Sustainable Pickering Emulsions with Nanocellulose: Innovations and Challenges.

The proper mix of nanocellulose to a dispersion of polar and nonpolar liquids creates emulsions stabilized by finely divided solids (instead of tensoactive chemicals) named Pickering emulsions. These mixtures can be engineered to develop new food products with innovative functions, potentially more eco-friendly characteristics, and reduced risks to consumers. Although cellulose-based Pickering emulsion preparation is an exciting approach to creating new food products, there are many legal, technical, environmental, and economic gaps to be filled through research. The diversity of different types of nanocellulose makes it difficult to perform long-term studies on workers' occupational health, cytotoxicity for consumers, and environmental impacts. This review aims to identify some of these gaps and outline potential topics for future research and cooperation. Pickering emulsion research is still concentrated in a few countries, especially developed and emerging countries, with low levels of participation from Asian and African nations. There is a need for the development of scaling-up technologies to allow for the production of kilograms or liters per hour of products. More research is needed on the sustainability and eco-design of products. Finally, countries must approve a regulatory framework that allows for food products with Pickering emulsions to be put on the market.

Corn starch based films treated by dielectric barrier discharge plasma.

Cold plasma is an innovative strategy to strengthen the polysaccharide-based films characteristics. This study evaluated the effects of dielectric barrier discharge (DBD) plasma on the hydrophilic character, water vapor permeability (WVP), and tensile properties of corn starch-based films. Starch films were exposed to plasma processing operating at an excitation frequency of 200 Hz for 10, 15, and 20 min. DBD plasma resulted in further enhanced tensile strength and stiffness, and lower hydrophilicity and water solubility; however, it did not present significant effects on the WVP of the resulting films within the ranges studied. Higher hydrophobicity, strength, and stiffness were verified after 20 min. The results presented in this work suggest that the DBD plasma has the potential to make starch-based films a more suitable packaging material.

Films from cashew byproducts: cashew gum and bacterial cellulose from cashew apple juice.

ABSTRACT: Cashew is a major crop in several tropical countries. Its cultivation is mostly aimed to the production of cashew nuts, whereas its byproducts (including cashew tree gum and cashew apples) are underutilized. In this study, cashew tree gum (CG) has been combined to nanofibrillated bacterial cellulose (NFBC) produced from cashew apple juice, at different ratios (from CG-only to NFBC-only), to produce edible films. While the CG-only dispersion (at 1 wt%) behaved as a quasi-Newtonian fluid, the addition of NFBC provided a shear-thinning behavior, making the dispersions easier to process, especially to cast. Moreover, the films containing increasing NFBC contents exhibited better physico-mechanical performance. When compared to the CG-only film, the films containing at least 25% NFBC presented remarkably higher strength and modulus (even similar to some conventional petroleum-derived polymers), lower water vapor permeability (WVP), and lower water solubility, although at the expense of lower elongation and higher opacity values. The combined use of both polysaccharides was demonstrated to be useful to overcome the limitations of both CG-only films (very low viscosity, poor tensile properties and very high WVP) and NFBC-only films (very high viscosity, making the dispersions difficult to mix and spread). Moreover, the use of different NFBC/CG ratios allow properties to be tuned to meet specific demands for different food packaging or coating purposes.

Papain immobilization on heterofunctional membrane bacterial cellulose as a potential strategy for the debridement of skin wounds.

We combined the chemical and physical methods of papain immobilization through the aldehyde groups available on oxidized bacterial cellulose (OxBC) to provide high proteolytic activity for future applications as bioactive dressing. Bacterial cellulose (BC) was obtained by the fermentation of Komagataeibacter hansenii in Hestrin-Schramm medium for 5 days, followed by purification and oxidation using NaIO4. Surface response methodology was used to optimize papain immobilization (2%, w/v) for 24 h. The independent variables: pH (3-7) and temperature (5 to 45 °C) were investigated. The mathematically validated optimal conditions of 45 °C and pH 7 had a statistical effect on the immobilization yield (IY) of papain in OxBC (52.9%). These ideal conditions were also used for papain immobilization in BC (unoxidized). The IY of 9.1% was lower than that of OxBC. OxBC-Papain and BC-Papain were investigated using thermal analysis, confocal microscopy, and diffusion testing. The OxBC support exhibited a more interactive chemical structure than the BC support, and was capable of immobilizing papain by covalent bonds (-C-NHR) and adsorption (ion exchange), with 93.3% recovered activity, 49.4% immobilization efficiency, and better thermal stability. Papain immobilized to OxBC by adsorption displayed 53% widespread papain activity. The results indicate the potential of prolonged bioactivity in debrided chronic wounds.

Bacterial cellulose aerogels: Influence of oxidation and silanization on mechanical and absorption properties.

Biodegradable aerogels may help to develop eco-friendly technological pathways to increase the efficiency of chemical processes. In the present work, we describe the preparation of a novel bacterial cellulose aerogel oxidized by TEMPO, nanofibrillated in a blender, and silanized with methyltrimethoxysilane, resulting in four different types of aerogel. The aerogels produced from the double-functionalized cellulose suspension (BCOXNS) were compared to other non-oxidized (BCN and BCNS) and non-silanized (BCOXN) aerogels All aerogels were very light (density 10-14 kg.m-3) and very porous (porosity >99 %). The aerogels of BCOXNS showed better mechanical properties (tension of 13.0 kPa, modulus of elasticity of 39.4 kPa) and hydrophobicity, and could absorb organic solvents of different polarities. The BCOXNS could be recycled at least 7 times after absorbing organic solvents while retaining an absorption capacity of 83 %. This material can be used as a standard for the further development of aerogels based on bacterial biopolymers.

Papain immobilized on alginate membrane for wound dressing application.

Wound dressings based on natural polymers are of considerable interest in the pharmaceutical industry owing to their improved performance in the human body when compared to synthetic polymers. Alginate, a polysaccharide from brown algae, is commonly studied as a wound dressing owing to its biocompatibility and biodegradability. To improve its therapeutic features and thereby increase wound healing, papain (a proteolytic enzyme from Carica papaya latex) was proposed to be incorporated. Papain is capable of promoting the debridement of devitalized or necrotic tissues. The development of dressing based on alginate and papain aggregates the healing properties of both materials. In addition, the adsorption on a support can stabilize the enzyme structure and permits its release in a controlled manner. The optimal conditions for immobilization were evaluated (initial concentration, temperature, and pH), and the amount immobilized was measured by Bradford assay. The enzyme activity stability over 28 days was measured. The release profile was determined using Franz cell. In vitro cytotoxicity assays were performed using fibroblasts and keratinocytes. Optimal immobilization conditions were identified in a neutral medium at a papain concentration of 20 mg/mL and temperature of 25 °C. The enzyme remained active after immobilization (80 % of its initial activity), and the matrix protected the enzyme from deactivation (70 % reduction on the matrix compared to 94 % in a buffer solution). Franz cell displayed a release profile of 64.1 % of the enzyme after 24 h. The biological assays indicated a bioactive material with proteolytic properties.

In vitro degradability and bioactivity of oxidized bacterial cellulose-hydroxyapatite composites.

Hydroxyapatite-associated bacterial cellulose (BC/HA) is a promising composite for biomedical applications. However, this hybrid composite has some limitations due to its low in vivo degradability. The objective of this work was to oxidize BC and BC/HA composites for different time periods to produce 2,3 dialdehyde cellulose (DAC). The BC and oxidized BC (OxBC) membranes were mineralized to obtain the hybrid materials (BC/HA and OxBC/HA) and their physico-chemical, degradability, and bioactivity properties were studied. The results showed that OxBC/HA was more bioactive and degradable than BC/HA, which isa function of the degree of BC oxidation. High glucose levels in the BC degradation were observed as a function of oxidation degree, and other products, such as butyric acid and acetic acid resulted from DAC degradation. Therefore, this chemical modification reaction favors BC degradation, making it a good biodegradable and bioactive material with a potential for bone regeneration applications.

Painéis de partículas elaborados do mesocarpo do dendê como alternativa ao MDF utilizado na construção civil / Particles panels prepared from dendê mesocarp as an alternative to MDF used in civil construction

RESUMO A escassez dos recursos florestais integrada à necessidade de aquisição de produtos mais ecológicos demanda o uso de outros tipos de biomassa, além da madeira no setor construtivo. Diante disso, o mesocarpo do dendê - resíduo oriundo da agroindústria e com grande potencial de utilização para desenvolvimento de novos materiais - surge como alternativa na elaboração de painéis lignocelulósicos em substituição ao MDF (medium density fiberboard) convencionalmente utilizado. Dessa forma, o presente trabalho demonstrou a viabilidade da produção e a integridade estrutural desse tipo de painel na fabricação de elementos construtivos a serem empregados na construção civil, mediante estudo comparativo entre suas propriedades com as de painéis de MDF. A metodologia consistiu na realização de ensaios de caracterização dos painéis, por meio da determinação de suas propriedades físicas (absorção de água, inchamento e densidade) e mecânicas (resistência à flexão e módulo de elasticidade), além da morfologia dos painéis produzidos, mediante a técnica de microscopia eletrônica de varredura (MEV), análise química (por meio do espectro de infravermelho com transformada de Fourier) e térmica, por meio de curvas termogravimétricas e derivada. Dos resultados obtidos, tem-se que a produção desses painéis sem aglutinantes, obtidos pela incorporação do mesocarpo de dendê, agrega valor à cadeia produtiva do dendê, além de surgir como alternativa aos desafios inerentes à produção tradicional dos painéis de madeira e, consequentemente, como opção de elemento construtivo a ser integrado à construção civil.

ABSTRACT The lack of forest resources integrated with the need of purchasing more environmentally friendly products requires the use of other types of biomass besides wood in the construction sector. Therefore, the dendê mesocarp - waste arising from the agro-industry and with great use potential in developing new materials - is an alternative in the preparation of lignocellulosic panels to replace MDF (Medium Density Fiberboard), that is conventionally used. Thus, this work demonstrated the feasibility of the production and the structural integrity of this type of panel in the manufacture of building blocks to be used in civil construction through a comparative study of their properties with the MDF panels. The methodology consists in performing characterization tests in panels through determining their physical (water absorption, swelling and density) and mechanical (flexion resistance and modulus of elasticity) properties, besides analysing the morphology of the panels produced by the Scanning Electron Microscopy (MEV) technique, performing a chemical (via infrared spectrum Fourier transform) and thermal analysis through derived thermogravimetric curves. The results obtained suggest that the production of these panels without a binder, obtained by the incorporation of dendê mesocarp, adds value to the production chain of dendê, in addition to emerge as an alternative to the challenges inherent to the traditional production of wood panels and, consequently, is considered as an option of a constructive element to be integrated with the construction.

Acetic Acid Bacteria in the Food Industry: Systematics, Characteristics and Applications.

The group of Gram-negative bacteria capable of oxidising ethanol to acetic acid is called acetic acid bacteria (AAB). They are widespread in nature and play an important role in the production of food and beverages, such as vinegar and kombucha. The ability to oxidise ethanol to acetic acid also allows the unwanted growth of AAB in other fermented beverages, such as wine, cider, beer and functional and soft beverages, causing an undesirable sour taste. These bacteria are also used in the production of other metabolic products, for example, gluconic acid, l-sorbose and bacterial cellulose, with potential applications in the food and biomedical industries. The classification of AAB into distinct genera has undergone several modifications over the last years, based on morphological, physiological and genetic characteristics. Therefore, this review focuses on the history of taxonomy, biochemical aspects and methods of isolation, identification and quantification of AAB, mainly related to those with important biotechnological applications.

Bacterial cellulose nanocrystals produced under different hydrolysis conditions: Properties and morphological features.

Bacterial cellulose (BC) is a polymer with interesting physical properties owing to the regular and uniform structure of its nanofibers, which are formed by amorphous (disordered) and crystalline (ordered) regions. Through hydrolysis with strong acids, it is possible to transform BC into a stable suspension of cellulose nanocrystals, adding new functionality to the material. The aim of this work was to evaluate the effects of inorganic acids on the production of BC nanocrystals (BCNCs). Acid hydrolysis was performed using different H2SO4 concentrations and reaction times, and combined hydrolysis with H2SO4 and HCl was also investigated. The obtained cellulose nanostructures were needle-like with lengths ranging between 622 and 1322nm, and diameters ranging between 33.7 and 44.3nm. The nanocrystals had a crystallinity index higher than native BC, and all BCNC suspensions exhibited zeta potential moduli greater than 30mV, indicating good colloidal stability. The mixture of acids resulted in improved thermal stability without decreased crystallinity.

Extraction and characterization of nanocellulose structures from raw cotton linter.

This study aimed to characterize nanocellulose extracted from cotton (Gossypium hirsutum) linters. The nanocellulose was subjected to electronic microscopy, thermal analysis, X-ray diffractometry, light scattering, and contact angle. The properties of the nanocellulose are considerably different from the linter. The acidic hydrolyses applied to extract the nanocrystals increased the crystallinity index and the hydrophilicity and decreased the thermal stability. On average, the nanocrystals were 177 nm long and 12 nm wide, with an aspect ratio of 19 when measured by microscopy. The light scattering results were coherent with the crystal dimensions. Cotton linter is a potential source of nanocellulose crystals, particularly to be used in the production of hydrophilic nanocomposites. Extraction of nanocellulose from raw cotton linter does not require pulping.

Índice de sustentabilidade agroambiental para o perímetro irrigado Ayres de Souza / Environmental sustainability index for Ayres de Souza irrigated district

Uma análise integrada do atual uso dos recursos naturais do Perímetro Irrigado de Ayres de Souza, localizado no Vale do Acaraú, Ceará, foi realizada através do desenvolvimento de um índice de sustentabilidade agroecológica. Os dados dessa pesquisa foram oriundos de questionários aplicados a 33 produtores agrícolas beneficiados pelo projeto de irrigação. Os indicadores de sustentabilidade foram estimados pelo emprego de análise fatorial, método da análise fatorial/análise de componentes principais. O índice de sustentabilidade estimado a partir dos indicadores selecionados registrou uma situação de sustentabilidade fragilizada ou de insustentabilidade reversível. As unidades produtivas apresentaram um porcentual de 60,6 por cento com alguma sustentabilidade; e os demais 39,4 por cento estão em condições de insustentabilidade. Os resultados também mostraram que os fatores dominantes do índice de sustentabilidade foram: nível da atividade agrícola praticada, agricultura familiar, condições atuais do sistema água-solo e infra-estrutura, fontes alternativas de renda e experiência em tratos culturais.

The aim of this work was to make an analysis of natural resources at Ayres de Souza Irrigated District sited in Acaraú basin, Ceará, Brazil. This study was performed through an agro ecological sustainability index (ASI). The approach was based on 33 cross-over form applied to small farms located in the irrigated district. Factors Analysis/Principal Components Analysis were applied to select the sustainability indicators of the irrigated district as well as to define the agro ecological sustainability index. The results showed that the Index is capable of demonstrating clear differences among productivity unit management system with respect to sustainability. 60 percent of the pooled productivity units presented weak sustainability and the other 39.4 percent were unsustainable. The dominants factors of the Index were: level of agricultural management practices, family agriculture, framework of irrigation and alternative income source.

Fatores determinantes da qualidade das águas superficiais na bacia do Alto Acaraú, Ceará, Brasil / Assessment of the surface water quality in the upland of Acaraú watershed, Ceará, Brazil

Análise Fatorial/Análise da Componente Principal (AF/ACP) foram empregadas com o objetivo de identificar os fatores determinantes (naturais e antrópicos) da qualidade das águas superficiais na bacia do Alto Acaraú, Ceará. Realizaram-se coletas trimestrais, no período de fev/2003 a mar/2004, em seis pontos localizados nas áreas de influência urbana e de drenagem de perímetros irrigados. Foram analisados os parâmetros pH, temperatura, cor, turbidez, nitrato, amônia total, amônia livre, amônia ionizada, sódio, cloretos, potássio, sulfato, dureza, cálcio, magnésio, alcalinidade total, alcalinidade do bicarbonato, condutividade elétrica, sólidos suspensos, oxigênio dissolvido, demanda bioquímica de oxigênio, fósforo total, ortofosfato solúvel, clorofila "A", coliformes totais e coliformes termotolerantes. Através das técnicas de estatística multivariada, AF/ACP, foram selecionadas as variáveis que explicavam o maior percentual da variância total dos dados. Três componentes são responsáveis pela estrutura da qualidade das águas explicando 88 por cento da variância total. O modelo mostrou que o primeiro fator (39,81 por cento da variância) expressou-se como um componente mineral. O segundo, explicando 29,22 por cento da variância, apresentou-se como um componente de nutrientes. No terceiro fator (19,16 por cento da variância), identificou-se como um componente de escoamento superficial das áreas agrícolas e clima. A rotação dos fatores, os parâmetros indicadores da qualidade das águas estão, principalmente, relacionados com a solubilidade dos sais (natural), com nutrientes e transporte de sedimentos (ação antrópica).

Factor analysis/Principal Component Analysis (FA/PCA) were applied to the data set on water quality in upper Acaraú River basin (Brazil) to study the effects caused by human activities on water. Variables were measured at six key sampling sites (villages and agricultural areas) in four campaigns from February/2003 to March/2004. The samples were analyzed for pH, temperature, color, electrical conductivity, turbidity, nitrate, ammonia, sodium, chloride, potassium, sulfate, total hardness, calcium, magnesium, total alkalinity, alkalinity bicarbonate, total suspended solids, dissolved oxygen (DO), 5-days biochemical oxygen demand (BOD5), total phosphate, orthophosphate, chlorophyll-a, and feacal coliform. Multivariate statistical techniques, (FA/PCA), allowed the identification of variables that explain the major percent of total variance. Three components were identified as responsible for the data structure, explaining 88 percent of the total variance of the data set. Model showed that the first factor (39.81 percent of variance) assigned as mineralization factor. The second one (29.22 percent of variance) represented as nutrients group. The third factor (19.16 percent variance) assigned as a combination of agricultural area runoff and weathering. Varimax rotation showed that the mainly water quality parameters were related to mineralization (natural process) and non-point pollution (anthropogenic activities).

Impactos ambientais da carcinicultura de águas interiores / Environmental impacts of the inland shrimp farming

O objetivo deste trabalho é identificar os principais aspectos e impactos ambientais relacionados à carcinicultura em águas interiores, através da análise das etapas do processo e dos diferentes tipos de cultivo, em 32 fazendas localizadas nas bacias do Médio e Baixo Jaguaribe, Ceará, Brasil. Essa avaliação foi realizada aplicando-se questionários e realizando-se a caracterização dos efluentes e do solo de 3 viveiros selecionados. Os principais impactos ambientais estão relacionados à ocupação de áreas de preservação permanente pelos viveiros de engorda, conflitos pelo uso da água em região semi-árida, contaminação de corpos hídricos que são fonte de abastecimento humano para os municípios da região e aumento de doenças entre os trabalhadores rurais pela manipulação inadequada de produtos químicos durante o cultivo. Esses impactos podem ser reduzidos a níveis compatíveis com a capacidade de suporte do meio, quando respeitada a legislação e adotada boas práticas de manejo. Recomenda-se também a condução de estudos que avaliem a capacidade de suporte da bacia hidrográfica, visando balizar o licenciamento ambiental e a concessão de outorgas de água para o desenvolvimento da atividade.

This work aims to identify the main environmental aspects and impacts of the inland shrimp farming, through the analysis of the process stages and different cultivation techniques in farms located in the Baixo Jaguaribe region, Ceará State, Brazil. This evaluation was done applying questionnaires along with all farm owners or managers and making physical-chemical analysis of the effluents and the tanks soil in three selected farms. The main environmental impacts identified are related to the occupation of preservation areas by the shrimp tanks, greater conflicts between water users, contamination of the water resources that are also the main source of drinking water to the municipalities and the increase of diseases among rural workers by the inadequate manipulation of chemical products during production. These impacts can be reduced to match with the region environmental capacity, when the legislation is respected and the good practices are adopted. Besides, it is also recomended to carry out research studies that access the watershed environmental capacity to sustain shrimp farming growth, in order to orient environmental and water use licensing.

Impactos ambientais do lançamento de efluentes da carcinicultura em águas interiores / Environmental impacts of inland shrimp farming effluents

A bacia do Baixo Jaguaribe-CE depara-se com a instalação progressiva de fazendas de camarão às margens do rio Jaguaribe onde não há interferência de água salina. Esse trabalho tem como principal objetivo avaliar as características físicas, químicas e bacteriológicas dos efluentes contínuos e da despesca de fazendas de camarão, refletindo sobre os possíveis impactos do lançamento desses efluentes e formas de atenuação desses impactos. Foram analisadas amostras da água de captação e dos efluentes de dois viveiros de duas diferentes fazendas. Os parâmetros analisados para os efluentes contínuos foram: pH, turbidez, nitrato, amônia total, condutividade elétrica, DBO5, fósforo total, fósforo solúvel, alcalinidade total, sólidos totais, sólidos totais dissolvidos, sólidos suspensos, coliformes termotolerantes e clorofila a. Para os efluentes da despesca foram acrescentados OD e a fração de sólidos sedimentáveis. Os resultados mostraram que, embora os efluentes contínuos se apresentem dentro dos padrões estabelecidos pela legislação, na despesca os valores obtidos para pH, amônia total, sólidos suspensos e sedimentáveis estão acima dos valores permitidos contribuindo para a deterioração progressiva da qualidade da água dos corpos hídricos da região.

Nitrification of effluents: microbiological characterization

This work is concerned with the microbiological monitoring of nitrification processes carried out in two distinct continuous reactors: submerse fixed-bed and airlift fluidized bad reactor. In the first case the system was operated using a synthetic effluent with variable salinity while in the second an actual petroleum refinery effluent was tested. On the basis of analys is for ammonia, nitrite and nitrate and nitrate at the inflow and outflow streams, system performance was evaluate. By inoculating appropriate solid medium, biotypes were isolated and colonies morphology was characterized. In general, colony of ammonia oxidizin bacteria (group 1) were round, initially transparent later, but becoming whitsh or phosphorescent. It took 36 to 48 hours for those colony to develop. The nitrite oxidizing bacteria (group 2) were generally white or redish-brown with colonies, developing time between 24 and 36 hours. In spite of the existence of various types of colonies, lamina observation under microscope revealed mainly Gram (-) bacilli with varied size. Typical width X length for individual bacterium cells were as follows: 1 X 1,5mm for group 1, normally arranged in chains, and 0,5 X 1,0mm for group 2, generally shaped as small aggregates.