Beef sausage structure affected by sodium chloride and potassium lactate

A histological and ultrastructural study was conducted to characterize changes in the muscle fibre structure of three fresh sausage preparations, depending on meat composition, sodium chloride (NaCl) and potassium lactate (K-lactate) contents. After addition of 0.8% and 1.6% NaCl, 65% and 51%, respectively, of the area observed showed well preserved fibres (histological data). The altered regions presented a large disorganization of the myofilaments and a solubilization of the sarcolemma and of the Z lines. K-lactate addition had no marked effects on meat structure. The preparation containing some sheep meat was more sensitive to salt than the others containing only bovine meat. The level of alteration was much lower than those obtained in pork meat in another study. Technological conditions used to modify the internal muscle fibre structure during sausage processing depend on the species used. Therefore, the classification of the sausage preparation to “meat preparation” or “meat product” under the EU regulation (EC) No. 853/2004 (which assign meat preparations to meat if the product has undergone a process insufficient to modify the internal muscle fibre structure of the meat) must be systematically controlled when changing the meat sausage composition.     

Malolactic fermentation of Tempranillo wine: contribution of the lactic acid bacteria inoculation to sensory quality and chemical composition

Malolactic fermentation (MLF) of Tempranillo Rioja wines (Spain) inoculated with two lactic acid bacteria (LAB) strains were studied and compared with spontaneous MLF. Inoculation with selected Oenococcus oeni lyophila shortened MLF duration up to 19 days and lead to wines with more fresh and fruity characters, especially when implantation was 100%. We demonstrated modifications in the concentration of volatile and nitrogenous compounds and a good correlation between analytical and sensory attributes was also noted. In addition, the low initial amino acid concentration and the consumption of these compounds by the inoculated yeast strain during alcoholic fermentation resulted in wines with very low biogenic amines levels (under 3.75 mg L^?1) after MLF and 3 month storage period in all cases. The results showed the significance of choose the most suitable starter to elaborate quality wines and suggest the control of amino acid content in must and wine to prevent the formation of biogenic amines.     

Ochratoxin A in red paprika: relationship with the origin of the raw material

The occurrence of ochratoxin A (OA) in paprika elaborated from peppers grown in several countries (Peru, Brazil, Zimbabwe and Spain) was studied, using an immunoaffinity clean-up column coupled to liquid chromatography and fluorescence detection. The preparation of the methyl ester (OA-Me) and liquid chromatography-electrospray-ion trap-mass spectrometry was used both to confirm the identity of the chromatographic peak that correspond to OA and to quantify it at low levels or in dirty fractions. A total of 115 strains of moulds were isolated; 85 of the fungal strains were obtained from OA contaminated paprika samples and identified as belonging to the Aspergillus Section Circumdati group (A. ochraceus) and Section Nigri group (A. niger, A. carbonarius). Among the latter ones, 31% of the A. ochraceus isolates and one A. niger were OA producers in vitro. None of the mould strains isolated from paprika samples with undetectable levels of OA or concentrations below 1 microg kg(-1) were toxin producers. Great differences in OA content in paprika samples were found, and a relationship with the climatic conditions of the geographic origin of the samples, and with cultural and technical practices in pepper manipulation is suggested.     

Copper(I)‐Catalysed Multicomponent Reaction: Straightforward Access to 5‐Hydroxy‐1H‐pyrrol‐2(5H)‐ones

A copper‐catalysed multicomponent coupling reaction between readily available (Z)‐3‐iodoacrylic acids, terminal alkynes, and primary amines was developed to smoothly access a small library of 5‐hydroxy‐1H‐pyrrol‐2(5H)‐ones in good yields. This practical and general process was applied to a short‐steps synthesis of the natural product pulchellalactam.

     

Impact of agglomeration on the relaxometric properties of paramagnetic ultra-small gadolinium oxide nanoparticles

Ultra-small gadolinium oxide nanoparticles (US-Gd(2)O(3)) are used to provide 'positive' contrast effects in magnetic resonance imaging (MRI), and are being considered for molecular and cellular imaging applications. However, these nanoparticles can aggregate over time in aqueous medium, as well as when internalized into cells. This study is aimed at measuring in vitro, in aqueous medium, the impact of aggregation on the relaxometric properties of paramagnetic US-Gd(2)O(3) particles. First, the nanoparticle core size as well as aggregation behaviour was assessed by HRTEM. DLS (hydrodynamic diameter) was used to measure the hydrodynamic diameter of nanoparticles and nanoaggregates. The relaxometric properties were measured by NMRD profiling, as well as with (1)H NMR relaxometers. Then, the positive contrast enhancement effect was assessed by using magnetic resonance scanners (at 1.5 and 7 T). At every magnetic field, the longitudinal relaxivity (r(1)) decreased upon agglomeration, while remaining high enough to provide positive contrast. On the other hand, the transverse relaxivity (r(2)) slightly decreased at 0.47 and 1.41 T, but it was enhanced at higher fields (7 and 11.7 T) upon agglomeration. All NMRD profiles revealed a characteristic relaxivity peak in the range 60-100 MHz, suggesting the possibility to use US-Gd(2)O(3) as an efficient 'positive-T(1)' contrast agent at clinical magnetic fields (1-3 T), in spite of aggregation.     

Electrodeposition growth of nanowire arrays with height gradient profiles for microwave device applications

A simple and nonexpensive adapted dip-coating technique is presented and used to fabricate arrays of magnetic nanowires with a linear varying height profile. This approach allows controlling the wire height from tenths of nanometers up to several micrometers. Furthermore, the main parameters of this height gradient can be controlled, such as the maximum wire height and the lateral span of the wire array, which can be predicted with excellent accuracy using a proposed analytical model. Moreover, we show that by sequential electrodeposition with dip-coating, arrays of these height varying wires can be grown. This technique represents a novel method to fill porous templates with controlled spatial growth, leading to the fabrication of novel structures and providing control over structural features on the nanoscale level. In particular, the use of these asymmetrically loaded magnetic nanowired substrates to obtain improved microwave nonreciprocal behavior is shown for a microwave phase shifter.     

Microwave-assisted synthesis and characterization of Ti1 − xVxO2 (x = 0.0–0.10) nanopowders

Ti_1 ? xV_xO₂ (x = 0.0–0.10) nanopowders were successfully synthesized by a microwave-assisted sol–gel technique and their crystal structure and electronic structure were investigated. The products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and UV–Vis spectroscopy. The results revealed that TiO₂ powders maintained the anatase phase for calcination temperature below 600 °C, but gradually changed to the rutile phase above 800 °C. The formation of the rutile phase was completed at 1000 °C. For Ti_1 ? xV_xO₂ (x = 0.05) powders, the phase transformation appeared at 600 °C. The absorption edge of Ti_1 ? xV_xO₂ (x > 0) powders broadened to the visible region with increasing V concentration and a strong visible light absorption was obtained with 10% V doping. V doping and subsequent coexistence of both anatase and rutile phases in our Ti_1 ? xV_xO₂ nanoparticles are considered to be responsible for the enhanced absorption of visible light up to 800 nm.