Effect of protein addition in properties of gels produced with jackfruit (Artocarpus integrifolia) seed starch: rheological and texture properties.

Starches and proteins are two major types of biopolymer components in many foods. The interactions of protein with starches greatly influence the matrix structure and properties of starch-based food systems. In this study, the physical-chemical properties and the effect of the commercial whey protein concentrate in the texture and rheological properties of jackfruit starch gels were evaluated. The experimental design was completely randomized, using a 4 × 4 complete factorial scheme, with four levels of starch (3, 6, 9 and 12%) and four levels of protein (0, 2, 4 and 6%). In higher concentrations of starch the addition of proteins delayed the beginning of gelatinization, led to an increase in G' and G″ and decrease in the tan (δ) values, characterizing the gel as strong, e.g., the gel network became more structured. However, in the treatment with 6% starch the addition of protein led to a decrease in gel strength. For gels with 9% starch the increase in protein concentration, led a slight increase in the hardness and cohesiveness, characterizing a more rigid and cohesive gel. Overall, gels with 3 and 6% of starch showed characteristic behavior of a weak gel and with 9 and 12% of strong gel. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05793-1.

Reducing the environmental impacts of Brazilian chicken meat production using different waste recovery strategies.

Chicken meat has achieved significant index rates worldwide, with Brazil leading production and exports. The agribusiness significance has led to strengthening attention to the environmental burdens produced by the poultry industry. This research considered reducing the environmental impacts in the life cycle of Brazilian chicken meat regarding strategies for recycling waste from the production process. An attributional cradle-to-gate life cycle assessment was performed, with the functional unit of 1 kg of slaughtered and unpacked chicken meat. The two suggested scenarios used: i) chicken bedding for biogas production and ii) chicken carcass waste as meat meals in feed production. Handling poultry litter for biogas production avoided methane and ammonia emissions, reducing over 50% of the environmental indicators of Climate Change, Terrestrial Acidification, and Freshwater Eutrophication. Reuse poultry waste to produce meat meals reduced from 12% to 55% in all impact categories, decreasing emissions from carcasses destined for decomposition in landfills and using less raw materials from bovine sources. Investigating the environmental performance of the chicken meat production chain encouraged the circularity of natural resources and waste recovery strategies in the system boundary, thus helping to accomplish Sustainable Development Goals 7, 9, 12, and 13 of the UN Agenda 2030.

Sustainability assessment of coffee production in Brazil.

This paper aims to assess the sustainability of coffee production in Brazil by a framework at the farm level. The framework developed comprises four dimensions of sustainability structured from the literature review. Primary data were collected from 20 coffee farms selected from the most producing communities in the Planalto de Vitória da Conquista locality, sited in Centro-Sul Baiano middle region at the Bahia state. The main environmental issues identified related to coffee farmers are inadequate management of water consumption, influenced by the lack of knowledge about irrigation techniques in some cases, and the use of synthetic fertilizers and pesticides. The economic evaluation of the activity revealed a low index of producers belonging to a class organization. In social aspects the issues are low level of technical/technological instruction for coffee producers, temporary workers are often used, the old age of most producers, the lack of family succession for the activity, low incomes, the high number of temporary workers, and the absence of the worker gains. As for the technical dimension, only half of the farmers invest in innovation, which causes high obsolescence of their equipment and machinery and a low participation rate in training courses. In the environmental dimension, the farmers return the packages of pesticides to the stores where they bought them. In the technical dimension, most farmers perform soil analysis. Besides addressing the identified challenges, the initiatives can help achieve the Sustainable Development Goals, especially the 9th, 12th, and 13th.

Environmental life cycle assessment of cow milk in a conventional semi-intensive Brazilian production system.

The environmental performance of cow milk produced in a conventional semi-intensive system was assessed using a cradle-to-farm gate attributional life cycle assessment. The impacts of 1 kg FPCM-fat and protein corrected milk were obtained considering six midpoint impact categories from the ReCiPe 2016 method: climate change (CC), terrestrial acidification (TA), freshwater eutrophication (FE), land use (LU), water consumption (WC), and fossil resource scarcity (FRS). The modeling of the product system and calculating the environmental impacts considered the use of SimaPro™ software. Enteric methane and nitrogen emissions and inputs for feeding animals (fertilization for pasture production, use of seed in corn crops, and milk replacer in calves feed) were the main contributors to impacts in milk production in most categories. In addition, the indirect energy use and wastewater generation in milking and milk cooling also were relevant. Literature-based strategies are suggested to mitigate the identified environmental impacts to achieve the best environmental performance without decreasing technical and quality milk production. We emphasize the importance of improving productivity per milk cow, knowing the origin of the supply chain inputs, and using it efficiently to produce animal feeds as the main strategies to improve milk's environmental performance. Changes in allocation methods did not substantially differ in impact categories. Sensitivity analysis foregrounds the consistency of results and conclusions of the current study despite the uncertainties associated with methodological choices, simplifications, suppositions, and the use and adaptation of international databases.

Improvement of texture properties and syneresis of arrowroot (Maranta arundinacea) starch gels by using hydrocolloids (guar gum and xanthan gum).

BACKGROUND: The incorporation of hydrocolloids into starch dispersions modifies their techno-functional properties, such as gelatinization, retrogradation, syneresis, and texture, among others. Their main function is to improve these properties and to promote greater stability of starch gels. Thus, the main objective of this study was to evaluate the effect of adding colloids (guar gum and xanthan gum) on the texture properties (hardness, elasticity, cohesiveness, and gumminess) and syneresis of the starch gels made from the common variety of arrowroot. Analysis of variance (ANOVA) and regression were carried out to analyze the effects of the treatments and variables with their respective interactions. RESULTS: The addition of guar gum and xanthan gum influenced the stability of the starch gels studied, and it was capable of reducing syneresis even at low concentrations, with a greater effect for xanthan gum. Both gums were capable of inhibiting syneresis at concentrations above 0.5%, throughout the storage time studied (5 days). The addition of these hydrocolloids was also shown to influence the following texture parameters: hardness, cohesiveness, and gumminess, but showed no effect on gel elasticity. CONCLUSION: The addition of hydrocolloids was shown to be an alternative way of increasing the stability and enhancing the textural properties of the starch gels in arrowroot. © 2020 Society of Chemical Industry.

Assessment of autochthonous aquatic macrophytes with phytoremediation potential for dairy wastewater treatment in floating constructed wetlands.

The phytoremediation potential of autochthonous aquatic plants has been increasingly explored. This study investigated the use of macrophytes found in natural ecosystems in the southern coast of the state of Bahia, Brazil, for treatment of dairy wastewater (DWW) using experimental systems of the floating constructed wetland type. Four species of aquatic macrophytes have been tested using floating platforms made from PET bottles. The chemical oxygen demand (COD), biochemical oxygen demand (BOD), total solids (TS), pH, and temperature of DWW were analyzed for 15 days. On the fifth day, a 74.8% (±7.7) decrease of BOD was achieved. Eichhornia crassipes (86.4%) and Eichhornia paniculata (84.8%) showed the best results, while Polygonum ferrugineum and Borreria scabiosoides achieved the removal of 65% and 74.2% of BOD, respectively. Considering the TS reduction in the DWW diluted with rainwater, the best results were obtained by Eichhornia crassipes (64.3%) and Eichhornia paniculata (65.18%). The macrophytes of the Eichhornia genus showed a greater potential for the treatment of DWW than the macrophytes Polygonum ferrugineum and Borreria scabiosoides, with a hydraulic retention time varying between four and five days.

Rheological and textural studies of arrowroot (Maranta arundinacea) starch-sucrose-whey protein concentrate gels.

The aim of this work was to study the effect of adding whey protein concentrate and sucrose on the rheological and textural properties of the gels obtained from arrowroot (Maranta arundinacea) starches. It was found that the starches evaluated presented low levels of protein, ash, lipids and acidity. Arrowroot starch of the common and round root varieties presented 17.80 and 35.96% of amylose content, respectively. The swelling power of the starch from common variety was higher than that of the round root but the solubility index was lower. Dynamic rheological measurement showed strong gel behavior and formulated gels with 4% sucrose and 1% protein were more elastic than the other formulations. Gels formulated with starch of the round root presented a higher gelatinization temperature than gels formulated with the common. The firmness of gels was directly proportional to the sucrose level, while the increase in the protein content led to reduction in the same.

Characterization of starch-based bioplastics from jackfruit seed plasticized with glycerol.

Biodegradable films based on starches from different botanical sources exhibited physicochemical and functional properties which were related with the starch characteristics. However, had inadequate mechanical properties and were hard and brittle. In this research, jackfruit seed starch plasticized with glycerol were developed and characterized. The starch and glycerol concentrations ranged from 2 to 6% w/w and 20 to 60 g/100 g starch, respectively. Bioplastics were obtained by the casting method and characterized in terms of color, mechanical properties, solubility, water vapor permeability (WVP), morphology and free energy of the hydrophobic interaction. Electronic micrographics showed the presence of some intact starch granules. The bioplastics were hydrophilic and those of 6% starch and 40% glycerol were the most hydrophilic ([Formula: see text] = 41.35 mJ m-1). The solubility of the films presented a direct relationship with the starch concentration ranging from 16.42 to 23.26%. Increased opacity and color difference were observed with increasing starch concentration. The WVP ranged from 1.374 × 10-3 to 3.07 × 10-4 g m/day m2 which was positively related with the concentration of starch and glycerol. Tensile strength, percent elongation and Young's Modulus indicated that the jackfruit starch and glycerol provided a film with good mechanical properties. The results replaced that jackfruit starch can be used to develop films, with low opacity, moderate WVP and relatively high mechanical stability, by using glycerol in the gelatinized starch dispersions.

Influence of compression parameters on mechanical behavior of mozzarella cheese.

Studies on the interaction between direction and degree of compression in the Texture Profile Analysis (TPA) of cheeses are limited. For this reason the present study aimed to evaluate the mechanical properties of Mozzarella cheese by TPA at different compression degrees (65, 75, and 85%) and directions (axes X, Y, and Z). Data obtained were compared in order to identify possible interaction between both factors. Compression direction did not affect any mechanical variable, or rather, the cheese had an isotropic behavior for TPA. Compression degree had a significant influence (p < 0.05) on TPA responses, excepting for chewiness TPA (N), which remained constant. Data from texture profile were adjusted to models to explain the mechanical behavior according to the compression degree used in the test. The isotropic behavior observed may be result of differences in production method of Mozzarella cheese especially on stretching of cheese mass. PRACTICAL APPLICATIONS: Texture Profile Analysis (TPA) is a technique largely used to assess the mechanical properties of food, particularly cheese. The precise choice of the instrumental test configuration is essential for achieving results that represent the material analyzed. The method of manufacturing is another factor that may directly influence the mechanical properties of food. This can be seen, for instance, in stretched curd cheese, such as Mozzarella. Knowledge on such mechanical properties is highly relevant for food industries due to the mechanical resistance in piling, pressing, manufacture of packages, and food transport, or to melting features presented by the food at high temperatures in preparation of several foods, such as pizzas, snacks, sandwiches, and appetizers.

Use of native aquatic macrophytes in the reduction of organic matter from dairy effluents.

Considering the diversity and the unexplored potential of regional aquatic flora, this study aimed to identify and analyze the potential of native aquatic macrophytes to reduce the organic matter of dairy wastewater (DW) using experimental constructed wetlands. The dairy wastewater (DW) had an average chemical oxygen demand (COD) of 7414.63 mg/L and then was diluted to 3133.16 mg/L (D1) and to 2506.53 mg/L (D2). Total solids, COD, temperature, and pH analyses were performed, and the biochemical oxygen demand (BOD) was estimated from the COD values. The best performance in the reduction of the organic matter was observed for Polygonum sp. (87.5% COD and 79.6% BOD) and Eichhornia paniculata (90% COD and 83.7% BOD) at dilution D1, on the 8th day of the experiment. However, the highest total solids removal was observed for Polygonum sp. (32.2%), on the 4th day, at dilution D2. The total solid (TS) concentration has also increased starting from the 8th day of the experiment was observed which may have been due to the development of mosquito larvae and their mechanical removal by sieving, thus changing the steady state of the experimental systems. The macrophytes Polygonum sp. and E. paniculata were considered suitable for the reduction of organic matter of DW using constructed wetlands.

Thermoresistant xylanases from Trichoderma stromaticum: Application in bread making and manufacturing xylo-oligosaccharides.

The enzymes Xyl1 and Xyl2 from T. stromaticum were purified and identified by mass spectrometry (MALDI-TOF/MS). Xyl1 contained three proteins with similarity to xylanase family 10, 62 and anarabinofuranosidase of the Trichoderma genus and Xyl2 contained a protein with similarity to endo-1,4-ß-xylanase. High xylanase activity was found at 50°C for Xyl1 and 60°C for Xyl2 and pH 5.0 for both, retaining more than 80% of activities for one hour at 60°C and pH 5-8. Ag2+ and ß-mercaptoethanol increased while SDS and EDTA inhibited the xylanase activity of both Xyl1 and Xyl2 extracts. The Km and Vmax values for purified Xyl2 were 9.6mg/mL and 28.57µmol/min/mg, respectively. In application tests, both Xyl1 and Xyl2 were effective in degrading beechwood xylan to produce xylo-oligosaccharides. In baking, adding Xyl1 increased the softness and volume of wheat bread and whole grain bread, qualities increasingly desired by consumers in this segment.

Life cycle assessment of cheese production process in a small-sized dairy industry in Brazil.

Current research identifies, analyzes, and suggests improvements for minimizing environmental impacts in the manufacture of cheese using the life cycle assessment. Data collection and development of the inventory were performed in a small-sized dairy industry in Brazil. A cradle-to-gate approach was conducted based on the primary data from cheese production and secondary data from databases. The ReCiPe method was used for the impact assessment, considering the categories climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, photochemical oxidant formation, particulate matter formation, water depletion, and fossil depletion. A sensitivity analysis was performed including evaluations of different fuels for generating thermal energy, strategies for cleaning of dairy plant and utensils, variations in the way of cheese production based on the fat content, and production percentage changes. The results showed that the skimmed milk and thermal energy productions, electricity usage, and water consumptions were the main elementary flows. The pallet residues showed the best to be used as fuel for thermal energy. Detergent combinations did not influence the impact categories. There was a direct relationship between fat content range (20 to 30%) and the contribution in six impact categories. Changes from 20% in cheese allocation factor influenced the impact assessment results. LCA allowed identifying the main elementary flow of cheese production, providing valuable information with the potential to verify opportunities for on-site improvements.

Influence of the manipulation technique of acrylic resin on mechanical strength of orthodontic plates / Influencia da técnica de manipulação de resina acrilica sobre a resistencia mecanica de placas ortodonticas

The focus of this study was to test the fracture resistance of upper arch dental retainers, made by two different manipulation techniques of acrylic resin. 84 plates Wraparound type retainers were made by two different manipulation techniques forming two groups (n = 42): Group 1 (Addition Technique) and Group 2 (Pressing Technique). All the retainers were duly shaped in U form with the aid of standardized plaster cast models. During the confection process the standardizing of the retainers was conducted carefully regarding their thickness and dimensions with the aid of a gauge and a straight caliper. After confection they remained immersed in water for 24 hours at 37°C. Next, they were tested through mechanical compression until fracture in a universal mechanical testing machine. Data were analyzed by Student's t test. The significance level was set at 5% ( = 0.05). It was found that the average was of 79.12 N for Group 1 and of 77.07 N for Group 2 with a standard deviation of 17.30 N and 16.31, respectively, showing that there is no significant difference in resistance for the retainers when made through any of the two methods (P=0.788). The addition and pressure techniques of acrylic resin do not influence the resistance to compression of the upper dental retainers.

O foco deste estudo foi testar a resistência à fratura de retentores odontológicos do arco superior, feito por duas diferentes técnicas de manipulação de resina acrílica. 84 placas de retentores tipo Wraparound foram feitas por duas diferentes técnicas de manipulação que formam dois grupos (n = 42): Grupo 1 (técnica de adição) e Grupo 2 (técnica de prensagem). Todos os retentores foram devidamente moldado em forma de U, com o auxílio de modelos de gesso padronizados. Durante o processo de confecção a padronização dos retentores foi conduzida cuidadosamente em relação à sua espessura e dimensões, com o auxílio de um medidor e um compasso de calibre linear. Após a confecção eles permaneceram imersos em água por 24 horas a 37 °C. Em seguida, eles foram testados através de compressão mecânica até a fratura em uma máquina universal de ensaios mecânicos. Os dados foram analisados pelo teste t de Student. O nível de significância foi de 5% ( = 0,05). Verificou-se que a média foi de 79,12 N para o Grupo 1 e de 77,07 N para o Grupo 2, com um desvio padrão de 17,30 N e 16,31, respectivamente, indicando que não há diferença significativa na resistência para os retentores, quando feita através de qualquer um dos dois métodos (P = 0,788). As técnicas de adição e pressão de resina acrílica não influenciaram a resistência à compressão dos retentores dentárias superiores.

Reducing the life cycle GHG emissions of microalgal biodiesel through integration with ethanol production system.

Despite environmental benefits of algal-biofuels, the energy-intensive systems for producing microalgae-feedstock may result in high GHG emissions. Trying to overcome energy-costs, this research analyzed the biodiesel production system via dry-route, based on Chlorella vulgaris cultivated in raceways, by comparing the GHG-footprints of diverse microalgae-biodiesel scenarios. These involved: the single system of biomass production (C0); the application of pyrolysis on the residual microalgal biomass (cake) from the oil extraction process (C1); the same as C0, with anaerobic cake co-digested with cattle manure (C2); the same conditions as in C1 and C2, by integrating in both cases (respectively C3 and C4), the microalgae cultivation with an autonomous ethanol distillery. The reduction of GHG emissions in scenarios with no such integration (C1 and C2), compared to CO, was insignificant (0.53% and 4.67%, respectively), whereas in the scenarios with integration with ethanol production system, the improvements were 53.57% for C3 and 63.84% for C4.

The acrylic's design or the addition of internal orthodontic wire changes the resistance of orthodontic plates? / O desenho do acrílico ou a adição de fio ortodôntico no seu interior altera a resistência das placas ortodônticas?

Objective: Evaluate resistance of Hawley retainers in three different acrylic configurations in order to evaluate if its format or the addition of internal wire interferes in its resistance. Material and Method: 45 Hawley retainers were fabricated, divided into three groups (n = 15): Group 1 - acrylic covering the entire hard palate, Group 2 - plate with relief at the deepest region of the palate, leaving it with a "U" conformation and Group 3 - similar to Group 2, with the addition of 0.7mm wire 2cm internally of the acrylic at the region of the palatine ridges. The compressive strength was tested in a universal mechanical testing machine (Stable Microsystems, London, United Kingdom), measuring the applied force until plate rupture occurred. The differences between the formats being compared by the Kruskal-Wallis test. The significance level was set at 5% (α = 0.05). Result: Group 1 showed the highest resistance, with a mean of about five times higher than Group 2 and three times higher than Group 3. Conclusion: acrylic reduction in dental retainer plates is directly related to the reduction of its compressive strength, the inclusion of orthodontic wire inside the acrylic increases the resistance of the plate, being a good alternative when more comfort is wanted for the patient without loss of the mechanical characteristics of the dental retainers.

Objetivo: Avaliar a resistência de placas de contenção tipo Hawley em três diferentes configurações do acrílico, a fim de se avaliar se o formato deste ou a adição de fio no seu interior interfere na sua resistência. Material e Método: Foram confeccionadas 45 placas de contenção móveis tipo Hawley, divididas em três grupos (n=15): Grupo 1 - acrílico recobrindo todo o palato duro; Grupo 2 - placa com alívio na região mais profunda do palato, deixando-a com uma conformação em "U" e Grupo 3 - similar as do Grupo 2, com a adição de fio 0.7mm de 2cm no interior do acrílico na região da rugosidade palatina. A resistência à compressão foi testada em uma máquina universal de ensaios mecânicos (Stable Microsystems, London, United Kingdom), medindo-se a força aplicada até que ocorresse a ruptura da placa. Resultado: o Grupo 1 foi o que apresentou maior resistência, com uma mediana cerca de cinco vezes maior que o Grupo 2 e três vezes maior que o Grupo 3. Conclusão: a redução do acrílico nas placas de contenção está diretamente relacionada com a redução em sua resistência à compressão; a inclusão do fio ortodôntico no interior do acrílico aumenta a resistência da placa, sendo uma boa alternativa quando se deseja maior conforto ao paciente sem que haja detrimento das características mecânicas dos aparelhos de contenção.

Saúde e segurança no ambiente rural: uma análise das condições de trabalho em um setor de ordenha / Health and safety at rural environment: an analysis of work conditions in a milking sector

A saúde e a segurança no trabalho são fatores preponderantes em todos os setores produtivos, assim como no agronegócio e, especificamente, na cadeia produtiva do leite. Neste artigo, apresentam-se os resultados de uma análise das condições do ambiente de trabalho de um setor de ordenha de leite localizado na região Sudoeste do Estado da Bahia. Buscou-se identificar os riscos ocupacionais (físicos, químicos, biológicos, ergonômicos e de acidentes), bem como aspectos relativos à higiene do alimento. A pesquisa consistiu de um estudo de caso, com características qualitativas e exploratórias, tendo por finalidade descrever a situação encontrada no setor, confrontando-a com as legislações vigentes. Foram diagnosticados, predominantemente, riscos ergonômicos e de acidentes, além de irregularidades nas condições higiênico-sanitárias, que podem constituir riscos biológicos. Não foram constatados riscos químicos ou físicos no setor. Os resultados apontam para a necessidade de melhoria no setor, que vão desde mudanças estruturais, questões organizacionais, como o oferecimento de treinamentos sobre procedimentos operacionais e em saúde e segurança no trabalho.

The health and safety at work are important and might be considered as essential and relevant for all productive sectors, including agribusiness, specifically in the milk chain production. This paper presents the results of an environment work conditions analysis in a milking sector at southwest region of Bahia State. The study aimed to identify the occupational risks (physical, chemical, biological, ergonomic and accidents), as well as aspects related to food hygiene. The research consisted in a case study with qualitative and exploratory characteristics, aiming to observe and report the real conditions identified in the work environment and comparing with the current legislation. It was diagnosed predominantly ergonomic and accident risks, as well as irregular sanitary conditions that can result in biological risks. It was not found chemical or physical risks in the sector. Facing the results, it was proposed some recommendations involving issues related to organizational conditions, by offering training on operational procedures and health and safety at work.

Identificação dos riscos ocupacionais em uma unidade de produção de derivados de carne / Identification of occupational risks in a meat product processing plant

Os trabalhadores das indústrias de alimentos estão constantemente sujeitos a atividades que demandam cuidados acentuados em relação ao controle dos produtos, os quais podem acarretar desgastes emocionais e psicológicos. Estes fatores podem influenciar diretamente no ritmo da produção e, consequentemente, na qualidade do produto, podendo ainda contribuir para a ocorrência de acidentes. Este trabalho teve como objetivo identificar os riscos ocupacionais presentes em uma unidade de produção de derivados de carne. Estes riscos estão relacionados com o tipo de atividade desenvolvida e, de acordo com a constituição, intensidade e tempo de exposição, podem causar danos à saúde ou integridade física dos trabalhadores. No estudo foram observadas as condições do local de trabalho, tais como instalações físicas, maquinários e atividades desenvolvidas pelos operadores e demais frequentadores. Também foram realizadas entrevistas informais com os trabalhadores, de modo a obter informações sobre os processos realizados e esclarecimentos sobre a forma de realização das atividades. Foram identificados riscos físicos, químicos, ergonômicos e de acidentes, cujas ações para sua eliminação vão desde medidas simples e de baixo custo até outras mais complexas. As medidas preventivas, se adotadas, poderão contribuir para garantia de um ambiente de trabalho mais seguro e com menor possibilidade de ocorrência de acidentes em relação aos riscos identificados.

Food processing and production are activities that demand close attention and can lead to emotional and psychological exhaustion to workers involved in it. These factors can affect production rate and, consequently, the final quality of product and may also contribute to the occurrence of accidents. The current study identified the occupational risks present in a meat products processing plant. Such risks related to the labor development and the intensity and exposure time can cause damages to the worker?s health and physical integrity. The study observed the conditions of facilities, machinery and the activities performed by the workers and other visitors. Some interviews were carried out in order to obtain information about the process or activities developed. Physical, chemical, ergonomic and accident risks were identified, and the actions to eliminate them range from simple and low cost actions to more complex ones. The preventive actions, once adopted, could contribute to a safer work environment and with less possibility of accident occurrence, with regard to the identified risks.

Sistemas osso-implante ex vivo utilizando haste intramedular polimérica para imobilização de fraturas femorais em bovinos jovens / Ex vivo bone-implant systems using polymeric intramedullary nails for fixation of femoral fractures in young calves

O desenvolvimento de novos aparatos usando materiais disponíveis e de baixo custo pode ser uma alternativa viável para o tratamento cirúrgico de fraturas em ossos longos de bovinos. O objetivo deste estudo foi avaliar a resistência mecânica de fêmures de bovinos jovens com fratura diafiseal, imobilizados com hastes intramedulares bloqueadas, compostas por diferentes polímeros. Para tanto, testes físicos de compressão e flexão, por meio de uma máquina universal de ensaios foram realizados em quatro grupos distintos de seis fêmures obtidos de bovinos jovens. Em um dos grupos, os ossos foram mantidos íntegros (grupo controle), enquanto que os outros os ossos, foram fraturados e imobilizados com uma haste intramedular bloqueada, composta por polipropileno, poliacetal ou poliamida (uma para cada grupo). Independente do polímero utilizado, nenhuma das hastes estudadas ofereceu aos fêmures fraturados resistência comparável ao osso íntegro, quando consideradas em conjunto as forças de flexão e compressão. A concordância desses achados com resultados in vivo previamente publicados, demonstra que a metodologia utilizada para testes ex vivo pode ser útil na seleção de materiais mais resistentes para confecção de novos modelos.

The development of new devices using available and low cost materials may be an useful alternative for the treatment of long bone fractures in large animals. The aim of this study was to evaluate the mechanical strength of young bovine femur with diaphyseal fracture fixed with different polymeric intramedullary nails. Bending and compression tests using a universal machine were carried out in 4 distinct groups of 6 femurs from young calves. In one of the groups bones were intact while in the other three fractured bones were fixed using an intramedullary nail made of polypropylene, polyacetal or polyamide (one for each group). Considering bending and compression tests together, none of the used polymers offered strength to the fractured bones similar to the intact ones. The agreement of this findings with those from previous published in vivo results indicates that the employed ex vivo methods for mechanical assays may be useful in the search of stronger materials to be used in development of new devices.

Falhas na utilização de poliacetal e poliamida em forma de haste intramedular bloqueada para imobilização de fratura femural induzida em bovinos jovens / Failures in the use of polyacetal and polyamide in the form of intramedullary interlocking nail for immobilization of induced femoral fracture in young cattle

Apesar da expressiva evolução da ortopedia veterinária nos últimos anos, as fraturas de ossos longos em grandes animais são constante desafio para o médico-veterinário. O presente estudo é parte da proposta de desenvolvimento de um sistema de haste intramedular polimérica, de baixo custo e fácil aplicação, para uso em bovinos jovens e neonatos. Os objetivos foram avaliar, in vivo, hastes de poliacetal e poliamida para imobilização de fraturas femorais em bovinos jovens. Cinco bezerros machos foram submetidos à anestesia geral e tiveram os fêmures esquerdos fraturados e, em seguida, imobilizados, utilizando-se uma haste cilíndrica de poliacetal ou poliamida inserida no canal intramedular e bloqueada por quatro parafusos corticais de aço inoxidável, inseridos na diáfise em seu sentido lateral-medial e igualmente distribuídos distal e proximal à linha de fratura. Durante um período de 60 dias pós-cirúrgico, os animais foram avaliados por meio de exames clínicos e radiográficos. Houve fratura em quatro das cinco hastes de poliacetal implantadas pela primeira vez e em duas das quatro hastes de poliamida que foram implantadas após a quebra das de poliacetal. Todas as falhas ocorrerem nas primeiras duas semanas de imobilização. Não foram verificados quaisquer sinais de rejeição aos materiais usados. Os resultados demonstram que as hastes de poliacetal e poliamida não apresentaram resistência suficiente para, de acordo com o modelo proposto, promover imobilização precoce de fraturas de fêmur em bovinos jovens.

In spite of the expressive development of veterinary orthopedics in the last years, long bone fractures in large animals remains a challenge for veterinary surgeons. This study is part of a proposal for development of a low-cost and easy-to-use polymeric interlocking nail designed to be used in newborns and young cattle. The objectives were to evaluate, in vivo, polyacetal and polyamide nails for immobilization of femoral fractures in calves. Five calves were submitted to general anesthesia and the left femur was fractured and then fixed using polyacetal or polyamide rods (nails) interlocked with four cortical screws (stainless steel) equally applied to the distal and proximal fracture line. In the postoperative period, calves were clinically assessed during 60 days by clinical and radiographic exams. Fractures occurred in four of the five polyacetal nails implanted in the first time and in two of the four polyamide nails implanted after the polyacetal nail failures. All failures occurred in the first 14 days after implantation. No rejection signs against the polymers were observed. In conclusion, polyacetal and polyamide did not have enough resistance to be used as intramedullary interlocking nails in this system designed to promote early femoral fractures immobilization in young calves.