Lipase immobilization on biodegradable film with sericin.

An ecofriendly and low-cost film composed by cassava starch, polyvinyl alcohol, and sericin blend (CS-PVA-SS) was synthesized, characterized, and applied as a novel support for Botryosphaeria ribis EC-01 lipase immobilization by enzyme-film-enzyme adsorption. Film revealed thickness between 230 and 309 µm and higher flexibility and malleability in comparison with film without SS. Based on p-nitrophenyl palmitate hydrolysis reaction, the activity retention of immobilized lipase was 987%. For optimal conditions, the yield in ethyl oleate was 95% for immobilized enzyme. Maximum yield was obtained at 49°C, molar ratio oleic acid:ethanol of 1:3, 1.25 g lipase film or 50 U (1.03 ± 0.03 mg protein) and 30 h. Even after seven cycles of use, immobilized lipase showed 52% reduction in ester yield. Biodegradable and biorenewable film is a promising material as a support to immobilize lipases and application in biocatalysis.

Production of starch-polyester bio-support for lipases immobilization: synergistic action of itaconic acid and nanoclay.

The objective of the present work was to develop biodegradable polymeric films (starch-PBAT) as support for the immobilization of lipases using sodium montmorillonite (MMT) as a reinforcing agent (2% w/w) and itaconic acid (IA - 0.5-1.5% w/w) as a compatibilizing agent. The films were produced through a two steps blow-extrusion. The addition of MMT increased the tensile strength and Tg of the films, while the presence of IA made the films more flexible, reducing their Tg. Lipases from Burkholderia cepacia LTEB11 were immobilized in the films by the adsorption method. The ester yield (% of ethyl oleate synthesis) has shown best results (96%, 6 h) for immobilized enzyme in the MMT film and six cycles of reuse were carried out until a reduction of 50% in the catalytic activity of the enzyme.

Computer Vision Classification of Barley Flour Based on Spatial Pyramid Partition Ensemble.

Imaging sensors are largely employed in the food processing industry for quality control. Flour from malting barley varieties is a valuable ingredient in the food industry, but its use is restricted due to quality aspects such as color variations and the presence of husk fragments. On the other hand, naked varieties present superior quality with better visual appearance and nutritional composition for human consumption. Computer Vision Systems (CVS) can provide an automatic and precise classification of samples, but identification of grain and flour characteristics require more specialized methods. In this paper, we propose CVS combined with the Spatial Pyramid Partition ensemble (SPPe) technique to distinguish between naked and malting types of twenty-two flour varieties using image features and machine learning. SPPe leverages the analysis of patterns from different spatial regions, providing more reliable classification. Support Vector Machine (SVM), k-Nearest Neighbors (k-NN), J48 decision tree, and Random Forest (RF) were compared for samples' classification. Machine learning algorithms embedded in the CVS were induced based on 55 image features. The results ranged from 75.00% (k-NN) to 100.00% (J48) accuracy, showing that sample assessment by CVS with SPPe was highly accurate, representing a potential technique for automatic barley flour classification.

Structural, thermal, and morphological characteristics of cassava amylodextrins.

BACKGROUND: Amylodextrins from cassava starch were obtained by acid hydrolysis, and their structural, thermal and morphological characteristics were evaluated and compared to those from potato and corn amylodextrins. RESULTS: Cassava starch was the most susceptible to hydrolysis due to imperfections in its crystalline structure. The crystalline patterns of amylodextrins remained unchanged, and crystallinity and peak temperature increased with hydrolysis time, whereas thermal degradation temperature decreased, independent of treatment time and starch source. Cassava amylodextrins had similar structural and morphological characteristics to those from corn amylodextrins due to their A-type crystalline arrangements. A-amylodextrins were structurally and thermally more stable than potato amylodextrins (B-type). Starch nanocrystals (SNC) were observed by transmission electron microscopy from the third day of hydrolysis in cassava amylodextrins, whereas potato and corn amylodextrins displayed SNC only on the fifth day. A-SNC displayed platelet shapes, whereas B-SNC were rounded. The SNC shape was related to the packing form and geometry of unit cells of allomorphs A and B. CONCLUSION: Microstructures (agglomerated crystalline particles) and nanostructures (double helix organization) were observed for amylodextrins. Cassava starch was shown to be a promising material for SNC production, since it requires less hydrolysis time to obtaining more stable crystals. © 2017 Society of Chemical Industry.

Os efeitos do farelo de aveia e da farinha de soja na resposta imune humoral de ratos alimentados com dieta hipercolesterolêmica / The effects of oat bran and soy flour on humoral immune response in rats fed hypercholesterolaemic diets

Estudos anteriores têm demonstrado os efeitos sobre o sistema imune e sobre os níveis de colesterol da dieta com fibra solúvel e proteína de soja em ratos. Nesse estudo, nós avaliamos os efeitos do farelo de aveia e da farinha de soja na resposta imune humoral de ratos Wistar tratados com dietas hipercolesterolêmicas. Os animais (6 grupos) foram alimentados com diferentes dietas por 6 semanas e inoculados duas vezes com antígeno (IgY). As amostras de plasma foram coletadas após cada inoculação e os níveis de anticorpos anti-IgY (IgM, IgG1 e IgG2a) foram avaliados por ELISA. Os animais que receberam 1% de colesterol apresentaram um aumento de IgG1 anti-IgY e uma redução de IgM e IgG2a anti-IgY em relação aos animais controle. Estes efeitos foram anulados em animais alimentados com 1% de colesterol e farelo de aveia ou aveia + proteína de soja, mas não em animais alimentados com 1% de colesterol e proteína de soja. As dietas contendo 1% de colesterol resultaram em lesões hepáticas e aumentaram o peso relativo do fígado e do baço, mas não afetaram o perfil lipídico, o ganho de peso e o consumo de alimentos ou eficiência na conversão alimentar. Em conclusão, uma dieta com alto teor de colesterol influencia na produção de classes de anticorpos em resposta a um antígeno de forma que pode ser revertida pelo farelo de aveia.

Previous studies have demonstrated the immunological and hypercholesterolaemic effects of soluble dietary fibre and soy protein in rats. In this study, we evaluated the effects of oat bran and soy flour on humoral immune response in Wistar rats fed hypercholesterolaemic diets. Animals (6 groups) fed with different diets for 6 wks were inoculated twice with antigen (IgY). Plasma samples were collected after each inoculation and anti-IgY antibody (IgM, IgG1 and IgG2a) levels were evaluated by ELISA. Animals receiving 1% cholesterol presented an increase in anti-IgY IgG1 and a reduction in anti-IgY IgM and IgG2a relative to control animals. These effects were abrogated in animals fed 1% cholesterol and oat bran or oat bran+soy protein, but not in animals fed 1% cholesterol and soy protein. Diets containing 1% cholesterol resulted in hepatic lesions and higher liver and spleen relative weights, but did not affect lipid profile, weight gain, food intake, or food conversion efficiency. In conclusion, a high-cholesterol diet influences classes of antibodies produced in response to an antigen in a way that can be reversed by oat bran

Thermoplastic starch/polyester films: effects of extrusion process and poly (lactic acid) addition.

Biodegradable films were produced using the blown extrusion method from blends that contained cassava thermoplastic starch (TPS), poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with two different extrusion processes. The choice of extrusion process did not have a significant effect on the mechanical properties, water vapor permeability (WVP) or viscoelasticity of the films, but the addition of PLA decreased the elongation, blow-up ratio (BUR) and opacity and increased the elastic modulus, tensile strength and viscoelastic parameters of the films. The films with 20% PLA exhibited a lower WVP due to the hydrophobic nature of this polymer. Morphological analyses revealed the incompatibility between the polymers used.

Influence of thickness on properties of plasticized oat starch films

The aim of this study was to investigate the effect of thickness (between 80 and 120 µm) on apparent opacity, water vapor permeability and mechanical properties (tensile and puncture) of oat starch films plasticized with glycerol, sorbitol, glycerol:sorbitol mixture, urea and sucrose. Films were stored under 11, 57, 76 and 90% relative humidity (RH) to study the mechanical properties. It was observed that the higher the thickness, the higher was the opacity values. Films without the plasticizer were more opaque in comparison with the plasticized ones. Glycerol:sorbitol films presented increased elongation with increasing thickness at all RH. Puncture force showed a strong dependence on the film thickness, except for the films plasticized with sucrose. In general, thickness did not affect the water permeability.

Snack bars with high soy protein and isoflavone content for use in diets to control dyslipidaemia.

The objective was to develop a cereal bar product rich in isoflavones and soy protein to be used in diets for controlling dyslipidaemia. A soy snack bar with 39.88 g/100 g dietary fibre, 34.25 g/100 g protein, 100.39 mg/100 g isoflavones and 245.47 kcal/100 g was produced. The shelf life of the product was tested over a period of 6 months. The hardness, water activity and darkness of the snack bars increased with storage time. Clinical trial was carried out to evaluate the effectiveness of the soy snack bar on the lipid profiles of 22 dyslipidaemic subjects for a period of 45 days. There was a decrease in levels of triglycerides (TGs) (- 20%) and an increase in high-density lipoprotein cholesterol (HDL-c) (+8%) comparing with baseline values. Therefore, relatively high intakes of soy protein and isoflavones in moderately hypercholesterolaemic subjects (>200 mg/dl) may have a moderately beneficial effect on plasma lipid profiles, as TG and HDL-c levels, without additional diet restrictions.

Properties of extruded xanthan-starch-clay nanocomposite films

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 percent) 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.

Biodegradable foams based on starch, polyvinyl alcohol, chitosan and sugarcane fibers obtained by extrusion

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 percent), (X2) chitosan (0 - 2 percent) and (X3) fibers from sugar cane (0 - 28 percent). 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 percent relative humidity of storage.

Efeito de fibras vegetais nas propriedades de compósitos biodegradáveis de amido de mandioca produzidos via extrusão / Effects of vegetal fibers on properties of cassava starch biodegradable composites produced by extrusion

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 por cento) 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 percent) 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.

Effect of relative humidities on microstructural, barrier and mechanical properties of Yam starch-monoglyceride films

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.

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.

Efeitos plastificante e antiplastificante do glicerol e do sorbitol em filmes biodegradáveis de amido de mandioca / Plasticizing and antiplasticizing effects of glycerol and sorbitol on biodegradable cassava starch films

Neste trabalho foram estudados os efeitos plastificante e antiplastificante do glicerol e do sorbitol sobre as propriedades de sorção de água e mecânicas de filmes de amido de mandioca . Os filmes foram produzidos por casting empregando-se amido de mandioca (3 g/ 100 g de solução filmogênica) e diferentes concentrações de glicerol ou sorbitol (0, 5, 10, 15, 30 e 40 g/100 g de amido). Glicerol e sorbitol apresentaram efeito antiplastificante quando empregados em baixas concentrações (≤ 15 g/100 g amido) e sob baixos valores de atividade de água (≤ 0,58). O efeito antiplastificante pode ser demonstrado pelo decréscimo da hidrofilicidade e da flexibilidade dos filmes nestas condições. Em concentrações mais elevadas de plastificante e sob maiores atividades de água, os plastificantes empregados exerceram o efeito esperado de plastificação.

In this work were studied the plasticizing ­ antiplasticizing effects of glycerol and sorbitol on moisturesorption and mechanical properties of cassava starch films. Films were produced by casting with cassavastarch (3g starch/100 g filmogenic solution) and different concentrations of glycerol or sorbitol (0, 5, 10, 15, 30and 40 g/100 g starch). Glycerol and sorbitol acted as antiplasticizers when used at a low concentration(≤ 15 g/100 g starch) and low values of water activity (≤ 0,58). The antiplasticizing effect could be demonstratedby the decrease in hydrophilicity and in flexibility of the films at these conditions. At higher concentrationsand higher water activity values, the employed plasticizers exerted its plasticizing effect

Embalagem ativa para brócolis minimamente processado utilizando 1-metilciclopropeno em sachê biodegradável / Active packing for fresh-cut brocolis using 1-methylcyclopropene in biodegradable sachet

Brócolis minimamente processados foram embalados em bandejas de polipropileno com sachê contendo 1-metilciclopropeno (1-MCO) e selado com filme biodegradável de amido. os brócolis foram armazenados por 8 dias a 12ºC e após este tempo a cor e a textura mantiveram-se similares às do produto fresco, sem desenvolvimento de odor não característico ou podridão. A embalagem ativa contendo 1-MCP na forma de sachê foi eficiente no aumento da vida de prateleira de brócolis, retardando o amarelecimento e a perda de vitamina C. Esta é uma alternativa para o tratamento com 1-MCP para produtos minimamente processados e além disso, o sachê pode absorver a água condensada, reduzindo a deterioração e o desenvolvimento de odor não característico.

Fresh-cut broccoli florets were packed in polypropylene pots containing a sachet with 1-methylcyclopropene (1-MCP) and sealed with biodegradable starch-based film. Broccoli was stored for8 days at 12oC and after this time the color and the texture of the product were similar of the fresh broccoli,with no off-flavor development or decay. Active packaging with 1-MCP in a sachet was efficient to extentshelf life of broccoli florets retarding yellowing and vitamin C losses. It is an alternative of 1-MCPtreatment for fresh-cut products and besides, the sachet can absorbs condensed water reducing spoilageand off-odor development

Efeito de embalagem biodegrádavel de amido no armazenamento de queijo processado / Effect of biodegradable starch packing on storage of processed cheese

Há um interesse crescente no emprego de matérias-primas provenientes de recursos renováveis para a produção de embalagens para alimentos. Dentre os biopolímeros mais promissores para este fim estão os amidos de diversas fontes botânicas, que são biodegradáveis, têm custo baixo e estão disponíveis em todo o mundo. Assim sendo, este trabalho teve como objetivo avaliar o efeito de embalagens biodegradáveis de amido de inhame no armazenamento (30 dias / 4°c) de queijo processado obtido de fonte comercial, e comparar o seu desempenho com o de embalagens convencionais. Os resultados obtidos mostraram que a embalagem convencional foi mais eficaz na retenção do peso e atividade de água das amostras do que a embalagem de amido. Quanto á contagem microbiana, apenas as amostras não embaladas apresentaram contaminaçãao. A acidez titulável e o ph não diferiram nas amostras embaladas durante todo o tempo de armazenamento (teste de tukey, p. <0,05). Considerando os resultados apresentados, verificou-se que a utilização de embalagens de amido de inhame pode ser uma alternativa para este tipo de produto, desde que, mais estudos sejam realizados no sentido de aprimorar a embalagem de amido como barreira às trocas de vapor de água

There is an increasing interest in the utilization of renewable resources for the production of foodpackaging. Among the biopolymers, starches from several sources have been considered as one of themost promising material for this purpose; and the reasons for this are that starches are biodegradable,inexpensive and available in all world. This work had the objective of evaluate the effect of yam starchbiodegradable packaging on storage (30 days / 4oC) of comercial-processed cheese and to compare withconventional packaging. The results showed that conventional packaging presented the better behavioron weight and water activity retention of samples during all storage time than starch packaging.Considering microbiological counts, only control samples (unpackaged) showed contamination.Titratable acidity and pH of packaged samples did not differ for starch or conventional package (Tukeytest, p ≤ 0.05) during all storage time. Considering the presented results, yam starch could be used as analternative to package processed cheese, but more studies have to be done to improve starch films as awater vapor barrier

Efeito do método de extração na composição química e nas propriedades funcionais do amido de inhame (Dioscorea alata) / Effects of extraction method on chemical composition and functional properties of yam starch (Dioscorea alata)

Tubérculos de inhame (Dioscorea alata) constituem-se em uma fonte não convencional de amido. O amido de inhame tem sido estudado como um polímero promissor na confecção de biofilmes por conter cerca de 30 por cento de amilose, polímero responsável pela capacidade de formação de filme dos amidos. Os amidos obtidos dos tubérculos de inhame foram extraídos por dois diferentes métodos e as características químicas e funcionais das amostras foram analisadas. O primeiro método, descrito por Alves, Grossmann e Silva (1999) foi executado em seis dias, gerando 7 por cento de amido com grau de pureza acima de 95 por cento. O segundo método, descrito por Cereda et al. (2003), rendeu 13 por cento de amido com grau de pureza de 84 por cento e foi realizado em três dias. Os amilogramas Brabender mostraram que as pastas de amido apresentaram estabilidade sob tratamento térmico, com menores valores de viscosidade para os amidos obtidos pelo segundo método de extração. A capacidade de formação de filmes das amostras extraídas pelos dois métodos foi similar, formando-se filmes com alta resistência mecânica, porém o amido obtido através do segundo método formou filmes mais opacos. Para adaptação à indústria, o segundo método de extração pareceu ser o mais adequado, porque o rendimento foi maior e recuperou menos tempo

Effect of treatment with alkaline hydrogen peroxide associated with extrusion on color and hydration properties of oat hulls

Um delineamento fatorial incompleto 33 foi utilizado para estudar o efeito do tratamento com peróxido de hidrogênio alcalino associado à extrusão sobre algumas propriedades funcionais da fibra da casca de aveia. As variáveis do tratamento avaliadas incluíram teor de peróxido de hidrogênio (%), umidade da amostra (%) e temperatura de extrusão (ºC). A análise de variância (ANOVA) mostrou que a temperatura foi a variável mais importante para as propriedades de hidratação. Os maiores valores de capacidade de retenção de água (CRA) e volume de intumescimento foram obtidos na condição de 7% de peróxido de hidrogênio, 32% de umidade e 90ºC de temperatura, obtendo um incremento de 70% na CRA e 55% no volume de intumescimento. A medida instrumental de cor foi usada para analisar as modificações ocorridas neste parâmetro. O mais alto valor de luminosidade foi alcançado com maior nível de peróxido de hidrogênio (7%), obtendo-se, nessa condição, produtos mais claros. Ensaios realizados para controle mostraram que tanto a extrusão quanto o tratamento químico tiveram efeito nas propriedades avaliadas, e que o efeito conjunto foi superior ao de cada um isoladamente. As modificações ocorridas nas fibras foram acompanhadas indiretamente, através das propriedades de hidratação.