Influence of farming conditions on colour and texture of European catfish (Silurus glanis) flesh

The colour of raw fillets and the texture of cooked fillets of European catfish (Silurus glanis) were studied. The catfish fillets resulted from two types of farming conditions used in France. Sensory and instrumental analyses were performed on the fillets. Two farming parameters were found to affect the colour and texture of European catfish fillets: water temperature and farming time. The shorter the farming time was, the lighter the fillets were, while a higher water temperature produced yellower and greener fillets. A higher water temperature and a longer farming time produced softer cooked fillets, while the higher the water temperature was, the less juicy the cooked fillets were. A good correlation and complementarity were observed between sensory and instrumental analyses of the colour and texture of European catfish fillets. Copyright © 2007 Society of Chemical Industry     

Facilitated transport of diuron and glyphosate in high copper vineyard soils

The fate of organic herbicides applied to agricultural fields may be affected by other soil amendments, such as copper applied as a fungicide. The effect of copper on the leaching of diuron and glyphosate through a granitic and a calcareous soil was studied in the laboratory using sieved-soil columns. Each soil was enriched with copper sulfate to obtain soil copper concentrations of 125, 250, 500, and 1000 mg kg(-1). Glyphosate leaching was influenced by soil pH and copper concentration, whereas diuron leaching was not. In the calcareous soil, glyphosate leaching decreased as copper levels increased from 17 mg kg(-1) (background) to 500 mg kg(-1). In the granitic soil, glyphosate leaching increased as copper levels increased from 34 mg kg(-1) (background) to 500 mg kg(-1). The shapes of the copper elution curves in presence of glyphosate were similar to shapes of the glyphosate curves, suggesting the formation of Cu-glyphosate complexes that leach through the soil. Soil copper concentration does not influence diuron leaching. In contrast, increasing copper concentrations reduces glyphosate leaching through calcareous soils, and conversely, increases glyphosate leaching through granitic soils. Our findings suggest that the risk of groundwater contamination by glyphosate increases in granitic soils with elevated copper concentrations.     

Broad-Spectrum Antifungal Agents: Fluorinated Aryl- and Heteroaryl-Substituted Hydrazones

Fluorinated aryl- and heteroaryl-substituted monohydrazones displayed excellent broad-spectrum activity against various fungal strains, including a panel of clinically relevant Candida auris strains relative to a control antifungal agent, voriconazole (VRC). These monohydrazones displayed less hemolysis of murine red blood cells than that of VRC at the same concentrations, possessed fungicidal activity in a time-kill study, and exhibited no mammalian cell cytotoxicity. In addition, these monohydrazones prevented the formation of biofilms that otherwise block antibiotic effectiveness and did not trigger the development of resistance when exposed to C. auris AR Bank # 0390 over 15 passages.     

Chemically Controllable Magnetic Transition Temperature and Magneto-Elastic Coupling in MnZnSb Compounds

Magneto-caloric materials offer the possibility to design environmentally friendlier thermal management devices compared to the widely used gas-based systems. The challenges to develop this solid-state based technology lie in the difficulty of finding materials presenting a large magneto-caloric effect over a broad temperature span together with suitable secondary application parameters such as low heat capacity and high thermal conductivity. A series of compounds derived from the PbFCl structure is investigated using a combination of computational and experimental methods focusing on the change of cell volume in magnetic and non-magnetic ground states. Scaling analysis of the magnetic properties determines that they are second order phase transition ferromagnets and that the magnetic entropy change is driven by the coupling of magneto-elastic strain in the square-net through the magnetic transition determined from neutron and synchrotron X-ray diffraction. The primary and secondary application related properties are measured experimentally, and the c/a parameter is identified as an accurate proxy to control the magnetic transition. Chemical substitution on the square-net affords tuning of the Curie temperature over a broad temperature span between 252 and 322 K. A predictive machine learning model for the c/a parameter is developed to guide future exploratory synthesis.     

Study of the formation of acid-based geopolymer networks and their resistance to water by time/temperature treatments

Acid-based geopolymers are known for their high temperature resistance and good mechanical performances. Some compositions also exhibit water resistance, which make them suitable for outdoor applications. This work aims to understand accurately the steps occurring during the geopolymerization process and focuses on the type of networks forming at early stages of the reaction. The sample, prepared from metakaolin and phosphoric acid, has been analyzed at different durations and temperatures during its solidification, in order to identify which compounds would crystallize. The structural characterizations have been performed using Fourier transform infrared spectroscopy and X-ray diffraction. Several Al–O–P compounds and especially AlPO₄ polymorphs crystallize in these conditions. They belong to three families of aluminophosphates and are a reliable indication of the amorphous organization of the original sample. The first one is similar to the phases that appear in the phase transition sequences of silica, the second one is composed of AlPO₄-based zeolites, and the last one is characterized by the presence of aluminum in an octahedral network. The transitions between the different phases are also discussed. Finally, the water resistance of the calcined samples is improved, and the release of acidic species in the water is limited even after a calcination at low temperature.     

Volume relaxation in a borosilicate glass hot compressed by three different methods

The temperature dependence of glass relaxation has been intensively studied; however, the effect of an imposed pressure history on relaxation behavior is poorly understood. In this study, we subjected SCHOTT N-BK7^® borosilicate glasses to isostatic compression in a Paterson press (PP) and a gas pressure chamber (GPC). The pressure ranged from 0.1 GPa to 2 GPa for various dwell temperatures and times near the glass transition region. Comparison with our recent results on the same glass using the piston-cylinder apparatus (PC, 0.5-1.5 GPa) reveals that the density of a glass, which has been quenched from the equilibrium state under high pressure at 2 K/min (pressure quench), increases approximately linearly with increasing pressure up to 2 GPa. Considering the volume recovery results at ambient pressure, we assert that the preceding high-pressure treatment in PC (uniaxial loading) generates a similar isostatic pressure effect on N-BK7 glass as those of PP and GPC treatments. Finally, we verify the previously proposed two-internal-parameter relaxation model on the volume recovery data using the three different compression methods. With a new set of parameters in the model, we can account for the pressure and temperature dependence of volume relaxation even for the samples quenched from nonequilibrium states at high pressure.     

Antihypertensive activity of casein-enriched milk fermented by Lactobacillus helveticus

Milk proteins contain peptidic angiotensin I-converting enzyme (ACE) inhibitors, which can be released by proteolysis during milk fermentation by some strains of Lactobacillus helveticus. Reconstituted milk media containing skim milk powder (12%), skim milk powder (10%) with added sodium caseinate (5%) or whey protein isolate (5%) were fermented by L. helveticus strains R211 and R389, and further tested for bacterial growth, proteolysis (free NH₃ groups) and ACE-inhibitory activity. The antihypertensive activity in spontaneously hypertensive rats (SHR) was also investigated with caseinate-enriched milk unfermented (UFM) and fermented by the two strains of L. helveticus. Caseinate-enriched milk fermented by both strains showed higher proteolysis and ACE-inhibitory activity, indicating that ACE-inhibitory peptides are probably released from caseins during milk fermentation. Significant decreases in mean arterial blood pressure in SHR rats were measured following oral administration of UFM milk at doses of 1.0 and 2.5 g kg⁻¹ of body weight, and milk fermented by R211 or R389 strains at doses of 0.5, 1.0 and 2.5 g kg⁻¹ of body weight. The antihypertensive activity of UFM could be explained by the release of ACE-inhibitory peptides from caseins during the digestion process.     

Food matrix impact on macronutrients nutritional properties

The food industry is aware of the consumer’s desire to purchase delicious, convenient and nutritious foods. Rapid development of functional foods has induced the food industry to evaluate and revise the composition of their processed foods as well as their processing conditions and methods to improve nutritional and health effects. The addition of new bioactive compounds to a food requires that the bioactive agent is in the active form by the time it reaches the gastrointestinal tract, where it is assimilated. However, the question is whether or not the processes and the composition of traditional foods are carefully balanced to ensure the optimal nutritional properties. This paper aims to review the concepts and facts that are the basis of the new area of research regarding the role of food structure on the nutritional properties of conventional and functional foods. Several original approaches have emerged, bringing together scientists from fields such as food science, nutrition and physiology, which bring enlightening new perspectives to the development of delicious and nutritional foods.     

Comparative behaviour of goat β and αs1-caseins at the air–water interface and in solution

Here we present a comparative study of caprine β- and α_s1-caseins behaviours at the air–water interface and in solution. Both caseins were purified from the milk of a single goat homozygous at the α_s1- and β-Cn loci, with a high degree of purity (98%). Physical measurements (ellipsometry, surface pressure and surface rheology) were performed at the air–water interface, whereas SAXS measurements were performed on casein solutions. Our results clearly show that self-organizations, both at the air–water interface and in solution are different for β- and α_s1-caseins. β-casein is unfolded in solution and forms a network at the interface, while α_s1-casein forms compact objects in solution and is organised in fluid domains at the interface. We also show that the presence of Ca²⁺ in the subphase strongly disturbs the interfacial layer formed by the caseins. It is elsewhere worth noting that in solution, the aggregation of α_s1-casein induced by calcium ions is associated with a pronounced change in the molecular structural organisation of the protein, which seems to adopt, in these conditions, an unfolded structure.