Publications by authors named "Luis Henrique M DA Silva"

Understanding nonionic surfactant-protein interactions is fundamental from both technological and scientific points of view. However, there is a complete absence of kinetic data for such interactions. We employed surface plasmon resonance (SPR) to determine the kinetic and thermodynamic parameters of bovine lactoferrin-Brij58 interactions at various temperatures under physiological conditions (pH 7.

View Article and Find Full Text PDF

Naringenin (NG) is a flavonoid with many bioactive properties, however, its bitterness limits its use in foods. It is known that complex formation with proteins can mask this undesirable sensory property. Therefore, a trained panel evaluated the effect of bovine lactoferrin (LF) on NG bitterness using time-intensity analysis.

View Article and Find Full Text PDF

Protein conformation and the 3D water structure play important roles in the ability of bovine serum albumin (BSA) to form stable nanostructures with bioactive molecules. We studied the influence of BSA unfolding and those of two Hofmeister salts, sodium chloride (NaCl) as kosmotrope and sodium thiocyanate (NaSCN) as chaotrope, on BSA/lutein binding at pH 7.4 using fluorescence spectroscopy.

View Article and Find Full Text PDF

Lactoferrin (LF) is a glycoprotein that serves as a potential vehicle for small bioactive molecules in food. In an effort to improve this functionality, the kinetic and thermodynamic interaction of LF with naringin (NR) was studied by surface plasmon resonance (SPR). The results demonstrated that the association rate constant between LF and NR was 5.

View Article and Find Full Text PDF

Fe(II) and Fe(III) have distinct chemical and biological functions. Consequently, it is more important to determine the fraction of both oxidation state that knowing the total iron concentration in a sample. However, green methods for iron speciation are still limited.

View Article and Find Full Text PDF

Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated.

View Article and Find Full Text PDF

We report the synthesis of 10,12-pentacosadyinoic acid (PCDA) and PCDA + cholesterol (CHO) + sphingomyelin (SPH) vesicles dispersed in water and the determination of their colorimetric response induced by small amount of organic solvents. In the absence of solvent, PCDA and PCDA/CHO/SPH vesicles showed an intense blue color. The addition of CHCl(3), CH(2)Cl(2), and CCl(4) caused a colorimetric transition (CT) in both structures with the following efficiency: CHCl(3) > CH(2)Cl(2) ≅ CCl(4).

View Article and Find Full Text PDF

The partitioning behavior of pentacyanonitrosilmetallate complexes[Fe(CN) 5 NO] (2-), [Mn(CN) 5 NO] 3(-), and [Cr(CN) 5 NO] 3(-)has been studied in aqueous two-phase systems (ATPS) formed by adding poly(ethylene oxide) (PEO; 4000 g mol (-1)) to an aqueous salt solution (Li2 SO4, Na2 SO4, CuSO4, or ZnSO4). The complexes partition coefficients ( K complex) in each of these ATPS have been determined as a function of increasing tie-line length (TLL) and temperature. Unlike the partition behavior of most ions, [Fe(CN) 5 NO] 2(-) and [Mn(CN) 5 NO] 3(-) anions are concentrated in the polymer-rich phase with K values depending on the nature of the central atom as follows: K [Fe(C N) 5 NO] 2 - >> K [ Mn (CN 5 NO] 3 - > K [C r (C N) 5 NO ]3 - .

View Article and Find Full Text PDF

Ions are known to concentrate in the salt-enriched phase of aqueous two-phase systems, with the only known exception being the pertechnetate anion, TcO(4)(-). We have discovered a second ion, nitroprusside anion (NP), which is markedly transferred from the salt phase to the polymer phase. The partitioning behavior of [Fe(CN)(5)NO](2-) anion was investigated in ATPS formed by poly(ethylene oxide) of molar mass 3350 and 35000 g mol(-1), and different sulfate salts (Na(2)SO(4), Li(2)SO(4), and MgSO(4)).

View Article and Find Full Text PDF