Efeito do resfriamento sobre a textura post-mortem da carne do peixe matrinxã Brycon cephalus Chilling effect on the post-mortem texture of the matrinxã fish muscle Brycon cephalus

Os mecanismos que causam o amolecimento e a perda na textura post-mortem da carne de matrinxã foram determinados por meio das mudanças na microestrutura do músculo, imediatamente após a morte e depois de 12 horas de estocagem a -3&deg;C. As observações na microestrutura, realizadas com microscópio eletrônico de transmissão, foram semelhantes aos resultados obtidos na força de ruptura do músculo medidos com o texturômetro. Os valores da força da ruptura foram menores para a carne após o resfriamento. Observou-se que as fibras do colágeno do tecido conectivo pericelular se desintegraram e que as do colágeno do tecido conectivo do miocommata conservaram sua arquitetura e integridade. Houve pouca degradação da linha Z. Isso sugere que o amolecimento post-mortem da carne de mantrinxã, durante a estocagem a -3&deg;C, é causado pela degradação do tecido conectivo pericelular.<br>In order to determine the mechanisms that cause the post mortem muscle softness of the matrinxã Brycon cephalus, changes in the micro structure of the muscle were observed immediately after death and after 12 hours of storage at -3º C, measuring the firmness of the flesh with test instruments. Observations by the transmission electron microscope were similar to the results obtained in the breaking strength of the muscle measured with a texturometer. The values of the breaking strength of the fish muscle were smaller after chilling. At the same time, it was observed that the collagen fibers of the pericellular connective tissue had disintegrated, while the collagen fibers of the miocommata connective tissue maintained their organization and integrity. No evident breakdown of Z-discs was observed. It is suggested that the post-mortem tenderization of the matrinxã muscle during chilled storage was due to the disintegration of the collagen fibers in the pericellular connective tissue and, in a smaller extent, to the weakening of Z-disk

Monitoring the sardine (Sardinella brasiliensis) fermentation process to obtain anchovies Monitoramento do processo de fermentação da sardinha, Sardinella brasiliensis, para obtenção de anchovas

Anchovies are traditional fish preserves, prepared from fermented fish of the engraulidae family, mainly in European countries. In Brazil, sardines (Sardinella brasiliensis) are an alternative fish for preparing these types of preserves, provided that the preservation process results in a high quality product. In this research, sardines were prepared for preservation and physicochemical, microbiological and sensory analyses were carried out during the preservation process. Whole or eviscerated sardines, with or without condiments/preservatives and with 20% of salt (w/w) were used. Sardines were analyzed fresh, and at 1, 15, 30, 45 and 60 days along the preservation process. The use of whole sardines, with or without condiments/preservatives, presented best results, with increased non-proteic nitrogen in the dry matter, higher levels of total volatile bases and higher contents of lactic acid and sodium chloride. The higher acidity observed in the whole sardine treatments resulted in better control of halophylic mesophilic microorganisms, which were kept under 1.4 x 10³ CFU g-1 in both treatments. Total coliforms and Staphylococcus aureus reached 21 and 3.0 x 10² CFU g-1, respectively. Escherichia coli and Salmonella spp were not present in the fresh sardines or in any of the four treatments, indicating that the concentration of salt used was appropriate to maintain the product under adequate microbiological control. Both whole or eviscerated sardines under the conditions of this experiment were appropriate in terms of the microbiological safety of the preserves. Treatments using whole fish, either with or without condiments/preservatives, also presented better sensorial properties such as color, flavor, taste and texture, as compared to the eviscerated fish treatments. Whole sardines produced good quality, anchovy-type preserves, which can be used for consumption and marketing purposes.<br>As sardinhas brasileiras podem ser utilizadas para o preparo de pescado fermentado, à semelhança do que é feito com as anchovas na Europa, desde que o processamento permita a obtenção de um produto com qualidade. O objetivo desta pesquisa foi monitorar o processamento de fermentação de sardinhas, Sardinella brasiliensis, utilizando 4 tratamentos, a saber: peixes inteiros e eviscerados, ambos com ou sem condimentos, e 20% de sal. As sardinhas foram analisadas in natura e nos períodos de 1; 15; 30; 45 e 60 dias de fermentação. O pescado mantido com vísceras apresentou maior facilidade para fermentação e revelou maiores teores de bases voláteis, nitrogênio não protéico e acidez em ácido lático (19,82 mg 100 g-1). A contagem total de mesófilos se manteve na faixa de 10³ UFC g-1. Coliformes totais e Staphilococcus aureus apresentaram baixas contagens. Escherichia coli e Salmonella não foram detectadas. O processamento do pescado com vísceras, não interferiu na segurança microbiológica e propiciou os melhores resultados para cor, aroma, sabor e textura do produto final

Search for new Higgs bosons via same-sign top quark pair production in association with a jet in proton-proton collisions at s=13TeV

A search is presented for new Higgs bosons in proton-proton (pp) collision events in which a same-sign top quark pair is produced in association with a jet, via the pp→tH/A→ttc‾ and pp→tH/A→ttu‾ processes. Here, H and A represent the extra scalar and pseudoscalar boson, respectively, of the second Higgs doublet in the generalized two-Higgs-doublet model (g2HDM). The search is based on pp collision data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Final states with a same-sign lepton pair in association with jets and missing transverse momentum are considered. New Higgs bosons in the 200–1000 GeV mass range and new Yukawa couplings between 0.1 and 1.0 are targeted in the search, for scenarios in which either H or A appear alone, or in which they coexist and interfere. No significant excess above the standard model prediction is observed. Exclusion limits are derived in the context of the g2HDM