Influence of short-term pre-aging in vacuum on physicochemical characteristics and consumer acceptability of modified atmosphere packed beef steaks

peer-reviewedThe objective of this study was to investigate the physiochemical changes and consumer acceptability of meat packed in high oxygen modified atmosphere during 12 days of storage with and without pre-aging in vacuum for 7 days. Steak samples from forequarter muscles Infraspinatus and Supraspinatus were stored at 2°C and tested for colour, Warner–Bratzler shear force (WBSF), storage/cooking loss, and consumer acceptability. Overall consumer acceptability at the beginning of modified atmosphere display was higher for aged Infraspinatus samples, however at the end of display samples from both treatments were equally rated by consumers. No impact of aging was observed in terms of storage loss, while cooking loss was slightly affected by aging, resulting in higher losses in aged samples at the end of modified atmosphere storage. Inclusion of an aging process prior to modified atmosphere display improved the tenderness of Infraspinatus muscle at the 8th day of display and led to a considerable increase in redness of both muscles.Appreciation is extended to the European Regional Development Fund, within the Innovative Economy Operational Programme (2007–2013) of the European Union, for financial support within ProOptiBeef Project

Microstructure and mechanical properties of friction stir welded joints made from ultrafine grained aluminium 1050

In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were subjected up to 8 passes of Incremental Equal Channel Angular Pressing (IECAP) following route C. Plates in different stages of IECAP were joined using Friction Stir Welding (FSW). All welded samples were investigated to determine their mechanical properties and structure evolution in the joint zone. The joining process reduced mechanical strength of material in the nugget zone, which was explained by the grain growth resulting from temperature rise during FSW. Nevertheless, the obtained results are promising in comparison to other methods of joining aluminium

Variation of Meat Quality Parameters Due to Conformation and Fat Class in Limousin Bulls Slaughtered at 25 to 27 Months of Age

The aim of the present study was to determine the influence of age of animal, hot carcass weight, pH, conformation and fat class on basic beef quality attributes (tenderness, sarcomere length, basic chemical composition, marbling and colour) in a group of purebred animals. The object of the study was beef of Limousin bulls (25 to 27 months, hot carcass weight - 432±31 kg, “U” conformation class, “2”–“3” fat class). Analysed cuts were Infraspinatus muscle from the blade and Longissimus dorsi muscle from the cube roll and the striploin. Tenderness was analysed with universal testing machine, colour - chromometer analysis, sarcomere length - microscopic method, basic chemical composition - near-infrared spectroscopy and marbling - computer image analysis. No differences in tenderness and sarcomere length were observed within the age groups of Limousin bulls (age of 25, 26, 27 months) (p>0.05). Moisture (p = 0.0123) and fat (p = 0.0250) content were significantly different for meat of animals slaughtered at the age of 25 and 27 months. No influence of pH value on tenderness was observed, but at the same time, influence on sarcomere length (p = 0.039) and b* component of colour (0.045) was found. For “U” conformation class, in subclasses, as well as for fat classes “2”–“3”, there were no differences in tenderness, sarcomere length and colour components. Higher fat content was observed in the higher fat class, rather than in lower, however this feature was not associated with marbling

Particulate Matter Emission from Dual Fuel Diesel Engine Fuelled with Natural Gas

The paper presents the results of examination of particulate matter emission from the Diesel engine FPT 1.3 MJT simultaneously fuelled with diesel oil and natural gas CNG. The basic premise for engine adaptation was the addition of a small amount of CNG to reduce exhaust gas opacity and particulate matter emission. At this assumption, diesel oil remained the basic fuel, with contribution amounting to 0,70-0,85 of total energy delivered to the engine. The dual fuel engine was examined using an original controller installed in the Diesel engine FPT 1.3 MJT which controlled the diesel fuel dose. The dose of the injected natural gas was controlled by changing the opening time of gas injectors at constant pressure in the gas collector. The examined issues included the exhaust gas opacity, and the total number and fractional distribution of the emitted particles. The measurements were performed at twenty selected measuring points corresponding to the New European Driving Cycle (NEDC) test. The performed tests have demonstrated a positive effect of gas addition on exhaust gas opacity and particulate matter emission. Depending on test conditions, the exhaust gas opacity was reduced by 10÷92%, and the total number of particles by 30÷40%. The performed tests have revealed that a small addition of gas can reduce the load of the DPF filter, extend its lifetime, and increase engine reliability. Longer time intervals between successive DPF filter regenerations improve ecological properties of the engine

Eveningness and its possibility of predicting burnout symptoms among physicians and nurses – preliminary results

Introduction

Joining ultrafine grained aluminium by friction stir welding – processing, microstructure and mechanical properties

Nowadays different processes are used to improve mechanical properties of materials. In metallic materials, grain size refinement down to nanoscale is one of the most efficient strengthening mechanisms, as predicted by Hall-Petch relationship. Such microstructure refinement can be obtained in several ways, among others by severe plastic deformation (SPD). Although a tremendous progress has been made in the development of SPD methods, the main drawback is the restriction in billet dimensions. The most common shape – rods, are manufacturing with diameter about few or sometimes over a dozen millimetres. Incremental ECAP is a novel tool to manufacture plates with ultrafine grained structure. Possible sizes of plates are promising for future applications, e.g. in automotive industry. Another issue related to ultrafine grained materials is joining without losing their properties governed by the nanoscale structure. Traditional methods cause grain coarsening which is highly unwanted. In this work plates from Al 1050 after Incremental ECAP were joined using Friction Stir Welding. The quality of joints was determined using microscopic observations. Also, the structure of joints and base materials was investigated by light microscopy and transmission electron microscopy. Mechanical properties were measured by microhardness and tensile tests. To investigate mechanical properties like yield strength and tensile strength mini samples were used. Samples were separately cut from the joints and initial materials as well. It allowed to investigate the differences in both areas. The results revealed that joints zone are characterized by lower values of microhardness and tensile properties compared to base materials. Structure investigation showed changes in grain sizes caused by joining process

Dog Tear Film Proteome In-Depth Analysis.

In this study, mass spectrometry was used to explore the canine tear proteome. Tear samples were obtained from six healthy dogs, and one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used as a first step to separate intact proteins into 17 bands. Each fraction was then trypsin digested and analysed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) to characterize the protein components in each fraction. In total, 125 tear proteins were identified, with MCA (Major Canine Allergen), Serum albumin, UPF0557 protein C10orf119 homolog, Collagen alpha-2(I) chain, Tyrosine -protein kinase Fer, Keratine type II cytoskeletal, Beta-crystallin B2, Interleukin-6 and Desmin occurring as the most confident ones with the highest scores. The results showed that the proteomic strategy used in this study was successful in the analysis of the dog tear proteome. To the best of our knowledge, this study is the first to report the comprehensive proteome profile of tears from healthy dogs by 1D SDS PAGE and MALDI-TOF. Data are available via ProteomeXchange with identifier PXD003124

Cloning and expression of a new recombinant thrombolytic and anthithrombotic agent - a staphylokinase variant

To develop a more potent antithrombin agent with thrombolytic and antiplatelet properties, a new staphylokinase (SAK) variant was constructed. The kringle 2 domain (K2) of tissue type-plasminogen activator (t-PA) containing a fibrin-specific binding site (i), the RGD sequence (Arg-Gly-Asp) for the prevention of platelet aggregation (ii) and the antithrombotic agent - hirulog (iii) was assembled to the C-terminal part of recombinant staphylokinase (r-SAK). cDNA for the hybrid protein SAK-RGD-K2-Hirul was cloned into Pichia pastoris pPIC9K yeast expression vector. The introduction of K2 t-PA, the RGD sequence and hirulog into the C-terminus of r-SAK did not alter the staphylokinase activity. We observed a higher clot lysis potency of SAK-RGD-K2-Hirul as evidenced by a faster and more profound lysis of 125I-labeled human fibrin clots. The potency of thrombin inhibition by the hirulog C-terminal part of the recombinant fusion protein was almost identical to that of r-Hir alone. These results suggest that the SAK-RGD-K2-Hirul construct can be a more potent and faster-acting thrombolytic agent with better antithrombin and antiplatelet properties compared to r-SAK and SAK-RGD-K2-Hir