RESUMO A produção de blendas de PLA/ PBAT tem por objetivo superar as desvantagens que cada polímero possui individualmente, como fragilidade, limitações de processabilidade e custo. Neste estudo, investigamos a miscibilidade e as propriedades de filmes biodegradáveis de PLA - Poli (ácido lático), PBAT- Poli (butileno adipato-co-tereftalato) e de suas blendas com proporções de 95/5, 70/30, 30/70 e 5/95 de PLA/PBAT, respectivamente, produzidos pelo método de evaporação de solvente. As blendas produzidas foram caracterizadas pelas técnicas de espectroscopia Raman, calorimetria exploratória diferencial (DSC), termogravimetria (TGA), microscopia eletrônica de varredura (MEV), viscosimetria de soluções diluídas e ensaio mecânico de tração. A análise dos espectros Raman, temperatura de transição vítrea (Tg), e TGA indicaram imiscibilidade dos polímeros em todas as composições estudadas. As análises mecânicas apontaram para diminuição da rigidez das blendas com a adição do PBAT. Os valores dos parâmetros de interação obtido pela análise de viscosimetria de soluções diluídas, sugerem miscibilidade parcial da blenda contendo 5% de PBAT. O estudo da miscibilidade e das propriedades das blendas de PLA/PBAT obtidas por evaporação de solvente possibilitarão a produção de novos materiais por diferentes técnicas visando novas aplicação para este material.

ABSTRACT The production of PLA / PBAT blends aims to overcome the disadvantages that each polymer had individually, such as fragility, processability and cost limitations. In this study, we investigated the miscibility and properties of biodegradable films of PLA - Poli (lactic acid), PBAT-Poli (butylene adipate-co-terephthalate) and their blends with proportions of 95/5, 70/30, 30/70 and 5/95 PLA / PBAT, respectively, produced by the casting method. The blends produced were characterized by the techniques of Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TGA), scanning electron microscopy (SEM), diluted solutions viscosimetry and mechanical tensile testing. The Raman spectra, glass transitions temperature (Tg), and TGA analysis indicated that the polymers are immiscible in the compositions studied. Mechanical analyzes point to a decrease in the stiffness of the blend with the addition of PBAT. The interaction parameters, obtained by viscosimetry analysis of diluted solutions, suggest partial miscibility of the blend with 5% of PBAT. The study of the miscibility and properties of the PLA / PBAT blends obtained by solvent evaporation will enable the production of new materials by different techniques aiming at new applications for this material.

Abstract This work investigated the influence of microcrystalline cellulose (MCC) in thermoplastic starch/poly (butylene adipate-co-terephthalate) films produced by blown extrusion, using different MCC contents (4, 7 and 10 g.100 g-1). The films were characterised for their mechanical, structural and barrier properties. Increasing fibres concentration reduced the tensile strength (6.9 to 4.6 MPa), the elongation at break (568 to 147%) and weight loss in water (12.8 to 11.1%) of the films. The rigidity of the films increased from 19.8 MPa (without MCC) to 79.2 MPa in the samples with 10 g.100 g-1 of MCC. SEM images showed the occurrence of some agglomerates in this sample. The water vapour permeability of the films was not affected by the presence of MCC. The production of starch/PBAT/MCC films by blown extrusion was successful; however some adjustments are necessary to improve the dispersion of the particles at the polymeric matrix.

The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terephthalate) (PBAT) blown films produced by reactive extrusion were evaluated using citric acid (CA) and maleic anhydride (MA) as compatibilizers. Scanning electron microscopy images showed more homogeneous structure when CA and MA were included in the formulation. The tensile strength (MPa) was improved with the inclusion of the highest proportion of both compatibilizers (1.5 %wt). A larger elastic component with values between 0.42-0.45 for the degree of solidity (1-c1) was observed for the intermediate concentration of compatibilizers. A high level of glycerol (10 %wt) results in films with increased % elongation. Three partially miscible phases were observed in the blends. Biodegradable films of starch/PBAT with better properties could be produced by one-step reactive extrusion using CA and/or MA as compatibilizers.

The objective of the present study was to study the effect of the variables of the osmotic dehydration process on sliced Fuji apples (Malus domestica) using a 2 x 3² factorial design. The variables studied in the apple slices were the pretreatment (blanching or acidification), the temperatures (30, 45 and 60ºC) and the FOS concentration (40%, 50% and 60% m/v) of the osmotic solution. There was no difference among the pretreatments for the water activity and titratable acidity. The slices pre-treated by the acidification presented less enzymatic browning (greatest luminosity L* value) combined with a greater soluble solid contents (thus, this treatment was selected). Treatments T4 (45ºC and 40% m/v) and T7 (60ºC and 40%m/v), using the acidification presented responses within the recommended standards and FOS were validated by the repetition.

A fractional factorial design 2(5-1) was used to evaluate the effect of temperature, pH, and concentrations of yeast extract, tryptone and Nitsch's trace elements on the biomass, total carotenoids and protection against singlet oxygen by carotenoid extracts of the bacterium Thermus filiformis. In addition, the carotenoid composition was determined by high-performance liquid chromatography connected to a diode array and mass spectrometer detectors (HPLC-DAD-MS/MS). The production of biomass ranged from 0.113 to 0.658 g/L, the total carotenoid from 137.6 to 1,517.4 mg/g and the protection against singlet oxygen from 4.3 to 85.1 %. Results of the fractional factorial design showed that temperature had a negative effect on biomass production and a positive effect on carotenoid content and protection against singlet oxygen, besides, high levels of pH value, concentrations of yeast extract and tryptone had a positive effect on biomass production only at lower temperatures. The main carotenoids of T. filiformis were thermozeaxanthins. In the tested conditions, changes in the levels of the variables influenced the biomass, carotenoid production, and protection against singlet oxygen, although they did not influence the carotenoid profile. The results of this study provide a better understanding on the interactions among certain nutritional and cultivation conditions of a thermophile bacterium, Thermus filiformis, on biomass and carotenoid amounts, as well as on the antioxidant capacity.

The aim of this work was to manufacture the biodegradable nanocomposite films by extrusion from different combinations of cassava starch, xanthan gum and nanoclays (sodium montmorillonite - MMT- Na) and to characterize them according to their microstructure, optical, mechanical and barrier properties. Films were manufactured from nine starch/xanthan/nanoclay combinations, containing glycerol as plasticizer. Scanning electron microscopy (SEM) of the starch-xanthan extruded films showed reticulated surface and smooth interior, indicating that the gum was mostly concentrated on the surface of the films, while starch/xanthan/nanoclays films showed a more homogeneous surface, suggesting that the introduction of nanoclays provided a better biopolymeric interaction. In general, nanoclays addition (2.5 - 5.0, w%) generated more transparent and resistant films, with lower water vapor permeabilities and lower water sorption capacities and xanthan gum addition improved the elongation ofa starch films.

O objetivo deste trabalho foi produzir tofu a partir da cultivar de soja BRS 267, utilizando diferentes condições de processamento, e avaliar a influência dos tratamentos sobre a qualidade do produto. Utilizou-se um planejamento experimental do tipo fatorial fracionário 2(5-1), no qualas variáveis independentes (tratamento térmico, concentração de coagulante, tempo de coagulação, corte do coágulo e tempo de dessora) foram testadas em dois diferentes níveis. A variável resposta analisadas foram dureza, rendimento, teor de sólidos totais e de proteínas do tofu, sendo obtidos modelos polinomiais para cada uma delas. As condições de processamento escolhidas para a obtenção de tofu com as características desejadas (~4N de dureza, rendimento de 306 g tofu.100 g-1 grãos, 12g proteínas.100 g-1 tofu e 22 g sólidos.100 g-1 tofu) foram: tratamento térmico longo (após a ebulição, aquecer por mais 10 minutos, em banho-maria), 2% p/p de coagulante sulfato de cálcio di-hidratado, 10 minutos de coagulação, corte do coágulo e 30 minutos de dessora.

The aim of this work was to make tofu from soybean cultivar BRS 267 under different processing conditions in order to evaluate the influence of each treatment on the product quality. A fractional factorial 2(5-1) design was used, in which independent variables (thermal treatment, coagulant concentration, coagulation time, curd cutting, and draining time) were tested at two different levels. The response variables studied were hardness, yield, total solids, and protein content of tofu. Polynomial models were generated for each response. To obtain tofu with desirable characteristics (hardness ~4 N, yield 306 g tofu.100 g-1 soybeans, 12 g proteins.100 g-1 tofu and 22 g solids.100 g-1 tofu), the following processing conditions were selected: heating until boiling plus 10 minutes in water bath, 2% dihydrated CaSO4 w/w, 10 minutes coagulation, curd cutting, and 30 minutes draining time.

Biodegradable foams made from cassava starch, polyvinyl alcohol (PVA), sugarcane bagasse fibers and chitosan were obtained by extrusion. The composites were prepared with formulations determined by a constrained ternary mixtures experimental design, using as variables: (X1) starch / PVA (100 - 70%), (X2) chitosan (0 - 2%) and (X3) fibers from sugar cane (0 - 28%). The effects of varying proportions of these three components on foam properties were studied, as well the relationship between their properties and foam microstructure. The addition of starch/PVA in high proportions increased the expansion index and mechanical resistance of studied foams. Fibers addition improved the expansion and mechanical properties of the foams. There was a trend of red and yellow colors when the composites were produced with the highest proportions of fibers and chitosan, respectively. All the formulations were resistant to moisture content increase until 75% relative humidity of storage.

Citric acid was used as a compatibilizer in the production of starch and PBAT films plasticized with glycerol and processed by blow extrusion. Films produced were characterized by WVP, mechanical properties, FT-IR-ATR and SEM. WPV ranged from 3.71 to 12.73×10-11 g m-1 s-1 Pa-1, while tensile strength and elongation at break ranged from 1.81 to 7.15 MPa and from 8.61 to 23.63%, respectively. Increasing the citric acid concentration improved WVP and slightly decreased film resistance and elongation. The films micrographs revealed a more homogeneous material with the addition of citric acid. However, the infrared spectra revealed little about cross-linking esterification reaction

A preocupação com o volume de lixo tem gerado interesse no desenvolvimento de embalagens biodegradáveis capazes de substituir, ao menos em parte, os plásticos convencionais sintéticos, como é o caso das embalagens de poliestireno expandido (Isopor). Ojvetivou-se,neste trabalho caracterizar, quanto ao índice de expansão (IE), densidade, índice de absorção em água (IAA), índice de solubilidade em água (ISA) e cor (coordenadas L*, a* e b*), compósitos biodegradáveis expandidos produzidos via extrusão, a partir da mistura de amido de mandioca, glicerol (plastificante) e dois tipos de fibras vegetais. Os compósitos foram preparados em extrusora mono-rosca, com três diferentes teores de fibras de aveia ou de cana-de-açúcar (0, 5 e 10 g/100 g amido), dois teores de umidade (18 e 26%) e teor fixo de glicerol (20g/100 g sólidos). A adição das fibras não afetou significativamente o IE, a densidade e o IAA, porém diminuiu o ISA dos materiais, o que é uma vantagem, favorecendo a utilização das fibras no reforço dos compósitos. A adição de fibras levou ao escurecimento das amostras, com decréscimo da luminosidade (L*) e, ainda, ao aumento nos valores dos parâmetros de cor a* e b*. Este estudo é passo fundamental para produção em escala industrial dos compósitos, que necessitam de condições de processo que forneçam resultados reprodutíveis de expansão e capacidade de absorção e solubilidade em água, propriedades de grande importância nesses produtos.

The concern with the volume of waste has generated interest in the development of biodegradable packaging able to replace, at least in part, the conventional synthetic plastics, such as packs of expanded polystyrene (Isopor). This study aimed to characterize the expansion index, density, the water absorption index (WAI), water solubility index (WSI) and color (coordinates L*, a* and b*) of expanded biodegradable composites produced by extrusion, from the mixture cassava starch, glycerol (plasticizer) and two different types of vegetable fibres. The composites were prepared in a single screw extruder, with three different levels of oat or sugar cane fibres (0, 5 and 10 g /100 g starch), two levels of humidity (18 and 26%) and a fixed level of glycerol (20 g/100 g solds). The addition of fibres did not affect significantly the expansion index, density and WAI of materials, and reduced WSI of products, which is an advantage and promotes the use of these fibres in the reinforcement of composites. The addition of fibers led to the darkening of the samples, with decrease in lightness (L*) and increase in the values of the color parameters a* and b*. This study is a key step for a future industrial scale production of these composites, which requires process conditions that provide reproducible results of expansion and absorption capacity and solubility in water, properties of great importance in these products.

Estudou-se o efeito da adição de monoglicerídeo nas propriedades microestruturais, mecânicas e de barreira de filmes de amido de inhame, em diferentes umidades relativas (UR), comparando-as com as de filmes de amido- glicerol. Uma extrusora mono-rosca foi usado para produzir o complexo amido-monoglicerídeo, antes de produzir o filme, e o processo foi efetivo para inibir a separação de fases que geralmente ocorre nesse tipo de filmes. A adição de monoglicerídeo, que é um composto hidrofóbico, reduziu a hidrofilicidade, a transparência e a permeabilidade ao vapor de água dos filmes. O valor desta, para os filmes de amido-glicerol (1,7 x 10-10 g Pa-1 s-1 m-1) foi maior que para os de amido (1,2 x 10-10 g Pa-1 s-1 m-1) e para os de amido-monoglicerídeo (1,0 x 10-10 g Pa-1 s-1 m-1). Os filmes com glicerol tiveram maior cristalinidade relativa (B e V H), com um ligeiro aumento em altas UR, enquanto que nos filmes com monoglicerídeo a cristalinidade foi constante. Os filmes de amido-monoglicerídeo apresentaram piores propriedades mecânicas que os filmes de amido-glicerol, mas foram mais estáveis sob diferentes umidades relativas.

The effect of monoglyceride on microstructural, barrier and mechanical properties of casted yam starch films were investigated in different relative humidities (RH) and compared with glycerol-starch films. A single screw extruder was used to produce the starch - monoglyceride complex before film production and this process was effective to inhibit the phase separation in films. The addition of the hydrophobic compound reduced hydrophobicity, transparency and water vapor permeability of films. This later value for starch-glycerol film (1.7 x 10-10 g Pa-1 s-1 m-1) was higher than starch (1.2 x 10-10 g Pa-1 s-1 m-1) and monoglyceride-starch films (1.0 x 10-10 g Pa-1 s-1 m-1). Films containing glycerol had higher relative crystallinity (B and V H) with a slight increase at higher RH values, while for monoglyceride films, the crystallinity was constant. Monoglyceride-starch films presented poor mechanical properties when compared to glycerol- starch ones but they presented a stable behavior under different relative humidities.

Este trabalho avaliou a relação entre a composição química aproximada do charque (CHM) com a maciez durante todas as etapas de sua produção. CHM foi produzida do m. Vastus lateralis bovino (patinho) de aproximadamente 4-5 anos de idade. A força de cisalhamento do charque cru mostrou o valor aproximado de 3 vezes maior em dureza comparada à matéria prima enquanto que no caso do CHM cozido houve 6 vezes maior em aumento sob as mesmas condições.O índice de umidade diminui de 39 a 58% (p<0,05) para CHM cru e cozido, respectivamente, em relação à matéria prima. O modelo matemático da influência destes componentes mostrou que a força de cisalhamento aumentou exponencialmente com a perda de umidade. A textura do charque é o resultado da associação de multifatores envolvendo proteínas miofibrilares que provocam eventos bioquímicos dinâmicos como a sua ligação com as moléculas da água. É a quantidade destas que determina a textura final do charque.

This work evaluated the relationship of charqui meat (CHM) chemical composition with the tenderness throughout its production. CHM was prepared from beef Vastus lateralis of 4-5 years old. Shear force of fresh CHM showed an approx. 3-fold increase in toughness compared to the raw material while, in the case of cooked CHM it was 6-fold increased in relation to the raw charqui. The moisture content decreased by 39.0 and 58.0% (p<0.05) for uncooked and cooked CHM, respectively, in relation to the raw material. Mathematical modeling of the influence of these meat components showed that shear force increased exponentially with the loss of moisture. The texture of CHM was the result of a multitude of factors involving myofibril proteins which promoted dynamic biochemical events such as the binding of water molecules. It was the amount of the latter which ultimately determine the final charqui meat texture.

A desidratação osmótica é uma etapa essencial na elaboração de produtos de fruta através da Tecnologia dos Métodos Combinados ou de Obstáculos ("Hurdle Technology"), pois reduz a atividade de água para níveis que, combinando um ou mais obstáculos, aumentam a estabilidade do produto. Neste processo há uma perda de água da fruta para a solução e incorporação de sólidos solúveis pelo produto. Este último fluxo é considerado uma desvantagem do processo pois pode alterar o sabor do produto. Neste trabalho estudou-se a ação de revestimentos comestíveis a base de alginato e gelatina aplicados em abacaxis, previamente à desidratação osmótica, como barreira à incorporação de sólidos solúveis. Os abacaxis com e sem revestimento (controle) foram desidratados em solução de sacarose sob condições isotérmicas. Foram determinadas as isotermas de dessorção de abacaxis revestidos com gelatina, alginato e sem revestimento e os parâmetros cinéticos do processo de desidratação osmótica. Abacaxis revestidos com alginato apresentaram menor velocidade de ganho de sólidos, sem alterar a velocidade de perda de água, quando comparado ao controle.

The osmotic dehydration is an essential stage to manufacture fruit products by Hurdle Technology because it reduces the water activity to levels that, combined with one or more obstacles, increase the stability of the product. This process causes a loss of water from the fruit to solution and soluble solid incorporation by the product. This last flow is considered a disadvantage of the process because it can modify the product flavor. In this work, the action of alginate and gelatin edible coatings as a barrier to soluble solid incorporation during osmotic dehydration was studied. Pineapples with and without coating (control) were dehydrated in sucrose solution under isothermal conditions. The desorption isotherms of pineapples coated with gelatin, sodium alginate and without coating, as well as the kinetic parameters of the osmotic dehydration process were determined. Alginate coated pineapples presented minor solid incorporation without modifying the water loss flow when compared with the control.

O presente trabalho teve por objetivo avaliar o efeito do anelamento do tronco realizado em diferentes épocas, sobre a antecipação da maturação dos cachos da videira 'Rubi', na região noroeste do Paraná. Foram estudados os seguintes tratamentos: testemunha sem anelamento; anelamento com 5-6ºBrix de sólidos solúveis totais (SST) no suco das bagas; anelamento com 7-8ºBrix de SST no suco das bagas, e anelamento com 9-10ºBrix de SST no suco das bagas. O delineamento experimental foi o de blocos ao acaso, com quatro tratamentos e cinco repetições, sendo cada parcela composta por uma planta. O anelamento consistiu na remoção de uma porção da casca do tronco, de aproximadamente 3-4 mm de largura, utilizando-se de um incisor de lâmina dupla, a uma altura de 1,5 m do solo. Foram avaliados semanalmente, a partir da instalação do experimento, o teor de SST e a acidez titulável (AT) do suco. Por ocasião da colheita, compararam-se o peso e o comprimento dos cachos, e o peso, a largura e o comprimento das bagas. Para a estimativa do período ótimo para maturação de cada tratamento, empregou-se análise de regressão, tendo como parâmetro a relação SST/AT = 20. O maior período de antecipação da maturação em relação à testemunha sem anelamento foi obtido quando o suco das bagas apresentava teor de SST entre 5-6ºBrix, ou seja, 8 dias. Não foram observadas diferenças entre os tratamentos quanto às características físicas dos cachos e das bagas.

This work was an attempt to evaluate the trunk girdling effect on different periods to hasten the maturation of 'Rubi' table grape in the northwest of Parana state, Brazil. The following treatments were studied: Control without girdling; Girdling when total soluble solids (TSS) of berries ranged from 5-6 ºBrix; Girdling when TSS of berries ranged from 7-8 ºBrix; and Girdling when TSS of berries ranged from 9-10 ºBrix. A randomized block design with four treatments and five replications was used as an statistical model, and each plot was composed by one plant. Girdling consisted of removing a narrow ring of bark entirely round of the trunk using a double-bladed 3.1 mm knife, 1.5 m far from the ground. Total soluble solids and titratable acidity (TA) were evaluated weekly through berries samples collection, from the establishment of the experiment up to its harvesting. Through regression analysis, it was estimated the advanced fruit ripening period of each treatment considering the index of maturity TSS/TA = 20. The highest period of advanced fruit ripening was observed when girdling was realized when TSS of berries ranged from 5-6 ºBrix, i.e., 8 days. There was no difference in relation to the cluster and berry physico-characteristics between treatments.

Um dos requisitos para o sucesso na produção comercial de agentes de controle biológico é manter sua viabilidade por longos períodos, em condições não controladas, aumentando a vida de prateleira. A atividade de água (Aw) é um parâmetro importante no estudo da estabilidade no armazenamento de produtos desidratados, mas sua determinação direta exige equipamentos nem sempre disponíveis. As isotermas de sorção de água correlacionam Aw com a umidade de um produto; a isoterma de adsorção é importante para definir o sistema de embalagem e a de dessorção o processo de secagem. O objetivo deste trabalho foi determinar as isotermas de sorção de conídios de Beauveria bassiana e ajustá-las utilizando um modelo matemático. A adsorção e a dessorção foram determinadas por técnica gravimétrica a 25ºC e os dados ajustados pelo modelo de BET. Na dessorção, inicialmente os conídios apresentaram alto conteúdo de umidade (98% em base seca) e Aw (0,93); de 98% a 50% foi observada uma baixa redução na Aw, pois a água estava na forma livre. Quando a umidade estava em torno de 505, uma pequena redução na umidade resultou em grande depressão na Aw, pois a água estava na forma ligada. A curva de adsorção mostrou que quando a umidade variou de 9% a 50% um pequeno aumento na umidade dos conídios resultou num grande acréscimo na Aw. O modelo de BET representou adequadamente as isotermas de sorção dos conídios de B. bassiana, sendo útil no estudo do armazenamento do patógeno.

One of the requirements for successful commercial production of biological control agent is the maintenance of viability for long periods at room temperature, increasing shelf life. The water activity (Aw) is an important parameter to study the stability in the storage of dehydrated products but its determination demands equipments not always available. The water sorption isotherms correlate the Aw with the moisture of a product; adsorption isotherm is important to define the packaging system, and desorption isotherm the drying process. The objective of this study was to determine the sorption isotherms of Beauveria bassiana conidia and adjust them using a mathematical model. The adsorption and desorption were determined by gravimetric technique at 25°C and data were adjusted by the BET model. During desorption, conidia initially presented high moisture content (98% in dry basis) and Aw (0,93); from 98% to 50% a low reduction in Aw was observed, because the water was in a free form. When moisture was around 50%, a small reduction on moisture resulted in a great decrease in Aw, because the water was in a bound form. The adsorption curve showed that when moisture varied from 9% to 50% a small increment in conidia moisture resulted in a high increment in Aw. The BET model adequately represented the sorption isotherms of B. bassiana conidia, being useful to define the ideal moisture to storage this biological control agent.