Efeito do processamento por alta pressão no prolongamento da vida útil de uma bebida funcional de bolota

The consumption of plant-based beverages can be an excellent way to increase the intake of bioactive compounds promoting consumers’ health. However, unprocessed plant-based beverages have a short shelf life and thermal treatments are usually required, affecting the overall quality of the beverages. High pressure processing (HPP) may be a solution since it has been recognized for retaining nutritional and sensorial quality of fresh foods. The acorn is very abundant in Portugal but still is sub-valorised to the point of staying in the field without any use, despite its high nutritional value, phytochemical compounds, antioxidant, anticarcinogenic, and cardioprotective properties. This work aimed to develop a functional acorn beverage, free of gluten and lactose. Thereafter, the impact of HPP (450 and 600 MPa for 5, 12.5, and 20 min) and conventional thermal processing (85 ºC for 30 min) on the microbiological safety (Enterobacteriaceae, mesophiles, psychrophiles, molds and yeasts, Staphylococcus and lactic bacteria) and physical-chemical characteristics (pH, colour, antioxidant activity, and food compounds) was assessed. The initial acorn leaching reduces in 42.5 % the content of hydrolysable tannins, which are responsible for the undesirable astringency. The pressurized samples maintained microbiological stability over ten weeks of analysis, which was not verified for untreated samples. Moreover, HPP at 450 MPa/5 min was enough to inactivate B. cereus, E. coli and P. aeruginosa. The HPP better preserved the colour (lower ΔE*), but the pH increased after both treatments (from 5.1 to 5.9 and 6.2, for thermal processed and pressurized samples). The degree brix is very low in all samples (0.1 – 1.6 %), with higher values in the thermal processed samples. Total phenolics as well as antioxidant activity (ABTS, DPPH, and ORAC) were similar among the different treatments being gallic acid the main phenolic compound found in this beverage. The total carbohydrates, lipids, and protein contents were similar between the different treatments, as well as the lipid fraction, that shows elevated values of both MUFA and PUFA, namely nutritionally relevant fatty acids like oleic, linoleic, and linolenic. The lipid fraction also reveals low thrombogenicity and atherogenicity indices. This beverage is source of amino acids once it contains all the essential amino acids determinate. Regarding mineral content, potassium was the principal compound quantified but other minerals were found in minor amounts. The absence of 5-hydroxymethylfurfural was confirmed in both treatments. In the sensory analysis performed, the consumers preferred the pressurized treated sample. With this study some tests were performed in order to proceed with the development of a functional beverage with this fruit that is a surplus in Portugal and around the world.O consumo de bebidas vegetais pode ser uma excelente forma de aumentar a ingestão de compostos bioativos que promovem a saúde. No entanto, as bebidas vegetais não processadas têm um tempo de prateleira curto e geralmente são necessários tratamentos térmicos, afetando a sua qualidade. O processamento por alta pressão (HPP) pode ser uma solução, pois tem sido reconhecido por manter a qualidade nutricional e sensorial de alimentos frescos. A bolota é muito abundante em Portugal, mas ainda é subvalorizada, a ponto de permanecer no campo sem utilidade, apesar de seu elevado valor nutricional, compostos fitoquímicos, propriedades antioxidantes, anticarcinogénicas, e cardioprotetoras. Assim, este trabalho teve como objetivo desenvolver uma bebida funcional de bolota, isenta de glúten e lactose. O impacto do HPP (450 e 600 MPa por 5, 12.5, e 20 min) e do processamento térmico convencional (85 ºC por 30 min) na segurança microbiológica (mesófilos, psicrófilos, bolores e leveduras, Enterobacteriaceae, Staphylococcus, e bactérias lácticas) e características físico-químicas (pH, cor, atividade antioxidante, e compostos antioxidantes) foi avaliado. A lixiviação inicial da bolota reduziu em 42.5 % o teor de taninos hidrolisáveis, responsáveis pela adstringência indesejável. As amostras pressurizadas mantiveram a estabilidade microbiológica ao longo de dez semanas de análise, o que não se verificou para amostras não tratadas. Além disso, o HPP a 450 MPa por 5 min foi suficiente para inativar B. cereus, E. coli, e P. aeruginosa. O HPP preservou melhor a cor (ΔE* menor), mas o pH aumentou após ambos os tratamentos (de 5.1 para 5.9 e 6.2, em amostras processadas termicamente e pressurizadas, respetivamente). O grau brix foi muito baixo em todas as amostras (0,1 – 1,6 %), mas com valores mais altos nas processadas termicamente. Os fenólicos totais e a atividade antioxidante (ABTS, DPPH, e ORAC) foram semelhantes entre os diferentes tratamentos, sendo o ácido gálico o principal composto fenólico detetado. O conteúdo total em hidratos de carbono, lípidos, e proteínas foi semelhante, bem como a fração lipídica, que mostrou elevados valores de MUFA e PUFA, ácidos gordos nutricionalmente relevantes, como oleico, linoleico e linolénico. A fração lipídica revelou também baixos índices de trombogenicidade e aterogenicidade. Esta bebida é fonte de aminoácidos, uma vez que contém todos os aminoácidos essenciais determinados. Em relação ao conteúdo em minerais, o potássio foi o principal composto quantificado, mas outros foram encontrados em menores quantidades. A ausência de 5-hidroximetilfurfural foi confirmada em ambos os tratamentos. Na análise sensorial realizada, os consumidores preferiram a amostra pressurizada. Com este estudo foram realizados alguns ensaios a fim de prosseguir com o desenvolvimento de uma bebida funcional com este fruto que é um excedente em Portugal e no mundo.Mestrado em Biotecnologi

Aos olhos das crianças:: a formação de valores políticos

Este trabalho procura investigar os elementos centrais que envolvem a concepção de política entre crianças de 9 a 11 anos matriculadas no ensino fundamental de escolas públicas e privada do Distrito Federal. Intenta-se identificar de que maneira se dá a formação de valores políticos no relacionamento das crianças com os seus agentes socializadores e como isso se processa no seu cotidiano. Desenvolve-se ao longo do trabalho discussão em torno de três parâmetros conceituais da política – o institucional, o relacional e o participativo –, e a forma como eles se articulam na formação dos valores políticos desses agentes sociais. Recorre-se, fundamentalmente, ao marco teórico definido como “sociologia da infância”, considerando o seu caráter teórico-metodológico que compreende a criança como ator social ativo no processo de construção de significados da realidade. Discutem-se aspectos relacionados à história social da infância, aos diferentes processos e agentes de socialização e realiza-se leitura das crianças como sujeitos em constante formação e interação social. Está-se aqui tratando de “sujeitos-ação”, os quais se situam em ambientes reais e demarcáveis, que constroem concepções de mundo interativas e cambiáveis. Trata-se, portanto, de dar voz a um segmento social secundarizado na literatura política, e de revelar uma face pouco explorada sobre o pensar e o agir político nas sociedades modernas. _________________________________________________________________________________ ABSTRACTThis work seeks to investigate the central elements that involve the conception of politics formulated by children from 9 to 11 years old registered in the Distrito Federal private and public schools of fundamental education. This research intends to identify the way the formation of political values are been related with the children and their socializating agents and how is it processed in their daily lives. It is developed on the course of the work a debate around three political conceptual parameters – the institutional, the relational and the participatory–, and the way that they are articulated in the formation of the political values of those social agents. It is go through, fundamentally, to the theoretical landmark defined as "sociology of childhood" considering its theoretical-methodological character which understands children as an active social actor in the process of construction of reality’s meanings. This work discuss, also, aspects related to the social history of the infancy, to the different processes and socialization agents and make a reading about the children as an individual in constant formation and social interaction. Here are been threated the "action subjects", which are situated in a real and demarcated ambient, that build their own interactive world conceptions. It is a research that intends, therefore, to give voice to a social segment looked down upon the others elements in the political literature, and to reveal a face poorly explored on political thinking and acting in the modern societies

Resveratrol affects differently rat liver and brain mitochondrial bioenergetics and oxidative stress in vitro: Investigation of the role of gender

Resveratrol (3,5,40-trihydroxy-trans stilbene) is commonly recognized by its antioxidant properties. Despite its beneficial qualities, the toxic effects of this natural compound are still unknown. Since mitochondria are essential to support the energy-dependent regulation of several cell functions, the objective of this study was to evaluate resveratrol effects on rat brain and liver mitochondrial fractions from male and females regarding oxidative stress and bioenergetics. No basal differences were observed between mitochondrial fractions from males and females, except in liver mitochondria, the generation of H2O2 by the respiratory chain is lower for female preparations. Resveratrol inhibited lipid peroxidation in preparations from both genders and organs. Furthermore, brain mitochondria in both gender groups appeared susceptible to resveratrol as seen by a decrease in state 3 respiration and alterations in mitochondrial membrane potential fluctuations during ADP phosphorylation. As opposed, liver mitochondria were less affected by resveratrol. Our data also demonstrates that resveratrol inhibits complex I activity in all mitochondrial preparations. The results suggest that brain mitochondria appear to be more susceptible to resveratrol effects, and gender appears to play a minor role. It remains to be determined if resveratrol effects on brain mitochondria contribute to deterioration of mitochondrial function or instead to mediate hormesis-mediated events.This work is supported by PTDC/AGR-ALI/108326/2008 to M.S.S. from the Portuguese Foundation for Science and Technology, FEDER/ Compete/National Funds. A.C.M., A.M.S. and V.A.S. are recipient of SFRH/BD/33892/2009, SFRH/BD/76086/2011 and SFRH/BPD/ 31549/2006 fellowships, respectively

Nitrogen compounds prevent H9c2 myoblast oxidative stress-induced mitochondrial dysfunction and cell death

Oxidative stress has been connected to various forms of cardiovascular diseases. Previously, we have been investigating the potential of new nitrogen-containing synthetic compounds using a neuronal cell model and different oxidative stress conditions in order to elucidate their potential to ameliorate neurodegenerative diseases. Here, we intended to extend these initial studies and investigate the protective role of four of those new synthetic compounds (FMA4, FMA7, FMA762 and FMA796) against oxidative damage induced to H9c2 cardiomyoblasts by tert-butylhydroperoxide (t-BHP). The data indicates that FMA762 and FMA796 decrease t-BHP-induced cell death, as measured by both sulforhodamine B assay and nuclear chromatin condensation evaluation, at non-toxic concentrations. In addition, the two mentioned compounds inhibit intracellular signalling mechanisms leading to apoptotic cell death, namely those mediated by mitochondria, which was confirmed by their ability to overcome t-BHP-induced morphological changes in the mitochondrial network, loss of mitochondrial membrane potential, increased expression of the pro-apoptotic proteins p53, Bax and AIF and activation of caspases-3 and -9. Importantly, our results indicate that the compounds’ ROS scavenging ability plays a crucial role in the protection profile, as a significant decrease in t-BHP-induced oxidative stress occurred in their presence. Data obtained indicates that some of the test compounds may clearly prove valuable in a clinical context by diminishing cardiac injury associated to oxidative stress without any toxicity.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa SFRH/BD/17174/2004, PTDC/QUI/ 64358/200

Effect of high pressure processing on a functional acorn beverage

info:eu-repo/semantics/publishedVersio

Vital imaging of H9c2 myoblasts exposed to tert-butylhydroperoxide – characterization of morphological features of cell death

BACKGROUND: When exposed to oxidative conditions, cells suffer not only biochemical alterations, but also morphologic changes. Oxidative stress is a condition induced by some pro-oxidant compounds, such as by tert-butylhydroperoxide (tBHP) and can also be induced in vivo by ischemia/reperfusion conditions, which is very common in cardiac tissue. The cell line H9c2 has been used as an in vitro cellular model for both skeletal and cardiac muscle. Understanding how these cells respond to oxidative agents may furnish novel insights into how cardiac and skeletal tissues respond to oxidative stress conditions. The objective of this work was to characterize, through vital imaging, morphological alterations and the appearance of apoptotic hallmarks, with a special focus on mitochondrial changes, upon exposure of H9c2 cells to tBHP. RESULTS: When exposed to tBHP, an increase in intracellular oxidative stress was detected in H9c2 cells by epifluorescence microscopy, which was accompanied by an increase in cell death that was prevented by the antioxidants Trolox and N-acetylcysteine. Several morphological alterations characteristic of apoptosis were noted, including changes in nuclear morphology, translocation of phosphatidylserine to the outer leaflet of the cell membrane, and cell blebbing. An increase in the exposure period or in tBHP concentration resulted in a clear loss of membrane integrity, which is characteristic of necrosis. Changes in mitochondrial morphology, consisting of a transition from long filaments to small and round fragments, were also detected in H9c2 cells after treatment with tBHP. Bax aggregates near mitochondrial networks were formed after short periods of incubation. CONCLUSION: Vital imaging of alterations in cell morphology is a useful method to characterize cellular responses to oxidative stress. In the present work, we report two distinct patterns of morphological alterations in H9c2 cells exposed to tBHP, a pro-oxidant agent frequently used as model to induce oxidative stress. In particular, dynamic changes in mitochondrial networks could be visualized, which appear to be centrally involved in how these cells respond to oxidative stress. The data also indicate that the cause of H9c2 cell death following tBHP exposure is increased intracellular oxidative stress