Effect of enzymatic treatment on the cross-flow microfiltration of acai pulp: Analysis of the fouling and recovery of phytochemicals

This study aimed to investigate the effects of pectinase enzyme treatment of acai pulp on cross-flow microfiltration (CFMF) performance and on phytochemical and functional characteristics of their compounds. Analyses of fouling mechanisms were carried out through resistance in series and blocking in law models. The enzymatic treatment was conducted using Ultrazym(R) AFPL (Novozymes A/S) at 500 mg kg(-1) of acai pulp for 30 min at 35 degrees C. Before microfiltrations, untreated and enzyme-treated acai pulps were previously diluted in distilled water (1:3; w/v). CFMFs were conducted using commercial alpha-alumina (alpha-Al2O3) ceramic membranes (Andritz AG, Austria) of 0.2 mu m and 0.8 mu m pore sizes, and 0.0047 m(2) of filtration area. The microfiltration unit was operated in batch mode for 120 min at 25 degrees C and the fluid-dynamic conditions were transmembrane pressure of Delta P = 100 kPa and cross-flow velocity of 3 m s(-1) in turbulent flow. The highest values of permeate flux and accumulated permeate volume were obtained using enzyme-treated pulp and 0.2 mu m pore size membranes with steady flux values exceeding 100 L h(-1) m(-2). For the 0.8 mu m pore size membrane, the estimated total resistance after the microfiltration of enzyme-treated acai pulp was 21% lower than the untreated pulp, and for the 0.2 mu m pore size membrane, it was 18%. Cake filtration was the dominant mechanism in the early stages of most of the CFMF processes. After approximately 20 min, however, intermediate pore blocking and complete pore blocking contributed to the overall fouling mechanisms. The reduction of the antioxidant capacity of the permeates obtained after microfiltration of the enzyme-treated pulp was higher (p < 0.01) than that obtained using untreated pulp. For total polyphenols, on the contrary, the permeates obtained after microfiltration of the enzyme-treated pulp showed a lower mean reduction (p < 0.01) than those from the untreated pulp. The results show that the enzymatic treatment had a positive effect on the CFMF process of acai pulp. (C) 2012 Elsevier Ltd. All rights reserved.

Functional properties of gelatin-based films containing Yucca schidigera extract produced via casting, extrusion and blown extrusion processes: A preliminary study

Gelatin-based films containing both Yucca schidigera extract and low concentrations of glycerol (0.25-8.75 g per 100 g protein) were produced by extrusion (EF) and characterized in relation to their mechanical properties and moisture content. The formulations that resulted in either larger or smaller elongation values were used to produce films via both blown extrusion (EBF) and casting (CF) and were characterized with respect to their mechanical properties, water vapor permeability, moisture content, solubility, morphology and infrared spectroscopy. The elongation of the EF films was significantly higher than that of the CF and EBF films. The transversal section possessed a compact, homogeneous structure for all of the films studied. The solubility of the films (36-40%) did not differ significantly between the different processes evaluated. The EBF films demonstrated lower water vapor permeability (0.12 g mm m-(2) h(-1) kPa(-1)) than the CF and EF films. The infrared spectra did not indicate any strong interactions between the added compounds. Thermoplastic processing of the gelatin films can significantly increase their elongation; however, a more detailed assessment and optimization of the extrusion conditions is necessary, along with the addition of partially hydrophobic compounds, such as surfactants. (C) 2012 Elsevier Ltd. All rights reserved.

Liquid-liquid equilibria for systems composed of rice bran oil and alcohol-rich solvents: Application to extraction and deacidification of oil

The liquid-liquid equilibria of systems composed of rice bran oil, free fatty acids, ethanol and water were investigated at temperatures ranging from 10 to 60 degrees C. The results of the present study indicated that the mutual solubility of the compounds decreased with an increase in the water content of the solvent and a decrease in the temperature of the solution. The experimental data set was correlated by applying the UNIQUAC model. The average variance between the experimental and calculated compositions was 0.35%, indicating that the model can accurately predict behavior of the compounds at different temperatures and degrees of hydration. The adjustment of interaction parameters enables both the simulation of liquid-liquid extractors for deacidification of vegetable oil and the prediction of phase compositions for the oil and alcohol-rich phases that are generated during cooling of the stream exiting the extractor (when using ethanol as the solvent). (C) 2012 Elsevier Ltd. All rights reserved.

Quali-quantitative study of the phenolic and polyphenolic compounds and their antioxidant capacity in vegetal matrix processed with different technologies

Food technologies today mean reducing agricultural food waste, improvement of food security, enhancement of food sensory properties, enlargement of food market and food economies. Food technologists must be high-skilled technicians with good scientific knowledge of food hygiene, food chemistry, industrial technologies and food engineering, sensory evaluation experience and analytical chemistry. Their role is to apply the modern vision of science in the field of human nutrition, rising up knowledge in food science. The present PhD project starts with the aim of studying and improving frozen fruits quality. Freezing process in very powerful in preserve initial raw material characteristics, but pre-treatment before the freezing process are necessary to improve quality, in particular to improve texture and enzymatic activity of frozen foods. Osmotic Dehydration (OD) and Vacuum Impregnation (VI), are useful techniques to modify fruits and vegetables composition and prepare them to freezing process. These techniques permit to introduce cryo-protective agent into the food matrices, without significant changes of the original structure, but cause a slight leaching of important intrinsic compounds. Phenolic and polyphenolic compounds for example in apples and nectarines treated with hypertonic solutions are slightly decreased, but the effect of concentration due to water removal driven out from the osmotic gradient, cause a final content of phenolic compounds similar to that of the raw material. In many experiment, a very important change in fruit composition regard the aroma profile. This occur in strawberries osmo-dehydrated under vacuum condition or under atmospheric pressure condition. The increment of some volatiles, probably due to fermentative metabolism induced by the osmotic stress of hypertonic treatment, induce a sensory profile modification of frozen fruits, that in some way result in a better acceptability of consumer, that prefer treated frozen fruits to untreated frozen fruits. Among different processes used, a very interesting result was obtained with the application of a osmotic pre-treatment driven out at refrigerated temperature for long time. The final quality of frozen strawberries was very high and a peculiar increment of phenolic profile was detected. This interesting phenomenon was probably due to induction of phenolic biological synthesis (for example as reaction to osmotic stress), or to hydrolysis of polymeric phenolic compounds. Aside this investigation in the cryo-stabilization and dehydrofreezing of fruits, deeper investigation in VI techniques were carried out, as studies of changes in vacuum impregnated prickly pear texture, and in use of VI and ultrasound (US) in aroma enrichment of fruit pieces. Moreover, to develop sensory evaluation tools and analytical chemistry determination (of volatiles and phenolic compounds), some researches were bring off and published in these fields. Specifically dealing with off-flavour development during storage of boiled potato, and capillary zonal electrophoresis (CZE) and high performance liquid chromatography (HPLC) determination of phenolic compounds.

Advances in understanding of osmotic dehydration and vacuum impregnation of fruits

Osmotic Dehydration and Vacuum Impregnation are interesting operations in the food industry with applications in minimal fruit processing and/or freezing, allowing to develop new products with specific innovative characteristics. Osmotic dehydration is widely used for the partial removal of water from cellular tissue by immersion in hypertonic (osmotic) solution. The driving force for the diffusion of water from the tissue is provided by the differences in water chemical potential between the external solution and the internal liquid phase of the cells. Vacuum Impregnation of porous products immersed in a liquid phase consist of reduction of pressure in a solid-liquid system (vacuum step) followed by the restoration of atmospheric pressure (atmospheric step). During the vacuum step the internal gas in the product pores is expanded and partially flows out while during the atmospheric step, there is a compression of residual gas and the external liquid flows into the pores (Fito, 1994). This process is also a very useful unit operation in food engineering as it allows to introduce specific solutes in the tissue which can play different functions (antioxidants, pH regulators, preservatives, cryoprotectants etc.). The present study attempts to enhance our understanding and knowledge of fruit as living organism, interacting dynamically with the environment, and to explore metabolic, structural, physico-chemical changes during fruit processing. The use of innovative approaches and/or technologies such as SAFES (Systematic Approach to Food Engineering System), LF-NMR (Low Frequency Nuclear Magnetic Resonance), GASMAS (Gas in Scattering Media Absorption Spectroscopy) are very promising to deeply study these phenomena. SAFES methodology was applied in order to study irreversibility of the structural changes of kiwifruit during short time of osmotic treatment. The results showed that the deformed tissue can recover its initial state 300 min after osmotic dehydration at 25 °C. The LF-NMR resulted very useful in water status and compartmentalization study, permitting to separate observation of three different water population presented in vacuole, cytoplasm plus extracellular space and cell wall. GASMAS techniques was able to study the pressure equilibration after Vacuum Impregnation showing that after restoration of atmospheric pressure in the solid-liquid system, there was a reminding internal low pressure in the apple tissue that slowly increases until reaching the atmospheric pressure, in a time scale that depends on the vacuum applied during the vacuum step. The physiological response of apple tissue on Vacuum Impregnation process was studied indicating the possibility of vesicular transport within the cells. Finally, the possibility to extend the freezing tolerance of strawberry fruits impregnated with cryoprotectants was proven.

Profesión y Cultura académica de ingenieros en la Universidad Pública Argentina

El tema referido a la profesión académica y a las culturas académicas resulta de particular interés puesto que se considera que los profesores universitarios poseen ciertos rasgos de una cultura académica propia, la cual sería el origen y el soporte que legitima sus pensamientos y por tanto su acción dentro de las Universidades. De la necesidad de desentrañar esta cultura es que surge la idea de estudiar si existe un conjunto de creencias, valores y normas que influirían en cómo piensan y actúan los profesores-ingenieros universitarios. El presente trabajo se propone aportar un acercamiento al estudio de los grupos profesionales de los ingenieros, tratando de conocer más acerca de su identidad, trayectoria y cultura. Se propone una lectura longitudinal en el análisis, reconstruyendo trayectorias y abarcando distintos aspectos de la vida, no solo los laborales, analizando al ingeniero que ocupa un determinado lugar en la estructura social la cual está en constante evolución. La pregunta central que guía esta investigación es de carácter cualitativo y comparativo y se enuncia de la siguiente manera: ¿cómo se configuran la profesión académica y la cultura académica de los ingenieros académicos que se desempeñan en la Carrera de Ingeniería Electrónica de la Facultad de Ciencias Físico Matemáticas y Naturales, Ingeniería en Alimentos e Ingeniería Química pertenecientes ambas a la Facultad de Química, Bioquímica y Farmacia de la Universidad Nacional de San Luis? Para describir y caracterizar la profesión y culturas académicas de los ingenieros en la UNSL, se propuso el trabajo de campo con entrevistas en profundidad a ingenieros que se desempeñan como docentes e investigadores en la Universidad Nacional de San Luis. El estudio es cualitativo.Tras el recorrido de investigación realizado, el argumento central de esta Tesis que surge de la interpretación de los datos empíricos, queda definido de la siguiente manera: La profesión y cultura académica de los ingenieros entrevistados en la UNSL se conforma a partir de la compleja vinculación entre estos tres elementos: trayectoria individual, comunidad disciplinar o grupo disciplinar de referencia y, las características propias de la UNSL como institución. Esta profesión académica se desarrolla en el marco de al menos dos tipos de regulaciones: unas que son externas que provienen de las políticas educativas nacionales (como por ejemplo: las leyes, el sistema de incentivos, la categorización, etc.) y otras que son internas y que operan como exigencias normativas al interior de la disciplina, de la institución y de las propias actividades del cargo. En síntesis, la heterogeneidad de la profesión y cultura académica de los ingenieros entrevistados está definida por: el contexto ?la UNSL- y sus propiedades en tanto contexto de intercambio; las características individuales alrededor de la disciplina y, los intereses y motivos individuales y colectivos. Todo ello da cuenta de las relaciones sociales en la vida académica explicando la heterogeneidad, la diversidad y la dinámica que se genera. La historia de la UNSL, las características de las Facultades, la historia y evolución de las tres carreras -los campos de conocimiento, los distintos recorridos y configuraciones históricas de los mismos- forman parte de ese contexto de intercambio y se reactualizan permanentemente. La particular combinación de las distintas actividades académicas reviste carácter único e intransferible (por ejemplo: la distribución de tareas, los criterios para seleccionar docentes en los concursos, la vinculación entre la industria y la sociedad, etc.). Todo lo expresado a juicio y entender propio da cuenta de un modo especial y particular de entender, vivir y desarrollar la profesión académica de estos ingenieros en la UNSL.

Profesión y Cultura académica de ingenieros en la Universidad Pública Argentina

El tema referido a la profesión académica y a las culturas académicas resulta de particular interés puesto que se considera que los profesores universitarios poseen ciertos rasgos de una cultura académica propia, la cual sería el origen y el soporte que legitima sus pensamientos y por tanto su acción dentro de las Universidades. De la necesidad de desentrañar esta cultura es que surge la idea de estudiar si existe un conjunto de creencias, valores y normas que influirían en cómo piensan y actúan los profesores-ingenieros universitarios. El presente trabajo se propone aportar un acercamiento al estudio de los grupos profesionales de los ingenieros, tratando de conocer más acerca de su identidad, trayectoria y cultura. Se propone una lectura longitudinal en el análisis, reconstruyendo trayectorias y abarcando distintos aspectos de la vida, no solo los laborales, analizando al ingeniero que ocupa un determinado lugar en la estructura social la cual está en constante evolución. La pregunta central que guía esta investigación es de carácter cualitativo y comparativo y se enuncia de la siguiente manera: ¿cómo se configuran la profesión académica y la cultura académica de los ingenieros académicos que se desempeñan en la Carrera de Ingeniería Electrónica de la Facultad de Ciencias Físico Matemáticas y Naturales, Ingeniería en Alimentos e Ingeniería Química pertenecientes ambas a la Facultad de Química, Bioquímica y Farmacia de la Universidad Nacional de San Luis? Para describir y caracterizar la profesión y culturas académicas de los ingenieros en la UNSL, se propuso el trabajo de campo con entrevistas en profundidad a ingenieros que se desempeñan como docentes e investigadores en la Universidad Nacional de San Luis. El estudio es cualitativo.Tras el recorrido de investigación realizado, el argumento central de esta Tesis que surge de la interpretación de los datos empíricos, queda definido de la siguiente manera: La profesión y cultura académica de los ingenieros entrevistados en la UNSL se conforma a partir de la compleja vinculación entre estos tres elementos: trayectoria individual, comunidad disciplinar o grupo disciplinar de referencia y, las características propias de la UNSL como institución. Esta profesión académica se desarrolla en el marco de al menos dos tipos de regulaciones: unas que son externas que provienen de las políticas educativas nacionales (como por ejemplo: las leyes, el sistema de incentivos, la categorización, etc.) y otras que son internas y que operan como exigencias normativas al interior de la disciplina, de la institución y de las propias actividades del cargo. En síntesis, la heterogeneidad de la profesión y cultura académica de los ingenieros entrevistados está definida por: el contexto ?la UNSL- y sus propiedades en tanto contexto de intercambio; las características individuales alrededor de la disciplina y, los intereses y motivos individuales y colectivos. Todo ello da cuenta de las relaciones sociales en la vida académica explicando la heterogeneidad, la diversidad y la dinámica que se genera. La historia de la UNSL, las características de las Facultades, la historia y evolución de las tres carreras -los campos de conocimiento, los distintos recorridos y configuraciones históricas de los mismos- forman parte de ese contexto de intercambio y se reactualizan permanentemente. La particular combinación de las distintas actividades académicas reviste carácter único e intransferible (por ejemplo: la distribución de tareas, los criterios para seleccionar docentes en los concursos, la vinculación entre la industria y la sociedad, etc.). Todo lo expresado a juicio y entender propio da cuenta de un modo especial y particular de entender, vivir y desarrollar la profesión académica de estos ingenieros en la UNSL.

Profesión y Cultura académica de ingenieros en la Universidad Pública Argentina

El tema referido a la profesión académica y a las culturas académicas resulta de particular interés puesto que se considera que los profesores universitarios poseen ciertos rasgos de una cultura académica propia, la cual sería el origen y el soporte que legitima sus pensamientos y por tanto su acción dentro de las Universidades. De la necesidad de desentrañar esta cultura es que surge la idea de estudiar si existe un conjunto de creencias, valores y normas que influirían en cómo piensan y actúan los profesores-ingenieros universitarios. El presente trabajo se propone aportar un acercamiento al estudio de los grupos profesionales de los ingenieros, tratando de conocer más acerca de su identidad, trayectoria y cultura. Se propone una lectura longitudinal en el análisis, reconstruyendo trayectorias y abarcando distintos aspectos de la vida, no solo los laborales, analizando al ingeniero que ocupa un determinado lugar en la estructura social la cual está en constante evolución. La pregunta central que guía esta investigación es de carácter cualitativo y comparativo y se enuncia de la siguiente manera: ¿cómo se configuran la profesión académica y la cultura académica de los ingenieros académicos que se desempeñan en la Carrera de Ingeniería Electrónica de la Facultad de Ciencias Físico Matemáticas y Naturales, Ingeniería en Alimentos e Ingeniería Química pertenecientes ambas a la Facultad de Química, Bioquímica y Farmacia de la Universidad Nacional de San Luis? Para describir y caracterizar la profesión y culturas académicas de los ingenieros en la UNSL, se propuso el trabajo de campo con entrevistas en profundidad a ingenieros que se desempeñan como docentes e investigadores en la Universidad Nacional de San Luis. El estudio es cualitativo.Tras el recorrido de investigación realizado, el argumento central de esta Tesis que surge de la interpretación de los datos empíricos, queda definido de la siguiente manera: La profesión y cultura académica de los ingenieros entrevistados en la UNSL se conforma a partir de la compleja vinculación entre estos tres elementos: trayectoria individual, comunidad disciplinar o grupo disciplinar de referencia y, las características propias de la UNSL como institución. Esta profesión académica se desarrolla en el marco de al menos dos tipos de regulaciones: unas que son externas que provienen de las políticas educativas nacionales (como por ejemplo: las leyes, el sistema de incentivos, la categorización, etc.) y otras que son internas y que operan como exigencias normativas al interior de la disciplina, de la institución y de las propias actividades del cargo. En síntesis, la heterogeneidad de la profesión y cultura académica de los ingenieros entrevistados está definida por: el contexto ?la UNSL- y sus propiedades en tanto contexto de intercambio; las características individuales alrededor de la disciplina y, los intereses y motivos individuales y colectivos. Todo ello da cuenta de las relaciones sociales en la vida académica explicando la heterogeneidad, la diversidad y la dinámica que se genera. La historia de la UNSL, las características de las Facultades, la historia y evolución de las tres carreras -los campos de conocimiento, los distintos recorridos y configuraciones históricas de los mismos- forman parte de ese contexto de intercambio y se reactualizan permanentemente. La particular combinación de las distintas actividades académicas reviste carácter único e intransferible (por ejemplo: la distribución de tareas, los criterios para seleccionar docentes en los concursos, la vinculación entre la industria y la sociedad, etc.). Todo lo expresado a juicio y entender propio da cuenta de un modo especial y particular de entender, vivir y desarrollar la profesión académica de estos ingenieros en la UNSL.

Combination of optical and on-destructivemechanicaltechniques for the measurement of maturity in peach

Increasing consumer dissatisfaction related with lack of ripeness in peach has been repeatedly reported since 1990 to the present day. There is thus, a great interest in improving the assessment of peach maturity, currently based on Magness Taylor firmness (destructive, highly variable, and time consuming) and colour (not reliable for highly coloured varieties). The present research studies as an alternative several non-destructive (ND) measurements, based on multispectral imaging, visible spectra, and low mass impact response. Their relationship with maturity, as well as the potential of their combination was studied. As a result, two rather independent (R2 = 0.3) groups of non-destructive measurements, chlorophyll related optical indexes and low mass impact (LMI) measurements, were identified. Optical measurements showed the best behaviour for assessing maturity at harvest, while LMI measurements reflected handling incidences, showing a promising potential to be used to control transport and postharvest handling.

Bruise Development and Fruit Response of Pear (cv.'Blanquilla') under Impact Conditions

Pear fruits cv. 'Blanquilla', at various ripening stages, were studied under impact conditions. A 50-6-g spherical steel indentator, with a radius of curvature of 0-94 cm, was dropped on to the fruit from three heights: 4, 6 and 10 cm (0-0199, 0-0299 and 0-0499 J). The variables measured were analyzed. All variables were observed to be related to the impact energy except impact duration, which was related to the fruit firmness. Bruising correlated with impact energy when considering different heights, but not with any specific variable when studying the impact phenomenon at individual heights; however, there was a clear correlation between impact bruising and firmness. Three bruise shapes were observed, corresponding to preclimacteric, climacteric and postclimacteric fruits; a theory for this response is offered. According to the results, the impact response in postclimacteric pear fruits (with firmness values of less than 25 N, and a maturity index above 55) may be explained by the role played by the skin rather than by the pulp.

Decelerator elements for ramp transfer points in fruit packing lines

Two different decelerator elements used to reduce impacts on fruits on ramp transfer points in fruit packing lines were designed and tested. The performance of these elements, a powered decelerator and a multiple curtain, was compared to commercial decelerators (blankets). A ramp of length 60 cm was placed at an angle of 30º in an experimental fruit packing line between a roller transporter and a conveyor. The decelerators were placed on top of the ramp. Different tests were carried out to study the performance of the decelerators using instrumented spheres (IS 100) of various sizes. Results showed that decelerators can reduce the impact intensity down to safe thresholds. The powered decelerator was the most effective because it reduced the speed of fruits and did not cause retention of the fruit, when correctly regulated.

Monitoring spinach shelf-life with hyperspectral image through

Different procedures for monitoring the evolution of leafy vegetables, under plastic covers during cold storage, have been studied. Fifteen spinach leaves were put inside Petri dishes covered with three different plastic films and stored at 4 °C for 21 days. Hyperspectral images were taken during this storage. A radiometric correction is proposed in order to avoid the variation in transmittance of the plastic films during time in the hyperspectral images. Afterwards, three spectral pre-processing procedures (no pre-process, Savitsky–Golay and Standard Normal Variate, combined with Principal Component Analysis) were applied to obtain different models. The corresponding artificial images of scores were studied by means of Analysis of Variance to compare their ability to sense the aging of the leaves. All models were able to monitor the aging through storage. Radiometric correction seemed to work properly and could allow the supervision of shelf-life in leafy vegetables through commercial transparent films.

Discernment of bee pollen loads using computer vision and one-class classification techniques

In this paper, we propose a system for authenticating local bee pollen against fraudulent samples using image processing and classification techniques. Our system is based on the colour properties of bee pollen loads and the use of one-class classifiers to reject unknown pollen samples. The latter classification techniques allow us to tackle the major difficulty of the problem, the existence of many possible fraudulent pollen types. Also presented is a multi-classifier model with an ambiguity discovery process to fuse the output of the one-class classifiers. The method is validated by authenticating Spanish bee pollen types, the overall accuracy of the final system of being 94%. Therefore, the system is able to rapidly reject the non-local pollen samples with inexpensive hardware and without the need to send the product to the laboratory.

Bagaço de cana como enriquecimento ambiental para leitões recém desmamados

O objetivo do estudo foi avaliar o uso de bagaço de cana como enriquecimento ambiental para suínos a partir do comportamento e respostas fisiológicas do estresse causado pelo confinamento e mudança de ambiente, na fase de creche. O projeto foi conduzido no Laboratório de Biometeorologia e Etologia, da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, Pirassununga-SP, e no setor da Suinocultura da Prefeitura do Campus Administrativo Fernando Costa (PUSP-FC), entre os meses de abril e junho de 2015. Foram utilizados 66 leitões (NK75 X Naïma), machos e fêmeas desmamados aos 28 dias, separados em grupos homogêneos com relação ao peso, transferidos para baias da creche e distribuídos em dois tratamentos: Tratamento Enriquecido (TE) onde as baias foram fornecidas com cama profunda de bagaço de cana, de até 15 cm de profundidade e Tratamento Não Enriquecido (TNE) as baias foram utilizadas da forma convencional, sem cobertura no piso cimentado. Foram avaliadas diferentes respostas fisiológicas, especificamente, níveis de cortisol salivar, temperatura superficial por meio de um termómetro infravermelho e temperatura ocular a través de fotos termográficas. O comportamento dos leitões foi registrado e as análises das observações das atividades foram realizadas pelo efeito dos tratamentos e a interação do tempo. Os dados de desempenho dos animais foram analisados, igualmente como o Ganho de peso diário (GPD) e a conversão alimentar (CA). Animais que receberam enriquecimento ambiental apresentaram concentrações de cortisol mais baixas (P<0,001) durante a primeira semana pós-desmama. A partir da segunda semana pós desmama até o final da fase da creche houve efeito do tratamento (P<0,05), encontrando níveis de cortisol até quatro vezes mais altos para o TNE referentes aos níveis basais, enquanto o TE continua tendo níveis mais baixos (P<0,05). Animais que receberam enriquecimento ambiental tiveram maior frequência em comportamentos exploratórios (P<0,05) e maior atividade brincando (P<0,05) durante toda a fase experimental. Leitões que foram criados em baias pobres manifestaram maior frequência em comportamentos agonísticos (P<0,05) e em repouso (P<0,05). A correlação entre a temperatura superficial do dorso e termografia ocular indicou uma associação moderada positiva (P<0,0001) com a temperatura ocular mínima (r=0,43) e máxima (r=0,41). Apesar de não existir diferença estatística para o desempenho entre tratamentos (P>0,05), o TE apresentou maior ganho de peso diário (0,47±0,015 kg.dia-1) e total (23,47±0,73 kg.dia-1). A conversão alimentar foi maior no TE (2,88±0,25), provavelmente porque os leitões precisavam de mais alimento para compensar a energia gasta pela sua atividade de fuçar e brincar. Ambientes enriquecidos durante a fase da creche melhoram o bem-estar dos animais em confinamento, diminuindo o estresse pela desmama, motivando o animal a expressar comportamentos próprios da espécie suína, tais como fuçar e explorar.

Cortisol fecal em ovinos: curva de excreção e estabilidade

O presente estudo foi dividido em dois experimentos, tendo como objetivo determinar a curva de excreção do cortisol fecal e sua estabilidade nas fezes perante exposição à diferentes períodos de tempo e temperatura entre as colheitas e análises, correlacionando os níveis de cortisol fecal com o pico de cortisol sanguíneo. No experimento 1, seis fêmeas mestiças (Dorper x Santa Inês) tiveram suas fezes totais colhidas durante 24 horas após a aplicação do hormônio adrenocorticotrófico (ACTH), além de colheitas de sangue realizadas antes da aplicação do ACTH, 60, 120 e 300 minutos depois; durante as quais foram atribuídos escores de reatividade para cada animal. Logo após as análises foi iniciado o experimento 2, no qual 9 cordeiros mestiços (Dorper x Santa Inês) foram submetidos a uma situação de estresse térmico durante os horários das 11 às 15 horas da tarde, tendo suas fezes colhidas às 23 horas do mesmo dia. Após a colheita, as fezes foram agrupadas e homogeneizadas em três grupos distintos, de onde retiraram-se alíquotas referentes aos tratamentos propostos: três temperaturas (15°, 25° e 35°) e quatro tempos (1, 3, 6 e 12 horas). Os dados da curva de excreção foram analisados por ANOVA, bem como pela correlação entre os valores de cortisol sanguíneo, fecal e reatividade. Para análise da estabilidade foi utilizada ANOVA multifatorial com dois fatores (temperatura e intervalo de tempo). Para avaliação das variáveis comportamentais foi realizada a transformação de escala dos dados para \"arco-seno raiz de porcentagem\", procedendo-se à análise de variância. O modelo estatístico contemplou os efeitos de dia (1, 2 e 3) com análise individual por animal. Os parâmetros de cortisol sanguíneo, frequência respiratória e temperatura retal foram analisados pelo teste t e correlação de Pearson. Todas as comparações de médias foram realizadas por teste F e teste t (PDIFF). A reatividade durante a colheita não exerceu efeito significativo sobre os valores de cortisol sanguíneo, os quais demonstraram médias maiores 60 minutos após a aplicação do ACTH e, após 300 minutos as ovelhas apresentaram níveis de cortisol considerados normais para ovinos sem estresse. Por outro lado, o pico de cortisol nas fezes foi verificado aproximadamente 10 a 12 horas após o pico de cortisol no sangue, não sendo verificadas diminuições significativas nas concentrações que indicassem o retorno aos níveis basais durante o período de 24 horas (P>0,05). Não foram observadas diferenças significativas entre os tempos e temperaturas aos quais as amostras de fezes foram submetidas (P>0,05), verificando-se uma tendência a manutenção da concentração do cortisol fecal em ovinos durante o período de 12 horas após a colheita.