet extraction technique at three different times, 4, 6 and 8 hours, with the best yield at 6 hours for jurema preta and 4 hours for cajueiro. In the flavonoid presence test the jurema preta extract presented higher concentration and in the total phenolics test, using the Folin-Ciocalteau method, the cashew tree obtained the highest concentration. Both extracts showed significant antioxidant capacities by the two methods, phosphomolybdenum and DPPH. Cashew tree presented better inhibition halo against Staphylococcus aureus, and therefore its minimum inhibitory concentration (MIC) was determined, 0.0170 g.mL-1. This extract was incorporated into the PBAT for the ethanolic migration test, by means of which a kinetic model was determined and it was observed that the migration rate, 0.0167 ?g.mL-1.min-1, was reduced by about a day, indicating good extract potential for these types of packaging.

Abstract The aim of this investigation was to assess the effects of gamma radiation on nanocomposite films (NC films) formed by PCL (polycaprolactone) with MCM-48 nanoparticles (PCL/MCM-48) and PCL with MCM-48 NPs modified with (3-aminopropyl)triethoxysilane (APTES) (PCL/MCM-48-NH2). The nanocomposite films were obtained using the solvent casting method. After preparing the films, they were irradiated at 25 kGy in the presence of air and analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), transmission electronic microscopy (TEM), as well as for their mechanical properties. The exposure of NC films to gamma radiation at 25 kGy did not cause major changes in either thermal or mechanical properties such as tensile strength and modulus of elasticity. The results revealed that gamma radiation was a successful choice for the sterilization of these materials.

Abstract In this work were developed and evaluated new antimicrobial films of polyhydroxybutyrate (PHB) additivated with polyethyleneglycol (PEG) and clove essential oil (CEO). The PHB/PEG/CEO films were prepared using the solution casting technique. The CEO concentrations varied between 0.0 and 15% (w/w), related to the total mass (1.4 g), without considering the solvent used. The CG-MS analysis showed that the major component of the CEO was eugenol (72.96%). The antimicrobial activity from the CEO was evaluated against three bacteria (E. coli, E. aerogenes and S. aureus). The migration of CEO in the films occurred with all tested simulants. Thermal analysis has shown that the addition of 15% w/w of the CEO causes the biggest changes in the chemical structure of the material, resulting in less energy during film processing. The mechanical data demonstrated that the addition of 15% w/w of the CEO results in more flexible films.

RESUMO A celulose, polissacarídeo de origem vegetal, é um biopolímero abundante encontrado na natureza e, portanto, de grande valia para a ciência dos materiais em aplicações na área médica, cosmética, refinaria e outros. Como alternativa à produção tradicional de celulose, tem-se a via microbiana, que resulta numa fibra de caráter nanométrico e com boas propriedades mecânicas. Dentre os diversos micro-organismos que produzem celulose bacteriana (CB), e que apresenta resultados satisfatórios destaca-se a bactéria estritamente aeróbica e Gram-negativa conhecida como Gluconacetobacter hansenii (ATCC - 23769). Esse biopolímero apresenta enorme potencial de aplicação devido às suas propriedades térmicas, mecânicas e biocompatibilidade. Muitas pesquisas estão sendo realizadas para otimizar os processos produtivos de CB, resultando em maiores conversões com um menor custo produtivo. O presente trabalho teve como objetivo, produzir as membranas de celulose bacteriana em meio de manitol (C-MM) ou Hestrin e Schramm (C-MH), e também caracterizá-las por meio de análises de espectroscopia de infravermelho (IV), termogravimétrica (TGA), e difração de raios X (DRX). Como principais resultados, as celuloses produzidas apresentaram imagens morfológicas similares, mas no meio de manitol apresentou maior rendimento (2,09 g.L-1) na produção de CB, quando comparado ao Meio Hestrin e Schramm (HS) (1,15 g.L-1). Além disso, a celulose bacteriana produzida no meio de manitol apresentou maior cristalinidade (78%) que a produzida no meio de Hestrin e Schramm (HS) (65%). Através da análise de IV, foi possível confirmar os grupos funcionais existentes na celulose bacteriana sem a presença de quaisquer contaminantes oriundo do processo de produção. Já com relação a análise termogravimétrica, o polímero formado a partir do meio de manitol apresentou maior estabilidade térmica. Desta forma, os biofilmes produzidos nos diferentes meios apresentaram propriedades diferentes, revelando que as características poliméricas são modificadas em função do meio de crescimento bacteriano.

ABSTRACT The cellulose, polysaccharide of vegetable origin, is an abundant biopolymer found in nature and, therefore, a valuable tool for the science of materials applications in the medical, cosmetic, refinery, and other areas. As an alternative to traditional cellulose production, we have the microbial path, which results in a nanometric fiber with good mechanical properties. Among the several microorganisms that produce bacterial cellulose (BC), the one that presents very satisfactory results is the strictly aerobic and Gram-negative bacteria known as Gluconacetobacter hansenii (ATCC - 23769). This biopolymer presents enormous application potential due to its thermal, mechanical and biocompatibility properties. Many researches are being developed to optimize the productive processes of BC, resulting in greater conversions with a lower production cost. This work aimed to produce the cellulose membranes obtained in mannitol (C-MM) or Hestrin and Schramm (HS) (C-MH) medium and to characterize them through infrared spectroscopy (IR), thermogravimetric (TGA) and X-ray diffraction (XRD) analyses. The celluloses produced presented similar morphological images, but the mannitol medium had a higher yield (2.09 g. L-1) in the BC production when compared to the Hestrin and Schramm medium (HS) (1.15 g. L-1). In addition, the bacterial cellulose produced in medium containing mannitol presented higher crystallinity (78%) than that produced in Hestrin e Schramm (HS) (65%). Through the IR analysis, it was possible to confirm the functional groups present in the bacterial cellulose without any contaminants from the production process. Regarding the thermogravimetric analysis, the polymer formed from the mannitol medium presented higher thermal stability. Finally, the biofilms produced in the different medium had different properties, revealing that the polymeric characteristics change according to the bacterial growth medium.

Abstract In this work were developed and evaluated films of poly(vinyl chloride)-PVC additivated with orange essential oil – OEO. These films were evaluated with FT-IR spectroscopy; mechanical tests; migration OEO in simulants; and determination of stability after sterilization by gamma radiation at a dose of 25 kGy. The OEO was assessed with GC-MS and analysis of antimicrobial activity. The films were prepared by the casting solution technique. The essential oil concentrations in PVC were 2%, 10% and 30% (w/w). The results showed that the OEO was incorporated into the polymer matrix and that this oil had antimicrobial activity against the bacteria E. coli and S. aureus. The migration of OEO in the films occurred with all simulants. The incorporation of OEO in the films also made them more flexible. It was also found that additive with 30% w/w OEO provides a protective effect for the polymer after sterilization by gamma radiation.

PET - poly (ethylene terephthalate) - bottle surfaces were exposed to chemical agents and evaluated with middle infrared spectroscopy (MIR) and near infrared hyperspectral imaging (HSI-NIR). Images (928-2.524 nm) were acquired at different times from bottle surfaces exposed to alkaline, acidic and ethanolic media. Savitzky-Golay smoothing (2nd order polynomial and 5-point window) combined with Standard Normal Variate (SNV) was used for pre-processing data. Scores from principal component analysis (PCA) on images showed discrimination of PET according to exposure time, particularly when employing NaOH. After the first two hours of chemical exposure, significant contribution of the (-C-O + OH) combination band indicated formation of glycol ethylene on the PET surface, which was confirmed from PCA loading plots. MIR reflectance spectra ranged from 4.000 to 650 cm-1. Changes in spectral intensities could be associated with depolymerization of PET when exposed to NaOH. These were confirmed with PCA and attributed to the carboxylate group of terephthalate.

Abstract Packages are essential for the food processing industry. Among the innovative alternatives there is antimicrobial packaging, which aims to reduce or inhibit microbial growing on the food surface. One potential to produce this type of package is poly(3-hydroxybutyrate)-PHB additivated with canola oil. In this work, films of PHB additivated with canola oil were produced in different compositions. Mid-infrared records, tensile mechanical testing and thermal analyses were performed on the films. The results of the mechanical tests indicated that the addition of canola oil to the polymeric matrix of PHB increases the material flexibility. The thermal analyses results showed that the addition of canola oil changes the thermal properties of PHB, such as the melting and crystallization temperatures, maximum crystallization rate and relative crystallinity. The knowledge of these properties is fundamental for the manufacturing process of polymeric materials, due to the specifications required for these materials in the intended applications.

Due to its ester bonds, poly(lactic acid) (PLA) undergoes biodegradation in humid environments, attracting market attention. The goal of this work was to observe the biodegradation in garden soil of PLA nanocomposites with neat (PLA/CNW) and surfactant modified cellulose nanowhiskers (PLA/CNW/S). Three types of surfactants were tested: poly(ethylene glycol) monooleate (PEGMONO) and poly(ethylene glycol) with molecular weight of 300 and 1000 Da. The films were obtained by solution casting, cut in strips of (2x2) cm and buried in garden soil, monitoring the temperature and humidity. After 90, 120 and 150 days changes were observed in the films by visual inspection, polarized light microscopy, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The results showed that the addition of surfactant favored the biodegradation of nanocomposites and that PLA/CNW/PEG1000 showed the fastest biodegradation rate.

Resumo Filmes de Poli(3-hidroxibutirato) (PHB) foram produzidos com a adição de óxido de zinco nanoestruturado (ZnOnano) em diferentes proporções (1%, 3%, 5% m/m). Os filmes foram caracterizados por TGA, DSC, MEV e infravermelho. A atividade antimicrobiana dos filmes na presença da bactéria E. coli também foi avaliada. Foram obtidos filmes homogêneos com boa dispersão das nanopartículas na matriz polimérica. A estabilidade do polímero não foi comprometida pelas nanopartículas, que funcionaram como agentes nucleantes aumentando a cristalinidade do polímero. A análise por componentes principais (PCA) mostrou que a nanocarga alterou as vibrações dos grupos funcionais indicando a existência de interações entre o ZnO e o polímero. O filme nanocompósito contendo 5% do óxido inibiu o crescimento da bactéria patogênica E. coli, mostrando-se, portanto, promissor em aplicações na indústria de embalagens para alimentos.

Summary Industrial Poly(hydroxybutyrate) PHB films were produced with the addition of nanostructured zinc oxide (ZnOnano) in different proportions (1, 3, 5% w/w). The films were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). The antimicrobial activity against the bacteria E. coli was also evaluated. Homogeneous films with good dispersion of the nanoparticles in the polymer matrix were obtained. The stability of the polymer was not compromised by the nanoparticles, which functioned as nucleating agents to increase the crystallinity of the polymer. The principal component analysis (PCA) showed that the nanoclay modified the vibrations of the functional groups, indicating the existence of interactions between the polymer and ZnOnano. The nanocomposite film containing 5% of ZnOnano inhibited the growth of pathogenic E. coli., thus showing promise for applications in the food packaging industry.

Devido ao impacto ambiental causado pelo descarte de embalagens PET, a reciclagem desse material tem sido bastante discutida e avaliada. Em particular, a reciclagem química viabiliza a obtenção dos monômeros utilizados na fabricação da resina PET: o etilenoglicol (EG) e o ácido tereftálico (PTA). Por isso, estudos de otimização desse processo são importantes tanto do ponto de vista ambiental, quanto econômico. Neste trabalho foram investigados certos parâmetros que influenciam a reação de despolimerização do PET pós-consumo via hidrólise alcalina, a fim de obter o PTA. Os ensaios foram realizados à temperatura de 70 °C, variando a concentração da solução de hidróxido de sódio e o tempo de reação. Os melhores resultados foram obtidos para concentração de NaOH 10,82 mol L-1 e tempo de reação de 9 h. Consequentemente, foi possível comprovar a viabilidade do processo, uma vez que as análises por infravermelho e Ressonância Magnética Nuclear confirmaram a obtenção do PTA em todas as reações realizadas.

Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L-1 NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed.

Samples of LDPE/modified starch blends 80/20 m/m before and after exposure to gamma rays were examined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. The effect of gamma radiation is clearly seen in the samples irradiated at a dose of 25 kGy. The main alteration in the polymeric material after exposure at the radiation range was a decrease in the mechanical properties, alterations in the chemical structure of the blend with an increase in the carbonyl and vinyl indices and the appearance of new crystalline symmetry generating a crystalline domain not existing before in the blend.

Nesse trabalho foi realizado um estudo sobre diferentes tipos de amido quanto ao crescimento, e a atividade amilolítica de culturas mistas e isoladas dos fungos Phanerochaete chrysosporium e Talaromyces wortmannii. Avaliaram-se também as propriedades térmicas e mecânicas das blendas de polietileno/amido anfótero (na proporção 80/20 (m/m)) antes e apos a inoculação das culturas mistas desses fungos.O amido regular Amidex 3 e o amido modificado Fox5901 foram os que se destacaram quanto ao crescimento celular e produção da enzima amilase. Apesar do pouco tempo de exposição dos filmes com os fungos, pode-se concluir que os microrganismos promovem mudanças físicas e químicas na estrutura da blenda, modificando suas propriedades térmicas e mecânicas. A alteração do grau de cristalinidade e das propriedades mecânicas das blendas podem ser indícios da modificação provocada pelo processo de biodegradação.

This study evaluated in relation the growth, and the amylolytic activity of mixed and isolated cultures of Phanerochaete chrysosporium and Talaromyces wortmanni on different types of starch. The thermal and mechanical properties in polyethylene/starch blends (proportion: 80/20 (w/w) before and after inoculation of the mixed cultures were evaluated. The regular starch Amidex 3 and the modified starch Fox5901 stood out in relation to the cellular growth and production of the amylase enzyme. In spite of the short time that the blends were exposed to the fungi, the microorganisms promoted physical and chemical changes in the structure of the blend, modifying its thermal and mechanical properties. The alteration of the degree of crystallinity and mechanical properties of the blends could be indications of the modification caused by the biodegradation process.

Poly (vinyl chloride), PVC, is a rigid polymer and for several of its applications must be compounded with plasticizing agents. The plasticizers minimize the dipolar interactions, which exist between the polymer's chains, promoting their mobility. In this work we studied the properties of PVC/plasticizer systems submitted to different doses of gamma radiation. We have used four commercial plasticizers amongt them di(2-ethylhexyl) phthalate, DEHP, which is present in a great number of commercial applications. The PVC/plasticizer systems have been studied as films made by the solvent evaporation technique. Irradiated and non-irradiated films have been characterized by viscosimetric analysis, mechanical essays and infrared spectroscopy. The results have shown that the rigid, non plasticized, PVC film presented the greatest degradation index, while among the plasticized films the one which presented the larger degradation index due to chain scission was the DEHP plasticized PVC.